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shedlock89

Sweating on top of handler located in an HVAC closet

shedlock89
2 months ago
last modified: 2 months ago

We have a 4 yr old Trane single stage 2 zone system. Bought the home last Nov and equipment not under warranty because not transferrable and never registered by builder or previous owner. Have had a few different companies come out. The closet the handler is in is not conditioned but is the same temp as the hallway. The humidity has been registering up to 72%. If we keep the door partly open it goes down to 55% or a bit lower. The top of the handler has water there which drips down the sides. We can feel some air leakage when we place our hand over the upper corners even when it was taped. The plenum has mastic which feels moist and has mold growth.

The solution included replacing the entire system to get rid of the single stage. Since the unit is only 4 years old and given the expensiveness of new equipment especially these days not a route we want to go. This was suggested because too much air flowing thru the system when one zone is closed. Says it will shorten lifespan of the damper motors. We already had to replace one a few weeks ago. The 2 zones are split between an upper and lower floor.

Another fix was to create an opening in the bottom of the handler to serve as a return with a grill and to also add a 4” duct off the supply to a new register in the closet ceiling. Can this make the coils get too cold and freeze up? The normal thermostat temp is 77 degrees upstairs and 74 down. The air coming out of the room registers varies between 57 and 64 degrees depending on what room. We were to also add insulation around the plenum.

Another suggestion was to replace the current plenum with duct board plenum. But he said they did not guarantee it would fix the sweating problem.

In our previous home we had a similar setup with the handler in an upstairs unconditioned HVAC closet (smaller closet) but had a different plenum than the one we have now. Did not have humidity issue.

In the photos the tape had been removed for the tech to inspect inside. We did not yet replace.

We are at a loss as to what we should do. Obviously we cannot just keep the closet door open to control humidity.


note: photos not uploading for some reason

Comments (69)

  • PRO
    Austin Air Companie
    2 months ago
    last modified: 2 months ago

    I don't understand why "too much air flow" would reduce the life of the damper motors. Perhaps one of the HVAC Pros can explain the science behind this theory.

    Improper design. Lack of knowledge. Let's learn from the internet. Let the builder's GC's & contractual obligations handle it. It turns on and off so it's working. Let's get 3 bids, and possibly 3 different opinions to make this even harder. (The value of a trusted HVAC contractor in today's world. -- my customers know this, maybe you reading this do not.)

    The answer: What does too much air flow do "if it has no where to go" - these are operative words.

    Let me tell you then you tell someone else without me to make sure you relay the information correctly. (This is how most HVAC operations work so you get a better understanding why zone systems get a bad rap.)

    Even the builder that is indirectly forced to do HVAC for the homes he builds can't decide one way or the other. Why?

    Experience. Problems develop and that builder is long gone after 1-2 years. After 5 years, building designs and standards may have changed --- along with the way the builder is now doing things. Time doesn't stand still. ( Things change with the way I do things from 5 years ago.)

    Oh goodness. Lots of conflict around HVAC isn’t there?

    This mostly has to do with zone systems in general. Certainly you can find differences of opinion all the way down to brand name of the equipment and a host of other design related conditions.

    Could a setting too high cause too much airflow creating the condensation I see?

    too little air flow can generate other issues. It isn't a one lane - one direction highway. The solution is knowing the proper way.

    Many times solutions get sold for fixing symptoms and then after those symptoms are corrected new problems develop. For a solution to be a solution it should do so without creating new problems.

    That would make sense about the bypass alleviating the force of the air flow as that is what it is there for, right?

    That is what the bypass is for. Often times they among other things are not implemented properly. What is proper from someone who doesn't know. If you call someone do they really know or are they just selling you?

    Design of the zone system is critical. A zone system should be elegant. Not haphazard. Control knowledge as well as other parts that make up a zone system come all together to create a system that works.


    (Doesn't matter if the system is single stage, 2 stage, multi stage, variable speed etc. -- I've installed zone systems for any and all equipment configurations. This is nothing new to me. Now if you want to take that as bragging? This is what I do for a living for 28 years. You would think I should know what I am talking about? Or do you want to hire someone who doesn't know and then complain that it doesn't work... you have choices!)


    If the type of bypass you have is ineffective at bypassing... these are things I don't know from a forum board.

    It seems like every one around here wants to sell us new equipment. Easy way out so they do not need to put much effort into diagnosing. And of course there is also the profit.

    The good old equipment drought of 2022. The HVAC market due to the pandemic as well as political issues has become a market of the haves and have nots.

    You can't sell something that isn't there and you can't get something if you're not selling it. Contractual obligations. This is nothing personal, just business they say. (seriously)

    As an HVAC contractor you are obligated to sign a committment of any where from $50K a year to $100K a year. The manufacturer isn't going to consider you a dealer without moving equipment.

    So if a company is being intimidated by losing dealer status and then not being able to get equipment because of it? If I had to fashion a guess that is probably why.

    I'm still able to work around these constraints. But what I sell to one, you may not get because I can't get it and that changes DAILY. If you need something you better buy it before someone else buys it out from under you.

    If a big box HVAC company is called out (the haves) --- often times they stock equipment in a warehouse they own. But there's expenses tied to that. Taxes, TV commercial air time, etc. Then your choice is limited to the brand they carry.

    Any company you choose to install equipment: you are more or less tying yourself to that company. So there's is plenty here to think about.

    ---------------

    I service the Katy, Texas area.

  • PRO
    Charles Ross Homes
    2 months ago

    "(Doesn't matter if the system is single stage, 2 stage, multi stage, variable speed etc. "

    With regard to a zoned system, nothing could be further from the truth than the above statement. The reason zoning is less than ideal with a single-stage compressor and single-speed air handler which the OP has is that it's darn near impossible to match the system cooling to the load when the load is anything less than 100% of design capacity (i.e., all zones open at the same time on a hot summer day.) The issue is a lack of turndown capability. The compressor operates a one speed and delivers a fixed cooling rate. The air handler is designed to deliver 100% of design air flow rate. So you get on-off control and short cycling when the loads are modest. The problem is made even worse if the air conditioner is oversized to begin with and the majority are.


    Multi-stage compressors and variable-speed air handlers have the capability to operate at lower cooling rates when needed to match the load. Variable speed compressors like Ray's one-size-fits-all Bosch inverter system, offer turndown capability to around 25% of full capacity. Those are good choices for a zoned system. The OP can throw away what they've got and install one of those, but given their budget and the four year age of their current system, retrofitting is a better option and has the potential to extend the useful life of their system.

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  • mike_home
    2 months ago

    I thought we might get an explanation based on physics why a damper would fail prematurely. If the reason for failure is too much air flow, then what is the maximum air flow rating for a typical damper? Does this rating change if the damper a normally open or normally closed type? What other features of a damper would make it more susceptible to a shorter operating life?

  • PRO
    Charles Ross Homes
    2 months ago

    There are a variety of different zone control dampers on the market. The ones for residential HVAC systems are relatively inexpensive sheet metal fabrications--- not industrial strength stuff. You can have a look and research performance data from whatever vendor you like with a simple google search.


    In my last home, which had two-zones of control on each of two separate systems, I used dampers from California Economizer. They were replaced after 15-years of service when I replaced the other components of the HVAC system-- including my outdoor unit which was submerged during Hurricane Isabelle.

  • PRO
    Austin Air Companie
    2 months ago

    The reason zoning is less than ideal with a single-stage compressor and single-speed air handler which the OP has is that it's darn near impossible to match the system cooling to the load when the load is anything less than 100% of design capacity (i.e., all zones open at the same time on a hot summer day.)


    Is it better to have variable / and or multi speed equipment?


    Sure. Absolutely.


    BUT... I fixed a zoned system installed by a builder on a home that was about 7 years old over a year ago.


    That system was a single speed system. Single speed on or off AC, single speed single stage furnace... with 3 zones.


    It can be done. Ideal no. But when you know how?


    I've been doing AC for 28 years. Zoning has been around much longer than you think it has. 2 Speed AC's 10 years ago were rare to find. Zoning systems? not so much.





  • PRO
    Austin Air Companie
    2 months ago

    I thought we might get an explanation based on physics why a damper would fail prematurely.


    Mechanical failure. Physics? we're at the nexus of the universe, physics doesn't work here. LOL.


    What might be some ways to open and close a damper? (control knowledge - why physics isn't needed.)

  • mike_home
    2 months ago
    last modified: 2 months ago

    The homeowner was told the zone dampers failed in less than 4 years due to too much air flow. The proposed fix is to remove the existing 4 year old single stage system and replace it. The motor in the zone damper at some point will cease to operate. I don't believe dampers fail prematurely because too much air is flowing, but I am always open to learn something new. At least Charles Ross Homes suggested installing a better quality damper. That is a better solution than replacing all the equipment.

    Physics, chemistry, mathematics, and control theory determine how HVAC systems will perform.

  • PRO
    Austin Air Companie
    2 months ago

    I've fixed home builder installed zone systems. Never once did I use physics as an excuse for a mechanical problem.


    Click on the picture link a few posts back. That was a builder gem on that house.


    We'll use excuses to tell you a single speed system can not be zoned so we can sell you a new system for 30 grand.


    Certainly. You've got choices... some one who really knows versus those who want to learn.

  • PRO
    Charles Ross Homes
    2 months ago
    last modified: 2 months ago

    I'll take basic physics for $200 please, Alex,

    Residential HVAC zone control dampers come in a variety of shapes, sizes, designs, and construction. They can be powered to open (spring closed,) powered to close (spring open,) or powered in both directions. They may have air seals or not. Like anything installed in the air stream they get beaten up over time--that includes the seals and the blades, too. The dampers, and the motors which drive them, are often installed in unconditioned crawl spaces and conventional, vented attics--both of which will reduce their life expectancy compared with installation in a conditioned space.

    Basic dampers stocked by your local supply house are likely to be ones rated for 0.5" w.c. which is an "ideal" operating condition. The better quality dampers are rated for 1" w.c. and come with a price tag that's around twice as much. If the OP's experience indicates the damper life expectancy is only four years, investing in higher-quality dampers would be my recommendation. That said, I recommend their entire system be reviewed by a competent HVAC design professional.

  • Elmer J Fudd
    2 months ago

    I missed it - the Shah review again. Twice in one week.

  • PRO
    Charles Ross Homes
    2 months ago

    @Elmer J Fudd,

    If you're tired of reading the "Shah" review, you can read the exact same review (word for word) on google reviews posted by a customer named "Umang Patel."

  • PRO
    Austin Air Companie
    2 months ago

    yeah because he was happy the job I did for him he asked me where he could leave a review.


    It's not normal for people to leave reviews, it's more common when things go wrong.... you know like when you have a 4 year old system that isn't working right ( as in this thread).


    I've done many other zone systems in my career without an atta boy. Some more challenging than others. (home builder inspired picaso's) .


    It's even more mysterious that this guy found me here on houzz but yet there is no conversation here about that?


    Because? Certain people have skills to be able to read between the lines of what I post versus all the detractors.


    Certain other people (occasionally) can't see the forest from the trees. From what I post and show reveals fact and fiction. What might be required / what might not. This is far different than just talking in circles claiming a problem is due to high air flow and then circling right around telling someone the air flow is too low. Claiming you don't need an Inverter, at the same time saying you can't zone a single speed system. That is what physics does for you?


    Physics sounds like something good to blame a problem on so you can charge more to rip everything out and start over 30 grand no problem. So you now see the reason for me posting the review yet again.


    I will keep posting it... just because I know it bothers you two so much.


    I service the Katy, Texas area. (this also bothers them --- lol)





  • PRO
    Charles Ross Homes
    2 months ago
    last modified: 2 months ago

    Ray,

    My initial reply to the OP noted that they didn't need to replace their single-stage, single speed system but could retrofit it instead with a variable speed blower. They can also retrofit the compressor with an APR valve if needed, which I suggested in a subsequent comment. By contrast, you used the OP's post as yet another opportunity to promote your one-size-fits-all Bosch inverter system.

    You apparently don't grasp the air flow challenges when zoning single-stage compressors and single-speed air handlers. I believe my initial comment is simple enough to explain it to a layperson, but I'll try to explain it to you in even simpler terms.

    A single-stage compressor operates at 100% capacity when "on" and zero capacity when "off" whether the system is zoned or not. A single-speed air handler operates at 100% air flow when the system is "on" and zero air flow when it's off whether the system is zoned or not. Zoning subdivides the design heating and cooling loads into parts that make up the whole. The problem is that individual zones represent less than 100% design heating or cooling load, but all the system can produce is 100%. The single-speed blower will push or attempt to push the design air flow rate through the coil and as much air as it can into the single zone ductwork as it is able to do. That will cause short cycling in the zone, poor dehumidification, and increase the wear and tear on dampers which have to operate in a higher static pressure environment.

    To mitigate the excess air flow issue when zoning single-speed air handlers, bypass ducts are often installed. A bypass returns some portion of the air leaving the coil back into the (return air) stream entering the coil. That reduces both the temperature of air entering the coils and the leaving air temperature since the compressor is a single-stage unit operating at 100%. The recycling continues as long as the zone is calling for cooling and can result in an appreciable temperature drop, which coupled with the low cooling load, can result in freezing of the coil. A variable speed blower can reduce the air flow without the need for a bypass, but it also carries a risk of freezing the coil when the cooling load is small since the single-speed compressor only operates at 100% or 0%. If the system is oversized (and the consensus is that the majority are,) the likelihood of freezing is increased. That can be reduced by retrofitting the compressor with an APR valve if operating experience indicates it is necessary.

    So you have both an excess air problem to deal and a low air flow problem to deal with. To be clear, the excess air flow is a consequence of a single-speed air handler when less than all zones are calling for cooling and the low air flow problem is caused by the same thing when the compressor is a single-stage compressor operating at 100% capacity.

    In my last home, I had a single-stage heat pump and single-speed air handler system subdivided into two zones with a bypass. Each of the zones had a similar heating and cooling load (i.e., each was 50% of full design loads.) The system worked fine for 18 years, although is was not as efficient as the variable-speed zoned system we had for the 1st floor.

    If you still don't understand zoning of a system consisting of a single-stage compressor/single-speed air handler you can consult ACCA Manual Zr which covers zoning. Here's what the ACCA says about the standard:

    “ACCA created Manual Zr because professional contractors recognized the need for an industry standard detailing how to handle excess air in dampered systems,” said John Sedine, chairman of ACCA Manual Zr Advisory Committee and president of Engineered Heating and Cooling of Cedar Springs, MI. “Excess air in zoned systems harms equipment (emphasis added,) causes uneven building temperatures, and creates unhappy customers. Following the guidelines in Manual Zr helps contractors work through these problems and provides workable solutions to excess air, which is certain to satisfy their customers.”

  • PRO
    Austin Air Companie
    last month

    You apparently don't grasp the air flow challenges when zoning single-stage compressors and single-speed air handlers. I believe my initial comment is simple enough to explain it to a layperson, but I'll try to explain it to you in even simpler terms.


    So I just got lucky with this one (below) in a hot climate that requires AC 9-10 months of the year?




    I service the Katy, Texas area.

  • PRO
    Charles Ross Homes
    last month
    last modified: last month

    The Shah review (there's also an identically-worded Patel review on google) gets presented about as often as the one-size-fits-all Bosch inverter prescription. Time to move on, Ray.

  • PRO
    Austin Air Companie
    last month

    LOL. Yeah you really hate that review don't you Charles?


    It gives me oh so much credit and none to you. You looking down from your ivory tower of contractually obligated partners can't stand it.


    Ha, ha, ha.


    PS: To those who don't know: I'm not under any contract. I call it as I see it.

  • PRO
    Charles Ross Homes
    last month

    I don't hate your review, Ray. Even blind chickens find corn.


    What I have a strong disdain for are your self-aggrandizing streams of consciousness which serve to pump up your ego at the expense of others. Folks come to these forums for help with problems. Some specific, actionable advice on how to help them do that--other than your well worn one-size-fits-all prescription to get a Bosch inverter system --would be a refreshing change.

  • klem1
    last month

    This has been discussed for a week and if op has solved the problem, I for one would like to hear about the solution. If not I have a proposal ,actually two,one for op and one for Ray and Chas.

    Shedlock if you haven't picked up your marbles and left I'd like to see if I can help you improve the situation without investing an unreasonable amount of money. Ray and Chas, would ya'll like me to start a new thread to see who can solve a real life hvac problem I once encountered? I can't think of a better way of proving yourself to those hanging out on houzz. To be fair I'll encourage everyone to join the fun and try their hand as well.

  • PRO
    Charles Ross Homes
    last month

    Klem,

    Houzz.com isn't a competition. It's a collaboration between individuals who have problems or information needs and others who freely offer assistance and advice. That help runs the gamut from really helpful to not helpful at all--even negative.


    Unfortunately, a "Pro" designation doesn't guarantee professional-caliber contributions to the forum. Houzzers need to sort through the good, the bad, and the ugly and decide which sources are worth the read or as one houzzer put it, what juice is worth the squeeze.

  • shedlock89
    Original Author
    last month

    We are still working on correcting our problem. The HVAC company came out on Friday and installed a return on the handler. Was to also put a supply into the closet but due to the roof line could not access the area in the attic. Also added insulation to the outside of the plenum (foil on one side and fiberglass on the other). The humidity remains in the 60’s but the unit appears dry.


    Someone gave me the name of someone who teaches HVAC in a school so I have reached out to him in hopes he would be interested in looking at our system. I will present the solutions posted here to him as well.

  • PRO
    Charles Ross Homes
    last month

    Where did they install the return?

  • PRO
    Austin Air Companie
    last month

    Charles you take what I say as ego, while you have your own ego type problem.


    But you'd rather focus on what I do rather than what you do. (build homes, while this is HVAC in general.)


    I post a "real" review of what I do to fix problems introduced by builders. A common theme among homebuilders.


    So the excuse of the month is to blame a licensed Retrofit HVAC contractor that you think has an ego problem? While I am stating my experience level of 28 years. I say it over and over because? Use your imagination.


    If I couldn't fix it, I wouldn't have left a quote. I chose not to offer a quote of 30 grand like the other contractors before me.


    Sometimes I jump to conclusions. It's a forum board comprised of little if any real facts most of the time.


    I live in the real world and come to the fake one daily while I drink my coffee.


    We won't use him because he has this ego.... no we'll use someone who is cheap, doesn't proclaim to know anything and then after he's done we'll lament the choice we made when we have nothing but trouble.


    So if I proclaimed to not know anything I would fit in here among the misfit toys on this board?


    I come here to put it at it is which far less talking in circles, Charles. Things like it has too much air / too little air / you don't need an inverter / you can't zone a single speed ac / you can zone one but it's not ideal.


    I offered you time to clean that up didn't I Charles? But no the excuse of the month is my ego is preventing you from doing it. Because you don't really know. It's far to easy to claim my single review doesn't prove that I can do it either? fake world continues to spin.


    ------------------


    Klem1, novel approach but I am not here to fix AC problems from a forum board. I am here to leave bread crumbs for those that want a real solution to their AC problem. Willing to pay for it and they live within my service area.


    I am not here to stoke my ego (in those terms) I am here to tell you of my experience level so you (the reader, not Charles or all these other detractors here) know of your choice to use me or not.


    Everyone can't use my services. The few the happy the comfortable. I will offer you choices of the comfort level you want. Repair / replace / inverter ac / regular ac / it's your choice. You have the choice.


    No matter your situation. Moving in a few years, just bought the home, moving in 15 years, 10 years, 5 years... what ever your situation is I can find a solution.


    Maybe you've been told to replace everything? But is that really right? These kinds of decisions are best decided in person one on one. That is why most people who contact me from Houzz do not post. I provide the insight they need to pick up the phone and call me direct.


    When I post things of this nature the builder has jumped in to post my number here when he likely doesn't realize that phone number is plastered all over you tube as well as a multitude of other venues.


    If you're not in my service area the help I provide is limited to my view(s) on this board. I don't attempt to trouble shoot HVAC systems over the phone.


    I service the Katy, Texas area.


  • PRO
    Charles Ross Homes
    last month
    last modified: last month

    "I am not here to fix AC problems from a forum board. I am here to leave bread crumbs for those that want a real solution to their AC problem. Willing to pay for it and they live within my service area."

    Houzz.com has regionally-targeted advertising plans which you can purchase, Ray. If you'll invest in one of those you can spend more of your time on folks in Katy, TX The bonus is that houzzers won't need to sift through the chaff you offer to get to the wheat.

  • PRO
    Austin Air Companie
    last month

    I exchange my time here for FREE, Charles.


    I view that is more important given the amount of circles your logic provides.


    As I have said countless of times before... you have your opinion, I have mine.


    My opinion has been proven to work in "real life" over and over and over again for the past 28 years.


    A builders opinion is good for 1-2 years. Why? because they build. It's not in their wheel house to go back.

  • shedlock89
    Original Author
    last month

    Where did they install the return?


    The return was installed in the section of the handler where the house return enters. So the grate is facing the door to the closet.

  • PRO
    Charles Ross Homes
    last month

    It's not clear from your description, but if they installed a return in the closet housing the air handler, it violates the 2018 International Residential Code, section M1602.2.4 which reads:


    4. Return air shall not be taken from a closet, bathroom, toilet room, kitchen, garage, mechanical room, boiler room, furnace room or unconditioned attic.

  • shedlock89
    Original Author
    last month

    4. Return air shall not be taken from a closet, bathroom, toilet room, kitchen, garage, mechanical room, boiler room, furnace room or unconditioned attic.


    The HVAC closet does not have any fumes like some of the areas in the above. How do they define a mechanical room? This was the 2nd company offering that as a solution.

  • PRO
    Charles Ross Homes
    last month

    I don't believe the 2018 IRC provides a definition of "mechanical room," but it does specify the required clearances for maintenance of appliances in "rooms":


    M1305.1.1 Appliances in Rooms

    Appliances installed in a compartment, alcove, basement or similar space shall be accessed by an opening or door and an unobstructed passageway measuring not less than 24 inches (610 mm) wide and large enough to allow removal of the largest appliance in the space, provided there is a level service space of not less than 30 inches (762 mm) deep and the height of the appliance but not less than 30 inches (762 mm), at the front or service side of the appliance with the door open.


    My take is that if you can easily enter the space with the air handler installed, it would be considered a "mechanical room." If you can't enter the space, it would be a closet. That said, I suggest you check with your local building code official for their take on it because theirs is the only opinion that matters.

  • Elmer J Fudd
    last month

    "I will keep posting it... just because I know it bothers you two so much."


    It doesn't bother me at all. I just don't want anyone to be misled thinking that this is one from a large stack of positive reviews. As it's the only one you ever use, and you use the same one sometimes several times a month, that suggests a different story.

  • PRO
    Austin Air Companie
    last month

    I just don't want anyone to be misled thinking that this is one from a large stack of positive reviews.


    How could they be any more mislead by much of the content on this board. Well around here we like to put our horses before the carts they are trying to pull...


    I clear plenty of that up by saying... I have a career and opinion based around 28 years of doing HVAC for a living.


    But there's this guy who lives in California that can wait around 5-6 weeks for his air conditioner to be replaced / or fixed.


    The thinker would say gee if he was doing this wrong for 28 years he'd certainly would have been undone by that living in a 9-10 month hot climate he works in opposed to the guy who can dicker around for 5-6 weeks waiting for air conditioning.


    Do you even listen to yourself talk Elmer? ha, ha, ha.


    Then the review I post is a complicated review that went to places most don't even think about.


    Well we like to see stacks of reviews where the whole HVAC system was replaced for 30 grand?


    I think people realize by now that they have choices. I doubt they use the one that says "we'll wait for 5-6 weeks to make sure we got a good HVAC person" either they are good or they have to keep going back to previous jobs where they screwed up.

  • Elmer J Fudd
    last month

    "But there's this guy who lives in California that can wait around 5-6 weeks for his air conditioner to be replaced / or fixed."

    The best service providers, be they in the trades or of other kinds, are busy. They have backlogs. They're not always immediately available. I've explained my facts to you a few times before and I think you forget or reject them because the world I describe isn't where you spend your time.

    Short response - I have two homes. About 4 years ago, I replaced 3 complete furnace + AC systems that were old but still functioning. There was no urgency to have the work done. I was careful in selecting bidders and was impressed by one of 3 in each location. Each spent just short of an hour doing legit heat calcs in preparing their bids. Each recommended smaller sizes from what were in place (no surprise). For the bigger job, I was told there was a 6-7 week backlog (turned out to be 6), for the smaller one, 2-4 (turned out to be 3). It's a positive sign when a provider you want to use is busy and scheduled ahead some weeks.


    While you hold on tightly to your one positive review, I checked what I could find for these two contractors this evening, a few years after they did my projects. Just on Yelp. One has about 20 reviews, the other about 30. All 4 and 5 stars, for a variety of work projects big and small. I'm in higher cost, populated areas and there's a lot of competition among tradesmen and contractors in both places. These two are still pleasing customers every week and I'm sure remain very busy.


    Here's a way to keep it straight:


    #1 Fair price but not necessarily the lowest one - #2 Top quality - #3 Available immediately. Pick two.

    I chose #1 and #2 in both cases and was happy to wait. Glad I did.



  • PRO
    Austin Air Companie
    last month

    Anyone can stack calls Elmer.



  • PRO
    Charles Ross Homes
    last month

    Customers tend to be less discriminating when their hot water heater just died or their sewer line is backed up or their furnace or air conditioner is not operating. They're less likely to ask for and check references. Often the contractor selection process is simply whichever contractor arrives first at the site. This "need for speed" is why a lot of marginal trade contractors exist in the repair/replacement space.

  • PRO
    Austin Air Companie
    last month

    If it's 100+ outside feel like temps well over 100F


    Inside the temp is over 90F within the span of a day. Night time temps only get down to mid to low 80's and humidity is another aspect.


    Loss of sleep, loss of productivity at work... I wouldn't accept a contractor who is telling me it's going to be a 5 week wait for service.


    It's my cooling, I want it now. LOL.

  • Elmer J Fudd
    last month
    last modified: last month

    "Loss of sleep, loss of productivity at work... I wouldn't accept a contractor who is telling me it's going to be a 5 week wait for service."

    You read my comments too quickly or you didn't follow what I said.

    All the existing equipment I had was working but due for replacement. I had functioning heat and air conditioning, there was no rush. I was happy to choose based on my impressions and choice factors, one of which was NOT time. It was no problem to wait if necessary to have the work done by highly rated contractors.

    One of the bidders worked up his estimate and emailed it to me a few hours later. He called for follow up and asked me if I was ready to move forward, his crew could start the next day. With that comment, he lost the job.

    The very best of any service type are busy and you have to wait for non-emergency work. Hacks can come tomorrow.

  • dadoes
    last month

    AAC, just to say, double Enter/carriage return for paragraphs (as is traditional on a typewriter) isn't necessary in posts here. The software recognizes a single Enter/carriage return as a paragraph break.

  • shedlock89
    Original Author
    last month

    As I noted earlier a tech installed a return register into the handler but no improvement seen. I am trying to find out if this is up to code.


    Yesterday a tech disengaged the upstairs zone from the zone control panel so the thermostat went dark and won’t work as a zone. The system works like a single zone system now. His idea was that there was too mich air flow from the single stage causing sweating. Well the sweating is worse.


    Does the bypass need to be closed? Does it matter?

  • PRO
    Charles Ross Homes
    last month

    You have two separate, but related problems. The sweating in the closet housing the air handler is because the surface temperature of exposed metal is lower than the dewpoint of the surrounding air. That's often the case where an air handler is installed in a humid garage environment, but it shouldn't be an issue for an air handler installed inside the conditioned environment. The root cause is that your system is producing much colder air than it should be. You can add insulation as needed to prevent air contact with cold metal surfaces and you can add ventilation to the closet as needed--just don't add a supply off the air handler nor a return. The former will make the problem worse (it will introduce air near dewpoint temperature) and the latter isn't allowed by code. Instead, install a small vent fan to bring room temperature air into the closet.


    The other (related) problem is that the system is producing air which is much colder than the norm. This is a consequence of subdividing the cooling load of a system with a single-stage compressor and fixed-speed air handler. It's a less than ideal set up for zoning, but it can work. I explained it, and possible remedies in a post above. For what it's worth, I have also seen this same cold surface temperature issue in systems which were not zoned, but where the pressure drop in the duct system caused a large reduction in the air flow across an already oversized coil. In one home, the fiberglass duct insulation was completely saturated and was sagging and dripping.


    If the zoning system has been turned off, you'll need to make sure your zone control dampers are open to permit flow everywhere and that the bypass is closed.

  • shedlock89
    Original Author
    last month

    Instead, install a small vent fan to bring room temperature air into the closet.


    Would a jumper vent between the hall and the hvac closet have the same effect?


    What about a louvered door to do the same thing in essence?


    Unsure where a small vent fan would be installed.


    If the zoning system has been turned off, you'll need to make sure your zone control dampers are open to permit flow everywhere and that the bypass is closed.


    Is the reason for closing the bypass simply because with a single zone a bypass is not needed or is there another reason?


    We did not verify the damper for the turned off zone is open but we could definitely feel much air coming through the ceilng register. Should we still verify?


    The root cause is that your system is producing much colder air than it should be.


    Should we have the freon checked?






  • PRO
    Charles Ross Homes
    last month
    last modified: last month

    @shedlock89,

    Jump ducts and transfer grills are great solutions where you have supply registers in a space but no return. That's not the situation in your mechanical closet. You need a means of supplying room temperature air to the closet to reduce the relative humidity in the space. Or leave the door off the space so there's no obstacle to impede air flow.

    If the zone controller is turned off, the bypass is closed and your zone control dampers are open you've essentially got a single-zone HVAC system. You don't need the bypass because the system has only two operating modes: on (and running at full capacity) or off. The air flow across the cooling coil and to each room should be comparable to their pre-zoning flow rates. If the temperature drop across the coil (the temperature at supply registers minus the room temperature) is more than 20F when operated with all zones open and the bypass closed, you've got an oversized system or inadequate air flow--not one that should be zoned without modification to address the capacity or air flow issues.

  • PRO
    Austin Air Companie
    last month

    This is a consequence of subdividing the cooling load of a system with a single-stage compressor and fixed-speed air handler. It's a less than ideal set up for zoning, but it can work. I explained it....


    Yeah to refresh your memory I provide you a glimpse here of how the builder explained it... LOL.

    (It was only after I chimed in did the builder admit his failure that a single stage system can be zoned as now his story is changing from above stating "but it can work")



    Contradiction 101....

    A zoned HVAC system with a single-stage compressor is less than ideal. You're at risk of freezing up your coil.


    You might start asking how a coil freezes? List all the ways Charles. You don't need to replace your system but it is less than ideal? so which is it?


    When only one zone is calling for air flow, your system is either trying to push the full system flow rate of air through the ductwork.......

    ...Instead, address the root cause of the problem--a leaving air temperature that's too low because the air flow rate across the coil is too low when only a single zone is calling for air.


    So which is it Charles... too much air or too little?



  • PRO
    Charles Ross Homes
    last month

    Ray,

    Less than ideal doesn't imply something won't work, it simply means there are better options if you want a zoned system. I had a single-stage heat pump and fixed-speed air handler for HVAC on the 2nd floor of my previous home. It was a zoning retrofit that provided two zones of control. It worked for 15 years until the heat pump gave out and then for another three after the heat pump and coil were replaced. It was less than ideal. The variable speed two-zone control system on the 1st floor was better. That system wasn't a retrofit; it was a brand new system with all new duct work.


    I'll make an attempt to answer the air flow question for you one more time, Ray because I don't want you attempting to design or sell someone a system without knowing the basics.


    A single-speed air handler isn't a variable speed air handler like your beloved Bosch inverter. It produces air at a single flow rate depending on the blower's fan curve. The more pressure drop, the less flow. Consider a two-zone system where the cooling load on each zone is equal (i.e. 50% of the total load.) When only a single zone is calling for cooling, a fixed-speed air handler will direct all the air flow it can produce into that zone. In this case, 100% of fan capacity for only 50% of the cooling load. The amount of air flow won't be fully 100% of the system's normal air flow due to the additional pressure drop compared with both zones open and calling for cooling. So there's an excess air issue. That means too much air, Ray.


    To deal with the "too much air" issue a bypass is typically installed. It recirculates a portion of the air leaving the coil back to the upstream side of the coil in a continuous loop. The temperature of the air entering the coil gets reduced, and continues to get reduced as the zone approaches set point temperature. There's not enough load on the coil and it's at risk of freeze up because the air flow in a single zone is less than the full air flow rate the single-stage compressor and coil are designed for. That's the too little air flow part.


    Variable-speed and multi-stage compressor systems are much better for zoning applications than single-stage, fixed-speed systems because they can adjust the air flow and the cooling to match the actual load. By contrast, single-stage compressors and fixed-speed systems are less than ideal.

  • PRO
    Austin Air Companie
    last month

    too little air creates just as many or more problems to too much air.


    There are a multitude of design factors that try hard to deal with both. But unless you understand the problem, you can not provide a solution.


    You can talk about it / suggest things / even argue about it ---but just being indirectly involved with HVAC because you build stuff?


    You seem to forget I live in a hot climate. 1 summer for Charles is like 3 summers for me. Those 3 summers for me is not just talking about it in a forum board setting.


    So you'll continue to claim I have crappy service and a host of other things because this isn't what you do Charles. You build, and indirectly have a mistress called HVAC.


    Me? I am married to HVAC. She's my wife. To others out side? "Happy wife, happy life."


    Celebrating my 29th anniversary this month. ha, ha, ha.




  • PRO
    Charles Ross Homes
    last month

    Ray,

    I think you've confused equipment design and performance with equipment longevity.


    I design, build, and remodel homes in coastal VA. Our climate zone is classified as a "mixed-humid" climate zone. In my opinion, it's more challenging designing for our climate zone than designing for a heating climate or a cooling climate zone because our climate zone behaves like both at different times of the year and humidity control is a concern throughout the year with special attention needed during our brief shoulder seasons. Indeed, the HVAC design temperatures for our area aren't that different from Houston, TX (which I'm led to believe is a suburb of Katy, TX.)


    Houston, TX: winter d.b. 32 F, summer d.b. 94 F, w.b. 79 F


    Norfolk, VA: winter d.b. 22 F, summer d.b. 91 F, w.b. 78 F


    I know you've stated that the design temperature for Houston, TX is 95 F. There is a winter design temperature, too. And that wet bulb temperature thing, well that helps you to know what latent cooling load you have (that's the dehumidification load, Ray.)


    Air conditioning equipment in Katy, TX may need to run a few more months of the year compared with our area. That's not a design issue, that's an equipment longevity issue.

  • PRO
    Austin Air Companie
    last month



    The closest Norfolk gets is June, July and August "your summer". These are "averages" listed in the above picture.


    Because Katy, Tx is hotter already... guess what that does when extremes happen?

  • PRO
    Charles Ross Homes
    last month

    There's a difference between weather and climate. HVAC systems are designed for climate--not weather. The design temperatures for various locales are listed in the International Plumbing Code appendix D.


    The design of an air conditioning system in Houston won't be much different from one designed for Norfolk, VA, although it may be hotter in Houston or in Norfolk on any given day. A system in Houston will operate for more hours in a year. That's a longevity issue not an equipment sizing or design issue.

  • mike_home
    last month

    Also added insulation to the outside of the plenum (foil on one side and fiberglass on the other). The humidity remains in the 60’s but the unit appears dry.

    Did adding the insulation solve the condensation problem? What is the temperature inside the closet with the humidity is in the 60s?

  • PRO
    Austin Air Companie
    last month

    A system in Katy, Texas will operate for more hours in a year.


    As in 3 summers versus 1 in Norfolk Va?


    Approx 9 - 10 months most years. Where as Norfolk is at best 3 months and done.



  • PRO
    Charles Ross Homes
    last month

    You're looking at weather averages, Ray. It can get hotter or colder than the monthly average high or low on any given day.


    I typically begin using my air conditioner in March and it runs through October. The only months I typically don't need to run it are December, January, and February. Of course, the need for air conditioning depends on a number of other factors, too, like the home's solar orientation, the type and R-value of insulation, air sealing, type of windows and amount of glazing area, etc.