I would lean towards a very dirty filter or a dirty indoor coil, both scenarios indicate air blockage.

Where is the air handler? You need to take a look at it and see if the blower is running normally. If not, it could be a problem with the blower or its controls. If the blower is operating normally, but you aren't getting any air, it could be a duct problem.
If the problem started all of a sudden, it isn't likley to be something as simple as a dirty filter.

In addition to the possibilities already mentioned and, if the fan is running normally, the evap. could be iced up.

Well it's definitely not a dirty filter. There are 2 intakes that I change religiously....and even changing them every month, they aren't that dirty but I do it just to be safe, unless there is another filter that I should have been changing. No breakers have flipped. I looked on the outside (when I first discovered this morning) and there is no ice that I saw on the coils whatsoever. The air handler hasn't made any strange sounds that I have heard. It has been quiet as a mouse.....In fact, it actually sounds like it always does but there is no air coming out of any of the vents

I just thought I would take a chance while waiting a few more hours for the HVAC guy and go in there and turn the fan on just to see if it would work, although I tried several times earlier......and it's working normally now, so I turned it over to AC and it's blowing out cold air as normal. Could something have been frozen up? I didn't realize a freeze up on an AC would cause the air handler itself not to work

Did you check to see if the air handler was iced up?

No. The technician came over (same one as the last three visits).......He said it was 2 lbs low of refrigerant and that was causing it to freeze up. How didn't find a leak or an oil leak of any sort whatsoever. In late Jan I had the compressor replaced and they charged me for refrigerant. Should I have been charged for refrigerant twice since there is NO leak, wouldn't that mean that enough wasn't added when it was recharged from the compressor replacement five months ago?

The reason air would not flow was that the evaporator coil (inside, not outside) was probably frozen solid. Turning the AC unit off but letting the fan run would melt the ice buildup (FAN=ON, MODE=OFF). This is a symptom of an incorrect refridgerant charge.

Finding small leaks requires specialized equipment and techniques. I'll let others comment on this.

mark

the refrigerant system on residential HVAC is a closed system. if you were two lbs low compared to previous service, then you have a leak. Refrigerant does not just disappear.

unless your tech injected dye to help locate the possibility of a leak or perhaps used other diagnostic methods, then you have wasted both time, money, as well as your comfort.

sounds like you received a typical gas n go service.

too bad, because if you do have a leak as I suspect, you will have same trouble in the future.

I would complain to your servicing dealer.

IMO

The company "Comfort Heating and Air" seem to be very reputable (as far as I know). The guy was super nice as was I. It's not a small company and they are an authorized Trane dealer(not sure if that means anything). The tech that came out told me that he checked for leaks and found nothing. I don't know what he did to "check" but my problem is, if...when the compressor was replaced Jan 10 and recharged with coolant, if there has been a leak from the time of installing and charging the system, is this my fault? Should I keep paying for recharges? I mean I called for service today, he repaired my air conditioning, but if in three mos it does the same thing, does this mean that the repair made today shouldn't be considered complete?

I do remember him telling me that typically if coolant is leaking, there will be "oil" leaking as well and he said he saw no oil. I wonder if it's possible that it has been 2 lbs low of coolant since the compressor was replaced in Jan?

WOW! As long as I have lived in this house (almost six yrs) I never remember the air coming out of the vents being this COLD!!!!!!!! I had to turn the thermostat up 3 degrees because I was freezing. Suddenly, 75 now feels like 72 did. How odd

If the humidity is dropped enough 77 can be very comfortable. The savings is nice when you can have the stat set at 75-77 compared to 70-72 and still be comfortable.

77 is the point where it starts getting a little uncomfortable. 75 is decent. I have it on 74 now and it seems perfect so I'm going to leave it there. I'm anxious to see how it will maintain the temp when it gets 90 or higher outside. It never has been able to maintain the temp from about 430 in the afternoon until 830pm (the hottest part of the day) on a sunny day especially, even with all blinds closed and curtains closed.....It would creep up to around 77 by 830 pm, then when it got dark it starts falling back down slowly. I thought this was normal behavior. Seeing that the coolant was 2 lbs low, perhaps it will be able to maintain the temp in very hot humid conditions.

Can someone tell me if it's possible to be 2 lbs low of coolant and there be NO leak? In Jan when the new compressor was installed could there have been some reason there was not a full charge? I'm sort of paranoid there is a leak.

If it was replaced in January, the tech might not have gotten the charge spot on. I've noted some pros on HVAC-Talk state that they need AC type weather to get the charge right. January is not typical AC weather in most places.

I'd like to hear some of the pros who regularly post here comment on this.

Yes...Jan is not A/C weather. What happened was Dec and Jan it was bitterly cold here and my power bills were outrageous. The heat was working though but it was brought to my attention when I checked the breaker box in the garage to see if a breaker had tripped (for something else) that 2 of the heat pump breakers had tripped and I was unknowingly running auxiliary heat only for 2 months of bitterly cold temps because the heat pump compressor failed. So seeing it was Jan, it had to be replaced and I guess the system has to then be charged up with coolant for the A/C at the time the compressor was replaced.

At any rate, if there is NO leak and I am 2 lbs low, should I get a credit for a recharge since it wasn't properly recharged in Jan? If there is in fact a leak, then that would be a different issue, but if there isn't and never was a leak, that's like I'm paying for coolant twice....Right?

Assuming they charged for the refrigerant by the pound the first time, there would be nothing wrong with them charging for an additional two pounds this time, in my opinion.

But if they charged by the job, they should not have charged you at all for the last visit, again, in my opinion.

Unless they used a charging cylinder in January, it's next to impossible to get the correct factory charge at the temperatures you experienced in January. They could have charged it sufficiently for heating but to properly charge it for cooling, the outside temperature needs to be at least 75 degrees. Any time I install a system in winter and even if I do use a charging cylinder, the customer knows I will be making a followup call in spring or summer to give the system a final check. The cost is built into the initial fee and it makes me and the customer feel better.

When they say they added 2 pounds of refrigerant, they mean 2 pounds of gauge pressure. for your system, this is very little refrigerant being dispensed. It would not be pounds in weight, it would be pounds in pressure.

Without being there and actually looking at the system, I can't tell for sure what was done. I'm suspicious about the amount of charge or, what else might be going on. I say this because a heat pump has an accumulator which among other functions, stores an amount of refrigerant. In a fixed cap tube system, the charge is critical and 2 psig can cause icing. In a system using automatic and thermostatic controlled metering device along with an accumulator, 2 psig is not that critical and icing should not be an issue,unless they are charging the system to a minimum charge where ice would then form if there is a loss in refrigerant. If you experience ice on cooler more humid nights or again next year, the latter would most likely be the case. I've seen many technicians add refrigerant until the ice disappears and then they stop. The manufacturer provides charts that give temperatures, humidity and what the charge for that model should be. I've seen many techs never use a wet and dry bulb sling cyclometer or the charts. They charge the system to a pressure that experience tells them it will cool and no ice will form. It does the job, everyone is happy but the unit is not running efficiently. You paid the extra money for efficiency you are not getting. It's kind of like adjusting an old carburetor by ear. The car runs, you can drive it but it's not where it should be for optimum performance.

I don't know if he used a charging cylinder in Jan. I do remember having to pay for labor which included the coolant charge. It was COLD and sunny the day he replaced the compressor. It took him about 5 hrs total. Like I said, when A/C season started in May, on very sunny days, even around 83 max, afternoon heat (even with blinds closed) would be too much for it and it would slowly crawl up from (74) to (77) before dropping back down at around 9pm. When he added coolant this last visit, the A/C has been working freaking GREAT! It has been blazing hot out in the 90s and very humid, and the A/C not only maintains the temp at (74) but it even cycles OFF occasionally at the hottest part of the day.............I really HOPE that there isn't a leak and he just simply didn't get the charge right. I do know that before the compressor failed, the only leak that I had prior to that was from vibration in the coil that caused a leak on the outside unit (which he repaired and even wrapped......That was two summers ago. Then of course the capacitor went out prior to that......

I did go to the attic to see what kind of mess they made...Usually there are wire clippings and sometimes things laying around that they leave. I did notice there is a black plastic drain pan about 4 inches deep that the air handler is sitting in. It had insulation from the house in it. I guess when the house was insulated they sprayed insulation all over and a lot of it wound up in that drain pan. I took as much out of it as I could. There was a little wet insulation in there (not too bad) and I suspect that was from when the air handler froze up from the low coolant.

Now my ice maker is broken and that has to be replaced. Oh the joys of owning my first home!

"When they say they added 2 pounds of refrigerant, they mean 2 pounds of gauge pressure."

They very well may have added two pounds by weight.
Many places charge by the weight of the refrigerant added now.

While the charging itself may be determined by pressure and temperature, the bill is based on weighting the cylinder before and after.

Currently 91 outside, sunny, very humid 6pm and the temp is exactly what I have it set on 73 :)

They very well may have added two pounds by weight.
Many places charge by the weight of the refrigerant added now.

Brickeyee,
Yes, some places do charge by weight but I doubt it very seriously in this case. For this unit, 2 pounds of refrigerant by weight is a substantial leak and it's not likely the coil would be iced up at this point, the unit would just not have cooled. It may have iced up early on when the charge was marginal but unlikely with 32 ounces having leaked out. With 32 ounces, the unit probably wouldn't have even started if it has a low pressure cut out.

Irisman....don't pay any attention to Brickeye. 98% of his posts are cut and pastes trying to discredit information other people offer. He's on an ego trip. We've all worked with back biters like that. They will usually do it with the boss when their victim is not around.

Brick..If the Tech determined the unit was 2 pounds of weight low, he would have had to evacuate all the refrigerant out and weighed it. Anyone who works on these things knows it was most likely 2 psig.

To answer MARK...yes it most likely meant enough wasn't added when the compressor was changed but as already mentioned, at those temperatures, it's pretty hard to be exact. The refrig. charge is determined for the cooling needs and design temps need to be achieved to be 100% accurate.

So you're saying if it were literally 2 lbs low it probably wouldn't be cooling at all? Because the day I was waiting for the A/C tech to arrive, it was HOT in here. I turned the A/C back on and it was working again, and it did indeed start cooling the house somewhat, I could tell a noticeable difference. Later when he arrived after checking it he told me it was 2 lbs low (his words) and he checked all usual places for oil and didn't see a drop of oil anywhere, said where there's a leak, there is usually oil......At any rate, once he charged it, it's been working fine. Since A/C started in May, I didn't think the air coming out of the vents felt as cool/cold as it should. It was cool, just not cold!

Here is what the receipt says:

checked unit. Blower motor pulling at 1.1 amps. System low on charge. Added 2 lb R-22. Unit is most likely freezing up and stopping airflow.

In the itemized section it says:
1st from 56..00
2nd from 46.00
Service charge 78.00

When you turned the unit off, the ice melted on the evaporator coil, inside the plenum on the furnace. This would be the coil you can't see unless you open an access to the plenum on the furnace. Thus, unblocking the coil, and when you turned it back on, the air was able to pass through the coil because the ice had melted during the time you had it turned off and you were receiving cooling. Since you began receiving cooling after the ice melted and you turned the unit back on, it indicates the refrigerant charge was marginal. He topped off your charge and the coil in the plenum (that you can't see) should not ice up due to a low refrigerant charge. Keep check on your furnace filters and change them when needed and you should be good to go.

If the unit had been 32 ounces low, you would most likely not have seen any cooling. For example, depending on the size of a unit and the length of you tubing, a 2.5 t0 3 ton unit holds 6 to 8 pounds of refrigerant (if R22). 2 pounds of refrigerant would equate to 1/4 to 1/3 loss of refrigerant.

Maryland Irishman. Thanks

Yes, correct. The Heat pump was turned OFF from about 4 am until 11 am (thus I guess it had time to defrost). The air handler is in the attic and that's where it froze up. Are you saying that it shouldn't have frozen up (up in the air handler, where you can't see) due to a low refrigerant charge? I re-read your post a few times and that sounded like what you were saying, but that's exactly what happened to mine. At any rate, it's still working fine. I keep the filters changed religiously (I have two return vents in the hallway), one on the ceiling and one on the wall. House is very clean and even after 30 days, they don't even look dirty in the least bit but I change them anyway just to be on the safe side.......

I can't remember if I mentioned this but I got the insulation out of the drain pan under the air handler. Is that drain pan specifically for freeze ups? I'm guessing when/if it freezes up, the ice melts and falls into that pan and there looked like some sort of pipe that water would flow out. I don't know ANYTHING about HVAC so pardon my ignorance.....Thanks for taking the time to respond to my posts.

Mark,

The confusion here was spurred when the conversation rotated from addressing your problem to whether the freeze up was caused by 2psig or 2 pounds of weight undercharge. I know at this point you are just trying to understand what went on with the unit to cause the freezing.I will try to clear that up without writing a book and without a lot of technical terms and jargon. It may also help others who subsequently read the thread. There's volumes written on this.

The evaporator coil is the coil inside your attic unit. When the refrigerant enters the coil, it enters as a spray or, flashes into the coil. It will remain a saturated liquid as it travels through various portions of the coil at progressively reduced liquid levels as the refrigerant absorbs heat and turns it into a vapor by the time it reaches the end of the coil. The air traveling through the coil fins (which aid in the removal of the heat), from the fan moving the air, provides the heat that causes the liquid refrigerant to begin evaporating, absorbing the heat from the air and then distributing it back into the home by the fan as cool air. The idea is to introduce enough refrigerant into the coil to allow the entire coil to absorb heat. Too much refrigerant into the coil causes the volume of refrigerant to evaporate at a further distance into the coil and thus, there is less heat being absorbed and there is still some liquid at the last run of the coil and this goes back to the compressor and can cause damage to the compressor in addition to minimized cooling. Not enough refrigerant will cause the liquid refrigerant particles to absorb the heat in the beginning of the coil and thus, not enough liquid travels through the coil to absorb more heat and thus, the air being distributed to the home is not cooled sufficiently.

R22 flashes off at -41 degrees at sea level pressure. As the pressure on it increases, it flashes off at a higher temperature. This is the same as if you are boiling water, it boils at 212 degrees but if you put a lid on the pot, the pressure will increase and it will boil at a higher temperature. If your pressure in the evaporator is low enough, the refrigerant in the coil might be, let's say, flashing off at -10 degrees at a early point in the coil. The air being blown through the coil contains moisture and since we know the moisture will condense (like on a cold water pipe) and, water freezes at around 32 degrees, that condensation will freeze on the coil at that point and air won't flow through that spot. That means the low pressure liquid will move further into the coil and then the condensation freezes there also. The longer the unit runs, the more the icing progresses until the coil is completely frozen up and no air can flow through it. The idea is to add enough refrigerant back into the system to raise the pressure sufficiently, to allow the refrigerant to flash off at a high enough temperature that it will not cause the condensation on the coil to freeze. If you look on a technicians gauges, you will see various markings which show the pressure of the refrigerant and what the resulting flash temperature is. Now, this is not the only information the tech must know while properly charging a system but I hope my very general description gives you an idea what is going on and why your unit froze up.

Don't try to equate all of this with your refrigerator or freezer, since the intents are entirely different and even different refrigerants and pressures are used.

When the folks here suggest to you to look at your filters, it's because if they are dirty enough, they will restrict the flow of air and can actually cause the same effects. You'll get reduced air flow and eventually can get freezing of the coil.

The drain pan is not specifically for freeze ups. As I hope I made clear, as the air moves through the coil to have heat removed from it, moisture in the air will condense on it just as it does on cold water pipes. The unit, if operating properly, removes gallons of moisture from the air. The pan is there to capture this water and channel it to a drain tube and dispose of it outside the house. Otherwise, the water would drip all over everything and make your insulation and ceiling wet. In your case since ice did build up, it did the same function as the ice melted once you turned the unit off. You won't normally get ice if everything is running properly and the unit is properly charged.

It was a good thing you removed the insulation from the pan. It could have eventually washed over to the drain tube and clogged it and then the gallons of water would have overflowed out of the pan into your attic.

Do not be concerned about not knowing anything about HVAC. That's what Professionals are for. A good, well trained Technician will help you understand as best they can. Not everyone is a teacher so you may get a one sentence answer with technical jargon. Also, after being out there in the heat all day fixing A/C's, you can bet some of the folks just want to move on. As you can probably expect, there is a lot more to understanding HVAC and when a guy shows up to do work, there's a lot more going on in is head than what is going on by his hands. It takes a lot of specialized training, equipment and a few years of experience to really nail it down good.

I hope things are a little more clear for you. If not, let's keep hammering away until it is!! Between myself and others here who truly want to help, we'll get through it!!

Thanks for taking the time to explain that. I really appreciate it. I'm anxious to see what happens when they come out this Tuesday to do preventative maintenance. I've read on these forums that preventative maintenance is a rip off. Since all the preventative maintenance in the world won't stop a system from failing. The only reason they are coming out is because it's prepaid from last fall. I'm not having them come in the fall to do winter maintenance (that's when I pay the 199) for spring and fall, thus, I paid last year 199 during the fall, so this spring is paid for so they are coming out.....And since this happened, I'm glad.....I just hope that when they come out they don't find that the charge is low, thus there is a leak :(...I'm sure it costs a fortune to find a leak and repair it. Let's hope there is no leak.

Maint. agreements can be handy on an older unit. If the right items are included in the agreement and the technician actually follows the checklist of items, it can pay off. Other than checking and/or topping off the refrigerant charge on a system, you can do most of the work yourself if you are mechanically inclined. I should include that doing a load balance (at least check it)might be better left to a professional.

Your maint. agreement should have an outline of the checks and work covered.

I personally doubt they'll find a leak. That's not to say they won't but from what you've described so far, I think you're ok.

I remember once when I rented a house for 2 years. The owner (landlord of the home) had preventative maintenance done twice per year and he followed the HVAC tech around and watched EVERYTHING he did.......Should I do this? (LOL).......I hate to be a pain about it but how in the heck do I know if they are doing what's on the checklist? I don't. I think when he comes I'm going to watch to see what he does.

I personally have no problem with a customer following me around. I prefer to educate them on certain items they can do themselves. A little communication goes a long way to make a user feel warm and fuzzy as long as they don't get in the way. I have clients that only need me or one of my techs. to come around every 3 years or so to do real maintenance and checks. The residential maintenance agreements do help me keep technicians busy during gaps in the schedules. I actually have clients who want someone to come out and change their filters. Most are elderly or afraid to touch anything. We usually try to schedule those when a tech. is going to be passing by and we can do it gratis if the customer provides the filter. It's amazing how that "value added" service has helped business.

But as you can see, for some people those maintenance agreements are worthwhile to some while others can save their money and do certain things themselves. Of course, for commercial clients, it's cheaper for them to buy an agreement than it is to hire someone full time to do it. And what's great is they can call the shop, ask questions and if the office Administrator can't answer a question (she does great), a tech. will call back. Even many handy types buy the agreement just to have resources (we also sell parts). These extras have allowed me to pretty much lock in whole neighborhoods.

Unfortunately, all techs or companies are not like you. I mean, here you are talking time out of your life to read posts on a forum to help someone (as if you're not busy enough).......There are so many HVAC companies to choose from here in Lexington. The one that installed mine is one of the larger ones in Lexington. I say that because I specifically see two ad's running for this company and another one on tv all the time ( I never see any ad's for any of the other companies but there are a lot in Lexington KY).

I think it's odd that the last three times something has went wrong on my heat pump, it's the exact same tech that shows up....I'm paranoid about HVAC because (like mechanics), you have zero clue about what could be wrong and they can easily say they did something and not do it or do something that doesn't need to be done. Hopefully that's not that case very often (but you never know)

Last few days have been in the low 90s, and my A/C is maintaining 73 temp. It is running constantly though (not cycling off) during the hot afternoon hours until the sun sets, then it will start cycling off.

Can I ask, if they tech finds a leak Tuesday.......Is that a major charge typically or is it something that can easily be fixed? Thanks

I think you would be surprised of how many companies out there are the same way. Finding them may be a chore but the results are worth the search. Just looking in this Forum, you can see many who are very proficient and do want to help.

Leaks can be very simple and easily fixed or very difficult and more costly. I think you will be fine Tuesday and the guy will come in, do what he does best and leave. I can tell you are one of those guys that if you don't have anything to worry about, you'll invent something. I think you should just assume your problem has been resolved. Think about it, even if they did find something major, you'd still have to deal with it. Worrying isn't going to change anything. But also think about it, the last time the guy came out, if he had suspected a leak, he would have certainly addressed it then. Most of the guys out there want to do a good job and do so. It's just the few that make most look bad.

You're correct in the fact that I'm obsessive over this. It's only because (since moving in this house in 2004 (brand new) the heat pump has been the ONLY thing to go out (5 times total)....And the heat pump is the LAST thing you want going out because it's the most expensive thing to repair. All said, since 2004

1st repair three years ago (leak in coolant tube from vibration on the outside unit (350 dollars)

2nd Capacitor (250 dollars)

3rd Compressor (labor plus coolant recharge 998 dollars)

4th 2 lbs low of coolant (180 dollars)

I forget what the other repair was, but there was one other one. And all of this happened with preventative maintenance twice yearly.

I surely understand your anxiety over the unit. I personally am suspicious over the replacement of 3 compressors in that short time. There's not much I can say with regard to that from long distance. I'd need to know why the compressors failed. There are so many things that could cause that and some of them would not be a technicians fault.

It sounds, from what you have shown here, the unit is fixed and now it's just a matter of following through on the maintenance. I think you'll be fine for now and after tomorrow, you should feel better.

No no....Misunderstanding .......:) Three compressors didn't fail (that was just the 3rd on the list of things that have went wrong making it look like three compressors since it was the third)

Ok......Tech shows up today for preventative maintenance. Same exact guy (but he thinks my air conditioning went out again) I had to tell him that nothing was wrong but that his office called to schedule my prepaid PM and he said ok....He didn't go into attic at all (he did when he was here a week ago)....He checked the outside unit and said the he took 1/2 lb of coolant out (said that he over charged it with coolant somewhat......So there is no leak...I should have charged him for the coolant he took back since I paid for it .....Oh well, it's working fine and this drama is hopefully over for a while.

Outside fan running fine, can feel heat around vent where you change the filter, thermostat seems ok, but can't feel any heat or air coming up through small vents through the house, what's wrong?