So, if I do not use bleach to clean the drain, how to you recommend that I should keep them clean? One way: use a good quality filter and change them at regular intervals. This method is not perfect. Second way: pitch drain line to a minimum 10-15 degree angle so that it empties fully, into a single trap if possible --- trap placement is just as important. Flat piping runs and elbows should be avoided as much as possible. (Don't forget about first step.) IE: gravity works for you just as much as it can work against you. It all comes down to the design of the drain system. Third way: wait until it clogs and then clean it out / or pay to have it cleaned out. Which way do you suppose most service companies are counting on? So by now you clearly see the 'two sides to every coin'. If something is billed as being perfect --- it is an out right lie, merely to swindle you. Drain line could still clog given the second way, but you cut the risk to fraction of what was possible with other methods. It's not always possible: architecture was built for beauty, not for how the HVAC system condensate line is to be run to prevent drain clogs. In some situations it may be better to level the home and start over. Ah the reasons why someone sells a home these days... it will boggle your mind. It should be noted that bleach does not clean the drain, it merely treats it by killing bacteria and algae growth. To keep bacteria and algae growth in check the drain has to be treated continually, because as you run the AC the bleach is eventually diluted and flushed down drain with condensate from the AC. The problem with retreating is that bleach is corrosive. If not flushed down the drain completely the fumes come up the drain and attack anything metal. Your all aluminum coil is no match for bleach. It will attack the heat exchanger as well. The more you treat the drain with bleach the more less likely you have drain clog, but at the expense of system damage due to the corrosiveness of the bleach you use to treat the drain.

hanks everybody for your kind reply! To tigerdunes, "You are worrying about nothing. Your condenser is 2 1/2 tons. Both furnaces are 60 KBTU. The difference is the blower motor size. You need at least a 3 ton blower motor. You will be fine. i suggest you look up the AHRI matching number for the system you installed. I would want to know if that coil size is the best selection as far as AC efficiency. I hope you did install a filter media cabinet." you were right. it is a 14 SEER AC. the 17-16 funace listed on the contract has a 4 ton blower motor at 1600 CFM. the smaller 14-12 furnace (what they actually installed) has a 3 ton blower moter at 1200 CFM. So you think this 2.5 ton AC will work well with this 14-12 furnace? I will ask the HAVC contractor to email me the matching numbers for the different coils and the 4-12 furnace. btw, what's the benefit of a filter media cabinet? Thanks! - JL PS: on the contract, it says, AHRI Matchup: AHRI # : 9473916. since they changed the furnace and coil, i guess it's no use any more. AHRI Certified Reference Number for the smaller furnace Carrier 59SC2C060S14-12, is 7126221

Sizing can be less of an issue when you have multiple units. Because each unit is controlled independently, provided of course the unit itself is not over sized for the area in which it serves resulting in excessive short cycling. In your case 3 ton plus 2 ton isn't necessarily equal to 5 tons of cooling... unless you drive those thermostats really low. By having two systems with total capacity of 5 tons (which, most of the time this would be oversized for a 1700 - 1800 sq ft structure) has a few advantages. 1. You have the ability to use one system only during low heat days or set the opposing unit higher. The unit set higher only runs if load conditions warrant.... meaning if it's not hot, the thermostat controlling the unit does not call... the unit can not run without a call... 2. Utility bills can be much less... because you rarely use both systems at the same time. You run the bedroom system when you sleep, the other when you're awake. If you have a home office in one the bedrooms you may need to rethink things a bit. 3. Extra capacity for when it's hot out. When it's hot you have the capacity to cool the home. (even while entertaining guests --- additional people add heat) Remember heat waves come, heat waves go... a so call 'properly sized' AC system is essentially properly sized roughly 10% of the time... especially if that system is a single speed AC system. Alot of people I come across like to sleep cool. So for that reason I doubt I would change the configuration of the space. Once you realize what you have, the choices you make are mostly budget type concerns. Essentially a set up like this runs like a 2 stage system. This kind of subject is above the pay grade of many... choose your contractor wisely. I service the Katy, Texas area.

I'm disappointed that what had at first seemed a very balanced comment was followed by what seems to be misinformation and misdirection. People buy ground source heat pump equipment because they want to and can afford it. Or decide they need to in their locations. They're hugely more expensive than alternatives, which is why they're still not very common. "When’s the payback on a Tesla? People still choose to buy them for reasons other than the ‘bottom line’." Not a comparable. A false analogy. "I would not choose natural gas or propane for reasons relating to the environment, safety, IAQ & paying for yet another utility hookup for an energy source that might not even be used for months on end during the year." What effect having a gas furnace has on indoor air quality. Another hookup? Most people prefer gas cooking appliances and besides, the OP is talking about an existing home, he either has gas service or he doesn't. "Rather than spending perhaps tens of thousands of dollars on a Solar Array, I would sooner invest that same money, hopefully less, in a ground loop for a Geothermal system." Sure you would, that's the business you're in. The ground source heat pump market is not growing as expected by those in the industry, which suggests that your opinion isn't widely held or easily sellable. In many parts of the country, solar panels can have a quick payback. Not so ground source heat pumps. "I often hear about Solar Panels when geothermal is mentioned, as an alternative way to save money by creating energy." In a place like Texas, where electricity is cheap (other than during cold weather crises as they just experienced) there's likely no payback from a solar panel installation. People do it as a personal statement, call it for environmental or other personal reasons. Like buying the Tesla, not a financial decision. An HVAC system blows warm air when it's cold, cool air when it's hot. It's one of those things people don't care about - either it works or it doesn't work. Spending extra money for an exotic system doesn't equate to extra payback when the home is sold. Neither owners, nor visitors, nor people passing by, nor anyone else, concern themselves with what's doing the work. It's equipment that doesn't produce an experience for someone in the house if it's working. In the US, there are vast areas where electricity is cheap. It will remain so for some time. People don't spend money today to potentially save money 10 years out when market conditions may or may be different. I suspect you could build a house with mahogany or teak framing. Or you could paint the framing bright colors. Why bother, you can spend less money and effort and get something else that will do the same job. "We almost never use setbacks at our home - even when going on vacation for weeks on end with no one home, our geothermal just runs." You're combining two different things to produce confusion. Thermostats that have a setback feature ALL are set up to provide lower overnight temperatures to have more comfortable sleeping conditions and then a recovery in the morning before wakeup time. As sleep specialists recommend. That in demand comfort features isn't possible with ground source heat pumps because the warm up period from a setback is too slow to be convenient to use, absent triggering a secondary heating source (like a furnace) to help. THAT'S why you don't "believe" in setbacks with a heat pump - they don't work. Turning down a thermostat during heating season when the home will be unoccupied is not a "setback" as that word is most commonly used. It's done to save money, why heat a vacant house? No setback thermostat is needed, even a dumb 50 year old analog thermostat can be turned down.