Air Conditioning - Compatibility of old acc with new system

I am gettingnew HVAC systems installed in 17 yr. old home. I had several quotes. The Carrier guy with the Puron systems was the lowest quote by a good margin so this takes away all of the philosophical arguments. However, included in the quote are 2 new programmable thermostats and a new condensate pump. When I questioned the need (current thermostats working fine and condensate pump replaced last year), I got the following response.

1. We prefer to use the new thermostats with the new systems because older thermostat circuit boards do not communicate with the new system circuit boards. We could have a potential problem in the future with older thermostats. This added approximately $55.00 per thermostat to the quote.
2. the new cooling coils produce about 2x the water as older cooling coils and we prefer to use the new condensate pump for this reason.

I don't want to be penny wise pound foolish but at the same time a buck is a buck. Is the guy serious or blowing smoke?

You dont say if you went with the V/S blowers here or not. That will have a hunidistat control on them. Then yes you might need a bigger pump and the new tstat. But you went with the low end R410a Puron guy. So hope they do a good job with new lines and Vac it out right. If not you will sure pay in the long run.

I guess somewhere in your judgmental commentary there is an answer to the question but it isn't worth it to me to pick it out. I am used to Forums that are a resource, not a soap box.

A thermostat is a bunch of switches. One turns on the fan, one turns on the compressor, one switches the reversing valve (in a heat pump). The only reason to change the thermostats for a new unit is if you changing from conventional 24 volt AC control to DC control.

A condensate pump it a box that fils with water. When the water reaches a certain level it makes a switch that turns on the pump. The pump pumps the water from the box until the the switch opens and turns the pump off. It's like a mini sump pump.

I see know reason to change either.

But, and there is always a but. The lowest bidder will usually give you the lowest quality install. Cheap is cheap.

Why are you changing the system?
What is the model the Carrier guy wants to sell you? This will help me look it up and fing the recommended thermostat and give more feed back.

Chris

Thank you.

The current systems are 17 yr old, builder's grade systems, originally 8 SEER at best. Only thing that has ever been done to the Main level unit (2.5 ton for 1080 sq ft.) is to replace A coil since the original one rusted out and leaked. The only real maintenance routine needed is to annually vacuum out the burner box due to mild to moderate accumulation of rust. Upstairs unit has been the issue. It has never cooled well. My belief is that it was marginally sized to begin with (2 ton unit for 1,230 sq. ft.). BTW, the house is in Atlanta, Ga. faces East/West but on heavy shade on the West side, bonus room over a 2 car garage (not heated or cooled). The ductwork in attic is about half hard duct with the other half being a very chinzy flex duct.with 0.5in insulation. Ductwork on Main level not accessible since I had the basement finished. Basement not in play as I had a 3rd system added down there when it was finished out. Maintenance on the upstairs has been to replace A coil for the same reason, vacuum burner box due to heavy accumulation of rust each year (enough to actually cover the burners) and periodically (approx every other year) add Freon. This system will not maintain a constant temperature in th hot summer months. Set it on 76 and it slowly creeps up, even though running all day, to 82-83 before finally recovering at night. It begns a cycle by blowing hot air and takes about 10 minutes for the air to become cool - never what can be described as cold. Oh yeah, I should mention that any time there is any type of storm in the area, I have to go out to the breakers at the compressors and throw the upstairs breaker back on. Gas bills go as high as $270 mid winter and electric bills as high as $300 late summer. Bills came down after installing Argon filled, low E, double pane windows throughout. We are lookiong to be in the house for about 6 more years. When the daughter goes off to school we will go off to the lake!

Original quote was for a Carrier Puron 13 SEER units - 3 tons upstairs and 2.5 ton downstairs. Furnaces to be 80%, 4 speed gas units. The guy says it is the residential replacement grade but never mentioned a model number. The attic flex ductwork to be changed to flex duct with 2in insulation. Also replacing the outside breakers. The quote was $10,800. The closest alternative quote was $12,700. No one offered to do a heat load calculation. When pushed on the subject, the Carrier guy will do it for $400. I pushed the guy to go down to a 2 ton on Main level and 2.5 ton upstairs. I have always thought the units were installed wrong by builder and that they should have been in this configuration. My reasoning for downsizing what the guy quoted was 1. the double pane windows have made a big difference. The downstairs unit doesn't run nearly as much - hard to tell with the upstairs unit although even when it is running, it feels moist and stuffy. Oh, I forgot to mention that the company that installed the A coils put in 3 ton coils so I currently have mismatched systems. I didn't know this until the sales reps all pointed it out. Anyway, I would prefer the units to be slightly undersized than oversized so that they will run longer to pull the moisture out of the house. As long as the upstairs unit can maintain 76 on a hot summer day I am ok, i.e. it doesn't have to fight it down to 68 since I will never set the thermostat there anyway.

Neighbor had the same folks install his systems last week. He said they did a good job on the install. He is an electrical engineer that is a project manager so he is used to dealing with HVAC on a commercial basis. I am depending on his thoughts and opinions somewhat since my knowledge is limited.

Both of my systems are working but are like me - in the fall of life! I thought about just replacing compressor upstairs but worry about the heat exchanger, being old and with many years of rusting away. Downstairs was an even harder decision but ditto on the heat exchanger and now I am aggravated with the wrong A coil in there. Spend money to put another in another coil? My bet is that new systems will be needed to sell the house so why not enjoy quieter units that are more energy efficient while we live here. Getting to show that appliances have all been upgraded, windows now double pane and new HVAC systems will imply to a buyer a higher level of overall maintenance than having some loud, rusty compressors strugging to keep up.

This is way more than you probably wanted to know to advise on some thermstats and a condensate pump!!! On a $10,000 bill, a few hundred on these things is not the issue. I just didn't like his answers. I wish he had just said, they come in the box with the new equipment so we just install them. His answers just didn't sit well with me-

First, anyone quoteing new systems should do a load calc as part of the quote. These days the the guy should have the software to do so on a laptop and do the calc while he is at your house checking things out. It's not just a heat load calc. It's heating and cooling. Taking into account windows (type and number of), appliances, trees, insulation, house orientaion(facing north, south etc.), and a lot of other factors.

The residential load calc software from Wrightsoft cost $474 (wrightsoft.com go to right-j section)

I also logged into Carrier, and as I thought they don't make a "4 speed" furnace. I've never heard of such a thing. You can get a "Variable" speed unit which is more efficient. You can also install heatpumps with a gas furnace, you didn't mention this as an option presented.

You definitly don't want to oversize. Your duct work was (should have been) sized for the Cooling units you have now. If you oversize your get poor perfomance and probably air noise from the registers.

Taking out new stats and pump will only save a could hundred bucks.

Sounds like someone thinks "Oh the guy next door, should be an easy sell". My advise is to get more quotes and do not make a contract without a load calc. You can specify up front or ask how the size of equipment was determine without a proper load calc.

You maybe in the fall of life but it doesn't mean you need to fall for a load of crap.

Chris

Well, actually they do make a 4 speed furnace in both the Performance and the Comfort Series - per their Website.

The guy said the attic ductwork is sized for a 3 ton unit which is one of the reasons he fought me on downsizing.

The revised quote for the 2 and 2.5 units vs the 2.5 and 3 ton units he wanted to install was $10,500 so I am only saving a little upfront money. However, I think the comfort level will be better and the units will operate more efficiently (which I hope will translate in a few $$$ monthly) with the smaller units. The small savings makes it almost counterintuitive to downsize but my gut is telling me to do it.

As to the load calculations, the guy swears to me that it will show that the larger units are needed as his company uses a 95 degree day in the calcs. He says he has been quoting systems for 18 years in the same area, with and without load calcs, and doesn't see the need for me to spend $400. It is a case of the guy either knows what he is doing and is just cutting a few corners in the communication phase or he is full of hot air. This is why his explanations of why I should go with new stats and pump is important to me.

You say the stats and pump will only save a few hunderd $$$. Again, it isn't only the money, it is wanting to know the truth that is bugging me but then again, a few hundred bucks isn't something that I would pull out of my wallet and throw off a tall building either.

As to an "easy sell" - he may have thought it walking in but he should be figuring out by now that this isn't necessarily true-

Me again - now I am getting more confused. The website shows the Comfort 80 unit as having 4-5 speed blower. However, when you go to the specs tab, it says single speed blower - WTF?

I chose to research this one since it was the cheapest 80 AFUE unit. I figure that is what he is quoting since he didn't specify.

but you only use one at a time. Most will use one speed for cooling and another for heating. Your looking at the homeowner (public) side of the Carrier website. I get to see the contractor side.

If you pick a unit your interested in and send a private message with your email (click on my screen name in the post) I'll email all the specs and manuals that come with the unit.

Chris

Very gracious offer. I will call the guy tomoroow and find out which unit he is proposing and then contact you.

HVAC companies wanted to charge you too do a Manual J? WOW! When I had multiple companies come out and give me quotes, they all did Manual J's for free.

If they really wanted your business, they would have done the same.


Just my thought on it anyways.

When I moved from the Virginia Beach area to Central VA at the end of 2005 I landed in a residential company. Up till then my residential experiances were side work or the last resort for a homeowner who bought a geothermal system from the company I worked at (Commercial side) and was at wits end with a screwed up system. Best thing about that was when I showed up for a residential geothermal job was to see the jaw drop when I told the homeowner "Now that I'm here, it costs you nothing. I'm here to fix it and your stuck with me until you are satisfied.".

Moving here was a shock as working for a residential company where they routinely did things wrong and knew it, I had to go. First thing I did was start looking for a good commercial company. I thik perhaps 7 out of 10 residentials are no good. Hate to say it.

wreck75

Manuals are no problem, glad to forward the info if it'll help you out. I think you can see that after your second post to this thread you started, everyone does stop by and lend a thought or two. I just wish more people would read the post they reply to and answer the question and not go off in some other direction.

Chris

I recall reading a thread either here or on one other HVAC forum that had a political battle between Freon or Puron that went on for maybe 12 pages. I purposely tried to avoid that forum with my little thermostat/condensate pump question and got hammered right out of the chute. However, I have enjoyed the interactions after the first response.

I just like folks answering a straightforward question with a straightforward answer. When I asked my contractor if I had to use new thermostats with the new system he comes back witrh "We Prefer to use new...and we could have a potential problem in the future" - what's up with that??? Either it works with the new system or it doesn't - why should it work at first and then have a problem in the future???. To me, a thermostat senses the temperature and tells the unit to start or stop. However, I now see that some units have thermostats that sense humidity and instruct the unit accordingly. That is pretty cool. Either mine will do that or it won't. It only matters to me if my little boxes of wires and circuits work on the new system or not. If not, no big deal - install the new ones. If yes, I will take the $110 and fill up the car with gas. Sadly, it may come to that. If yes, but you lose such and such feature, tell me that and I will decide if such and such feature matters to me. - Same with the condensate pump - so what if the new system puts out 2x the water. The pump will have to run 2x as much as now. No big whoop unless I am missing something. I looked at my neighbor's new pump and it looked just like every other pump I have ever seen and just like the pump they disconnected and left beside the new one!!!. I hate to say it but sometimes I don't want to spend hours researching a topic to know if I am being taken advantage of. I want to trust folks.

As far as your contractor is concerned, I'l give him a pass here. While I advised against changing something that works with something that works. He's just trying to cover his butt. What if he has his crew come in and do all this work for you and a month or two later you thermostat or pump craps out. He's thinking you'll be on the phone yelling at him.

The explanation could have been better, but that's probably why he wants to change them.

I do come to this forum to give straight forward answers. I figure why ask a question if you don't want the correct answer (guess). Sometimes I have to quess as not enough info was given in the first place.

Chris

Yeah, I see your point. He doesn't want to leave the job with a few pieces of equipment he knows nothing about playing a role in his new system. I just wish he had said it differently. I was very happy with everything until he blew the smoke up my shorts. Then I began to question everything about him and the system. He probably tossed in all the stuff that he could think of to make the proposal sound great but then I read it as optional stuff that I didn't need. I think you are right - I will give him a pass and blame it on poor communication. Thanks for taking so much of your time with me - I appreciate it.

PS: I did read up on the Carrier thermostats. Again, assuming the cheapest programmable unit, the new ones don't seem to do anything special that mine don't already do. Oh well, there is always EBay for the ones I now have!

As long as your are satisfied enough to make the decision you have to make with a feeling you are doing what is right for you, I am happy. To me, it doesn't matter how many posts, how many questions, or how made my wife gets (well that does matter) I'll keep answering questions. To the best of my ability and there are others here who will catch my faults and correct/educate both of us.

I like this site because people like you can come and ask if they are getting ripped off or just need advise as to what is wrong with the system they have or whatever else and the pros here can give them straight forward answers. No one here is making any money, just shareing knowledge.

People helping people.

Semper Fi

Chris