Advice needed on HVAC air handler options

[Giantsean]

Hi All,

I'll bore you with the history of why I'm asking, but suffice to say I fell victim to an HVAC setup gone bad (at least on the heating side - you can read about the saga in my old posts if you like). I'm posting this on the mail wall as it spans a few different areas.

So basically, I have a Trane TAM7 w/ a 2 ton evap coil and a hydro coil. Cooling works ok, heating not so much. Some techs have told me I need more CFM's to get air where it needs to go (it's at one end of the house and needs to get to the other), AND that a bigger heating coil wouldn't hurt either. I am trying to minimize costs since it's a brand new barely over a year old system, so replacing only what i need to is important.

That said, from what I understand the TAM7 is not particularly modular. If I want a bigger heat coil / more CFM's I need to upgrade, which means I need to get a bigger condenser as well. If there is indeed NO factory-friendly way to upgrade the wind or the heat I'm willing to try a new AH, so long as I can get a big variable fan, a big heat coil, and a 2-ton evap coil that will work with my existing 2-ton condenser. I'm pretty much open to any brand/combo as long as it's not total crap.

Sincere thanks for any advice or recommendations!

 

[WorthFlorida]

Your old post on this problem could not be found. Going with a bigger AH for more CFM can only be done if your duct work can handle it. What was in there before. Who suggested this size unit? How old is this TRANE? You may need to call on another heating specialist that doesn't deal with TRANE so the system can be sized correctly. One problem with TRANE is they have a lot of proprietary parts and components.

Here is an install manual and it lists a lot of models. If your model is listed then look it over to see if your system is set up to the maximum.
http://tranepennohio.com/secure/techdocs/TAM7-SF-2E-EN.pdf

 

[Sponsor]

 

[Giantsean]

Your old post on this problem could not be found. Going with a bigger AH for more CFM can only be done if your duct work can handle it. What was in there before. Who suggested this size unit? How old is this TRANE? You may need to call on another heating specialist that doesn't deal with TRANE so the system can be sized correctly. One problem with TRANE is they have a lot of proprietary parts and components.

Here is an install manual and it lists a lot of models. If your model is listed then look it over to see if your system is set up to the maximum.
http://tranepennohio.com/secure/techdocs/TAM7-SF-2E-EN.pdf

It's all new, ducts and machinery, as of just a little over a year ago. I believe the ducts can handle more as they are the same rough dimensions as the 2.5 ton attic handler which is putting out 1000 CFM, though I would not put too much faith in my installers' design skills. They suggested the 2 ton size but they were going to go w/ an ADP unit instead of the Trane. I asked them to do the Trane based on reviews and prior quotes. Should have known it wouldn't end well

Yeah I'm all over that manual. I have tried setting it in nearly every combination and ended up with max CFM/ton, constant mode (due to zoning), and setting the hydronic heat controller board to external coil mode (it's not - it's internal, but it works the best to move the air).

I would have LOVED to go with a true HVAC expert. I saw so many people ahead of the install and ended up going with a friends recommendation (bad move). I can say that regardless of the price, NOBODY who quoted me gave me the warm and fuzzies. I had to go with the least objectionable / seemingly best value. Maybe it's just our local area or the industry as a whole that needs a cleanup, but there are a ton of hacks around here. I could not even get someone to run a Manual J for me, even when I offered to pay.

If you want to see more on it, here is one of my original threads:
https://terrylove.com/forums/index.php?threads/are-my-hvac-guys-hacks.62148/

 

[Giantsean]

So today I'm doing some research on using a smaller condenser w/ a larger AH coil. While I am doing that I take another look at the manual for the TAM7/AAM7.

I noticed from the fan performance settings that the pairing of a 2 ton condenser with a larger (2.5 - 3 ton) AH yields roughly the same CFM ranges. "Dafuq?" thinks I. Then it dawns on me.

Referring to pages 10-12, where it specifies DIP switch settings and also specs per each setting. I have the S1 DIPs set up for a 2 ton multiplier - since it seemed like the correct choice, because it is a 2 ton outdoor unit. This got me thinking... how the hell would the AH even know what is attached to it? If I set it as if it was a 3 ton unit, even though it's not, does that mean the fan will put out 1200 CFM?

I have not tested it yet... but it would appear I may be onto something. The downside is that (with my research in mind) that this is an all or nothing setting. It may well bump up the fan speed thinking it has a 3 ton condenser attached, but it will be blowing too much air for a 2 ton coil. Now, I'm not sure the overall effect but I am guessing it will cool faster, cycle shorter, and dehumidify less. Still, even if I have to reset DIP's every heating season, it's still much better (read: cheaper) than swapping out an entire AH.

Anyone know of an easy way to confirm whether a fan is blowing harder without an anemometer?

 

[WorthFlorida]

Did you every get your problem?
At my church where I maintain has 8 Carrier Infinity seer 20- or 21 units. Both the AH and the condenser have microprocessor components. The thermostat will display the part numbers of each unit, hense the size, and will adjust the fan speeds and compressor speed (hi-low) depending on the heat load, set point and the outside temperature. There a pain to maintain since I lost three motors and so far changed out 5 if the 8 thermostats. I still have three more thermostats to go at $410 each (wifi). All proprietary parts and expensive.