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Trane TAM7 air handler runtime question

5.6K views 7 replies 4 participants last post by  cor_dog2  
#1 ·
Hello,

I recently had two TAM7 air handlers and two 2 ton XL15i heat pumps installed in my home.

So far this setup seems great, but now that we are getting into the colder weather I did notice one thing when the nights have been the coldest and that is that after the heat pumps themselves cycle off and the air handlers continue to run for a little bi before cycling off as well, is that the air coming out of the ducts gets very cold at the end of the cycle before the air handlers actually finally turn off and I think the reason is because my ductwork is in unconditioned space(attic and unfinished basement) and the cold weather in the attic and in the basement are cooling off my duct work before the air handlers turn off. So my concern is, is that my system is not as efficient as it could be.

So my big question I guess is.....is there any way to reduce the length of runtime of the air handlers after the heat pumps cycle off? I'm thinking that would solve my issue the easiest. Oh and I should mention I use the Schlage Link/Trane AZEMT500B Thermostats. I'm not sure if the setting would be available via the thermostat settings or if that would have to be modified on the air handler boards.

Any thoughts or advice would be greatly appreciated!!
 
#5 ·
Thanks....just to be 100% sure. Is that the "enhanced dehumidification" you are talking about? I'll have them check that and the dip switches. I think the air is at full force, but it might be ramped down a little. I'll have to pay closer attention next time. Usually when I've noticed it it's been in the middle of the night or really early in the morning when the weather has been at its coldest temps, so the few times I noticed it I was probably half asleep, lol.
Back to the enhanced dehumidification though real quick....is it recommended to keep that feature off in the winters and turn it back on it the summers when it is actually more humid?

Thanks everyone for your feedback!
 
#7 ·
Enhanced mode (comfort R) can be used for both winter and summer and allows the air handler to go through a ramp up profile. When system is turned on the unit should work like this using the cooling mode for this example:

50% first 1-1.5 min, then 70-80% for 7.5-8 mins then if needed the air handler will ramp up to 100% fan speed till the call for heat or cool ends then works in reverse. Allowing the system to ramp back down. It can be as easy as dip switchs not being set up to match the outdoor heat pumps cfm/air deliver. Or could be something more in depth?

Regardless it needs to reviewed over to ensure set up, install and wiring is correct along with the proper mode for your application is selected.
 
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#6 ·
There are several air flow options on shutdown. Talk to your dealer and see what is best for your application. Some are at 100% blower speed some are at 50%.
 
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#8 ·
Gotcha....I understand now.
Wish there was a Comfort/Enhanced mode option that still did the ramp up in the beginning, but had a shorter ending. In the service manual it says it runs for 3 minutes at 50% before shutting down. 3 minutes seems too long for my duct work for when the weather is either really cold or really hot. Looks like there is an option for 100% at 1.5 minutes which might help, but not sure if I would like it that way, so for now I think I'll just leave it alone since I'm in NC it doesn't get that cold too often.
I might call the company back and see what they think if it bothers me still down the road, but for now thought I'd just poll the group here to see what others thought and what others have their units set at and which mode they prefer. Thanks!
 
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