Home Repair (alt.home.repair) For all homeowners and DIYers with many experienced tradesmen. Solve your toughest home fix-it problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to alt.home.repair
~~~AAA~~~
 
Posts: n/a
Default New thermostat

I have a Trane BWD724A100A1 heat pump system servicing my 600 s.f.
apartment. The original Weathertron stat appeared to be inop in that
whenever heat is called for the aux heat blue light indicates. I purchased
a Honeywell TH8320U and outside temp indicator that I appeared to wire
correctly to this stat that I just installed. Now, a few ?s:

In the installer setup, should I set the compressor and/or aux heat
lockouts? If so, to what temps? I am in NYC area if that matters.

Is there much of an energy-use difference between using the compressor or
aux heat?

On occasion, after the new stat reaches the set temp during heat cycle, the
"heat on" indicator will turn off but the vents will continue to blow out
air, at decreasing temp. I put a thermometer in the ceiling duct and at
times this air continues to blow out for 20 - 30 mins going down to 63 F
which of course lowers the room temp, causing the heat to have to turn on
again. Even if I remove the stat from the wall plate the vents continue to
push out this cold air for at least several more minutes. As I said, this
only happens sometimes. Sometimes it appears to work correctly and the
ducts shut down shortly after the 'heat on' indicator turns off. How can I
stop this from happening?

Is there somewhere that I can see the correct Installer setup settings for
this configuration?


  #2   Report Post  
Posted to alt.home.repair
Travis Jordan
 
Posts: n/a
Default New thermostat

~~~AAA~~~ wrote:
I have a Trane BWD724A100A1 heat pump system servicing my 600 s.f.
apartment. The original Weathertron stat appeared to be inop in that
whenever heat is called for the aux heat blue light indicates. I
purchased a Honeywell TH8320U and outside temp indicator that I
appeared to wire correctly to this stat that I just installed. Now,
a few ?s:


Why do you say that the original thermostat wasn't operational?

Aux heat (AKA emergency heat) comes from resistance-heating "heat
strips" which at outside temperatures above about 20 degrees are
terribly inefficient compared to a heat pump.

On occasion, after the new stat reaches the set temp during heat
cycle, the "heat on" indicator will turn off but the vents will
continue to blow out air, at decreasing temp. I put a thermometer in
the ceiling duct and at times this air continues to blow out for 20 -
30 mins going down to 63 F which of course lowers the room temp,
causing the heat to have to turn on again. Even if I remove the stat
from the wall plate the vents continue to push out this cold air for
at least several more minutes. As I said, this only happens
sometimes. Sometimes it appears to work correctly and the ducts shut
down shortly after the 'heat on' indicator turns off. How can I stop
this from happening?


Sounds like a stuck fan relay on the air handler.

I'll speculate that your heat pump component isn't working at all, that
the new thermostat did nothing to change this, and that you've got an
intermittently stuck fan relay. Time to call a service tech.


  #3   Report Post  
Posted to alt.home.repair
~~~AAA~~~
 
Posts: n/a
Default New thermostat

The old stat was 22 years old and each and every time that the heat would
automatically go on, the blue auxiliary light would light up. Should the
auxiliary heat always be on during calls for heat? Also, the room
temperature and set temperature were not in sink, being off about 5 degrees.

AKA is the same as emergency heat? I thought they were separate issues. My
new TH8320U has Heat on, Aux Heat on, and then a separate Emergency heat
indicator. Am I not understanding this correctly?

If aux heat is inefficient above 20 degrees should I simply set the aux heat
lockout at 20 degrees and above so that only the compressor would operate?

Maybe an intermittently stuck fan relay? If so I guess I should get a
professional to look at this and fix if necessary.

Re the heat pump, I do get the Heat On indicator and warm air comes into the
room, and sometimes it will switch to saying Aux Heat On, also with warm
air. Since Heat On brings heated air, does that mean that the compressor is
in fact working?

If the room temp is indicated at 70 and the set temp is 72 I will see the
Heat On indication and warm air. If I move the set temp higher even a few
degrees, the Aux Heat On indicates. Normal?

Last Q: Is it better or not to utilize the temp lockouts for compressor and
aux since I added the outside temp accessory to this new stat?

"


"Travis Jordan" wrote in message
...
~~~AAA~~~ wrote:
I have a Trane BWD724A100A1 heat pump system servicing my 600 s.f.
apartment. The original Weathertron stat appeared to be inop in that
whenever heat is called for the aux heat blue light indicates. I
purchased a Honeywell TH8320U and outside temp indicator that I
appeared to wire correctly to this stat that I just installed. Now,
a few ?s:



Aux heat (AKA emergency heat) comes from resistance-heating "heat
strips" which at outside temperatures above about 20 degrees are
terribly inefficient compared to a heat pump.

On occasion, after the new stat reaches the set temp during heat
cycle, the "heat on" indicator will turn off but the vents will
continue to blow out air, at decreasing temp. I put a thermometer in
the ceiling duct and at times this air continues to blow out for 20 -
30 mins going down to 63 F which of course lowers the room temp,
causing the heat to have to turn on again. Even if I remove the stat
from the wall plate the vents continue to push out this cold air for
at least several more minutes. As I said, this only happens
sometimes. Sometimes it appears to work correctly and the ducts shut
down shortly after the 'heat on' indicator turns off. How can I stop
this from happening?


Sounds like a stuck fan relay on the air handler.

I'll speculate that your heat pump component isn't working at all, that
the new thermostat did nothing to change this, and that you've got an
intermittently stuck fan relay. Time to call a service tech.




  #4   Report Post  
Posted to alt.home.repair
Travis Jordan
 
Posts: n/a
Default New thermostat

~~~AAA~~~ wrote:
The old stat was 22 years old and each and every time that the heat
would automatically go on, the blue auxiliary light would light up.
Should the auxiliary heat always be on during calls for heat? Also,
the room temperature and set temperature were not in sink, being off
about 5 degrees.


Aux heat should only be on when the heat pump can't keep the temperature
at the set point. If it was really cold outside (say below 20 degrees
F) it might be normal for aux heat to be on virtually all the time.
OTOH the temperature error is certainly a good reason to change the
'stat. Your new 'stat is a very good piece of equipment.

AKA is the same as emergency heat? I thought they were separate
issues. My new TH8320U has Heat on, Aux Heat on, and then a separate
Emergency heat indicator. Am I not understanding this correctly?


On an all-electric (no gas, no oil....) system there is only one source
of supplemental (aux or emerg) heat - resistive heat strips.
"Auxiliary" heat means the strips are on in addition to the heat pump,
"Emergency" heat means the strips are on but the heat pump is off.
Uusally the selection of aux vs. emerg mode is made at the thermostat.
Emergency heat will also be selected by the heat pump when it is in
defrost mode.

If aux heat is inefficient above 20 degrees should I simply set the
aux heat lockout at 20 degrees and above so that only the compressor
would operate?


Not necessarily. Since your systems is "all electric" in most US
climates you are better off letting the heat pump run regardless of the
outdoor temperature. You will almost alwasy get cheaper BTU's from the
heat pump than from resistive heating. At lower temperatures the Aux
heat will be on most, if not all of the time.

http://oee.nrcan.gc.ca/publications/...dequipment.cfm

Maybe an intermittently stuck fan relay? If so I guess I should get a
professional to look at this and fix if necessary.


That would be my recommendation.

Re the heat pump, I do get the Heat On indicator and warm air comes
into the room, and sometimes it will switch to saying Aux Heat On,
also with warm air. Since Heat On brings heated air, does that mean
that the compressor is in fact working?


That would be the logical conclusion. If you have access to the outdoor
condensor you can check to see if the compressor is running; you should
also get colder-than-ambient air out of the exhaust side of the
condenser.

If the room temp is indicated at 70 and the set temp is 72 I will see
the Heat On indication and warm air. If I move the set temp higher
even a few degrees, the Aux Heat On indicates. Normal?


Perfectly normal. The thermostat thinks that the heat pump can't keep
up with the set point demand, so it turns on the heat strips (aux mode).
Most thermostats turn on aux heat when there is a 2 degree (F)
difference between the current temperature and the set point
temperature.

Last Q: Is it better or not to utilize the temp lockouts for
compressor and aux since I added the outside temp accessory to this
new stat?


I wouldn't use the lockouts unless you are sure you know the temperature
at which your heat pump costs more to run than it produces in heat
energy - which is going to be well below 20 degrees, perhaps as low as
zero or below. You might be able to divine this information from the
manufacturer of the system - assuming that the system was 'matched'
(outdoor condensor, inside coil and expansion valve) when it was
installed, or from a very experienced service tech in your area. Here
in my part of Florida it never gets cold enough to lock out the heat
pump.


  #5   Report Post  
Posted to alt.home.repair
Roy Starrin
 
Posts: n/a
Default New thermostat

On Tue, 28 Feb 2006 13:04:25 -0500, "~~~AAA~~~" wrote:

I have a Trane BWD724A100A1 heat pump system servicing my 600 s.f.
apartment. The original Weathertron stat appeared to be inop in that
whenever heat is called for the aux heat blue light indicates. I purchased
a Honeywell TH8320U
Is there somewhere that I can see the correct Installer setup settings for
this configuration?
http://www.alpinehomeair.com/related/TH8320U.pdf




  #6   Report Post  
Posted to alt.home.repair
Travis Jordan
 
Posts: n/a
Default New thermostat

Bubba wrote:
Travis
Electric back up heat is NOT inefficient. It is actually 100%
efficient. That doesnt mean it isnt expensive to operate.


Hi Bubba -
I didn't say anything about the efficiency of resistive heat.

I agree that a hack might have miswired the aux heat to come on whenever
the heat pump was operational - and they could have done that with a
jumper at the old thermostat. From the OP's description it sounds like
the new thermostat is wired correctly in this regard.


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
immersion thermostat still playing up Russ UK diy 11 January 11th 06 09:42 AM
New Thermostat + 2 Wire System (problems) CBHVAC Home Repair 0 December 3rd 05 10:19 AM
To anyone sick of alt.hvac Matt Morgan Home Repair 87 April 8th 05 06:17 PM
replaced thermostat - Em/AUX heat always on Giles Harney Home Ownership 1 December 22nd 04 09:42 PM
replaced thermostat, EM/Aux always on. Giles Harney Home Ownership 0 January 19th 04 09:40 PM


All times are GMT +1. The time now is 11:45 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"