Heat Pump Questions

Reply

  #1  
Old 12-28-15, 04:08 PM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Heat Pump Questions

Hello, I have a couple questions about my heat pump and air handler.

Heat Pump: American Standard 4A6H5030G1000AA
Air Handler: American Standard TAM7A0C36H31SDB

My first question is, do I have a single stage or 2 stage heat pump? I thought it was single stage but now I'm second guessing... I seem to see different answers across the internet.

Do I have a single stage or 2 stage air handler?

Is there a way I can tell? My Sensi thermostat requires me to identify these and I'm not 100% sure.

I've been reading that if I set the temperature 3 degrees or higher above the room's current temperature, the aux heat will come on. Is there a way to adjust this? Wouldn't it still be more efficient to run the heat pump even if it takes longer to heat the house?

That being said, when it was 35 degrees earlier, we got home and turned the heat on to 65. The current temperature was 57, so the aux heat came on...I think. The mode selected was "Heat" but "Heating Auxiliary" was also displayed on the screen. I'm guessing the aux heat came on because it's an 8 degree difference. However, the air coming out felt cool. I've felt my aux heat and it's like standing beside a fire. Why did it feel cool? Eventually the aux heat shut off and heat pump started up. Was my heat pump defrosting? That doesn't make sense at 35 degrees does it?

How do I know what temperature the heat pump will no longer operate at? Is there a way to adjust this, and is it safe? I've heard of people's heat pumps running until 30ish degrees and I just want my unit to be efficient as possible i.e. have aux heat run as little as possible.

Lastly, there is an o/b setting on the thermostat, where I select either o or b. Which do I select and why? Does it even matter since I no longer have a wire connected to o/b?

Thanks again!!
 
  #2  
Old 12-28-15, 05:18 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,398
Received 1,399 Votes on 1,296 Posts
I'm just going to touch on a few things here.

I can't find the system specs for your equipment. My partner, Houston, should be able to help there.

You have a heatpump.... therefore you need a wire on the O terminal or on O/B and set to O mode. That means the stat supplies power to the reversing valve in the A/C mode. When in heat mode the valve is not powered.

Your heatpump should be able to run to a very low temperature. When it gets too low the electric elements kick in.

We don't recommend using a setback stat on a heatpump. It is more efficient to let the heat pump run full time then to require the electric heating to energize.

It sounds like what you thought should have been aux heat was in fact just the heatpump running.

What we usually recommend is to post the make and model of the old stat and what wire was on each terminal.
 
  #3  
Old 12-28-15, 06:02 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,425
Received 17 Votes on 14 Posts
The heat pump has a single speed. It doesn't have a Y2 terminal or pigtail. The first 5 digits of the model brings up the manual.

I don't know what heat strips you have or how it is staged unless you post some pics of the heat strip nomenclature and the wire connections to the air handler.
 
  #4  
Old 12-29-15, 07:31 AM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
The amount of control you have on your heat strips will depend on the quality of your thermostat. If you have a cheaper stat then yes, usually if there is a large enough change in the set temperature the strips will come on for faster heat up. A high end stat will give you control on the heat strips and do things like lock them out till a specified temp or set the temp drop in the house at which point they will come on. I don't know that much about Sensi but it SHOULD have at least SOME of that ability. Check your manual to confirm though. A high end Honeywell like the IAQ offers maximum control if sensi doesn't meet your needs.

The quality of heat pump will decide how low it can go in terms of outdoor temperature. I run mine until -24c (-12F).....( heat strips locked out until -20c (-4f)). For mine that is the point at which it is no longer cost effective to run it vs straight electric heat. There should be a data sheet with your heat pump that tells you what that point is for you.

It is not advisable to to set back a heat pump. Heat pumps save money by long continuous run times and don't do well by being jacked all over the place. It takes a heat pump as much as 5 minutes to settle its pressure out and start pumping usable heat so if you cycle 4 times an hour that's almost 20 minutes of wasted energy.
Let it run long and continuous with as few cycles per hour as possible. This will save you the most money at the end of the day.
 
  #5  
Old 12-29-15, 07:58 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks for the reply PJmax. However, in a previous discussion, Houston told me to move the blue wire from o/b to c because I kept blowing a fuse. Here's a link to the thread:

http://www.doityourself.com/forum/he...wing-fuse.html

If it was in fact the heat pump running, why did "Auxiliary Heating" display on the screen? What is a setback stat?

Here is the make/model of the old thermostat and the wiring:

American Standard (Not sure which one is the model number so I'll just post the numbers I see ) ACONT602AF22MAA TH6220D1044

Y2 - Black
W2 - White
G - Green
W - Orange
B - Blue
Y - Yellow
R - Red
 
  #6  
Old 12-29-15, 08:08 AM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
If you have a "Y2" then it is indeed a 2 stage heat pump. If just Y then it is a single stage.

A set back stat is one that allows you to (for example) to set a schedule to set back the temperature at night and bring it up again in the day. Sensi is a set back stat. It is not advisable to set back a heat pump but if you choose to do so, only set it back a couple of degrees because it takes a long time for a heat pump to recover the heat.... unless of course you are subsidizing with heat strip during the warm up... which will INCREASE your heating bill PAST what you were trying to save by setting back in the first place.

Depending on how you have your thermostat set up, you can have the heat strips come on along WITH the heat pump so it is possible the strips and the pump were on all at the same time. Once again though, I believe the sensi does have heat strip lock out ability and you should probably set that so only the heat pump is running.
 
  #7  
Old 12-29-15, 08:10 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks Houston204, what do you mean by Y2 terminal? The black wire was connected to the Y2 terminal on both my old and current thermostat. I'm not too sure I want to take the cover off the heat strip part of the air handler. Is there anything else I can post that would help?
 
  #8  
Old 12-29-15, 08:13 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks again. Basically the sensi is asking me if I have a 1 stage or 2 stage heat pump and a 1 stage or 2 stage air handler. I will set the heat pump back to 2 stage. Still not sure about how many stages the air handler is. I'm talking with sensi now to see how to lock out the heat strips.
 
  #9  
Old 12-29-15, 08:25 AM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
The Y2 terminal is the control connection for the second stage on your heat pump. (Y controls the first stage). Make sure you actually have a Y2 connection on your new heat pump (Open the panel on your condenser outside and look). It is possible your old heat pump was a 2 stage and your new one is not. That being the case the Y2 connection at your thermostat would be taped off and not used.
 
  #10  
Old 12-29-15, 08:42 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks for all the helpful advice Bob.

We had this heat pump installed in May. Before that, all we had was an electric furnace from the early 80s. However, all of the additional required wires leading to the thermostat were already there, just not being used.

Here are my outstanding questions:

1 stage or 2 stage heat pump? (I will look at the condenser).

1 stage or 2 stage air handler?

Do I need a wire to the o/b terminal? And if so, why was it blowing my fuse?

Why was the air not scorching hot when the thermostat displayed "Heating Auxiliary"? Keep in mind that even though it said that, the mode selected still showed as "Heat". Maybe it was trying to use aux and heat pump at the same time, but I have an issue with the Aux heat?
 
  #11  
Old 12-29-15, 08:45 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
p.s. there is a brown wire to the thermostat that is not being used.
 
  #12  
Old 12-29-15, 09:11 AM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
1 stage or 2 stage heat pump? (I will look at the condenser).
Yes, a quick look under the hood for a Y2 connection will positively tell you one way or the other.

1 stage or 2 stage air handler?
I looked for info on that and couldn't find anything. Typical American Standard... they want you going to their service department for ANYTHING so they can charge you an arm/leg.
Logically speaking though if the condenser and air handler came as a package and the condenser is a two stage, they would NOT have stuck you with a single speed handler.

Do I need a wire to the o/b terminal? And if so, why was it blowing my fuse?
Yes. That controls the reversing valve (the device which switches the machine back and forth between a AC and a heat pump)

I read the other thread and it sounds like you were connecting the COMMON wire (c) to the O/B connection which would cause a short circuit and blow fuses. Usually (but not always) the O/B wire is orange and the blue is Common (C). You can check that wire color while you are looking under the hood for a Y2 connection if need be.... but you MUST have the reversing valve connected. It not only switches you back and forth between AC and heat, but it's also required for defrost mode.
 
  #13  
Old 12-29-15, 11:05 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks Bob. Actually, my air handler is variable speed. Is that the same term as 1 vs 2 stage?

The fuse was blowing when I had the blue wire connected to o/b, so Houston suggested changing it to c. The orange is connected to W/E, and was connected to W on the old thermostat.
 
  #14  
Old 12-29-15, 11:45 AM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
Variable speed is more than a 2 stage but for the purpose of sensi, set it at 2 stage.

Your best bet is to confirm all wire colors by looking where they connect. Open your condenser panel outside and see what wire color connects to the reversing valve (O/B). Connect THAT wire to O/B on the thermostat.

In fact it would probably be best if you could post a picture of the low voltage connections on both the air handler and the condenser. That way we can for sure figure out what's going on.
 
  #15  
Old 12-29-15, 01:06 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,398
Received 1,399 Votes on 1,296 Posts
I went thru all the specs for your unit. It's shown as a single stage Heritage model. No Y2 shown in any wiring diagrams. There is an X2 shown based on heating arrangements.

Pictures are still good..... http://www.doityourself.com/forum/el...-pictures.html
 
  #16  
Old 12-29-15, 01:38 PM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
I took the panel outside, and it's not quite as straight forward as expected, so here are a bunch of pics Name:  20151229_150716.jpg
Views: 1286
Size:  38.0 KBName:  20151229_150631.jpg
Views: 1477
Size:  32.7 KBName:  20151229_150619.jpg
Views: 999
Size:  30.5 KBName:  20151229_150544.jpg
Views: 1006
Size:  29.9 KBName:  20151229_150419.jpg
Views: 987
Size:  23.1 KBName:  20151229_150349.jpg
Views: 979
Size:  23.2 KBName:  20151229_150331.jpg
Views: 952
Size:  24.0 KBName:  20151229_150259.jpg
Views: 1013
Size:  27.3 KBName:  20151229_150253.jpg
Views: 1034
Size:  31.3 KB
 
  #17  
Old 12-29-15, 02:30 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,398
Received 1,399 Votes on 1,296 Posts
The Y2 connection would be shown in this diagram. Unfortunately the board compresses pictures which makes intricate ones unreadable. I don't believe I see Y2 here.

Name:  specs.jpg
Views: 999
Size:  17.1 KB
 
  #18  
Old 12-29-15, 02:58 PM
B
Member
Join Date: Mar 2015
Location: Canada
Posts: 186
Received 0 Votes on 0 Posts
I agree. I don't see a Y2 so it's a single stage. Not sure what that Y2 on your stat is connecting to but you should remove it and tape it off. Set the sensi for single stage pump.

Although it could be that the one connected to your Y2 right now is the reversing valve. Follow that back and see where it goes. I can't see what it is connected to on the board.
 
  #19  
Old 12-29-15, 04:16 PM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Thanks to both of you. I don't see it say y2 anywhere either, looking at the original pic, for what it's worth. Are you able to see what color the o/b wire is? Might it be the black one like you mentioned? Or is it not on that 6 pin connector? At least it seems that the pump is 1 stage. I'll male sure to set the thermostat to that.
 
  #20  
Old 12-29-15, 04:38 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,398
Received 1,399 Votes on 1,296 Posts
No.... the O/B or actually O wire is orange.
The black is for the heating function. Looks like it may be W1
 
  #21  
Old 12-30-15, 07:33 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Hi, I confirmed with the place that did the install that the heat pump is single stage.

When I turned the heat on this morning, the "aux heat" supposedly came on but was blowing ice cold air. I will be calling sensi today but it seems there is an issue with the aux heat not working correctly. I have the o/b setting set to o, but not sure that matters since i dont even have a wire connected to that right now since it blew a fuse every time the pump started.
 
  #22  
Old 12-30-15, 07:49 AM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Once the temperature was 1 degree away from the set, i turned the heat off and back on. THe heat pump came on and the air blew cool for a bit, maybe to blow out the excess cool air from the "aux heat". The air then became warm, but then became cool again like the ac was on. I'm guessing this has something todo with no wire on the o/b terminal. PJ, are you suggesting the orange wire goes there?

Will be calling sensi shortly.
 
  #23  
Old 12-30-15, 12:51 PM
G
Member
Thread Starter
Join Date: Jan 2014
Location: United States
Posts: 81
Received 0 Votes on 0 Posts
Ok so I called Sensi and they had me move the orange wire to o/b and the white wire to w/e. So far so good. The aux heat blows hot. The heat pump blows warm. The woman on the phone said that the aux heat should com on if I set heat more than 2 degrees above current temp, and said that a future software update may let me bypass that... The current temp was 64 and I set to 75. However, the heat pump came on, not aux heat. That actually makes me happy, as long as the aux heat will come on when it's too cold for the heat pump. Thanks everyone for their help, this has def been a learning experience.Name:  20151230_144252.jpg
Views: 1775
Size:  16.3 KB
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: