# How to stop auxillary heat from coming on defrost cycle and limit auxillary heat use?



## jsmith929 (Apr 16, 2009)

Easiest thing would be to just buy the outdoor sensor and adjust from that,others can probably give you more advice on the programming.


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## twilightcall (Jan 4, 2008)

The outdoor sensor will only allow me to set it to 40. I think I can get more out of my heat pump than that. IMHO heat strips shouldn't be needed until 25 or so right?


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## JohnH1 (Jan 9, 2009)

In defrost the aux will come on to keep from blowing cold air in the home. Defrost is basicly the same thing as running the a/c in the summer untill the coil is thawed. If the aux is comming on durring normal operation with the heat pump that normally means the heat pump can not keep up on its own and the aux is adding heat in addition to the pump. Is the aux running with the HP or by itself?


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## JohnH1 (Jan 9, 2009)

I missed the 40deg. Yes you can run much lower that that. with electric heat you should basicly run unrestricted. There is no reason to ever lock out the heat pump.


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## Marty S. (Oct 31, 2009)

Disconnect W on the heat pump. You will not bring on the back up in defrost that way. Be forewarned the air coming out of the registers is going to be COLD in defrost with no tempering. Your 2 ton should be able to do all the heating for a 800 sqare foot house down to 10 degrees or so depending on insulation and windows.


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## twilightcall (Jan 4, 2008)

Ideally I would rather the heat strips not come on until absolutely neccessary. They come on in the defrost cycle. I am not 100% sure but I believe with the pump on. If the temps don't get below 32 is there any reason I can't just run off of the heat pump? If so what would be the best way to bypass the aux. heat? 

Also I am not changing the temp at all in the house. I just set it and leave it alone. 

I know I can cut back on the CPH. Would it help if I set the t-stat to option 3 on 680 (room warmer than heat setting)

I am trying to avoid buying a new Tstat. The IAQ looks like the one with the good settings for aux. heat.

Awesome Marty. Thanks for the info. I was writing this when you posted that.


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## twilightcall (Jan 4, 2008)

Marty disconnect W on the outside unit or at the tstat?

We have very good insulation and windows.


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## Marty S. (Oct 31, 2009)

outside unit.


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## twilightcall (Jan 4, 2008)

Is there a wire I can remove at the T-stat instead like the Aux wire or ?. Thanks.


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## Marty S. (Oct 31, 2009)

No you don't want to remove it from the thermostat. An outdoor thermostat is a cheap option to consider. Can hook it up to break aux from the indoor stat so it can't run below x degrees.


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## twilightcall (Jan 4, 2008)

Ok thanks. Don't know alot about outside thermostats but will look into them. 

On my outside unit W1 (1st stage aux heat) should be the white wire.


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## beenthere (Oct 11, 2008)

twilightcall said:


> Is there a wire I can remove at the T-stat instead like the Aux wire or ?. Thanks.


Thermostat doesn't control strips during defrost. So the wire from the heat pump needs to be disconnected if you don't want aux heat during defrost.

The Honeywell IAQ(YTH9421) is the stat you should have gotten.
It would allow you to lock out the strip down to 5°F if you wanted to.

Disconnecting the strips from the stat is a bad idea. If you were to go away and the heat pump fail. You could end up with frozen and broken pipes.

One way you can lock out the aux with that stat until you really need it is to install the outdoor sensor in your house.

You can install it in your return duct if you want, and set it to 60. Then your house temp would have to drop to 60 before the aux came on.

What CPH do you have your heat pump set to. The lower that number, the quicker the aux comes on. But don't set it higher then 4. 

Another thing you can do. Is connect the aux heat to W3 instead of W2. That will delay aux heat longer.


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## twilightcall (Jan 4, 2008)

Awesome info. I greatly appreciate it. I agree the IAQ is the T-stat I should have. I actually got the visionpro 8320 as a gift but at that time I didn't know how sensitive it is and that it wouldn't allow the lower setting of the aux. heat. I would really like the IAQ but I can't buy it right now.

I will have to check on my CPH. I honestly just started learning about this yesterday when I got my second extremely high bill. The CPH hasn't been changed since it was installed so I would guess it would be at what Honeywell has as factory for this t-stat. (8 or 9?) I also don't know what my compressor run time is set to. It is whatever Lenox factory is. (not sure if it is 30min, 60 or 90)

Can the outside sensor be wired in by the indoor air handler? The reason I am asking is my return air duct isn't very long. (maybe 2 feet long) My house is 800 sq feet. 

I could set the aux heat to only 2 CPH but it would still come on when the defrost starts. 
I do want to stop the heat strips during defrost. I think the defrost cycle is 14 mins max for my unit and I think I would be ok with cold air coming out for a little while while defrosting. 

So while I am home could I set the t-stat to 1H/1C heat pump (no aux) to keep the aux from coming on until I can either wire the outside sensor to the return air or get an IAQ. 

Thanks Again.


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## beenthere (Oct 11, 2008)

As long as you reset it if your going away for any length of time(weekend, week etc). You can set it to 1 heat 1 cool. I'd also connect it to the W3 as I said before. So that when you go away, it isn't bringing in the aux heat right away anyways.

Yes, you can mount it near the air handler, or in the duct. The duct doesn't need to be long.

Your heat pump will remove roughly 5600 BTUs in 14 minutes of defrost. Most times it shouldn't be in defrost that long. But, the cooler the house is, the longer the defrost is. Disconnecting the W wire from the outdoor unit won't harm anything though. 

The heat pump default setting is 3 CPH. Aux default is 9(which is a comfort setting, and too high for economy operation).


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## twilightcall (Jan 4, 2008)

Thanks. That is good to know that removing the W wire won't harm anything. Plus I can always hook it back up if I think it gets to cold during defrost. 

Yes I can get it into the air handler with no problem. If I read the manual right it needs 2 wires for the sensor and connect it to S1 and S2 at the tstat? I would need to run 2 wires from the t-stat to the air handler but that is no problem. So basically the 2 wires from the sensor connect to my new 2 wire t stat wire and connect to S1 and S2 at t stat?
Also if I do wire in the sensor would I go into 340 and set it to #2 (outdoor control sensor, select heat pumps)? 

What in your opinion is the best solution? 1. Getting the IAQ when I can afford it and turning off the aux. heat (by selecting 1h/1c no aux) and defrost (disconnect W wire) until I can change t-stats? 

2. Keeping the 8320 and wiring in the sensor in the return air and setting it for 60 and I would still disconnect the W wire at the outside unit to stop the aux. in defrost.


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## beenthere (Oct 11, 2008)

When you install the sensor. Don't run the stat wire for it near any high voltage wires, it will interfere with the stat.

I would keep the 8320. Unless you have a VS blower.

340 gets set to 2.

If you find that having the sensor in the duct, and the lock out set to 60 allows your house to get too cold.

Then lie to the stat. By adding a 1500OHM resistor in series with the temp sensor, and it will think its 60° when its 65°. Or add a 2000OHM, and it will think its 60 when its 67°.


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## twilightcall (Jan 4, 2008)

Thanks. That is excellent info. 

Would you wire the resistor inline on 1 wire going to S2 or would I need to wire in 2 resistors one in each line. 1 for S1 and 1 for S2.

Does my wiring look correct? Thanks Again.


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## beenthere (Oct 11, 2008)

Thats the correct way in he drawing.


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## twilightcall (Jan 4, 2008)

Great. Thanks. I appreciate it. I went home for a minute and checked the t-stat settings. 

0170 is set to : 7
0200 : 0
0220 : 3
0240 for some reason wasn't listed
0250 : 9
0270 : 9

So I think I need to change 0270 to 2 and 0250 to 4 right? 

When I removed the t-stat I couldn't find a W3. I have a W2 that my Aux is on. Is there another letter it could be or another place to switch it to?

So, my plan is to take your advice and get the outside sensor, put it in the return air and continue to use my 8320.


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## beenthere (Oct 11, 2008)

240 is if you have a dual fuel system.
You can set 220 to 3 or 4. 4 won't bring in aux as quick as 3.
set 250 to 2
270 to 3

Ooops. The 8320 doesn't have W3. The IAQ does.


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## twilightcall (Jan 4, 2008)

220 says 1st stage compressor cyc. rate : is that for the compressor when it is on air conditioning or does that include heat also for heat pump? 

250 says second stage heat cycle rate so is this my heat pump cycles or aux cycles?

270 is emergency heat cycle this is aux heat strips cycle? 

I just want to make sure I got this 100%. '

Is there any place else to move the aux heat or just leave it on W2? Thanks AGain.


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## beenthere (Oct 11, 2008)

twilightcall said:


> 220 says 1st stage compressor cyc. rate : is that for the compressor when it is on air conditioning or does that include heat also for heat pump?
> 
> For both heat and cooling.
> 
> ...


No other place on that stat.


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## twilightcall (Jan 4, 2008)

Ok so 250 and 270 are the same but you can set them for different cycles but they still run the aux. heat?

Do you have any special resistor you like to use or is radio shack etc. fine?


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## beenthere (Oct 11, 2008)

250 controls aux/W2 terminal.
270 controls the E terminal.

If you don't have a wire on the E terminal(or a jumper from aux to E), you don't have emergency heat.

No special resistor needed. Radio Shack is fine.


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## wkumtrider (Jan 30, 2010)

I've been having the same issue with my heat pump. The aux heat comes on too much and is jacking up my electric bill. I have an Armana heat pump and a Honeywell RTH2510 stat. I'm trying to figure out how to use the aux heat less. My aux heat is attached to W on the t-stat. Can I just disconnect this and eliminate the aux heat?


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## Marty S. (Oct 31, 2009)

wkumtrider said:


> I've been having the same issue with my heat pump. The aux heat comes on too much and is jacking up my electric bill. I have an Armana heat pump and a Honeywell RTH2510 stat. I'm trying to figure out how to use the aux heat less. My aux heat is attached to W on the t-stat. Can I just disconnect this and eliminate the aux heat?


 If you want to, sure. The heat pump alone might or might not heat your house to the desired temp when it gets cold out though.


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## Mr Dodge (Feb 6, 2010)

Wku, Before you unhook your aux. heat I would compare usage to last year. Elec. rates have went up. JMO


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## beenthere (Oct 11, 2008)

wkumtrider said:


> I've been having the same issue with my heat pump. The aux heat comes on too much and is jacking up my electric bill. I have an Armana heat pump and a Honeywell RTH2510 stat. I'm trying to figure out how to use the aux heat less. My aux heat is attached to W on the t-stat. Can I just disconnect this and eliminate the aux heat?


Are you setting the temp back at night, and or when you go to work, and then having it recover to a higher temp. Don't do that with a heat pump.

Or is it just coming on during normal heat calls?

Could be your heat pump can't maintain temp at your current outdoor temps.


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## wkumtrider (Jan 30, 2010)

Right now I do have the t-stat programmed to change throughtout the day. At night it goes down to 62, stays that way all day while we are gone, and jumps up to 67 around 6:00 Pm when we return home. However, aux heat always comes on during normal heat calls. Temps right now are around 20 at night and 30-31 during the day. The bill is much higher than last year. Last year I also had a Rite Temp t-stat that did not use the aux heat nearly as much as the current honewell. Replaced the Ritetemp because touch screen went out.


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## beenthere (Oct 11, 2008)

wkumtrider said:


> Right now I do have the t-stat programmed to change throughtout the day. At night it goes down to 62, stays that way all day while we are gone, and jumps up to 67 around 6:00 Pm when we return home. However, aux heat always comes on during normal heat calls. Temps right now are around 20 at night and 30-31 during the day. The bill is much higher than last year. Last year I also had a Rite Temp t-stat that did not use the aux heat nearly as much as the current honewell. Replaced the Ritetemp because touch screen went out.


Heat pumps with electric aux heat. Shouldn't have their thermostats doing set backs. Since it brings on the strip heaters to recover, and uses more electric then you saved.

At 20 degrees outdoor temp. The heat pump most likely does need the aux heaters to maintain temp.

Your ritetemp stat, probably had a 2 degree differential before bringing on the aux heat. hat Honeywell doesn't.

Stop using the set back. And your electric bill will drop.

Check your electric bill for temps this year to last year. You may find your having a colder winter.


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## wkumtrider (Jan 30, 2010)

You are right about the Rite Temp. You could adjust the temp differential in .5 degree increments. This winter is colder than last year. I'll set the stat to stick with one temp and see how that works. Thanks for the help.


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## beenthere (Oct 11, 2008)

Your welcome.


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## wkumtrider (Jan 30, 2010)

By the way, what is your opinion on Ritetemp stats? The one I had was nice until the touch screen went out.


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## beenthere (Oct 11, 2008)

Personally. I don't like them. I prefer Honeywell.


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