Heat pump cycling


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Old 11-12-07, 02:30 PM
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Unhappy Heat pump cycling

I had a heat pump (fridgidaire 4 ton) installed with a Honeywell Vision pro th8320u thermostat 1 year ago. The house is heated and cooled very well but the heat pump cycles every 10 minutes right to the second. The temperature in the house does not change. I've had my system checked out by a profesional and everything is set properly but he agrees that the cycle is too often and can not come up with a solution.I'm in the process of buying a new thermostat but that is costly. I'm worried my elecric furnace fan motor and the compressor on the heat pump will wear out with the frequent stars and stops. Any suggestions?? Thanks:
 
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Old 11-12-07, 09:18 PM
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That is the best stat you can ever own..

go into the advance set up menu, and report back to me of what settings everything is at.

do you have an outdoor sensor on this?
 
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Old 11-13-07, 06:39 PM
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Settings

These are my settings:
0160- 0 0510- 0
0170- 7 0510- 0
0180- 1 0520- 0
0190- 0 0580- 5
0200- 1 0600- 32
0210- 0 0610-18
0250- 9 0650-90
0280- 1 0660-90
0300- 0 0680-2
0320- 1 0690- 2
0330- 1 0700- 0
0340- 2
0350- -9.5
0500- 0 Yes I have an outdoor sensor which gives
me the compressor lockout at -9.5 C.for the electric furnace to kick in.
 
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Old 11-13-07, 08:40 PM
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What is your back up heat? Gas or electric?

I didn't see #220 setting??
 
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Old 11-13-07, 10:09 PM
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My backup heat is electric forced air. I must have missed 220 but its set at 3. I've tried 1 and 2 and it made no difference:
 
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Old 11-13-07, 10:29 PM
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200 should be set to 0, It was set for Gas back up.

220, I'd set it to 2, and let learn for a few days, this is a learning t-stat.

250, Book says 9, but I like 4.

360, set to 7˚c? (40˚f)

500 is filter reminder, are you GOOD about changing the filter? if no, set to 2.
 
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Old 11-14-07, 07:49 AM
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The tech. that came out told me that I have to have 200 set at 1 cause I can't have my heat pump running at the same time as my forced air cause my unit that sits inside the furnace is mounted above my furnace elements. This give me my access to the compressor lockout. I'll try setting 220 from 3 to 2 and see if any difference. Is not the 250 for my furnace cycle rate? I don't have a 360 setting; but my 350 setting is at -9.5 and I'm getting the heat from my heat pump at that setting. My heat pump heats the house to the temp. set and shuts off than starts up again in 10 minutes; like the house has lost the 1 degree , but the temp in the house has not dropped per all my other thermomators. If the house would not heat up the heat pump would continue running. It does shut off and the house is warm at the temp. set.
 
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Old 11-14-07, 08:10 AM
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Originally Posted by somenolig View Post
The tech. that came out told me that I have to have 200 set at 1 cause I can't have my heat pump running at the same time as my forced air cause my unit that sits inside the furnace is mounted above my furnace elements.
Is this air handler an older model that was electric heat only and you later added the heat pump to it?

Is not the 250 for my furnace cycle rate?
Yes, it is. Even tho the book is suggesting 9, but no point cycling the air handler 9 times an hour.
I don't have a 360 setting;
That because 200 is set to 1, if it was set to 2, then it would show. 360 is Aux heat lock out.. meaning the aux heat will not come on above the temp you set it at.

My heat pump heats the house to the temp. set and shuts off than starts up again in 10 minutes; like the house has lost the 1 degree , but the temp in the house has not dropped per all my other thermomators..
Honeywell is a smart t-stat. They do not do the swing, so that's why you don't see the drop of temp. Your body can feel the temp swing.. being that it's not running long, you are not at 50% system capacity.. So it must not be be too cool out yet.. if it's very cold out and cycling often, then you got an oversized system.
 
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Old 11-14-07, 10:47 AM
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Wink

I can't have my heat pump running at the same time as my forced air cause my unit that sits inside the furnace is mounted above my furnace elements.
lost here??? The elements have to come on and run when the unit is in defrost. Also when the H/P cant keep upwith the home the elements will come on to help.
 
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Old 11-14-07, 05:41 PM
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That Honeywell Vision Pro 8320 is a wonderful piece of equipment no doubt. I dont think that I would trade thermostats.
When you are saying that the unit cycles every ten minutes to the second. Exactly what do you mean? Is that Runs ten minutes then off for ten minutes?? Run 45 minutes then off ten minutes?? Run ten minutes off 45 minutes etc.?? That really sounds unusual that the ten minutes is within seconds. Please post back I am curious.
 
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Old 11-14-07, 07:01 PM
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I haven't timed the running time but i think it varies. Its the off time . The heat pump will cycle on after being off for ten minutes
 
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Old 11-14-07, 07:14 PM
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Yes the air handler is older and the heat pump was added to it. I guess its the same on the 350 or the 360 setting whether you lock out the heat pump or the aux. heat. The heat pump defrosts on its own and does not use the electric forced air furnace elements. Thats the one draw back of this thermostat that I've been told is that the forced air furnace can't be activated to bring up the temperature automaticly. Its one or the other.
 
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Old 11-15-07, 01:40 PM
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Good thread, I had my Trane HP installed yesterday. I came home from work early today and noticed my run times were around 7 mins on 25 off. Its about 45 out with the thermostat (Trane 802 Thanks to Jay I know this is the same as the Honeywell) at 69 degrees.

I was thinking they were too short so I looked in the manual to see if there was a way to make it run longer and come on less times. I didn't see one so then I came here and remembered that it has to learn for a bit and then will fix itself. After a week or so and when it actually gets cold I will revisit the settings menu.

BTW Thanks for all the help you guys gave me. I got a correctly sized system, I sealed all my ducts, going to be adding insulation to my attic, and finding other sources of Heat/Cool loss.
 
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Old 11-15-07, 05:55 PM
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Defrost and Aux heat coils

Quote "Thats the one draw back of this thermostat that I've been told is that the forced air furnace can't be activated to bring up the temperature automaticly. Its one or the other."
somenolig typically the heat pump defrost is not controlled by the thermostat at all. Most units will have a low voltage wire from the defrost board on the outside condensor that will need to go back to your auxilary heat coils, this is what should pull in the auxilary heat upon in defrost mode not the t-stat. The t-stat (if wired correctly to a heat pump with electric heat auxilary coils) will control the auxilary heat during normal operation. When the heat pump cannot keep up and the room temp drops 2 degrees below the t-stat set point it will call for aux heat coils to kick in and the heat pump will continue to run. I am not familiar with that brand of heat pump but I assume it is a typical unit. If you have the original installation manual you can probably flip thru it and find out what you have for yourself in a few minutes. Typically they will have a section that describes the sequence of operation for when the heat pump goes into defrost mode. You will probably also see a recomendation in the book for not hooking up the aux heat coils to operate during defrost feature (for most economical operation) those little electric coils can really use some serious electricity.
 
 

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