Heat pump dropping out

Pushrod · 05-27-2007, 08:29 AM

My heat pump (Electric Heat) tends to drop out and switch to Gas periodically. I know that you can't raise the set temp. more than four degrees more than the room temp. Sometimes it will start on elec., raise the room temp maybe one degree, then switch to gas; sometimes it may raise the room temp. to the set, then when it should turn itself back on, it will switch back to gas. Most times once it has switched to gas, there is no way I can get the elec. heat to come on again. Any ideas or similar problems? My previous 36G never did this at all.

Pushrod · 05-27-2007, 08:29 AM

My heat pump (Electric Heat) tends to drop out and switch to Gas periodically. I know that you can't raise the set temp. more than four degrees more than the room temp. Sometimes it will start on elec., raise the room temp maybe one degree, then switch to gas; sometimes it may raise the room temp. to the set, then when it should turn itself back on, it will switch back to gas. Most times once it has switched to gas, there is no way I can get the elec. heat to come on again. Any ideas or similar problems? My previous 36G never did this at all.

JB Texas · 05-27-2007, 08:42 AM

If the outside air temp gets too low the heat pump is ineffective.

From my Owner's Manual:

"If the furnace must assist the heat pump three times in a row, the thermostat will shut down the heat pump for two hours and the furnace will take over asw the heat source. After two hours the heat pump will become active again and try to be the primary heat source."

Sounds like your system might be working normally.

BTW, I like your avatar. I was a P2 sailor at Whidbey as the P5's were phasing out.

vicsryd · 05-27-2007, 09:45 AM

What you are describing sounds like the logic that occurs when the heat pump is unable to raise the temperature in the coach.

Has this happened three times in a row and then the heat pump locked out completely for two hours? See page 8 of the service manual for a detailed description of the scenario that might apply to your situation.

If the outside temperature is above 35 degrees and this is occurring then there is probably a technical problem that needs to be addressed. I suggest before taking it to your Winnebago dealer contact RV Products service/support first and review the situation, your warranty status and, if necessary, a suggestion of where you should really go in your area to get it repaired.

Pushrod · 05-27-2007, 12:51 PM

Thanx for the input, I'll re-read my manual. Also the outside temperatures were from the mid 40's to the mid 50's. I know that if the outside temp is too low, it will affect the heat pump operation. This is the same unit I had in my Meridian and I never had this particular problem. I guess I will have to take it to my dealer, as it was looked at when we were at the factory, but maybe I didn't give them enough information, or it is one of those dreaded intermittent problems. We were the last (VP-47) unit to operate out of Oak Harbor; if you haven't been to the Seaplane Base recently, there is a wonderful Patrol Squadron Memorial there now. I think it was spearheaded by some of VP-2 members.

jimandsue60 · 05-27-2007, 07:15 PM

Could it be an amperage thing? I know ours acted a bit funny when on 30 amp service and trying to run some other items on shore power.

Seemed like the 2nd stage for the heat pump could not start because of amperage. It would start on the 1st stage and start to heat but because there wasn't enough amperage the 2nd stage would not start. The gas heater would then start, like jbtexas said, after 3 tries for the 2nd stage to start the system will lock out the entire heat pump system for 2 hours.

Are you hooked up to 30 or 50 amp? Try running it with the shore power disconnected and using the generator.

Jim

paz · 05-28-2007, 05:15 AM

It could also be a voltage problem. Even if you are hooked up to 50 amp, the high current draw of the air conditioner could cause the voltage to drop. This is especially true if you are on a long run far from the main supply. There may be too much resistance in the wire. If you have an AC volt meter, check the voltage next time you have a problem. If it isn't at least 108 volts of so, that isn't enough voltage to run the air conditioner.

Pushrod · 06-11-2007, 09:08 AM

I have done a little more investigation on my problem, and by the way, I have an appointment for service in acouple of weeks, just hope the gremlins are still there when we take in for service. Okay, outside temp was 58 degrees, inside room temp was 62. Set the ELEC temp to 65. Heat pump did come on, room temp got to 65, then gas heat also came on, both ran for a couple of minutes, then shut down. The room control was still set on ELEC, but only the gas(floor) unit would come on if the set temp was raised only two degrees. My Meridian would not do this, the only time the gas would override the elec was when you raised the set temp more than four degrees than the room temp. Any ideas?

RV Wizard · 06-11-2007, 11:49 PM

A freeze sensor on outside coil will terminate heat pump operation and bring on gas mode. Based on the relative humidity of the time it may or may not casue this condition. Check voltage, amperage, temperatures, humidity of when you have the trouble and whether or not you may have shed through EMS so the tech can analize it correctly if it turns out to be intermitant.

tomsm · 06-12-2007, 03:23 AM

Since you're experienced with the nuances of this system from your Meridian, and probably operated it in the same environmental conditions, my guess is just a bad thermostat. Mine was replaced for just the opposite condition - it would never call for help from the gas heater. That was 2 years ago and no more problems.

Pushrod · 06-26-2007, 12:02 PM

Okay, will be to the dealer in two weeks.... Did some more investigation this last outing. I was on 30amp shore power, and my digital plug-in meter in the coach told me I had 60cycle/115vac. When the heat pump came on, the voltage would start gradually dropping, low enough (down to 99vac) that the meter would signal an alarm for low voltage. When the acv got down to 104, the thermostat would call for gas heat. My theory is that the compressors are heating up, and dragging so much that they are causing the voltage drop, triggering the call for gas heat.Hopefully this "gremlin" will appear at the service dept.

Ray,IN · 06-28-2007, 01:11 AM

Anytime a motor, or in your case compressor motor, which is designed to operate at 120VAC, operates at less than 108 VAC it is sustaining damage. I don't know where the 99VAC alarm you mentioned came from but it is incorrect.