Heat: Gas & Heat Pump together?

SCVJeff · 05-21-2007, 05:50 PM

I just turned the heat pump on to excercise it a little ('06 Meridian), and noticed that the propane heater came on as well. The manual shows that it's either one or the other, correct? I "think" the only commonality between the Heat Pump and the propane is the thermostat. Has anyone run across this?

SCVJeff · 05-21-2007, 05:50 PM

I just turned the heat pump on to excercise it a little ('06 Meridian), and noticed that the propane heater came on as well. The manual shows that it's either one or the other, correct? I "think" the only commonality between the Heat Pump and the propane is the thermostat. Has anyone run across this?

Norm Newhall · 05-21-2007, 06:51 PM

Somewhere in that same manual, it should explain that if the difference between ambient temperature and thermostat setting is 5 degrees or more - both heat sources will come on. On the next cycle, it will be the heat pumps alone...........

SCVJeff · 05-21-2007, 07:42 PM

Makes sense, and I just found the sentence explaining it. Originally when I looked at the flow chart I thought it curious that it appeared to be only one or the other. Thanks!!

AFChap · 05-22-2007, 06:42 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">5 degrees or more </div></BLOCKQUOTE>
Believe that is 3 degrees on mine. Sometimes I wish it were more ...3 isn't much! Many times, when I get up in the morning I move the thermostat up 3 degrees to get the heat pump on but not the LP furnace, then go back before it turns off and move it up a couple more degrees. The less LP I have to buy, the better!!

Izzyblueye · 05-23-2007, 03:48 AM

I do the same exact thing. PIA, wish they would in their infinite wisdom had allowed for a lock out on the propane. I understand under certain circumstances why they programed it the way they did. However, we should be able to by-pass this feature.

CaptChet · 05-23-2007, 06:26 AM

I am not an expert but I think that the reason they have the system wired to work both at the over 3 degree differential is so that the Reverse Cycle System will not be overworked, trying to make up, say, a six degree difference. The System functions well on slight increases but becomes overworked and possibly damaged if called on to function for an extended period as required to make up six degrees.As noted above, I am not an expert, but I do have several degrees from the University of Life's Experiences.

Kiwi · 05-23-2007, 10:12 AM

I think the feature is more of a "safety net".

Think about this. The thermostat has no outside air temp sensor, but the HP does. If it is too cold outside, the HP will refuse to start.

Even though the T stat on "Electric" mode, if the difference you are calling for is greater than a set amount (mine is about three degrees) the gas will kick in.

If this did not happen, the rig could get very cold inside before a deep sleeper like me would wake up -- this could be uncomfortable for small children and pets who depend on us to keep them warm.
Walt

Izzyblueye · 05-23-2007, 11:37 AM

Yes the feature is a "Safety Net" and a good one. However, when the outside temp is well within the operating range of the heat pump this rule still applies. I just think we should be able to override it and not have to do it with the thermostat within such rigid confines.

TXiceman · 05-23-2007, 06:11 PM

A heat pump is basically an A/C running backwards. It has to have a heat source to pick up the heat and move it indoors. If the outside temperature is too low, typically about 35 to 40 dF, the heat pump will shut down and go to auxiliary heat.

The definition of air conditioning is the removal of heat from an area where it is objectionable and rejecting it to another area where we don't care. In the case of a heat pump, we want the heat in the out side air, so we use an A/C unit in reverse mode to take advantage of this ability and reject the heat indoors where we want it. Once you are around 40 dF, there is not enough heat available in the outside air to make the system work. You will see the outside coil ice up and you will have to shut the unit down, or some actually have electric heaters to deice the coil.

This is a pretty simplistic explanation, but hope it helps.

Ken