2002 Journey 37DL, AC on when elec heat on?

[medarwin]

Hello,

I haven't had much occasion to use the heat pump (elec heat) in this unit but when I did last week, the overhead AC came on and stayed on. This unit has the basement residential style heat pump/AC unit. No matter what I did, anytime the thermostat switch was moved to Elec Heat, the AC unit pushes out cool air from the top and somewhat warm air from the floor ducting. Switching the unit to the conventional gas heat position results in warm air from the floor ducts. I am trying to determine whether this is a thermostatic issue or a heat pump issue. I bought the coach in January and at that time the roof ducted heat worked.




Has anyone experienced this? I'm at a loss to figure this one out. Also cross posting this on the General forum under problems.

Many thanks if anyone can shed light on this. Darwin

[slapfoot]

It is working as it is supposed to. If you let it run a while, heat will come from your ceiling ducts. Only heat from the furnace will come from the floor registers. I always set my fan speed to low when using the heat pump portion of the unit. If no heat comes after running a while, you have other problems.

[medarwin]

It will actually bring the temp down in the coach if I let it run long enough. The air coming through the floor ducts is very low volume, not at all what the force is when the gas furnace is on. Frustrating. I am wondering if a fault in the thermo is telling the heat pump to do this?

[JaminSamin]

medarwin - I copied this from my ac/heat pump manual for model 6535 series. I'm guessing that is the unit that's in your Journey.

9. A TYPICAL HEATING CYCLE OF THE HEAT PUMP
(Electric Heat Mode)

Begins with a call from the wall thermostat for Electric Heat.

Indoor fan starts on High Speed.

Both reversing valves switch to heat mode.

Compressor 1 starts.

Outdoor fan starts 2 seconds later (Low Speed).

30 seconds later the Heat Pump circuit board will energize the
Compressor Relay #2.

Compressor 2 starts, the outdoor fan goes off (subject to
available 115 volt power supply).

Outdoor fan starts again 2 seconds later (High Speed).

Both systems (compressors) operate to satisfy the thermostat.

Both compressors shut off at set point temperature. (Mine shuts off one degree above what the thermostat is set)

If the Heat Pump is unable to maintain the coach temperature,
the thermostat will automatically cycle the furnace on. The
new True-Air Thermostats (Electric Heat Mode) will call for
second stage (Furnace) heating operation anytime the
temperature inside the coach is more than 5 degrees cooler
than the customers chosen setpoint temperature. It is entirely
possible the furnace and the heat pump may both operate at
the same time to satisfy the thermostat.
[end]

Remember your basement AC and electric heat pump will only discharge from the ceiling, the propane furnace from the floor...period.

What I think is happening is you are calling for electric heat but asking for too much temperature initially. This triggers the propane furnace to help (not necessarily a bad thing) that is why you get ceiling and floor at the same time.

If you want the electric heat pump to come on all by itself you should set the thermostat to no more than four degrees above what the thermostat says the room temp is. Remember the colder the outside temp the less effective the heat pump will be. Mine works down to 38 degrees but not all are the same you'll have to experiment. Be patient the colder it is outside the longer it will take the heat pump to start producing heat, it may take a few minutes.

Once it starts to throw heat and the thermostat temp starts to rise you can increase the thermostat (maintaining the four degree or less temp cushion). That will keep your propane furnace from cycling on.

I hope this wasn't to long winded and helps.

[slapfoot]

Yup, mine works just like JaminSamin said.

[AFChap]

I agree it sounds like your unit is running as designed.

Electric heat = heat pump, which sounds & acts just like the ac since it is the same unit. It uses Gas heat to bring the temp up faster when needed. And when the outside temp is cold enough (around 38-40 depending on humidity) the heat pump will lock out and you get LP furnace only.

Gas heat = LP furnace(s) only

On mine, if you set the desired temp more than 3 degrees warmer than the t-stat display temp, it will run both electric heat and gas heat until the desired temp is reached.

When running the heat pump, the air from the overhead ducts will feel cool at first, but will get warmer as the unit runs.

[medarwin]

I understand and agree with all the above responses. Trouble is, the "heat pump" actually lowers the temp inside the coach if I leave the "heat"on. I can't determine whether this is conditioned, chilled air or just outside ambient air. Either way, it appears that the basement unit is malfunctioning, either by sensing a call for cold air from the thermo or just blowing in outside air because the heat pump compressor is not engaging.

Darwin

[smlranger]

What is the ambient temp outside? If it is below about 38 - 36F, the heat pump will not provide heat....or very little heat. If you have it in the Elec Heat mode, and the heat pump cannot raise the temp, the LP furnace should kick in and provide heat from the floor vents.

Or, you might have a bad reversing valve in the AC/Heat pump unit.

We owned a 2002 Journey 36DL for 8 years and the heat pump did a better job of heating than it did of cooling in warm weather.

[AFChap]

Two ways to tell is a compressor is kicking on:
- On 30a shore power OR on generator power, watch the amp meter on the OnePlace center. One compressor will pull apx 17a. If the second compressor kicks on apx 1 1/2 minutes later, both together will pull apx 24a.
- OR, listen closely when you turn it on. In heat pump mode, the compressor kicks on slightly BEFORE the inside blower. In ac mode, the inside blower comes on before the compressor.

[JaminSamin]

Medarwin - did you ever get to the bottom of what was happening?

[medarwin]

Actually, no. The temps here in NC finally started dipping enough at night to experiment a little. Here is what is happening:
Heat pump activated on electric heat. Blows cold, conditioned air through ceiling vents. Air very cold, using a hand held fridge thermometer it appears to be around 50 deg. Temp inside coach begins dropping. Once it passes the magic mark of 5 degrees less than the set temp on the thermo, the gas furnance kicks on and starts to fight the AC. Essentially I have two systems working at cross purposes.
I am fairly certain this is either the reversing valvr itself or the solenoid or relay that controls the reversing valve. I have no idea how to test this and have not had any luck searching for information on how to do this. Open to suggestions and help.

Thanks, Darwin

[tmw188]

Just for testing purposes I would bring the coach up to temp with the LP furnace, once satisfied I would set the heat pump setting two degrees only higher than the room temp and see how it functions them. I agree with the others comments but I have the OEM stat with my basement air and it seems to work around that two degree difference.

[JaminSamin]

It sounds like your indoor blower is working but it's just blowing unheated air. This could mean your compressors aren't starting and or remain running. I've attached a picture of my control board opened up and marked a few things in case you want to do a basic check of the capacitors and see if the compressors are starting.

Start by Lifting up and securing the grill covering the basement ac heat pump unit. Remove the service panel. What you see should be similar to the picture I attached.

With the thermostat set to elec heat and 2 degrees above the ambient temp on the thermostat put a clamp meter on #1 the black wire and see what kind of amps compressor 1 is pulling. After it starts and settles out it should be anywhere between 6-8 amps. If it shows less or nothing you may have a bad start and or run capacitor, pull them both test and replace it needed. If you get the 6-8 amps and it holds move the clamp meter over to #2 the orange wire to #2 compressor it should start 30 seconds after #1. The amp draw should be very close to #1. If not check the capacitors for #2 compressor.

It's a start, if your lucky it's just capacitors that need replacing. I hope this helps, let us know what you find.

1 - Black wire from #1 relay to #1 compressor
2 - Orange wire from #2 relay to #2 compressor
A - Start capacitor for #1 compressor
B - Start capacitor for #2 compressor
C - Run capacitor for #1 compressor
D - Run capacitor for #2 compressor

[tmw188]

Thanks for posting that great information with photos.