Coleman Heat Pump blowing cold air

[dshinnick]

Hey all-

We have a 2015 Itasca Sunstar (Winnebago Vista) with a Coleman A/C which also functions as a heat pump.

When in heat pump mode it frequently...but not always....blows hot for awhile then blows cold. Not A/C cold, but ambient-temp cold.

Notes:

1. When it blows cold it never ultimately switches itself off; we have to do it. Makes sense, really, because it never reaches the "set" point.

2. When it does operate normally it blows hot, reaches the correct temp, and shuts itself off.

3. When it starts to blow cold I set the thermostat down a degree below our current temp. It shuts off, as it should. I then set the temp up a degree above our current temp; this kinda "reboots" the unit. After the appropriate cycling delay, it comes back on, hot. For a few minutes, then goes cold again. I can repeat the "reboot", and it does it again: comes on hot, then cold.

4. I have looked at the unit on the roof: all appears fine, no leaf or debris buildup around the unit at all that I can see.

Based on #3, the fact that it comes on warm and then turns cold, I'm wondering if it could be the thermostat on the wall giving erroneous commands to the roof unit. The thermostat says "RV Comfort-HP". Next line: "Coleman Made".


Any thoughts?

Thanks-

Dave

[Hikerdogs]

The roof AC units on some models are also heat pumps. As mentioned earlier the system is reversed when in the heat pump mode. If you get warm air for a short time then it turns cool or cold the evaporator is frosting over.

There should be a temperature sensor stuck in the coil. When it senses the coil has frosted over it will shut down the compressor (fan will keep running) until the frost melts. Either the sensor is defective or it is no longer positioned properly. In most cases it's either a small probe wedged between the fins, or a button that's held to the side of the condensor with double sided tape.

[down_home]

.............

[FIRE_UP]

dshinnick wrote:
Hey all-

We have a 2015 Itasca Sunstar (Winnebago Vista) with a Coleman A/C which also functions as a heat pump.

When in heat pump mode it frequently...but not always....blows hot for awhile then blows cold. Not A/C cold, but ambient-temp cold.

Notes:

1. When it blows cold it never ultimately switches itself off; we have to do it. Makes sense, really, because it never reaches the "set" point.

2. When it does operate normally it blows hot, reaches the correct temp, and shuts itself off.

3. When it starts to blow cold I set the thermostat down a degree below our current temp. It shuts off, as it should. I then set the temp up a degree above our current temp; this kinda "reboots" the unit. After the appropriate cycling delay, it comes back on, hot. For a few minutes, then goes cold again. I can repeat the "reboot", and it does it again: comes on hot, then cold.

4. I have looked at the unit on the roof: all appears fine, no leaf or debris buildup around the unit at all that I can see.

Based on #3, the fact that it comes on warm and then turns cold, I'm wondering if it could be the thermostat on the wall giving erroneous commands to the roof unit. The thermostat says "RV Comfort-HP". Next line: "Coleman Made".


Any thoughts?

Thanks-

Dave

Dave,
Just wondering. I'm not the sharpest tool in the shed but, to my knowledge, Winne stopped using the "heat pump" which, was also kind-a known as a basement A/C unit, way back about 2009 or so. I could be off by a year or so. Now, also, I'm not the most schooled on roof top A/C units but, if that's what you have, is there a *heat pump* in those or, is there just some sort of heat strip type heater in them?
Scott

[DFord]

When your heatpump is in heating mode, the air conditioning feature is reversed. It removes heat from the outdoor air and puts it inside - just the reverse of what it does in cooling mode. This often causes the outdoor coil on the roof to frost over and block the flow of air. As long as it's above freezing, shutting off the compressor and allowing the fan to continue to run defrosts the outdoor coil. If they wanted to be nice, they'd turn on an electric heating element to temper the air indoors while it's melting the frost.

Heat pumps for the home have two different fans - one indoor and one outdoor. When the outdoor unit frosts up, the outdoor fan stops while the compressor and indoor fan continue operating. The system switches back in air conditioner mode and begins heating the outdoor coil. When it warms enough, it reverses again back into heating mode with both fans running. That's a lot more complex than your RV heatpump where the indoor and outdoor fans have to run at the same time because the motor is common to both.

[dshinnick]

But when I "reboot" the system it comes up warm just a few minutes later. And, where can I see this heat exchanger to verify it's icing up?

[carringb]

The heat exchanger on the outside is almost certainly icing up. Unfortunately thats the nature of a compact heat pump, especially if you are anywhere other than a dessert climate. Commercial office trailer heat pumps have a built-in de-ice mode, where it reverts to A/C mode for a few minutes to quickly melt any ice. But your unit probably just needs to be shut off for 5-10 minutes.

[dshinnick]

I should have included this in my original post. This occurs when the temps are well above 40.

[Blaster_Man]

What is the outside temp? Heat pump doesn't work well below 40.