Relay board?

I Have a Duo-Therm unit in my 2000 Dutchmen Voyager Pop up camper.  When I turn the thermostat on the fan blows, but I do not get any heat when it is set to heat and I get no AC when it is set to AC.  I did discover that there is no propane line that runs to this unit, so it must have electric heat which I do not fully understand.  I was told the relay board might be bad.  Would the relay board being bad possibly cause it to not heat or cool?  I've researched the model online and found relay boards, but I don't see a way to get to the board from the outside of the camper so I am thinking I may have to pull the counter up to get to it.  I have attached a screen shot of the back sticker.  Any advice is appreciated.  Thanks in advance.

*Edit:
This wouldn't be a unit that also needs DC to run the control board would it?  I am having trouble finding a manual for this specific one, but I have a battery box with no battery in it and wire hook ups.  I thought mainly it was for the lights and there is a DC option for the fridge if you go somewhere with no electric hook ups.

Unfortunately I can?t help you regarding the problem you?re having, but the reason you don?t have a propane line to the unit is that it?s a heat pump - essentially it runs one way to make cold air and the other way to make warm air, all done with just electricity. Typically RV heat pumps can make warm air down to about 30 degrees

Sun2Retire said:

Unfortunately I can?t help you regarding the problem you?re having, but the reason you don?t have a propane line to the unit is that it?s a heat pump - essentially it runs one way to make cold air and the other way to make warm air, all done with just electricity. Typically RV heat pumps can make warm air down to about 30 degrees

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Thank you for the response, that is one more thing I have learned from you all

IS the thermostat wall or ceiling mounted.
Wall T-Stats often control multiple devices. LIke a Roof top A/C and a basement or main floor Furnace.

Some Air Conditioners have the ability to control a furnace (Carrier Air V with I/R Remote)

John From Detroit said:

IS the thermostat wall or ceiling mounted.
Wall T-Stats often control multiple devices. LIke a Roof top A/C and a basement or main floor Furnace.

Some Air Conditioners have the ability to control a furnace (Carrier Air V with I/R Remote)

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Thermostat is mounted on the wall by the door,  It handles AC and heat.

*Update*

I took things apart just so I could mess around and I don't know what I did but when I turn the heat on, it blows out legit hot air for 15-20 seconds and then it starts to cool down, but you can definitely feel that it is hot air, same for AC, when I switch on the AC now you can feel it comes out cold unlike just air blowing but only lasts 20-30 seconds and then the air warms up just like a fan blowing.  I feel I am getting somewhere and trying to avoid taking it anywhere for service as it just isn't in the budget right now.  Thanks for any help.

Since you get 20-30 seconds of proper operation, whether heating or cooling, it sounds as though the compressor cuts out after a bit of load. It probably has an internal breaker for over-pressure and maybe one for thermal overload as well.  Neither is user-repairable and generally not worthwhile to have professionally repaired either. Those units are not designed to be repaired except to replace a circuit board or the fan motor.

Since you now know the fan starts and the compressor engages in both heat & cool modes, it seems to me there is no reason to suspect the circuit board or fan.

Gary RV_Wizard said:

Since you get 20-30 seconds of proper operation, whether heating or cooling, it sounds as though the compressor cuts out after a bit of load. It probably has an internal breaker for over-pressure and maybe one for thermal overload as well.  Neither is user-repairable and generally not worthwhile to have professionally repaired either. Those units are not designed to be repaired except to replace a circuit board or the fan motor.

Since you now know the fan starts and the compressor engages in both heat & cool modes, it seems to me there is no reason to suspect the circuit board or fan.

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Ok thanks for the response.  Was really hoping it was something I could fix myself.  I'm debating pulling it out and buying a standard window AC unit and installing in there.  Do people have any luck doing that?

NFranzen said:

*Edit:
This wouldn't be a unit that also needs DC to run the control board would it?  I am having trouble finding a manual for this specific one, but I have a battery box with no battery in it and wire hook ups.  I thought mainly it was for the lights and there is a DC option for the fridge if you go somewhere with no electric hook ups.

Click to expand...

RVs are meant to be operated with a battery in place, even when you are planning on always being plugged in. I would suggest getting an inexpensive ?marine deep cycle? at Walmart, Costco, Sam?s etc and seeing how everything works with the battery installed

The thermostat needs 12vdc, and probably the a/c controller board as well.  If your lights work without a battery installed, the pop-up must have a 12v converter that produces 12v power when plugged to shore (120v external) power. That will supply any 12v needs for the thermostat and a/c as well.

Gary RV_Wizard said:

The thermostat needs 12vdc, and probably the a/c controller board as well.  If your lights work without a battery installed, the pop-up must have a 12v converter that produces 12v power when plugged to shore (120v external) power. That will supply any 12v needs for the thermostat and a/c as well.

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Yes there is a 12v converter as the lights work when plugged in.  You mentioned before about the compressor possibly being bad and not worth fixing, but what about the heat, it does not use the compressor to my knowledge does it?  Why would it heat for 20-30 seconds and then stop?

NFranzen said:

but what about the heat, it does not use the compressor to my knowledge does it?  Why would it heat for 20-30 seconds and then stop?

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A heat pump does use the compressor to make heat as well as cold

Sun2Retire said:

A heat pump does use the compressor to make heat as well as cold

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Ah ok, I did not know that.  Thank you.  Any cons to just buying a home window AC unit and installing it in the same place?

NFranzen said:

Any cons to just buying a home window AC unit and installing it in the same place?

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I?m not familiar with your rig or the setup so others can better comment. With a straight AC vs the heat pump you have you would lose the ability to heat unless you also have a furnace. It seems like you would have a furnace as RV heat pumps only work down to about 30 degrees at which point you have to switch to a furnace (or possibly your unit has heat strips which would also work). Again, others could better advise here so I?m sure they?ll chime in

Sun2Retire said:

I?m not familiar with your rig or the setup so others can better comment. With a straight AC vs the heat pump you have you would lose the ability to heat unless you also have a furnace. It seems like you would have a furnace as RV heat pumps only work down to about 30 degrees at which point you have to switch to a furnace (or possibly your unit has heat strips which would also work). Again, others could better advise here so I?m sure they?ll chime in

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No unfortunately ours just has the heat pump, no furnace or anything.  I don't think the heat would be an issue, we mainly need AC.  We have a space heater we can take and use towards the end of the season if necessary.

Here you go:
https://www.manualslib.com/manual/897652/Duo-Therm-Cool-Cat-410001-511.html?page=2#manual

Koodog said:

Here you go:
https://www.manualslib.com/manual/897652/Duo-Therm-Cool-Cat-410001-511.html?page=2#manual

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Yes I have looked through that manual thank you, I have a 611 but I doubt there is much of a difference.

It's called a "heat pump" because it literally does pump heat in either direction. If pumping heat from the interior to the outside, it is cooling, but if pumping it from the outside to the interior, it is heating. Same compressor, just different direction of heat flow.  Think of it as heating being the "reverse" of cooling. There is plenty of heat in the outside air even on days we consider cold, e.g. 38-45 degrees.

Not all roof a/c units are heat pumps, but your particular model of DuoTherm is one.
The Duotherm heat pumps have an outisde temp sensor that shuts the compressor off if the temperature drops below 40. It's conceivable that sensor has failed and thinks it is too cold outside.  It's also possible that the system itself has a problem and the excessive pressure failsafe built into it is causing the compressor to stop (before it destroys itself).  An RV a/c pro could probably determine that, but most RV techs aren't a/c specialists and so they simply replace units that don't work well.  You could perphaps do it yourself, using either a new or used (from an RV salvage yard).

You can stick a window a/c in if you have a place for it and can secure it adequately for travel.  It does what it does, as far as cooling is concerned, and a 5000-6000 btu unit may well be sufficient, even though your existing unit is probably 12,000 btus.

Thanks for the info and schooling Gary, I appreciate it

I believe you mentioned your system is installed under a counter, typically called a "basement" system.  My son-in-law removed his failed under-the-counter factory air conditioner in his Pop-Up camper and replaced it with a small window style unit, about a 10,000 BTU.  He used the 120VAC wiring that was connected to the factory ac unit, making the connection within a standard metal junction box. The AC power was fed from a circuit breaker in the camper's power panel.  The other thing that needed to be done was to make sure the replacement window unit adequately drained the condensation into the drain pain and out of the trailer.  He added some extra sheet metal to the drain pan walls to insure there was no water escaping to the floor.
If you go this route, make sure the output air does not get deflected back to the intake (where the filter is typically located) or you'll have freeze-up on the AC.
Good Luck.