Domestic 459136 cool blowing hot - Dometic Rooftop RV Air Conditioner

Go to google, type in the brand new of air conditioner followed by AC followed by error code E1

for example, google search for:

Domestic AC error code E1

Where Domestic is the brand name. Are you sure is it Domestic and not Dometic?

Most combination boilers will shut off heat to the heating side if there is any call for domestic hot water, There may be a slight flow or the flow switch may be stuck on. Shut off the domestic water and see if that helps otherwise find the flow switch and tap to dislodge a potential jam. If this does not work you may need to call a professional to further diagnose it.

Add a domestic water expansion tank to the cold water line going into the water heater or at the water main coming into the building.

your auxillary fan is not working. this fan is responsible for cooling the freon that is being circulated in your cooling system... check if there are any loose wires in front of the engine bay.

the auxillary fan is located right beside your radiator fan.

do you have an automatic change over thermostat? this would switch it from heating to cooling.

You likely have a restriction in the heater coolant hose circuit - perhaps a coolant control valve not fully opening, or a kinked hose.
Insufficient coolant volume is flowing to keep the heater core hot.
Try back flushing the heater core system with a garden hose to check flow.

Sounds like your freon has leaked out and your heater blower resistor is burned out. Deffinitly take this to the dealer.

Is it leaking antefreeze?
The thermostat might be gone or needs a bigger thermostat
It could be a vaccum leak for the drivers side blowing cool air and the passenger side blowing warm air
Does it have dual air control switches one for drivers side and one for passengers side?

So the boiler relief valve is leaking? What is the boiler pressure when the relief valve leaks? The relief valve will have a pressure rating on it. If the relief valve leaks when the pressure in the boiler is lower than the relief valve setting then its just a bad relief valve. If the relief valve is leaking when the boiler pressure gets above the relief valve pressure setting then the relief valve is doing its job and there is another problem. Several things can cause the boilers pressure to go higher than the relief valves setting. It could be a bad expansion tank or one that needs to be drained and re-charged. It could be a bad cold water fill valve that isn't shutting off and is over filling the system, rasing the pressure above the relief valve setting. If this boiler also does your domestic hot water, I have seen where the domestic hot waters heat exchanger has a hole in it and the domestic hot water is mixing with the boilers water and over pressuring the boiler.