20 Most Recent Friedrich PDE15K3SB Portable Air Conditioner Questions & Answers

Keep +10 degree from your room temp and also thermostat in "heat" . And then check. But in your case, I think RV not energized. If no proper voltage in RV in heat mode, check the wiring to RV. If voltage in means RV not working properly. You have to change RV. Thanks.

A Power Reset will fix most things. Turn off the power at the breaker for a couple of hours. It resets the main board and all the relays. Service Manuals in the link https://www.google.com/search?q=Friedrich+Model+MR36TQY3JMA+mini+split+blinking+codes ..

bad thermostat.

Press fan and speed together for 3 seconds

Time to get an air conditioning engineer in to service it.

check with a dealer locally that brand is not sold here in usa

check for blockage if ok check for crack

heating switch over or unit failure --circuit or conrtol failure

That's what happens with loose electric connections. Need to go from the breaker to the AC unit power run inspecting each wire splice, all electric connections need to be clean and tight.
A loose connection becomes electrical resistance and electrical resistance consumes power, power consumed is dissipated as heat. Overheated, charred, discolored connections can be cut off and reconnected when found.
Start by tightening the circuit breaker wires, and neutral if any.

Did you use the Reset button? Did you call (800) 541-6645 and ask Customer Service? Is the Air Conditioner plugged into a power strip? Is the reset on the power unit ON or OFF? If the unit is plugged into a wall AC outlet is the circuit breaker to that AC outlet in need of reset? Is there a foul odor?

Here's some things that could be causing your issue. A clogged air filter could be one possible cause. However I suspect the units high limit switch is the culprit. This is an image of a high limit switch for visual reference only.

Here is a link to the manual but probably need to get a service tech out. The error codes are on page 36 http://friedrich.gear.host/documents/dss/MM18YJ-MM24YJ.pdf