I have a portable air conditioner/hvac and I'm having issues with it in heating mode. It's actually summer where I live but it was somewhat chilly as a storm passed over so I wanted to test heating on the unit I have.

Ambient temp was 19-20C according to my phone and another thermometer but the heating on the hvac/portable would not start unless I set it to 27C which is the maximum on the unit. It then cycled off shortly after as though it had reached it's 27C but my temp sensors only read a mere 1-2C increase to 22C. I wanted the hvac to produce heat at 24C. Does this sound like the thermostat in the hvac is faulty?

  • Dirty filters can cause this what was the temp of the air coming out of the unit? Once it thinks the air is warm it will shutdown a model # would help us look into possibilities. – Ed Beal Jan 1 '18 at 13:04

The thermostat in your unit is a bi-metal type and probably way out of adjustment. Some, however, are not adjustable. Check with the manufacturer to see if there is a way to adjust the thermostat.

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  • I actually had the back cover off yesterday to clean the coils and I was going to take a pic of the thermostat. I don't think it's one like you describe, it is shaped more like a small bulb or bullet and just clipped into the back of the evaporator coils. Are you familiar with those ones? – Kol12 Feb 10 '17 at 0:22

I believe some thermostats can be adjusted to have a narrower allowable range of variation. The downside of narrowing the range could be that the heat cycles on and off perhaps too quickly.

The filter idea sounds intriguing. In addition, where I live I have the sense that when the humidity is high, the thermostat gets quite confused and gets a little wacky. It seems that if I run the dehumidifier for a while, the situation improves....

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