How to Solve Window Air Conditioner Electrical Problems

Window Air Conditioners and Electrical Circuit Problems © By: Dave Rongey

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Window Air Conditioners and Electrical Circuit Problems
Electrical Question: A TV and window air conditioner were rendered inoperable after the (5,000BTU) air conditioner was turned on (15A circuit). It appeared that the CB tripped, but it had not, so I tripped the suspected CB, checked for obvious fire hazard (burnt stuff), turned on the CB and the fault manifested itself by:

• At the beginning of the problem the “electric burning” smell coming from the TV and the air conditioner going off (and now won’t turn on — “no signs of life”) ? no CB trips.
• There were malfunctioning lights and switches, including: turn one light on or off and other lights grew brighter of dimmer (no flickering) then eventually they don?t work at all ? again, no obvious CB trip (red banner visible or CB switch in ?off?). But cycling the CB off-to-on would re-establish power
• In a three bulb bathroom light unit unscrewing one light caused the other two to glow very brightly (probably would burn out if left on)
• I couldn’t isolate circuits by turning off their CB?s — turned off both CB’s in a mini 15A unit and some of the circuits still were powered (replaced the mini CB ? didn?t help)

After four days of study (with problem circuits shut down), including studying your very helpful site, I commenced procedures which you suggest, hitting pay dirt at the step (to paraphrase): [examine where the trouble began,] which was at the air conditioner (but maybe not?). This is what happened (all CB’s on — my new voltage/current tester in hand) before I even started checking anything:

Heat is coming from the electric baseboard heater unit located a foot beneath the outlet which the air conditioner is plugged into; the other baseboard units are cold; the 24v thermostat unit is off.

I turned off all CB’s to the electric heat system and everything is now normal! (except the TV and air conditioner which were cooked). The switches, lights, outlets all normal. But there will be a day of reckoning — when winter comes and I have to power up the heat.

Any ideas?
I’m trying figure out how one heater unit can be on when the thermostat is off and the other heaters are off. I would hope that simply bypassing this one heater might solve the problem but I have a hunch it won’t be that simple.

Anyway, thanks for reading this. I hope you can help.

This electrical question came from: Jim, from Bethel, Connecticut

See more about Home Wiring for Connecticut

Dave’s Reply:
Thanks for your electrical question Jim

Electrical Circuit for a Window Air Conditioner

• It is best to install a dedicated circuit for window air conditioning units because they typically require a high amount of power.
• If the window air conditioner is plugged into an existing shared circuit then it this may cause an electrical short somewhere withing the circuit, most likely at an outlet or a splice in one of the outlets of the shared circuit.

RESOURCES

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