Coleman-Mach 48008-966 AC large voltage drop
Back in October I got a new Coleman-Mach 48008-9660 3 P. S. heat pump and a 9630-715 non-ducted ceiling assembly. With warmer weather, I've noticed a problem with the air conditioning. On LOW COOL...
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It sounds like your compressor is trying to re-start too soon.
After they have shut off, most compressors need some time for the refrigerant pressure to subside on the high-pressure side of the evaporator coils.
If too much of this pressure remains when the compressor attempts to start again, it makes the compressor work much harder while starting - or may even prevent it from starting.
While it's attempting to start against too much pressure, the compressor draws an excessive amount of current. If it fails to start, it will continue drawing a lot of current for a few seconds, until the overload protector opens the circuit supplying power to it.
During those periods with it is drawing excessive current, the voltage being supplied to the RV tends to drop - which makes the lights dim and the fan slow down.
One way to increase the amount of time between compressor shut-off and re-start is to add some "thermal mass" to the temperature sensor. The extra mass requires more time to change temperature - which slows down the speed at which the sensor responds. So, you get longer delays between compressor shut-down and re-start.
Why my old Coleman had this problem, I installed a big wad of tinfoil over the temperature sensor, held in place with zip-ties.
It sounds hinky, but it works. :B
After they have shut off, most compressors need some time for the refrigerant pressure to subside on the high-pressure side of the evaporator coils.
If too much of this pressure remains when the compressor attempts to start again, it makes the compressor work much harder while starting - or may even prevent it from starting.
While it's attempting to start against too much pressure, the compressor draws an excessive amount of current. If it fails to start, it will continue drawing a lot of current for a few seconds, until the overload protector opens the circuit supplying power to it.
During those periods with it is drawing excessive current, the voltage being supplied to the RV tends to drop - which makes the lights dim and the fan slow down.
One way to increase the amount of time between compressor shut-off and re-start is to add some "thermal mass" to the temperature sensor. The extra mass requires more time to change temperature - which slows down the speed at which the sensor responds. So, you get longer delays between compressor shut-down and re-start.
Why my old Coleman had this problem, I installed a big wad of tinfoil over the temperature sensor, held in place with zip-ties.
It sounds hinky, but it works. :B
