Can I use a larger compressor?

[coolguy4]

The compressor in one of my window shakers died today. (No, not the one that I filled with R134A and propane. That one is still running great.) The unit is a Carrier 8000 BTU AC from the late 1990s. I went to turn it on, and the compressor won't start. However, I have a good 10,000 BTU compressor that I can put in. Would installing a 10,000 BTU compressor in an 8000 BTU AC be a problem? I know it'll draw more power, but will it still work okay? Thanks.

[ErHon]

how about checking wiring / fuses / relais and capacitor first before condemning the compressor?

[coolguy4]

how about checking wiring / fuses / relais and capacitor first before condemning the compressor?

I did. I swapped the cap with a known good one, and I checked for power at the compressor. The compressor has power and a good cap, but it won't even hum.

[ErHon]

i assume you also ohmed the comp, also against its outer shell (checking for short circuit to ground)

well, i did similar things in the past, putting in slightly different comp even without modding the cap tube, sure, after many years 5-or-6 its still working, and our cooling seasons here are long, 7-9 months.

but in reality, putting in a bigger comp depends on many different factors
how big is the condenser / evap?
it the fan speed /air flow high enough

perhaps you are lucky and the unit is capable handling slightly bigger comp

try it and you will know, whats to loose on a 1990 unit? its broken already...

[coolguy4]

i assume you also ohmed the comp, also against its outer shell (checking for short circuit to ground)

well, i did similar things in the past, putting in slightly different comp even without modding the cap tube, sure, after many years 5-or-6 its still working, and our cooling seasons here are long, 7-9 months.

but in reality, putting in a bigger comp depends on many different factors
how big is the condenser / evap?
it the fan speed /air flow high enough

perhaps you are lucky and the unit is capable handling slightly bigger comp

try it and you will know, whats to loose on a 1990 unit? its broken already...

Thanks for your help. Just curious- What'll happen if it doesn't work? Will the system just not work as well?

[Rob White]

.

Think of the compressor as a glorified suction pump, the bigger the pump the bigger the suction it will deliver. Lower the suction pressure and that lowers the evaporator pressure and temperature.
If you lower the pressure too much and if you lower the evaporator temperature too much complications such as evaporator freezing up may occur.

Depends on just how much a difference the temperature difference is.
In principle it should not make a high difference but it must be allowed for.

Rob

.

[coolguy4]

.

Think of the compressor as a glorified suction pump, the bigger the pump the bigger the suction it will deliver. Lower the suction pressure and that lowers the evaporator pressure and temperature.
If you lower the pressure too much and if you lower the evaporator temperature too much complications such as evaporator freezing up may occur.

Depends on just how much a difference the temperature difference is.
In principle it should not make a high difference but it must be allowed for.

Rob

.

Thanks. I guess I'll give it a try then.