A/C works at night only

[TravelinDog]

This may have already been covered somewhere so forgive me if it has.
My Coleman a/c which is 21 years old with very little use works great at night but when the temp is over 100 degrees in the daytime it blows cold for a few minutes then the compressor shuts of for a few minutes then come back on and starts blowing cold again.
It will do this over and over and never cool trailer down. I was thinking perhaps it is low on freon but I read that they are a closed and sealed system.
Could an rv tech check it if I took the unit to him?

[MEXICOWANDERER]

You mean to tell me the expansion valve on these units is not serviceable?

[TravelinDog]

sgip2000 wrote:

TravelinDog wrote:

Bill.Satellite wrote:
An R/V tech will tell you that you need a new A/C so be sure the guy you calls is also willing to replace it or you will have to pay a 2nd service call from someone who will. There's almost nothing to check other than to see if the fins are cleans and the inside filter is clean. If you can get on the roof you can do this yourself. You can't recharge the unit. There is a slim chance it could be the start capacitor but I don't think it would make any difference if it was hot or less hot outside.

I will replace the unit myself. From everything I've found on the internet a new Coleman Mach 3 will replace my current Mach 3. I'll be able to use the same thermostat and it's already a ducted unit. The 4 hold down bolts and then a simple plug-in.
I hope it's as easy as it sounds.

Hardest part is getting it to the roof.

Yeah I figure with 2 ladders and my son it shouldn't be too much of a problem.

[sgip2000]

TravelinDog wrote:

Bill.Satellite wrote:
An R/V tech will tell you that you need a new A/C so be sure the guy you calls is also willing to replace it or you will have to pay a 2nd service call from someone who will. There's almost nothing to check other than to see if the fins are cleans and the inside filter is clean. If you can get on the roof you can do this yourself. You can't recharge the unit. There is a slim chance it could be the start capacitor but I don't think it would make any difference if it was hot or less hot outside.

I will replace the unit myself. From everything I've found on the internet a new Coleman Mach 3 will replace my current Mach 3. I'll be able to use the same thermostat and it's already a ducted unit. The 4 hold down bolts and then a simple plug-in.
I hope it's as easy as it sounds.

Hardest part is getting it to the roof.

[TravelinDog]

Bill.Satellite wrote:
An R/V tech will tell you that you need a new A/C so be sure the guy you calls is also willing to replace it or you will have to pay a 2nd service call from someone who will. There's almost nothing to check other than to see if the fins are cleans and the inside filter is clean. If you can get on the roof you can do this yourself. You can't recharge the unit. There is a slim chance it could be the start capacitor but I don't think it would make any difference if it was hot or less hot outside.

I will replace the unit myself. From everything I've found on the internet a new Coleman Mach 3 will replace my current Mach 3. I'll be able to use the same thermostat and it's already a ducted unit. The 4 hold down bolts and then a simple plug-in.
I hope it's as easy as it sounds.

[TravelinDog]

sgip2000 wrote:
Does the evaporator have frost on it when it stops working?

No frost.

[kerrlakeRoo]

Along with the other questions, what do you have for a power cord and where are you using it? If this is at your home on a lightweight extension cord to a 20 to 30 amp pigtail, it's likely the cord is getting hot and causing your voltage to drop.

[TravelinDog]

time2roll wrote:
What is the voltage in the RV? Low voltage is hard on the motor.

Otherwise the cycling points to excess current through the compressor indicating the motor is about shot. At 21 years it would be OK to just replace the upper unit.

Trailer is plugged into the house so I'm assuming it has the full 120 volts. It doesn't trip the breaker in the house or the trailer.

[sgip2000]

Does the evaporator have frost on it when it stops working?

[Bill_Satellite]

An R/V tech will tell you that you need a new A/C so be sure the guy you calls is also willing to replace it or you will have to pay a 2nd service call from someone who will. There's almost nothing to check other than to see if the fins are cleans and the inside filter is clean. If you can get on the roof you can do this yourself. You can't recharge the unit. There is a slim chance it could be the start capacitor but I don't think it would make any difference if it was hot or less hot outside.

[time2roll]

What is the voltage in the RV? Low voltage is hard on the motor.

Otherwise the cycling points to excess current through the compressor indicating the motor is about shot. At 21 years it would be OK to just replace the upper unit.