Briskair - compressor running - no cooling

[jkasprick]

I have a duotherm - Briskair roof top air conditioner. When you turn it on the fan runs and the compressor runs continuously. I have eleminated the thermostate being the problem and cleaned all filters and the condensdor and evaperator. I am not sure what else to check. Any help would be appreciated. Thanks

[RJay]

If you slowly increase the temperature setting on the thermostat will it shut off? Depending on the thermostat setting and the outside air temperature the A/C could run for hours.

[RVhauler]

Return line from evaporator to the compressor should be cold. If it is not then most likely you have a refrigerant leak. To locate/repair a leak on an RV AC is a PIA and if you are having it done at a shop, then it is as cheap or cheaper normally to replace the the unit reguardless of it's age.

[RV Wizard]

Is this by chance a heat pump? If so you could possibly have a bad cross over valve.

[jkasprick]

not the problem it works and tests fine. If the refigerant has leaked out or is low than the compressor should not run as far as I know. The compressor will run constantly when the thermostate is turned to cold but no cool air. This is not a heat pump, just a roof top A/C unit, Doutherm Briskair with mechanical controls right on the unit.

[RV Wizard]

If the amp draw of the compresor is low then you either have a unit that has a leak or a blade in the compressor is stuck; resulting in no compression.

[jkasprick]

what should the draw be?

Quote:

Originally Posted by RV Wizard If the amp draw of the compresor is low then you either have a unit that has a leak or a blade in the compressor is stuck; resulting in no compression.

[RVhauler]

These units do not have a low pressure switch to shut down the compressor when refrigerant is low and also very few have line taps to hook guages to for testing. Amp draw should be on a sticker on the compressor or if not found else where under the cover. Amps may not be shown just for compressor but for the entire unit (compressor/fan).

[mx842]

I know this thread is a little old but I seem to be having the same problem as the OP. It's too hot outside now to get up on the roof of my soon to be toy hauler but I looked this morning and there did not seem to be just 4 screws like someone said to remove the outside cover. As I said I didn't get all the way on the roof but it looks like the cover is pop riveted to the base with about 30 or so pop rivets. Am I missing something or is this just so you have to take it into the RV place for service.

[RV Wizard]

Quote:

Originally Posted by mx842 I know this thread is a little old but I seem to be having the same problem as the OP. It's too hot outside now to get up on the roof of my soon to be toy hauler but I looked this morning and there did not seem to be just 4 screws like someone said to remove the outside cover. As I said I didn't get all the way on the roof but it looks like the cover is pop riveted to the base with about 30 or so pop rivets. Am I missing something or is this just so you have to take it into the RV place for service.

What brand of unit do you have; a model number will also be helpful. If it is the Brisk air there should be screws into the base around the perimeter of the shroud; probably below where you see the rivets. If riveted, someone has take the factory installed screws out and installed them.

[mx842]

Quote:

Originally Posted by RV Wizard What brand of unit do you have; a model number will also be helpful. If it is the Brisk air there should be screws into the base around the perimeter of the shroud; probably below where you see the rivets. If riveted, someone has take the factory installed screws out and installed them.

After it cooled down to 95* yesterday I went up on the roof and took out all the screws and removed the cover. I found out it was not the 15,000 btu unit I thought it was and found it to be a 13,500 btu unit in stead. It had a piece of duck tape on the front that said it was inspected in 2000. that's kind of strange because the trailer is an 05.

I cleaned out all the junk that was in there and blew out the coil and there was a lot of mess in there and I thought that may have been the reason for it not working. I turned the unit back on and let it run for about 10 minutes but it would not cool at all. I went back up to the top unit and all the lines felt the same. The compressor was hotter that the rest of the lines and the coil but not too hot to touch. The compressor was running but not cooling. I'm thinking that something is either stopped up or out of freon. But what do I know?

I'll see if I can get a model number but from what I'm looking at it looks just like the one that is on my buddies camper and it is an 09 they all look the same to me.

[TXiceman]

After the unit has run fro a few minutes, the smaller line from the compressor to the condenser should be pretty warm to hot. This is the compressor discharge. The larger line to the compressor is the suction line from the evaporator. It should be pretty cool ans sweating if there is much humidity. If it is very dry, it may not sweat, but should be cold.

The compressor should be drawing something in the 11 amp range. Depends on the model. Ther should be a tag listing the unit amps and the compressor amps.

Ken

[mx842]

Quote:

Originally Posted by TXiceman After the unit has run fro a few minutes, the smaller line from the compressor to the condenser should be pretty warm to hot. This is the compressor discharge. The larger line to the compressor is the suction line from the evaporator. It should be pretty cool ans sweating if there is much humidity. If it is very dry, it may not sweat, but should be cold. The compressor should be drawing something in the 11 amp range. Depends on the model. Ther should be a tag listing the unit amps and the compressor amps. Ken

Thanks, I do understand what is supposed to happen in relation to the pressure and discharge lines but what is happening is that all the lines coming to and from the compressor are pretty much the same, there is not much difference in temp between the two. The line at the top of the compressor is a little warmer than the larger line at the bottom but both are warm to the touch with the controls at max cool after over 15 min run time.

[lonestarace]

We had this same problem 2 weeks ago.

One thing you might try is changing the start capacitor for the compressor. It didn't fix ours, but it might yours?

We ended up putting 2 new roof airs on ours since they were both 12 yrs old.

We hope this helps.