Community Forums

IFlyABus · 08-06-2016, 09:34 PM

Has anyone added Freon to their rooftop air conditioners? If so, what kind does it take?

**Lt Dan** · 08-06-2016, 10:17 PM

I think you will find it difficult to add any refrigerant to the roof units. They are a sealed system, so you would have to install piercing taps, which could introduce leaks or weld in ports, which would require draining, vacuum pumping and re-charging the system. It could be done, but it would require more than an average do it your selfer's skill. Our Mach 8 unit shows that it uses R-410A refrigerant.

MtnTrek · 08-06-2016, 10:48 PM

Yes, LT Dan summed it up pretty well.
There will be a label on the unit stating the charge weight (oz.) as well as refrigerant type. (R-22 [older], R-410A [newer])
As he said these units have no service valves, they are hermetically sealed. So if they develop a leak (cracked line, joint, etc.) there is a more serious problem / damage than simple adding more gas will fix.
Are you sure the compressor is even running? Electrical problems are far more common.
Good luck.

IFlyABus · 08-07-2016, 08:27 AM

All three run, at least air is blowing inside. But if I set zone 3 at 72 for example, and zone 2 at 75, zone 3 runs and never shuts off, but the temp gets up to 78*, and the air coming out feels like the room air, not refrigerated.

If I turn off zone 3, and let zone 2 run, it gets down to 74-74* in zone 3. My initial thought was low freon, like a car. Haven't had time to climb up on the roof and explore yet.

IFlyABus · 08-07-2016, 08:28 AM

Is there a fuse for these roof top units aside from the three CB located in the closet? Perhaps something for a compressor relay that would prevent it from kicking in, yet the blower fan can run?

MtnTrek · 08-07-2016, 12:21 PM

The CB is the main circuit protection. No fuses. There is perhaps a time delay relay / potential relay for the compressor. Failing capacitors are common also.
If you were to just run that unit do you hear the compressor try to start? Typically you might hear the fan start first then the compressor starts a few seconds later. Or you might hear it try to start and drop out.

**Lt Dan** · 08-07-2016, 01:25 PM

Quote:

Originally Posted by IFlyABus

Is there a fuse for these roof top units aside from the three CB located in the closet? Perhaps something for a compressor relay that would prevent it from kicking in, yet the blower fan can run?

There should be a control circuit board inside the unit which may be under the inside blower housing. This circuit board would have the compressor and fan relays on it. Before you go into that, I would do as MtnTrek said and replace the start and run capacitors on the compressor first. Those are relatively inexpensive and the most common cause of a compressor not starting.

IFlyABus · 08-08-2016, 11:56 PM

I'll look into the capacitors as the culprit when I get home on Thursday. Thanks for the idea!

Esc Pod · 08-10-2016, 06:51 AM

In our last coach, back air stopped blowing cold. Fan worked fine. Culprit was a cracked coolant line. Had to replace whole unit. Could not find anyone willing to repair the line.