Coach not building air in subfreezing temps.

[Scott & Heather]

Thanks BW for the clear explanation. You're right, I neglected my sketchy wiring for the heater. This WILL be rectified ASAP. I did install a block heater on my new engine before filling it with coolant. Stated the bus in 10°F the other day with zero issues.'

[Scott & Heather]

Thawed out the purge valve and fixed the issue. Thanks guys.

[chessie4905]

While doing the install, open all air tank drains and leave open for 24 hours. (in warmer weather so all oil and water drains completely, including muffler/ping tank) If you are getting oil along with the water, strongly consider replacing air compressor. Air driers don't like oil. It messes up the dessicant.
Make sure you power the purge valve on the drier.

[dtcerrato]

We bused for 40 years in the same one. Two years ago we finally added a drier. Well I do purge my tanks once & awhile but no sign of moisture ever. I think the drier works great. Cleaned up the air too! & won't freeze with the heater...

[buswarrior]

Thawed out the purge valve and fixed the issue. Thanks guys.

The last trick, leave the purge valve in the closed position on shut down in freezing weather. Fan the brakes until compressor is cut in, and shut it down.

Then the purge valve can freeze all it wants, you will be able to build air pressure.

As the newer coaches, with inherently tighter air systems, (no shutters, no belt tensioners, no engine pneumatic controls) fall into busnut hands, this problem will get worse, not better, as the slower leak down gives the purge valve longer to cool off and freeze open.

Happy coaching!
Buswarrior

[6805eagleguy]

While doing the install, open all air tank drains and leave open for 24 hours. (in warmer weather so all oil and water drains completely, including muffler/ping tank) If you are getting oil along with the water, strongly consider replacing air compressor. Air driers don't like oil. It messes up the dessicant.
Make sure you power the purge valve on the drier.

Yes, right now drier is on parts bus, way up underneath, I just glanced at it briefly while pulling engine

[windtrader]

Install religiously according to recommendations, maintain the drier, all your moisture related problems go away

To summarize as there was a lot of different ideas thrown out there, does a maintained dryer and regular tank purging solve this?


So far over three years, I have yet to see any moisture come out of the values so the dryer must be doing its job.

[chessie4905]

they do have a recommended service interval. Maybe double the time for our use?

[Scott & Heather]

Chessie

I have a brand new compressor installed. New everything in the engine compartment. So no oil drama for me.

[chessie4905]

Do you currently have snow to top of tires?

[buswarrior]

To summarize as there was a lot of different ideas thrown out there, does a maintained dryer and regular tank purging solve this?


So far over three years, I have yet to see any moisture come out of the values so the dryer must be doing its job.

Your air drier is doing it's job.

The only one that really matters for you is the discharge muffler drain in the curb side engine access, as i noted, drained every day of operation, 365 days a year, and you'll have boring winter operations. It catches air and oil before the journey to the air drier.

Happy coaching!
Buswarrior

[Scott & Heather]

Do you currently have snow to top of tires?

Pretty close. We have two feet on the ground but it's slowly settling.

[chessie4905]

Yeah, I saw your post on Facebook.