OTR - Prevost Nashville

Thank you all.

The high temp today will be 65F so it will be a while before I can test temps etc.

By overhaul i meant changing most all hoses, dryer, oil and belt - the system never worked before we did this (there was a bad hose) and now does.

anyone have a picture of the "valve" Jon speaks of in the evaporator bay?

The evaporator bay has changed over the years so the valve location and type is going to vary. It is a solenoid valve on the cooling system line going to the heat exchanger in the OTR evaporator compartment. The heat exchanger and the evaporator coil are sandwiched together and the only time coolant should flow through the valve is when you require heat in the coach, or when you need to temper the cooling air of the AC system. If you don't have OTR none of this applies.

Jon your round tires "sig" reminds me of the time I plowed two furrows in a gravel parking lot for about 100'.

We were in OK over the weekend, and are down the middle cruiseair in our Marathon as of Thursday evening. By late Friday afternoon, ambient temps were 111 F in the shade, and we weren't parked in the shade.

At 5:00 temps were increasing in the bus and the rear CA begin cycling off on high pressure. The sun was beating down on the rear of the bus and hot wind was blowing the condensor discharge back on itself. Temps begin escalating quickly with only the front CA running. In the Marathon design, the front CA is the least efficient so we were going downhill quickly.

Time to make a change. Fired up the engine on high idle, and ran the OTR. Brought interior temps down from near 90 to mid 70's in about 20-30 minutes. By sundown the outside temps were around 105, and the 2 remaining CA's could keep up given the head start the OTR gave them.

Saturday, round 2. Ran the OTR from 12 to 6 all afternoon. Ambient temps again above 110. Interior temps - salon area was in the mid 60's and the front and rear of the bus were around 70. Could have run the front down lower by running the driver blower on high but there was no need. Fortunately the "park" we were in was fairly deserted so the noise wasn't noticed or complained about.

BTW, I burned 1.17 gph on high idle with the OTR running. Best $30 I have ever spent on Saturday afternoon.

AAP shipped me a new CA compressor this morning.

Great post Gordo..... If that doesn't make an OTR believer out of the skeptics I don't know what will !!!!!

I sure wish I had it in my coach. There is nothing like redundancy in AC systems.

Remind me to park next to you at POG 10 - just in case we get a heat wave!

As you know Tuga, I have 4 roof top air cond on my bus and just returned from a 3 week trip up to Michigan and Wisc. Of course it was cool there but extremely hot going up and back thru MS., TN. KY, IL, AR, IN, MO, AL and on the road never ran anything but Dash air and one roof top unit off of the invertor and never had problem with heat. When parked at night ran only 2 roof top units. I am happy with performance and the fact that they can be replaced so cheap. No problems to date after 11 years.

Must be a southern thing Dan. What you consider heat and what I consider heat might be two different things. When I visited my aunt and uncle in FL they would not turn on the AC in their house until it got to 85 degrees inside the house.

By then I was gasping for air and trying to dial 911.

But when they get down to 75 in the house they are walking around with winter coats on.

It was cool enough with me wearing a t-shirt, but I am sure I would not be as happy running in West Tx , az., NM but you can probaly guess that I am not going to try it!!! Sold my first Bus with 3 cruise airs and delivered to Flagstaff because it was much cooler than Phoenix.If I were traveling a lot in the very hot states I am sure the OTR would be very desireable, however I am just a poor redneck from MS and cannot afford the fuel to go that far!!

I'll bet if Gordon had roof airs, the outcome would have been much better. The roof airs don't shut down like the CA's. We just finished up a month of travel with the worst ambient temp of 101 and most of the time running was in the 90's. All we needed for most of the trip was the dash and the 2nd overhead evaporator running and only had to fire the gen with the roof airs one day while getting through the Chicago area at 101.

With the extreme temps Gordon experienced, OTR would be a must.