[Hugh]

What kind of dash control do you have a pic of it would help, I am not sure if you have the kind they use from 2000 and on or the the other style ?!!

[AL]

Not clear if you are inquiring about O/R heat or dash heat. If dash heat, there is a valve in the engine compartment that increases the flow of hot water heat when opened. When closed it decreases heat and assists A/C.

Hope this helps.

[Dan]

I know from my experience the key to getting heat to the driver’s area is more of an issue than cooling. First you have to set the driver’s temperature to one that will give you the temps you want. My readout or setting for heat is higher than the temp I set for cool. I am sure this can be adjusted, but I am not going to make the effort. I set about 68 for cool, but to get the heat I want I set it at about 76.

If I need heat I also make sure the coach heat is on also. If it is not on the coolant does not seem to circulate to the driver’s heat exchanger. I can get heat to the rest of the coach either by making sure the coach heat control is on, or I can turn on the webasto, both of which seem to circulate the coolant so I get heat to the front. When the engine coolant is hot (at least around 160 or so) the Webasto circulating pump and the Webasto heat exchangers are working as needed but the Webasto burner is not firing because it is not needed so there is no more fuel being burned.

[Peter]

If all the valves are open when u start the coach the webasto light will come on the dash if all you want is heat when you turn on the dash control for heat , on mine you do not have to turn on the webasto for that feature to work it does it automatically, and the tell tale light will blink if there is something wrong with the webasto

[Bill]

thanks all –

Peter, I’m going to try to add a picture of the controls in the next postIt is a side by side control below the radio area on the dash

1. Webasto works awesome. It was only 45 outside so it ran minimally to keep the coach very comfortable.

2. The Prevost bus air is the real question. Cools but only heated the coach to about 70. – and the air coming out must have been close to that. As I flew down to pick up the bus I don’t have my ir temp reader, so I will know more once I get home.

3. Peter, the webasto light was on at the dash.

4. I will look for the a / valve . I’m assuming if it exists it is off as the driver area at full is maybe 70 degree air….would be a issue if it were really cool

---

2005 XL Thompson Coach

Rarely tow anything behind us.

Sold: 1993 Liberty that we loved for 12 years.

[Larry]

Congratulations on buying a new to you Prevost. There is no better ride.

I carry a couple, maybe three digital meat thermometers in the coach. One is always in the OTR vent by the driver on the left side of the dash. We don’t have any digital readout on the temps inside the coach (or outside for that matter) that the driver can see, so this is my way of knowing what is coming out of the vents.

This thermometer is what led me to have Jeff Rowe look deeply into the OTR air conditioning. For almost a year and half after buying the coach we for some reason didn’t drive in really warm weather where we needed the OTR A/C running on “high”. What little maintenance documentation we did find on the coach was a trip to Liberty in North Chicago where the OTR was worked on (I can’t remember what they did, Jeff got the documentation from Liberty). Jeff worked on the OTR during the initial zero out (I think replacing a valve on a freon line) and again while we were at his shop for the first Prevost Maintenance seminar. Before leaving Jeff’s I had the OTR A/C on wide open and the temp coming from the driver’s vent just didn’t seem cold enough for me, or Jeff either. He put his gauges back on, checked the electrical connections (did you know there are three pairs of cylinders in the Carrier compressor that come on and drop out based on demand?), and finally reached the conclusion that there was an obscure technical problem with the compressor … “it is shot”. So a reman was ordered and installed. Somewhere I have a picture Jeff sent me after pulling the original compressor out and removing the heads. A number of the reed valves were broken which then resulted in the compressor being as Jeff ascertained … “shot”.

For me, when diagnosing anything its important to have accurate information … rather than anechdotal information. From my experience “it feels cold” or “doesn’t feel cold enough” or “isn’t warm or hot enough” just isn’t enough information. Using the digital meat thermometer to know A/C and heating temps is a perfect example of having accurate information.

My recommendation: Every Prevost owner should have a digital infrared (IFR) temperature gun and a handful of digital meat thermometers.

Further comment on effectiveness of Cruise-Air heat pumps in heat mode: The day before Christmas Eve we drove the coach to Green Bay in a snow storm to park at the Onieda Casino by the airport and attended the Packer game on Christmas Eve. The casino has an interesting RV parking area with 50amp service (you park on the left side of an access road around the back of the casino for which they charge only $15 a night). It got to 30 degrees that night. I didn’t run the Webasto, I turned all the Cruise-Airs to heat mode. At 30 degrees outside air temp and 28 degrees the following night in La Crosse (with the generator running) the Cruise-Airs were pumping out very warm air (I now realize I should have practiced what I preach and checked on the air temps at the discharge!).

We spent a night in Virgina a few years ago when it was 19 overnight and windy. Ran the Webasto that night. Getting up in the morning and walking to the enclosed commode made me very clearly understand why many coaches a spec’d with heated floors. The floors over the driveline (trans, driveshaft, and axles) can get awfully cold!

Good luck in figuring out your problem.

[Archived]

Check your front shutters too, they’ll let in some cool/cold air

[Kurt]

dick,

thanks for the reply.

It is is an amazing ride / drive. – absolutely love it. 850 miles home, and not even tired from the traveling.

I do normally carry a ir temp gun – a lesson learned when I had a Itasca with basement air. I Flew in to Nashville, so I didn’t have it with me… I meant to grab it, and forgot :-(. One of those things when the work week goes by like a blur (things get forgotten )

the meat thermometer is a good Idea -I’ll definitely grab one.

I swung by jeffs to pickup a brake buddy I purchased from the “flea market” –

he jumped on board for a few minutes for us to show him a couple items – I had not used the heat on OTR , so I was unaware at that time other wise I would have had him assist right then.

For now now she is inside awaiting the next trip. Perhaps that will be back down to TN for the seminar. I’m trying to work that out with my work schedule. Till then the OTR will stay off.

mike

[Archived]

found the gate valve in the engine bay to assist the heat. Thanks all for the info!