[needtocamp]

Tom might have some insight because he had a chassis around your model year and he had some trouble getting air where he wanted it most. I don’t know the outcome of his efforts to fix that.

When I select a temperature on my coach I am done. I don’t have to push any other buttons other than perhaps the ones to put more air on my feet or to defrost the windshield. I do know I have to set the heat slightly higher in temp than the temp I select for AC to have that as comfortable as I want it. That might be due to the fact the heat from the dash has to overcome a lot of cold air spilling from the windshields

I am not sure if this is a Liberty feature or a Prevost feature, but when the coach senses the need for heat instead of AC I get a symbol on the display to show the Webasto is on. Since the Webasto was not turned on I am guessing the icon symbolizes that the Webasto circulating pump is functioning to insure adequate amounts of engine coolant are being delivered to the heat exchangers. I know the Webasto pump is on because if I step out of the coach I can hear it.

[Archived]

Good question G-man. I’ve also been wondering what that H20 button and Water Pump symbol represents. I searched my manuals but wasn’t able to find anything. I assumed it was a remnant from OTR which I don’t have, but after reading Jon’s post I guess it’s not. Anxious to find out the answer.

[Archived]

Hmm, very interesting and I am really curious now.

I am not sure if my Webasto was running as I was going down the road at night, did not pull over to check that. Last time I fired Webasto it was quite smoky on startup so that may be soemthing I would see in the mirrors during the day.

And to add to all this I have a new coolant leak this morning. After my last one I fixed before leaving (small section of hose and clamp on water pump) I see a new one, minor but looks like it is coming from in front of the radiator, basically leaking down just forward of the radiator and just behind tag axle wheel well.

A quick look seems to reveal a goodyear heater hose (I think) going to radiator near that area…I wonder if that has anything to do with me running the h2o pump for a while on the dash HVAC last night. Looks like a pain to get to the frontside of the radiator to do anything, so hope its an easy fix…not surprised I have a few leaks since this thing was not driven much….and its gonna see 5000 miles over the next week!

[Glenn]

G-man, most likely I had the same coolant leak that you have. I had to remove the exterior radiator fairing on my H3 to gain access to the breeze clamp at the bottom radiator outlet. A quick tightening of the clamp solved the issue. I chock it up to a teething pain of getting these things on the road again after a period of prolonged sitting.

[Archived]

Coolant leaks and air leaks start to show up more as temps drop. G-man, if you are in colder temps than you have been I am not surprised you see a few drops of coolant. As David says a little tightening of the clamps for coolant usually takes care of the problem.

On the pneumatic system however leaks that start to show up as temps drop are usually indicators that over time that fitting or device is going to leak even in warmer temps.

As to if the Webasto is running just be aware that if coolant temp is above 160 (I think that is the temp) the burner will not ignite, but the circulating pump will function as long as heat is called for. When I get the dash symbol I am presuming the indicator is the pump is circulating coolant through the OTR large heat exchanger as well as the dash heat exchanger. If I activate the Webasto on the Liberty installed Crestron, then I also get heat as needed from the house neat exchangers in the LR, kitchen, bath and BR, which supplements the OTR when driving.

Nothing has failed yet so I haven’t really gotten into the system and how it was set up.

[glen]

Not sure if this is relevant due to age difference, but my 1990 CC XL had both Webasto and a separate pump to bring heated coolant from the engine to the dash. Without the Webasto engaged, running that pump made a huge difference in the amount of heat from the dash and windshield vents. I was told that without the pump, the coolant flow through the heater hoses was slow enough that it would cool substantially before it got to the cockpit. Pump was to speed up the flow so it was still hot when it got to the radiators. It is a looong way from the engine to the cockpit, and mine was only a 40 footer.

[Archived]

David, thanks for that info! Not surprised there are a few leaks here and there, but a lil dissapointing all the same, but I will get it all sorted out…will have a look in that area. My last one I replaced the hose, its fine, other short section I removed to get acess I did not replace, now ITS leaking! HA!

Anyways, just to clarify I do not have OTR or crestron, and alos no circulation light or anything for Wabasto on the dash itself, just the h2o circ button and light on the HVAC unit itself.

I really need to learn more about the Wabasto, but if I understand correctly I need to select 12v heat on my DC panel in the bedroom then I can manipulate Webasto ob my SMX controls throught out the coach.

So, if Webasto does not fire when it is getting warm engine coolant abover 160* maybe best way is to moderate cabin temp via the SMX controls and forget dash heat altoegther….but very curious how it all works!

[Archived]

Apples to apples needed here boys..

Without Prevost OTR, your not going to see the Webasto run as Jon mentioned. You can run your Webasto for coach heat (furnace) while driving and since the coolant is already at 190/200 degree’s, the Webasto doesn’t fire, it just runs the circulation pump.

You have dash air and when heat is needed, it comes from the engine coolant being circulated through the loop to the front of the bus. The button your talking about is a pump that moves hot coolant through the loop to give you hotter temps by moving more coolant than just the engine water pump pressure. It’s usually only needed during very cold conditions. The dash air coolant loop also blends heat to the air conditioning when you turn the temp up if it’s too cold, just like a car.

Hope that helps…

[Larry & Diane]

As an add on to Tom’s post, I too have dashboard only Prevost a/c. When needing heat, I find that I have to set the temp much higher than I should have to to get it to get warmer in the bus. It isn’t cold from the windshield, but lack of the heat valve opening, or staying open long enough.

I have had discussions with Prevost in TN about this and they say there is no adjustment or calibration for the heater controls to fix this issue, so I have learned to bump the temp setting way up if I want heat.

The heating system pump does move more water and will help get it even hotter, but since I don’t use the bus in the winter here, I have not needed it much.

[Archived]

in our riveted Royale the h2o labeled switch controls a small pump to move engine coolant to the heater. The AC switch controls the AC compresser.

[Archived]

G-Man,

OK I have and 07 Marathon but this is what I have been told and experienced over the last year in the bus.

1) no matter what setting you are on you wil have a significant amount of airflow to defroster vents. I was told by someone at Prevost or read here that Prevost engineers were concerned about keeping the windshield from fogging and it was done intentionally and short of customers blocking them manually there isn’t much to do to adjust it. So I have just left that one alone and become used to it.

2) do you have a recirc buttom on the right bottom of your drivers HVAC control? Do you have an AUX? I was told on my PDI to always have the recirc on when running AC or Heat on the dash. It was explained to me that this helps push the heat or coolant up front. Until your post I never even noticed the h20 button I have it but its on the AUX side and to my knowledge I have never pressed it.

3) On the wabatso… here is what I have learned on it. your right you need to have the 12v heat or 12v water turned on in the bedroom panel or wherever it is on your coach. also on the SMX control you need to hit heat twice so that it is blinking and then and only then ( on my coach) will you get webasto heat from the webasto heaters. I was also told to turn off the main AC buttons (red backlighted) on dash.

I will try to pull out the Prevost book tomorrow and see what it has to say about the h20 button.

Hope some of this helps…

Bill

[Archived]

G-man,

Also one other thing… if your webasto is smoking you might want to service it or get it serviced… Mine was doing the same thing and needed a few things and now it doesn’t hardy smoke at all and is much quieter than it was before. I was told it should be service annually.

good Luck

Bill

[Don]

Bill,

I bleieve the h2o button only pushes coolant for more heat
capacity, not refrigerant.

[Archived]

Thanks everyone, that pretty much explains everything, much appreciated! Will try the h2o pump longer next time and see how it goes…also glad to know the defrost vents are designed that way. The whole dash HVAC is a bit clunky but mine seems to be working as intended!

[Archived]

I drove my royale in cold temps -20 and I never pushed the H2O button it does what Tom said the defrost all ways blows the only button I pushed was the AC button next to it to turn on compressor for AC , tha h2o button brings heat to the front faster never needed it it was hot enough for me