Dash vents blow hot air under heavy engine load?

[Cake sniffer]

I have the same exact issue, as well as a few more. 2021 Adventurer 29b

[gmulcahy]

Once we found out what the real issue was it was a quick fix and now it works great. I you you just purchased your motorhome i would strongly recommend installing a Safetyplus steering stabilizer, and a supersteer rear track bar. It will totally eliminate the trucks and wind blowing you off the road. I also installed 4 Koni shocks which makes it now ride like an Suv. Enjoy your new Coach.

[DTDetroit]

How do you get the dog house open?
BTW Thanks for posting this. I’m another one in the same boat. Adventurer 29B 2022 blowing hot air across alligator Allie in southern Florida right now.

[Hermes2]

Originally Posted by DTDetroit

How do you get the dog house open?
BTW Thanks for posting this. I’m another one in the same boat. Adventurer 29B 2022 blowing hot air across alligator Allie in southern Florida right now.

To remove the doghouse: First remove the two phillips head screws at the front left and right of the dog house (kind of hiding in the carpet). Second, use a hex wrench (should be one in the kit provided with the MH) to unlatch the back of the dog house (also hiding in the carpet). Then you can lift it off easily.

[Jim_SB]

Originally Posted by gmulcahy

Attachment 179278

GMulcahy,

Your post has been very helpful. I just bought a 2018 Winnebago Vista 31BE with 9,000 miles on it and the dash vents blow warm air constantly (A/C on or Off).

I’ve found a local shop who will evacuate and recharge the system in a week or two (they don’t have much room for large vehicles, a common problem here).

In looking at the diagram you supplied the VCS system shown appears identical to the one in my 2018. The only difference I can see so far is that my hot water line is routed into the BOTTOM of the VCS unit whereas your diagram shows it going into the TOP.

Could that make a difference? I wouldn’t think so. I haven’t read of any 2018’s having the reversed hose issue since that came about with the engine change.

Thank you. Jim

[Mickey_Z]

I agree, the reverse hose issue was tied to the V8 engine change for 2021 models. They were using the V10 hose locations which was 180 deg opposite. Winnebago eventually issued a recall notice to fix it.

[Jim_SB]

Just to close this out, my 2018 31BE had a faulty expansion valve. Once replaced and recharged the dash A/C began working.

[Wyatt]

Originally Posted by Jim_SB

Just to close this out, my 2018 31BE had a faulty expansion valve. Once replaced and recharged the dash A/C began working.

Always nice to get a follow up on a problem so we can all learn from it. Thank you.

[Jim_SB]

Another update - my 2018 Vista 31BE still has dash A/C issues. The unit works reasonably at engine idle (especially with the engine cold after first start of the day) but once the engine is warmed up the air coming out of the dash A/C isn’t cold. It is noticeably worse as engine RPM increases. Climbing a mountain pass the A/C gets warm. Sitting at a stop light idling it gets significantly cooler.

I’m convinced that the electric 3 way valve is being overpowered by the coolant flow at high engine RPM (and high pump flow). Even on a cool morning using the vents only it will be cool when I first turn the vent fan on but as the engine warms up so does the vent air.

I’m considering replacing the electronic 3 way valve - but I’m also considering simply going to a ball valve option so I can completely shut off water to the VCS climate system.

In going through the detailed diagrams on Winnebago’s parts site I see that for my unit (with the Triton V10) the long hose to the rear of the engine is the return line, whereas the short hose to the front of the engine is the heater source (feed) line.

Does that make sense? Many engines pull heat from the rear of the engine and return it to the front. This is the opposite although it may be by design. I just need to get it fixed and the ball valve may be the easiest (although cumbersome at times) option….

[Bobn1957]

Originally Posted by Jim_SB

Another update - my 2018 Vista 31BE still has dash A/C issues. The unit works reasonably at engine idle (especially with the engine cold after first start of the day) but once the engine is warmed up the air coming out of the dash A/C isn’t cold. It is noticeably worse as engine RPM increases. Climbing a mountain pass the A/C gets warm. Sitting at a stop light idling it gets significantly cooler.

I’m convinced that the electric 3 way valve is being overpowered by the coolant flow at high engine RPM (and high pump flow). Even on a cool morning using the vents only it will be cool when I first turn the vent fan on but as the engine warms up so does the vent air.

I’m considering replacing the electronic 3 way valve - but I’m also considering simply going to a ball valve option so I can completely shut off water to the VCS climate system.

In going through the detailed diagrams on Winnebago’s parts site I see that for my unit (with the Triton V10) the long hose to the rear of the engine is the return line, whereas the short hose to the front of the engine is the heater source (feed) line.

Does that make sense? Many engines pull heat from the rear of the engine and return it to the front. This is the opposite although it may be by design. I just need to get it fixed and the ball valve may be the easiest (although cumbersome at times) option….

I have an older unit that uses vacuum for the HVAC controls and had a similar problem with hot air coming out at high engine loads, so I installed a ball valve! It's a bit inconvenient as the valve is in the engine bay but effective! Typically heaters draw hot water from the water pump or nearby!

[Jim_SB]

This is the Winnebago hose routing diagram. It appears that the hot water is coming from the front of the engine into the side of the 3 way valve which directs the flow either towards the heater or back to the engine. I can confirm the hoses and the actuator/valve are installed in my unit as shown.

A simple test this morning shows the valve works smoothly and consistently in roughly a 90 degree range of motion (as the temp control in the dash is set from full cold to full hot and back). 90 degrees is typically all that is required for a ball valve to go from open to closed.

I haven’t pulled the hoses yet to peek inside and see if the valve is actually closing fully. I suspect it isn’t as that would explain the results I’m seeing and also why others have simply gone with a manual ball valve installed downstream as a fix (which I will do if required). I think the next step is to buy a ball valve, detach the hoses and see what’s really happening in there.

[Jim_SB]

The saga continues………

Yesterday I removed the 3 port water valve. It is definitely a ball valve, it’s all plastic from what I can see, it rotates 90 degrees from full cold to full hot and looking inside the valve while the dash control is operated it appears to be working perfectly……

Except hot water is still getting into my HVAC system. My guess is that the engine driven water pump creates more flow than the valve internals can handle.

As luck would have it one of the tee fittings popped off (it didn’t break, just popped out) of the valve body during removal. While it goes back into the valve easily enough now I don’t trust that it won’t leak or fail on me somewhere on a trip so I ordered a new unit.

While I’m waiting for that to arrive I’m going to install an inline ball valve in the hose going to the VCS heater core so it’s going to be a belt and suspenders fix.

Notably the replacement unit is a slightly different part number but appears identical. Perhaps Victory Climate Systems realized the original unit wasn’t up to the task?

Fingers crossed that one way or the other I will stop hot water from entering the VCS heater core.

[Jim_SB]

Success!!!

I ordered Victory Climate Systems 3 Way Water Valve 46-00395 off Amazon. $283 including tax and shipping. It looked identical to the old unit but, after installation, it works much better. Now with the engine idling and full (normal) operating temp I get a nice stream of cold air from the engine A/C dash vents.

While I had the old valve out I installed a 5/8” ball valve in one of the water lines to the HVAC box (the belt and suspenders approach). After initial testing it seems that it won’t be necessary. But if it ever is, well, it is already installed.

For what it’s worth the new Victory part has a slightly different part # than the original but from the outside they appear identical. Maybe VCS figured something out?

Whatever. I’m just happy to have it working properly.