Eliminate the cold air?

[Neal D]

Okay, this might sound like a silly question but here it goes.
We have a 2022 Phaeton 37BH and only recently started driving in the colder weather. What I noticed is that when driving I feel cold air coming in, I don't know exactly where it's coming from, but my legs are cold. I have the dash set of hot, but unless I set the blower on high, and angle the vents towards my legs, it's not comfortable. My question is whether this is normal, and if so what have others done to fix this?

[pespe]

I don't have a Phaeton, but I had the same issue in my Breeze (maybe that's to be expected with that name), But I ended up putting some foil-covered insulation in the big open areas behind the center console where is is open to the footspace - that closed off the flow of cold air and made the heat duct much more effective.

[d23haynes57]

Every class A I have driven or worked on, Gas or Deisel seems to have this problem. In summer there goes the AC. Part of the problem is air control from under the front cap overcoming the ability of the heating system to control it. Setting the AC to "Max" partly closes the outside air inlet and opens a recirculation flap. This helps for both heating and cooling. Then there is whatever air flow leaks in from under the dash area.

[zombiewoof]

I did a lot of work to stop this from happening.

I removed the two dashboard covers held on by velcro. There are two in the Bus not sure if the same with the Phaeton. With them removed I spent considerable time tie wrapping and organizing all the wires. I organized, tied off and shortened the flexible accordion vent tubes where applicable as well. In essence I cleaned up the whole area behind the dash. Once done this gives you ample space to insulate behind the dash. Another benefit of organizing and tying everything off is silenced all the rattling behind the dash. I bought 4” non faced fiberglass insulation, cut pieces to length and carefully placed them behind the dash. In most places there was enough room to double or triple the thickness. I also cut smaller pieces as applicable and stuffed them into the odd nook and crannies. Only two caveats to this. You need to leave air circulation space around the radio and backup camera. Second you need to not pack the insulation directly behind cozy heater (if you have AquaHot) so that it does not impede airflow through the cozy heater coils. Next was the A-pillars. I pulled off the plastic covers, dressed and organized the wires, then cut fairly precise strips of insulation and added them to the A-pillar. Once done I replaced the A-pillar trim. I went to the outside of the motorhome and pulled the generator access cover open to gain access to the front of the firewall. I used automotive butyl caulk (aka Dum Dum) to seal up any obvious penetrations.

This greatly reduced the air intrusion coming in through dash. It made it much easier to heat and cool the immediate passenger cockpit area, it reduced the road noise from behind the dash and eliminated all the rattles.

[shepardmike]

Originally Posted by zombiewoof

. Next was the A-pillars. I pulled off the plastic covers, dressed and organized the wires, then cut fairly precise strips of insulation and added them to the A-pillar. Once done I replaced the A-pillar trim.

THIS ^^^^^^

I noticed this when I was at RB when they were replacing my shades. There is ZERO insulation on the A-pillers. Took care of that when I got home....

[alank]

I think I've had this problem with every coach I've had, must have been all low end coaches.

The problem area is in an area that can't be seen, so the gap gets no attention. There is a front area that would be called a fire wall in a normal front engine car. It separates the inside from the outside down around your leg area. The bottom of the interior dash has to be sealed to the top of that firewall, or a lot of exterior air will come in through the crack from up under the front cap where the generator is.

Finding access to that area will be slightly different in each coach. One approach may be expanding foam applied all along the top crevice up under the front cap above the generator, A/C box and everything else that is in there. I would use a can of foam with a 2' tube on it to reach all the areas, it won't be easy, but the rewards great.

[oldenavy]

Had the same problem with our ‘20 Phaeton, driving it home from AZ in the winter. Ran the heat full blast and wore long johns the whole way. As others have confirmed, these things aren’t really made for cold weather.

[NLOVNIT]

I don't remember how I handled it with our Phaeton, but on both the Bounder & my PC, I had to put the dash on recirculate so the flaps in the ducts from the engine compartment would close. This kept the cold/outside air from being introduced into the dash system.

[Neal D]

Thank you for the replies, much appreciated. Since we are only recently retired, it's the first we have driven our coach in colder months of the year. Nevertheless, it appears to be an issue for most coaches regardless of the mfg'r or model.

I will certainly try some of the suggestions, the easiest being to set the dash air on recirculate, and then work on adding insulation if needed. One would think this would have been a consideration when designed / built, but obviously it was not.

[Nanci]

To help the cab stay warm when driving in cold weather we hook a full size flannel sheet over the tops of the slides on both sides. Really helps keep the front warmer. I Have command hooks toward the top of each slide to help the sheet stay in place.

[DRM901]

We have that issue as well. If you run the AH furnace, the passenger will have more hot air on their side.

For the driver, I think the only effective way is to use spray foam to the area from the generator side.

[MikeCh]

I have a different model class A but found the Proair heater box had openings where the heater hoses and ac piping enter the box. These openings allowed cold air to enter the box and it just seemed to fall to the floor which the heat could not overcome. I sealed these areas and insulated the box with insulation. This stopped the cold air from penetrating the box and made a significant improvement in the temp of the cabin while driving. I suggest looking at your heater box and look to see where the piping enters the box.

[Neal D]

Great ideas, I'll look into adding a bit more sealing and see if that helps. What's interesting is that it does not seem to impact the passenger side, just the drivers side (so my wife is happy).

[Galvanizd]

On mine, I have to adjust the vent angles and the heat/cool to cope with that. Dogs ride in the passenger well with the window , so we keep cool air on them.

By the way , in my manual, Tiffin address this and advised that air will come through even went in off position.....so Tiffin appears to be aware of this.