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Maddog2020 · 01-26-2014, 08:53 PM

We have a 2004 National RV Dolphin, Chevy Workhorse purchased recently. On our 1st trip we spent the night at a Walmart, temperature was around 0 degrees! In the morning the windshield was all frosted on the inside and we discovered no air was coming out on defrost. We wound up running the Generator and used a space heater on the dash all the way home.

I look at the issue and if I put the control on Vent, air blows out the vents. On Heat, air blows out on the floor. When I put it on defrost, air still blows out on the floor. Any ideas?

Thanks in Advance,
Jim

"007" · 01-26-2014, 11:20 PM

You may need to check the small plastic hose lines feeding the different function's off you vent control one may have fallen off hose connection or one may have a cracked hose.
Do you get heat out of the other vents if not the previous owner may have installed a ball valve so the heat of heater is shut off for summer use with AC portion of AC/Heater unit.

Maddog2020 · 01-27-2014, 06:55 AM

Yes, I do get heat from the floor and the vent, just not the top defrost. We leave for Florida in less than 4 weeks so hopefully I can figure this out before then. It's 5 degrees out today. I'm hopping it warms up a little by this weekend so I can check the hoses you mentioned. Thanks for the suggestion 007!

Pigman1 · 01-27-2014, 10:46 AM

If you haven't been in above freezing temps since the problem started, it sounds like you might have moisture in the system and your valves or actuating cylinders are frozen. Ice on the inside of the windshield is another excess moisture issue. Before I got to tearing into things, I'd get it into a warm garage or barn and see.

Moisture on the inside of windows, window frames, and walls is a problem with cold weather and the newer rigs. They're so tight the water generated by breathing, washing, cooking and normal bathroom functions can't get out so it condenses on cold surfaces. Dripping vents, water in air vent lines and such is the result. Always keep one or more overhead vents cracked or a window cracked when running in cold weather. Just a learning curve thing, but essential to get the water out, even though it's cold outside.

Maddog2020 · 01-27-2014, 11:08 AM

When we took our last trip (actually our 1st trip) near Christmas is was above freezing when we left. The defroster didn't seem to be working well then either, but I can't say for sure. Unfortunately I don't have access to a warm spot to try, for that I'll have to wait until we are further South. What if I run the propane heat for a few hours without being inside? Will that thaw things enough to try the defrost again?

That's good information about the moisture on the inside, I didn't think of that. Just sitting in the yard there is no frost or ice on the windshield, inside or out. Next time we spend the night in Arctic conditions, I'll try cracking a vent or window for sure.

Arch Hoagland · 01-27-2014, 11:14 AM

We keep the exhaust fan at the rear of the coach going all night with the small window over the sink cracked open a bit.

If we don't do that the windshield looks like you squirted a hose on it over night.

Pigman1 · 01-27-2014, 11:24 AM

I'm not familiar with your rig setup, but running the heat up high may help. Also if yours is a standard Class A setup, most all the forward air stuff is setup on the front bulkhead behind the fiberglass front cap and forward of the front firewall. A heat lamp, drop light or something in that area may also help. Just be anal about fire danger if you have a generator mounted there on a gasser. Good luck thawing things and I hope that's your problem. The lowest we've seen is about 12 degrees and a 35 mph wind, but that was about enough for me. We went through 20 lbs of propane like it wasn't even there. LOL

Maddog2020 · 01-27-2014, 03:30 PM

Pigman, looks like you have a diesel pusher. Ours has the 8.1 liter Chevy Workhorse gas engine in front. The generator is actually on the drivers side away from all that stuff. I may have to wait until we head to Florida to test the defrost theory. Hopefully this cold weather will break some before then.

Maddog2020 · 02-01-2014, 03:07 PM

Quote:

Originally Posted by Pigman1

If you haven't been in above freezing temps since the problem started, it sounds like you might have moisture in the system and your valves or actuating cylinders are frozen. Ice on the inside of the windshield is another excess moisture issue. Before I got to tearing into things, I'd get it into a warm garage or barn and see.

Moisture on the inside of windows, window frames, and walls is a problem with cold weather and the newer rigs. They're so tight the water generated by breathing, washing, cooking and normal bathroom functions can't get out so it condenses on cold surfaces. Dripping vents, water in air vent lines and such is the result. Always keep one or more overhead vents cracked or a window cracked when running in cold weather. Just a learning curve thing, but essential to get the water out, even though it's cold outside.

You nailed it!

We just got up into the mid 30's so I tried the defroster. I worked great! I will be leaving a vent or window cracked next time to avoid this issue. Thanks for the help!

Jim

Pigman1 · 02-01-2014, 05:11 PM

Great! Glad it's working. Good luck with it. These things are like trying to handle a skittish horse. You never know when some common thing you do is going to set them off.

Safe travels.