It is HOT in here...

[museumdude]

Question

I have two air vents just inside the door to my 2005 AirStream Land Yacht, and they both are blowing hot air when I am driving even though I have the air conditioning on for the chassis - the coach air is off, but this is a ductless system anyway. The heating system for the coach is off as well. Any ideas?

[overlander63]

Are they ducted from the front cowl area? If so, you could be getting engine heat (assuming it is a front-engine model).

[Paul Dobbin]

Our Land Yacht has a a big flap (vent door) under the dash that's controlled by vacumn. We can hear it open and close when we start or stop the dash air. At one time I left the vacumn line off of it and it blew (or emitted) hot air all the time. It was outside air. Later I discovered that it opened for "vent" also. Now we choose to keep it closed. Could this be what's happening to your Land Yacht?

[Santart]

Located on your dashboard is a rocker switch marked R.Heat. It has three positions although not marked. They are OFF, LOW, and HIGH. With the ignition on, and the engine not running, you will hear the blower running. Check the three positions and turn it off to stop the rear heat from entering those two vents. You'll be glad you have them in the winter as they transfer engine heat to the living area as you drive.

Frank

[museumdude]

Ok, now I feel a little foolish - the switch LABELED R HEAT was in the low position. Apparently, it has a high and a low setting, I can't hear the fan in low.

Thank you - ALL

[myfirstrv]

I did the same thing last year when I first got mine

[Michigander]

I noticed the same issue with our '05 LYG 30 w/ slide and had a shut off valve installed in the fluid line that brings hot radiator fluid to the heater core/ heat exchanger mounted underneath the floor by the steps. I plan to check the R Heat switch also, but believe that as long as hot radiator fluid circulates thru the cabin heater unit that heat will radiate from the vents wether the fan is on or not. Stay tuned.

Bob and Nancy Padilla
'05 AS LYG 30 SO
Jeep Wrangler Toad
Michigan

[harold1946]

I had to replace the faulty tempco valve that is inline on the outlet side hose going to the heater cores. Some have replaced it with a manual ball valve. Tempco replaced it free of charge.

[Michigander]

Please tell me what you know about the Tempco valve. What makes it open or close? Would it be the temperature control knob on the dashboard? And when the temp control knob is rotated to increase inside heat temperature, is that supposed to control the amount that the tempco valve is open? In other words, can the Tempco valve be adjusted to control for the amount of hot radiator fluid runs through the hose, or is it designed to be all or none, open or closed. Thanks,

Bob and Nancy
'05 LYG 30 S/O
Jeep Wrangler Toad
Michigan

[harold1946]

Originally Posted by padillab

Please tell me what you know about the Tempco valve. What makes it open or close? Would it be the temperature control knob on the dashboard? And when the temp control knob is rotated to increase inside heat temperature, is that supposed to control the amount that the tempco valve is open? In other words, can the Tempco valve be adjusted to control for the amount of hot radiator fluid runs through the hose, or is it designed to be all or none, open or closed. Thanks,

Bob and Nancy
'05 LYG 30 S/O
Jeep Wrangler Toad
Michigan

The tempco valve is an electronically controled valve that is on or off,controling flow to the heater cores. It doesn't have anything to do with temp. I wish it did as I have the same complaint as you, no heat control. I am waiting to see if you get any replies on that issue.
I found out about the tempco valve the hard way. Thought the dash air wasn't working and found the valve was allowing hot water to circulate so it was heating and cooling at the same time. A really sharp AC teck. found the problem right away. Said it's common problem with tempco.

[harold1946]

That sharp AC tech. (neighbor) just came over to visit, so now I can correct my screw up. The Evans tempco valve does vary the flow of water providing temperature control through the dash control which is a potentiometer. I should have realized that by the multiple wires going to the connector. Senior moment.
Evans Tempcon, Inc

[Michigander]

Thanks, Harold. I went to the Evans Tempcon site and saw a picture of my control setup there. My next step is to contact them to see if I can troubleshoot my situation. When I use my heater, the temperature has two settings, either hot or cold even though the knob looks like it should vary the temp. When I rotate the temp knob clockwise and it gets past about 1/3 of the way, the temperature of the air coming out of the vents goes all the way hot. I did report this to Airstream while it was still in warranty and the service tech said that's just the way it is. (Fortunately, they gladly took care of all the other little things that had to be worked out during the warranty period.) I'll keep you posted. Thanks, again.

Bob and Nancy
'05 AS LYG 30 S/O
Wrangler Toad
Michigan

[harold1946]

Bob
I have located some more info on the valve. Go to yahoo put in Evans valves and you will find a schematic and troubleshooting guide in PDF format. Just in case you haven't located the valve it is under the hood just above the dipsticks. good luck

[Michigander]

Thanks again, Harold. By the way, I had the bright idea of reading about the dash ac / heater in my owners manual. It says that the center rotary switch marked "cold-hot" controls the amount of hot water flowing through the heater core. So now I have to trouble-shoot why mine sends out either hot or cold air, with no in-between. I'll follow the yahoo lead and see where it gets me.