Reply
 
Thread Tools Search this Thread Display Modes
 
Old 12-27-2002, 10:41 AM   #1
1 Rivet Member
 
Join Date: Dec 2002
Posts: 10
Unhappy Furnaces blowing but no heat

I just bought a 1992 350 Classic and am new to the motorhome world. In trying to figure everything out I am able to get the front and rear furnace blowing, but cold air. I follow the instructions in the manual but no heat. Any suggestions??
__________________

__________________
Dave Emmerich is offline   Reply With Quote
Old 12-27-2002, 10:57 AM   #2
2 Rivet Member
 
Join Date: Nov 2002
Posts: 74
Images: 2
You might have air in the lines if the trailer had been sitting for a while. Try the burners on the stove. I always get nervous around propane, have it checked out by a pro. My brother loves to tell me about the story of the hunter who comes back to his trailer, opens the door, and the whole thing explodes. The door protects him from the blast. Knowing my brother he could have made this up of course.

Most these little heaters blow cold air when the thermostat calls for heat. At least the old ones do.
__________________

__________________
barbwire is offline   Reply With Quote
Old 12-27-2002, 12:00 PM   #3
Just a member
 
thenewkid64's Avatar
 
1978 28' Argosy 28
Tampa Bay , Florida
Join Date: Mar 2002
Posts: 4,539
Images: 21
Send a message via AIM to thenewkid64 Send a message via Yahoo to thenewkid64 Send a message via Skype™ to thenewkid64
You may want to check to be sure the gas petcocks are open. On the outside of you MH look under the skirt directly below the furnaces. There should be a copper gas line going into the floor of the coach. On this line there may be a small valve with a handle. if the handle is in line with the valve then the gas is on. If not then it is off and you will need to turn it.

Do the other gas appliances work? Water heater, refer, stove?

There is a main valve on the tank that also needs to be opened for any of them to work.
__________________
Brett G
WBCCI #5501 AIR # 49
-------------------------
1978 Argosy 28 foot Motorhome

Wise men talk because they have something to say; fools, because they have to say something. -- Plato


thenewkid64 is offline   Reply With Quote
Old 12-27-2002, 02:13 PM   #4
Rivet Master
Commercial Member
 
ViewRVs's Avatar
 
1977 20' Argosy 20
Charleston , West Virginia
Join Date: Feb 2002
Posts: 1,226
Images: 9
Send a message via Yahoo to ViewRVs
Dave,

Welcome to the group! Please say hi to all my wife's family in Boston! They treat me very well whenever I visit! I love to eat and Italians love to feed people. Wonderful fit!

Assuming you have Duo-Therm furnaces under the kitchen sink and in the rear bedroom....

1) Make sure the main gas valve is open on the main tank.

2) Make sure the gas valve at the unit is open (with the gas pipe (open) as opposed to perpendicular to the gas pipe (closed). The valve is behind a small metal panel with two wing-nut screws.

3) I would run the stove to get gas flowing through the lines and also the verify gas in the tank. (then shut off the stove) p.s. that indicator on the panel is next to worthless! Check the gauge on the tank (thanks again Brett).

4) Try one at a time. Mine took a little time before they started working. Now my center one works great but the rear one quit.

Things to consider:
5) Do you have mud dubber screens on the exterior vents?

6) You might want to have the boxes cleaned and sealed. These things have been known the cause problems. They don't work well when dust gets inside the box from the exterior vents.
__________________
Fred H.
1977 Argosy 20' Motorhome
Fred's Airstream Archives @ ViewRVs.com
ViewRVs is offline   Reply With Quote
Old 01-03-2003, 08:34 PM   #5
Rivet Master
 
zamboni's Avatar
 
Join Date: Jun 2002
Posts: 521
I to have this problem

I also am having trouble with our furnace. Gas in MH is functioning at all appliances, I just can't get the furnace pilot light to light or stay lit. The fan does run if the thermo is turned up.

I believe that the unit is original...23 years young. In Spring I'll have to check the voltages and the thermocoupler. Any other things to check would be greatly appreciated.
__________________
zamboni is offline   Reply With Quote
Old 01-03-2003, 09:02 PM   #6
Just a member
 
thenewkid64's Avatar
 
1978 28' Argosy 28
Tampa Bay , Florida
Join Date: Mar 2002
Posts: 4,539
Images: 21
Send a message via AIM to thenewkid64 Send a message via Yahoo to thenewkid64 Send a message via Skype™ to thenewkid64
Since the furnaces are auto ignition models you may want to test the sparker?? It should be a L shaped probe with a ceramic insulator that is ner the burner. If the gap is too great or there is some rust shorting it out it will not work.

Also you mention that the fan blows but the heat does not come. This could be a bad Sail switch that is not sensing the air pressure in the ductwork and so it will not let the furnace light. Try closing off with the louvers on a couple of ducts and see if the additional back pressure gets it to light.

The logic on most furnaces ignition procedure:

1. Start fan

2. Sense Air pressure Via the sail switch.

3. Open Gas Valve

4. Fire ignition for 5-10 seconds.

4A. If furnace lights, run until demand for heat stops or thermocouple indicates no flame.

4B.If furnace does not light, Shutdown igniton for time out period and retry starting at #2.

After three tries the logic usally stops trying to light and will require a restart from the thermostat.

Hope this points you in the right direction. Remember playing with fire (LP) can be dangerous!
__________________
Brett G
WBCCI #5501 AIR # 49
-------------------------
1978 Argosy 28 foot Motorhome

Wise men talk because they have something to say; fools, because they have to say something. -- Plato


thenewkid64 is offline   Reply With Quote
Old 01-04-2003, 08:53 AM   #7
Rivet Master
 
ALANSD's Avatar

 
1966 26' Overlander
Woodstock , Georgia
Join Date: Feb 2002
Posts: 8,463
also there is an air flow adjustment screw on many furnaces, if too much air is in the mix , and it does light, the air will be only slightly warmed if at all. If there is not enough air you will get heat but also a lot of sooting.
I am wondering what you do when the air adjustment screw is all the way in, to eliminate the soot, and there is no more adjustment left...the flame is supposed to be nice and blue, mine is starting to peak orange. Would I pull out the unit and clean the chambers? Replace the igniter( it looks new)
__________________

__________________
ALANSD is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Heat Pump and Furnace Operation Cracker Water Heaters, Filters & Pumps 21 12-10-2003 04:10 PM
Refer heat / venting JaceBeck 1999 Safari 3 08-21-2003 09:40 PM
Starter heat problems ALANSD Mechanics Corner - Engines, Transmission & More... 0 02-15-2003 03:51 PM
Heat protection ALANSD Airstream Motorhome Forums 14 11-03-2002 03:55 PM
Heat Riser ALANSD Airstream Motorhome Forums 7 09-11-2002 04:38 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:00 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.