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Topic: Front furnace issues (Read 716 times) previous topic - next topic

Front furnace issues

When I turn the furnace on in my 1989 Foretravel Grand Villa it goes through its normal process of producing heat. It goes through from one to several heat cycles. Then in a cycle it produces heat and stops its cycle, but the blower does not shut off and blows cold air continual until I shut off the thermostat.  I wait until the blower shuts off.  I then turn the thermostat up to temperature desired and it begins a heat cycle, heats and then eventually it stops heating, sometimes shuts off, but eventually it goes through a heat cycle and the blower does not shut off and blows only cold air again.  Early in the year it was only once in a great while. Now it is almost occurring with every heat cycle.  I hope this helps.  Can anyone narrow it down to one thing that is the problem?  Thank you for all your help. 
Curtis
1989 GV

Re: Front furnace issues

Reply #1 –
Standard furnace board will keep fan running when burner stops for any reason. Dinosaur replacement board usually will stop blower if burner stops or does not ignite.

Furnace has a sail switch that if it does not sense enough blower air flow will turn burner off. Problem us often low battery voltage that lets blower motor slow down, or problem could be with sail switch.

High plenum heat thermostat will open a switch until the thermostat cools, that turns off burner.

Use 120-volt space heaters to keep warm until furnace problem is resolved.

Re: Front furnace issues

Reply #2 –
My rear furnace did similar, and I now have a new furnace.

Re: Front furnace issues

Reply #3 –
I had the same problem as you. It now work because I got rid of the bad converter. My converter was putting out 11 or so volts so my furnace acted as yours. So check your voltage with the furnace running.

Is you battery being maintain at 13.xx volts or is your converter killing it?
Michael j
Livermore, Ca for now

1987  Grand Villa 2900 Rear Bath Front 460 Gas Engine.

Re: Front furnace issues

Reply #4 –
Mr. Heater Buddy (9,000 BTU version) quick connected into LPG supply and cracked a couple of windows.  No noise and uses very little LPG.  When not in use it gets out of the way easily (quick connect). 
First got it as a back-up for the furnace (no electric) and ended up using it all the time. pc
 
S/W Houston 95" U320C SE/40' 
Build #4778  Cummins M11
Repairs & Covered RV Parking (BAO)
PPL is close..

Re: Front furnace issues

Reply #5 –
I am taking the advice of getting a new furnace and then rebuilding and bench testing the rebuilt one.  A fellow worker who is certified HVAC told me, without looking at it, it sounds like the relay or limit switch. When I replace it with the new one I will fully rebuild the removed one for a spare. Here is the confusing part.  I shut off the furnace for almost two days and  then I got up this morning to work on it.  So I turned it on the let it cycle until it blew cold air, but it is now working perfectly.  Now I am totally confused.  Does anyone have any idea why now the furnace works like there was nothing wrong with it to begin with?  Oh yes, I will be setting a line up this spring to hook into a Mr. Heater Buddy for a backup. Thanks for all the great advice.  Hopefully retirement will allow me to get where snow and cold temperatures are rare. :))
Curtis
1989 GV

Re: Front furnace issues

Reply #6 –
"Does anyone have any idea why now the furnace works like there was nothing wrong with it to begin with?" "I am taking the advice of getting a new furnace and then rebuilding and bench testing the rebuilt one." I think you answered your own question. THEY KNOW!!!

Happy New Year!

Re: Front furnace issues

Reply #7 –
I was having trouble with my rear furnace and none of the RV shops could fix it.  Had the heating and plumbing shop to the house to do yearly maintenance on my stick house Lennox forced air furnace.  I mentioned the problem with my Foretravel furnace to him and he offered to look at it.  He had it working in less than ten minutes.  And he included it in the minimum labor charge for the house furnace!!  But several RV techs were at a loss???  You know who I'm calling the next I have trouble with either coach furnace.
1994 U225
build #4514

Re: Front furnace issues

Reply #8 –
Quote from: sonshineclg –
Oh yes, I will be setting a line up this spring to hook into a Mr. Heater Buddy for a backup. Thanks for all the great advice.  Hopefully retirement will allow me to get where snow and cold temperatures are rare. :))
I think I would prefer a Platinum Cat Welcome Page or a Webasto: Comfort solutions for motorhomes and caravans.  Much safer in my book!
1994 U225
build #4514

Re: Front furnace issues

Reply #9 –
Curtis,
I would start by unplugging and reconnecting every connection on the furnace just to be sure there isn't a high resistance connection.
John Duld
1995 U320C SE 40'

Re: Front furnace issues

Reply #10 –
Curtis,

Here are my experiences with my 88GV ORED

Same issue, we just kept turning it off at thermostat, it would sometimes work. K
Doing that for a week or so then, it just started working all the time. My Dad says the contacts get dust and little oxidation and when they sit for weeks or months it returns.. using it clears the oxidation. This went on for 2+ years.. untill we started to Full Time.
The selected media item is not currently available.
My advice and experiences are Free, you decide if they are worth anything .

John - driving Old Faithful
1994 U280 GV
C8.3, Banks, Pacbrake, 900 watts, Resonator, XLHD tow dolly
Retired Army Warrant Officer

Life is what you make of it - if it is lemons, make lemonade!
Former Coaches:
1988 GV 40' ORED 300HP CAT - 9 years
1990 Winnebago LeSharo - 3 years
2000 Newmar London Aire - 3 years (#18 of 23 produced)

Re: Front furnace issues

Reply #11 –
Okay, clean the points in the old style thermostat with some sand paper or a file.  Better yet, replace it with a Hunter battery operated digital thermostat.
1994 U225
build #4514