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Furnace miracle

TOMMY47
Explorer
Explorer
I was on a long trip in MH.
About 2 weeks in, furnace stopped working. Worked fine earlier.
Didn't work when tested during rest of trip ( 13more weeks),(Didn't need it then)
Home now. Tested it and it works just fine.
Any ideas why not then and why now?
7 REPLIES 7

wa8yxm
Explorer III
Explorer III
Ok, That is the very description of a faulty sail switch **OR** a low voltage problem.

Someone ask "What is a sail switch"

Well, I'm sure you know what a switch is, think Doorbell button
And you know what a Sail is. Makes boats move over the watter.

A Sail switch is a much smaller sail with a momentary normally open switch, when the wind blows the sail pushes against the spring and the switch closes.

If the switch is faulty, it won;'t close, if the sail is broken it won';t push.

IF the blower is not getting full power (or if the blower motor is bad) it won;'t make enough wind.

In the specific.. I'd guess it stopped cause the batteries were low and it works cause they have since been recharged.

Now, there is another no-ignition posibility (But you also said NO CLick and with this problem you WOULD have a click)

Propane vaproizes at temps abobe around -40 (C or F your choice, they are the same). I think it like 1-2 Degrees warmer.

BUTANE, which is less expensive vaproizes at temps where water is liquid.

If you fill up in the sunny south, some dealers rip you off by selling the lower cost BUTANE as Propane, so long as you stay above freezing you may never know the difference.... But if you come north.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

TOMMY47
Explorer
Explorer
Fan came on--No click- No ignition--Just fan.

PaulJ2
Explorer
Explorer
Remove and replug the circuit board edge connector, they have a habit of corroding the contacts.

wolfe10
Explorer
Explorer
Tommy,

Tell us at what point the furnace stopped working:

Did the fan come on?

Did the ignitior "click" and gas valve open?

Did you have ignition-- if so, how long.

The sail switch monitors air flow through the furnace "clean side". It will not allow ignition or gas valve to open if insufficient air flow, as it could cause superheated temperatures and possible a fire.

Causes of insufficient air flow are:

#1. Low voltage at the furnace so fan does not turn fast enough to generate enough air flow to close the sail switch.
2. Restriction in furnace air return.
3. Restriction in ducting or outlet vents.
Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

tvman44
Explorer
Explorer
Loose connection? ๐Ÿ™‚
Papa Bob
1* 2008 Brookside by Sunnybrook 32'
1* 2002 F250 Super Duty 7.3L PSD
Husky 16K hitch, Tekonsha P3,
Firestone Ride Rite Air Springs, Trailair Equa-Flex, Champion C46540
"A bad day camping is better than a good day at work!"

TOMMY47
Explorer
Explorer
What's a "sail" switch?

rbp111
Explorer
Explorer
I was camping last year, and it got cold. I put on our furnace, and it did not work. Played with it a while, then suddenly it worked. Then it did not. Called a professional technician in and he diagnosed it as a faulty sail switch. Changed it out, and it has never failed yet.