coach propane heater

[cottrelltrav]

temp in southern CA. 38 degrees this morning.
Our prophane heater blower came on, then heat for about 10 seconds. will cycle this way three times and then shut down.
We had prophane filled 2 days ago. I can't remember if we used the heater yesterday morning.
We has a similiar problem awhile back after getting prophane filled but valve at tank was off.
It sounds like we are not getting prophane to heater at a steady flow.

The coach is a 2002 Dolphin LX 36 foot.

Hope someone can help

Ron

[Batman_777]

Possible: Check the emergency propane shutoff switch. The unit may try to come on but, no propane. It goes through the cycle a few times and then gives up.

[RV Wizard]

How long has it been since the furnace was serviced? If the flame at burner is not sensed, then the ignition control board will lock out after three attempts to ignite furnace. If you are getting heat for about 10 seconds, then you are getting lp gas to the burner and it is igniting; it is just that the board does not know there is fire at the burner, hence shuts down. It could be one or more of several items, or it could just need a good cleaning. I would recommend a good cleaning first and then bench testing by a qualified individual.

[John]

Same symptoms and, like I did, make sure the tank valve is opened. Mine worked a lot better that way yesterday morning

[cottrelltrav]

After turning on and off at T-stat, the heater fired up and kept running. This morning, same thing. cycle 3 times, then shut down. kept trying until the heater stayed running. I have not had it serviced in 3 years so I think you hit nail on the head. Having said that, what is involved in the service. is it a matter of cleaning or is it more tech involved.

[RV Wizard]

While it may not require a technician to clean the unit; it will require a knowledgeable individual and some safety precautions. The unit will need to be removed (LP gas turned off first) and dismantled, careful not to damage gaskets or replace them if so. Clean the burner, nozzle, igniter, combustion chamber, blower wheels, control board and heat exchanger if need be. Bench testing is always good before reinstalling. Verifying 11" working pressure of the LP gas system is important. Leak testing the LP gas system, after re-installing, is mandatory before firing up the unit.

[Roadking]

It kind of sounds like the furnance is failing to "detect" flame after ignition. On most current furnances the controller board require positive flame detection with seconds after ignition. Upon failure to detect a flame the furnance will shut down with seconds after ignition. It's a saftey issue. After 3 failed attempts to detect positive ignition the furnance controller goes into "lockout" and will stop the ignition sequence until the controller is reset.

Your furnance (you don't mention the brand name) may use the iginition probe to perform both flame ignition and flame detection. For flame detection the probe is heated by the flame and this produces a very, very, very small micro-current which is sent back to the controller. If your furnance is of this type and previously worked without anyone touching it then the most likely problem is the ignition probe is dirty and fails to detect the flame. The probe must be cleaned or replaced. At the same time your furnance should be properly cleaned and serviced. Don't bend the probe as the placement in the flame is critical to both ignition and detection. This is a saftey issue, so unless you're knowledgeable and comfortable with performing the work yourself, pay the bucks and have a competent professional service the unit. Gaskets and other seals can be easily damaged and blower fans can be easily damaged causing leaks and vibrations.

[Clay L]

Quote:

Originally Posted by RV Wizard Leak testing the LP gas system, after re-installing, is mandatory before firing up the unit.

I pulled mine out a few days ago to clean off an accumulation of pet hair and dust that was causing a vibration. I had a heck of a time getting the propane fitting screwed back on. The space was limited and it just would not line up. I finally removed a speaker from the outside entertainment center so I could get my hand on the tubing to help get it in the right position.

Is there some RV tech secret that makes that easier?

I used a commercial leak check liquid on the fitting to make sure it was tight. Is that what you use or do you have a more sophisticated check?