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bradleyoder · 09-25-2015, 04:27 PM

We live (full-time) in our 1985 34' Excella. Our furnace worked great last night, but by morning it was blowing cold air. Sure enough the tank was empty, so I switched tanks. Water heater and furnace didn't relight. I adjusted water heater igniter till it lit, but when I checked igniter in the furnace, it doesn't seem that gas is getting to the chamber... Stove and water heater working fine. Help please. Thanks!

87MH · 09-25-2015, 04:33 PM

Try the ignition sequence at least four or five more times.

Sometimes it takes a bit of patience to clear the lines of contaminated gas.

Please report back how you resolved the problem.

Airline · 09-25-2015, 05:20 PM

It seems like its hardest to get the air out of the furnace lines...

Keep trying.

bradleyoder · 09-25-2015, 07:14 PM

Ok. Will do. Thanks!

Ted S. · 09-25-2015, 07:33 PM

This has happened to mine. Eventually it re-lit.

CRH · 09-25-2015, 07:37 PM

Light a stove eye for a bit to purge the lines.

bradleyoder · 09-25-2015, 08:27 PM

I did try the stove thing earlier, but not for several starting cycles. Sadly, six cycles did not do the trick tonight. I'll try with the stove tomorrow. Thankfully a Broan Big Heat (but very tiny) space heater is cranking away in lieu of the furnace, although I'm guessing propane is cheaper than kWh, which matters because it's our utility bill.

tjdonahoe · 09-26-2015, 01:36 PM

Make sure you have gas,turn on the valve, turn gas on stove until it lights.....works every time to fill the empty gas lines....

SemperBadger · 09-26-2015, 03:03 PM

If your tanks/system are relatively new they are probably equipped with an Overfill Protection Device and other safety devices. The excess flow valve part of this system (tank and regulator) can automatically prevent the flow of propane from the tank to your lines if it detects a sudden increase in gas flow. The idea is that it would prevent the flow of gas if one of your copper lines tore off the bottom of your trailer for example. The valve can accidentally trigger if you switch out propane tanks and open the valve on the new tank too quickly. This simulates the sudden propane demand that the safety feature was designed to address. If you just hook up and throw the valve wide open (like I used to on our BBQ grill) you are likely to encounter this problem every time you change tanks or close the valve for storage, etc.

I would close off the valve at the tank, light the stove for a minute to clear the propane and air out of the lines, then very slowly open up the valve on the propane tank. If you do nothing at all the situation should resolve itself once the pressure equalizes.

I'm not sure if that is your issue but something to consider...

OTRA15 · 09-26-2015, 03:12 PM

In my 1985 25' AS, the furnace circuit board gave up the ghost, and I had to replace it. Is your furnace original?

coloradopete · 09-26-2015, 04:28 PM

Be sure that the tank selector on the pressure regulator has been turned to the active tank. If you have access to a manometer, check the gas pressure at the furnace. Should be between 13-15 psi. If not, adjust the tank regulator to meet this standard. Also, you may need to replace the overheat cutoff safety switch. Easy to do and not expensive.

bradleyoder · 09-26-2015, 05:41 PM

Tried lighting with stove lit. No go. I think it's probably original. Terrified of having to replace something, or replacing the whole thing, because of having to possibly open up the floor to get to everything to disconnect and reconnect. Will keep trying the startup cycle with stove lit.

bradleyoder · 09-26-2015, 05:43 PM

As an aside, I don't know why the bathroom duct is very low pressure. Probably have to tear open the floor to get to duct junctions?

Streamracer · 09-26-2015, 07:00 PM

A few years ago the heater on my 86 would not light. First off If your batteries are not charged the sail switch will not close and let the gas valve open. Mine was okay and I replaced the circuit board and it solved the problem a time or two. Finally I figured out the gas solenoid was sticking closed. After disassembling and cleaning it my problem was solved. That has been a couple of years ago.

Punch · 09-26-2015, 07:29 PM

I agree with Streamracer about the batteries. If your blower has been running for hours trying to warm things up, very likely the batteries are discharged. This is the simplest and most often overlooked explanation of your symptoms. Make sure you have a good 13 volts from both batteries before thinking of an alternative explanation. In addition, if your batteries are a few years old, their performance might be marginal in any case. The furnace sail switch needs pretty much full voltage if it is going to open.

bradleyoder · 09-27-2015, 10:20 PM

But we are plugged into our 30 amp outlet constantly. Could the batteries be the issue if that's the case? I hear our converter turn on every now and then, seemingly to charge the batteries if the batteries are low, and all our other low-voltage appliances are working properly.

Punch · 09-28-2015, 06:06 AM

I am no expert on this, and I am sure an expert will be along shortly, but with the '94 LY that we owned, batteries turned out to be the problem. The non-ignition was happening even though we were plugged in to shore power. New batteries and Bingo!.... in business again.

My non-expert guess is that the furnace runs off the batteries and not the converter, and the furnace sail switch requires a higher voltage than any other DC appliance, and the converter doesn't kick in until the voltage is below that point. We had a mobile RV mechanic come out and diagnose our problem, which had been frustrating me for two cold trips in the MH.

bradleyoder · 09-28-2015, 06:38 AM

Thanks. I pulled out the igniter, and it seems to spark with plenty of gusto. It seems to me more gas issue, some sort of valve not opening or something like that… I don't smell any gas at all from the furnace when I'm doing the start up cycle… but it may be time for new batteries anyway!

OTRA15 · 09-28-2015, 07:06 AM

As we enter the winter months, if your batteries are more than a few years old, it may be a good insurance policy to replace them, especially with an older 34' unit which has multiple 12 volt appliances and lights. You can always keep the current batteries in reserve. Having new batteries will also eliminate one of the variables being discussed here.

Punch · 09-28-2015, 08:16 AM

Quote:

Originally Posted by bradleyoder

Thanks. I pulled out the igniter, and it seems to spark with plenty of gusto. It seems to me more gas issue, some sort of valve not opening or something like that… I don't smell any gas at all from the furnace when I'm doing the start up cycle… but it may be time for new batteries anyway!

Bradley... it all fits. The igniter has no problem. My igniter was snapping away happily too. It is the sail switch. No gas for the igniter to ignite, so yes you won't smell gas.