Furnace stopped working yesterday and then started working again last night

[ajw1970]

We have a 2022 Reflection-150 295RL with a Suburban furnace.

Yesterday, our furnace stopped working. The call for heat would start the fan but I wasn't hearing a clicking or ignition. The fan would shut off within 30 seconds.

The tankless water heater was working fine. The stovetop was working fine. We tried the oven for the first time yesterday and that does not work. I assume it's never worked. We get a spark but no fuel from what I can tell. I wasn't able to light that with a lighter either.

We tried resetting many times in a variety of way (read a lot of posts in here yesterday):

1) Disconnecting from shore power and disconnecting the main disconnect. Wait 30 seconds or longer.
2) Remove the furnace fuse and wait 30 seconds or longer.
3) We turned the thermostat off. Wait 30 seconds or longer.

We finally gave up and left the thermostat off and set the fireplace on high with a plan to call GD in the morning.

Just before going to the bedroom, I turned the thermostat back to heat just in case it might start working in the night.

This morning, the camper was holding the thermostat temp. It's working fine now for over an hour.

What could this have been? Just air in the lines? Maybe a sail switch that magically sorted itself out in the night?

We have clear exhaust flow from the furnace and clear vents.

One other propane related thing is that since arriving at this campground in NC, we have noticed the tankless water heater reach temps above the 124 degrees setting (which we thought was the highest setting). It's only 2 or 3 times and it's been while my wife was using the water for an extended period of time. I assumed that wasn't really a problem.

We've also had 2 or 3 times since we bought the camper new that the propane alarm went off on the water heater but after shutting off the propane tank to remove it, I discovered it was at least 50% full. I simply opened it back up and the water heater was happy again.

We just learned for the first time in reading posts yesterday about needed to bleed air from the lines by starting the stovetop after connecting tanks. I can't see how you could get air in the lines after things were working though.

[howson]

ajw1970

I agree the furnace issue is either an intermittent sail switch or it could be an intermittent main board problem. Intermittent problems are difficult to troubleshoot and isolate.

---

With regards to the "air in the lines" all I can do is relate my personal experience. The propane cylinders on my 315RLTS are closed as part of the pre-departure list. At the end of the day at the new campground opening the cylinders is on the arrival list. As part of the propane cylinder opening process a stove top is lit to ensure good flow of propane. It is rare to not have to hold the stovetop burner in the "light" position for 10 to 30 seconds (while occasionally turning the piezo lighter knob) to get the burner to light. Note that I've checked the camper's propane lines for leaks (monitored WC over 5 minutes and there was no loss in pressure) so there's system integrity.

Why does it take so long for the stovetop burner to light in the scenario described in the previous paragraph? I'm not sure...atmospheric and temperature differences? No idea.

Howard

[Scott'n'Wendy]

My guess would be sail sw. I say this because in my experience when a board falls...... it stays failed. Don't think air in the line is likely.
But it wouldn't hurt to remove and reconnect the connectors on the board to ensure clean contact.
like Howard says..... intermittent problems can be frustrating to solve

[TucsonJim]

We had the exact same issue last month. The furnace fan would come on for 30 seconds and then shut down with no ignition. We'd had a dust storm earlier that day. I assumed the sail switch was not making contact. I fired up my compressor and blew the dust out of the furnace where ever I could. The furnace fired right up, and worked perfectly dozens of times after that.

Jim
'

[cnote72]

When this happens with a residential furnace, it is usually a dirty flame sensor. I have no idea if these furnaces have a flame sensor, we just got our 5th wheel and haven’t been out camping yet. Surely there is something that proves flame so it doesn’t just dump propane if it’s not lit.

[Jlawles2]

I am having issues with my Blackstone not heating enough off the aux port on the side of the camper. So this past weekend I pulled the gas gauge out and checked the pressure. 9 in-H2O. I adjusted the regulator up as far as it would go but still only managed to get 10.5 in-H2O static.

You could have an issue with too low of gas pressure for the furnace, it seems the HWH is much less susceptible to gas pressure as some of the other appliances.

Also if you are not running the appliance at the end of the line, it could be that you are getting gas dilution creating the issue. I have opened both valves on the bottles and purged the lines all the way back to the stove in pre trip checks, then a couple of weeks later when I go to light off the refer for departure, I have to re purge the lines. Some how air gets back in to the lines every time.

[howson]

cnote72 -- from the description of the problem the gas valve is not opening and the furnace does not attempt to light. In the sequence of operation for our furnaces that means the appliance thinks the fan is not running, thus the most likely failure is the sail switch was stuck or the main board wasn't registering the switch position.

If the furnace had lit, then gone out quickly, and went through that process three times before locking itself out I'd also suspect the flame sensor (or main board).

Howard

[cnote72]

cnote72 -- from the description of the problem the gas valve is not opening and the furnace does not attempt to light. In the sequence of operation for our furnaces that means the appliance thinks the fan is not running, thus the most likely failure is the sail switch was stuck or the main board wasn't registering the switch position.

If the furnace had lit, then gone out quickly, and went through that process three times before locking itself out I'd also suspect the flame sensor (or main board).

Howard

howson You’re correct, apparently I didn’t read the original post correctly, I was thinking it lit and went out within 30 seconds.