New issue just woke up to

[5th_Wheelin]

Sound asleep, and was woken up to a very loud banging noise. Turns out it's the furnace. It's was running just fine all day and night. Now when it tries to cycle on it just makes a huge banging racket, like an automatic rifle and won't stop until I turn the thermostat to off.

Any ideas here? If I can't get it diagnosed by noon, I will be cutting our Christmas trip short and head back home.


Thanks in advance

[flybouy]

Check the obvious first. If you are boon docking check battery status. Then check propane, does your stove top work. If propane is good then check for a blocked orifice in the burner tube as spiders and the like will nest there looking for heat May also be a faulty board. More folks will chime in with suggestions. Good luck, let us know what you find.

[jsmith948]

I would check the furnace blower. Since the trailer is new, it seems unlikely that the bearing has failed allowing the fan to hit the housing. However, since it is a new trailer, there could be construction debris of some kind that has come in contact with the fan. That would be my first guess, especially if it is a metallic sound. You might have to remove one or more of the furnace ducts to be able to see the fan.

[chuckster57]

I agree, fan issue.

[5th_Wheelin]

Got both supply and return ducts off the furnace. Looked inside the unit and can't see anything abnormal. Really just empty inside the rectangle box other than some metal tubing. Took the panel off outside and nothing abnormal there either. Put my finger on the fan and it spins freely.

Any other suggestions? Could it be some type of misfire? Stove top burners light up no problem and continue to stay light. We just switched over to a new tank yesterday via the propane tank switch because we used up the first tank.

[rsl]

Now that it is light outside and you are awake turn it on and see what you can see or hear. Unfortunately a lot of RVing fixes are just a process of elimination trail and error game.

[JRTJH]

First, does it make this noise as soon as the fan starts to turn (before propane ignition) or after ignition? If it's before ignition, it's probably something in the squirrel cage blower assembly, if it's after ignition, it may be something associated with the firebox as it heats up and expands. Either way, since you have the side panels off, stand clear and don't stick any fingers into the furnace, turn on the thermostat and as the fan begins to turn, see if there is anything that you can "zero in" on the sound.

Remember, there are two squirrel cages on the motor shaft. The large one pulls air from inside the coach, over the heat exchanger and into the ducting. The small one is inside the firebox and pulls outside air into the furnace and exhausts through the vent on the outside of the trailer. The two squirrel cages are held onto the shaft with a small setscrew. You may find that one of them is loose, things work OK at very slow speeds (turning with a finger) but wobble significantly at normal operating speeds.

My guess would be the firebox squirrel cage setscrew is loose.

[5th_Wheelin]

The adventure continues! I buttoned everything back up so I could turn the furnace on in an attempt to try and troubleshoot in the daylight.....and the thing fires up and runs like it's supposed to. I guess I'll continue to keep an eye on it and hope the issue is somehow fixed.

Good news to take away, I'm becoming real familiar with the innards of the unit! Hahaha

Now on to cooking up some eggs and bacon.

[5th_Wheelin]

Oh, and you guys are a wealth of information. I can't thank you enough for taking time away from your day to help a rookie out.

[JRTJH]

We were all rookies at one time, no shame in asking for advice. Hopefully you "fixed" whatever was loose and it'll work like it should for the rest of this trip. Enjoy the "day after Christmas" and the rest of your trip.

[sourdough]

I would keep my eye on the fans. I had a new rv once that did a similar thing on my first trip. Had to replace the furnace because the "innards", (fans, bearings etc) were faulty.

[Ken / Claudia]

I think there is a clue in post #5. He switched over to a new tank for the first time. Without being there to inspect anything. My guess is he lost propane pressure ie 1st tank went empty. Then switched to new tank, could have been it popped a few times trying to start but, would not until #2 tank pressurized the line. Could avoid that if had both tanks turned on and used the auto tank switch as one gets low.

[5th_Wheelin]

I think there is a clue in post #5. He switched over to a new tank for the first time. Without being there to inspect anything. My guess is he lost propane pressure ie 1st tank went empty. Then switched to new tank, could have been it popped a few times trying to start but, would not until #2 tank pressurized the line. Could avoid that if had both tanks turned on and used the auto tank switch as one gets low.

While I'm still not sure what happened, I'm not inclined to think it was the LP tank switch. I say this because we switched tanks first thing in the morning because we woke up cold. The tank #1 ran out during the night. So from 6:30am until 2:30-3:00am the following morning (almost a full 24 hours) it was running on tank 2 with no issues.

We are still keeping an eye on it, but it hasn't done it again THANK GOD! But, we are afraid to leave the 5er with the furnace on now. I would hate for that to happen if we left for a short trip into town or on a hike. Sucks for my dog, but at least she has the fireplace to sit in front of while we are gone.

[Eastham]

A friend of ours had the same problem called the mobile Tec $75.00 later tec found 2 shishkabob sticks worked there way into the fan .has worhed fine since tec removed them.

[notanlines]

5th, I'm inclined to side with Ken on this. The only thing that happened is you changed tanks. I'll bet all is good. (Ken and I differ on keeping both tanks open...NBD)

[chuckster57]

Having ran out during a cold night ONCE, I keep both cylinders open. That’s what the auto switchover regulator is made for.

[ctbruce]

I'd disconnect my waterline at the least. Switch over to fresh water tank and water pump for the night. Enjoy, sounds like fun!

I also do not think it was the tank that was causing it, but it was the tank dying and running out of propane that did. Reason being that when you started the new tank the problem went away. Either that or you have one of Crazy Cain's ghosts stuck in the furnace.

Sent from my SAMSUNG-SM-N910A using Tapatalk

[Alpine]

I too leave both tanks open and let the regulator do its thing! Glad the furnace is working for you again. I have lost track over my "short" life, how many times I have taken something apart then put it back together and it "magically works again!!!

[sourdough]

As an aside note; I would always keep both tanks open. The regulator switches them for you preventing middle of the night hiccups. All you have to do is get familiar with your trailer and your usage; when the time seems like you should check, look at the tanks and see. I have an enclosed cowl with the 2 tanks and it takes me all of 30 seconds to pull down the cowl and check the tanks. One is empty....off we go. No shut down, freezing etc. etc.

[Tinner12002]

Sounds like a delayed ignition situation where gas supply is spotty causing mini explosions when its trying to light with air in the lines then back out when gas goes away. With that being said, I'm also with the group that says it was an issue that happened when switching tanks. Dirty burner will cause that also but being a new RV shouldn't have that issue, fan spun freely with no noise so it wouldn't be that as long as something hadn't gotten pulled through the duct system but it should have still been there when OP opened it up.