Furnance Issues

bjboles · 08-01-2021, 07:43 PM

2004 Winnebago Journey 34H. Need some troubleshooting help. I went to use the furnace this weekend, slid the thermostat to gas heat, thermostat clicks, then pops the 12v circuit breaker under the fridge. The blower fan never spins. I unscrewed the circuit breaker panel and checked the connection and they looked good. The furnace worked last fall before storage. House batteries charged to 12.8. Next step is to pull the cover by the hot water heater?

imnprsd · 08-01-2021, 10:35 PM

As a suggestion, I always make sure I can light my stove before trying to light the water heater and furnace in this order.

If you still can't get your furnace to light let us know what kind you have and is this the front furnace or the back furnace? A few pictures of your thermostat would be nice too.

bjboles · 08-02-2021, 05:09 AM

imnprsd, thanks for the suggestion on the lighting order. I wasn't aware that the Winnebago Journey had 2 heaters (Front & Back). I thought it was just the one located above the water heater. I don't think it's a lighting issue, the blower fan doesn't even turn on before the breaker trips. I'm leaning toward that. I will get you the info requested.

**creativepart** · 08-02-2021, 06:33 AM

Perhaps something built a nest in there over the summer and it’s blocking the fan, hence the blown breaker?

bjboles · 08-02-2021, 07:00 AM

Thanks creativepart. I'm more than likely going to pop the external cover off and inspect the fan for obstruction. Not sure what to really check above and beyond that.

imnprsd, here are pics of what what my setup is (pics for reference)

Morich · 08-02-2021, 09:27 AM

I tend to try to go with the most likely/easy to do things first before going to harder and in this case, I see one which is a common problem----if I'm reading the pictures right!

There are two round vents that wasps/mud daubers really love if they do not have some form of screen to keep them out. Those two round holes just look like an invite for them, so if they are not screened, I would start there as an easy place to check for air flow being blocked.

But it may not take a lot to check--- if you have the right items on hand. Something that forces air in or sucks it out can fit tight enough over those two round holes to check to see if air goes in and comes out the other hole!

I will include a snip of the parts drawing from this link:
https://www.winnebago.com/Files/File...04/4wkp34h.pdf

Type in page 220 at the top to slip down to the right page quickly for the full furnace layout but the main point is that the parts for the fan line up along the blue line.

ON RV furnaces, there is a safety item that will not let the gas flow until the airflow is checked by a sail switch which senses that flow. So if the fan shaft can't move, it is possible there is a nest stopping it?????

So if we can blow air over the fan to make it move, that will tell us it is free and we need to look somewhere else! If you blow air in and hear the fan moving, move to other causes!

This is the COMBUSTION airflow which is separated from the inside air but on the same shaft. So if there is a problem along the rest of the shaft as the blue line, that will also stop moving. Lots of things like rusty, bad bearings, dragging, etc. that it "could" be but if one moves they all move?

I believe item 44 will be the sail switch to make sure it is free to move. It hangs in the airflow and makes a convenient place to hang a nest!

bjboles · 08-02-2021, 09:51 AM

Thanks Morich. Does it matter if I blow through the top or the bottom? Should the fan be able to spin in both directions?

Morich · 08-02-2021, 10:11 AM

Right, either direction should get enough to move it as it should spin drag free. I actually do not know which is the normal in or out as I drew it.
Just looking at it as a "quickie" way to check for moving. Lots of things do require pulling it out but why do it if we can spot a nest in one of the tubes and fish it out with a wire?

Warning. If they are home, approach with caution.

There are times when I have found it won't move but if I used something easy to bend like 12 gauge wire, I have hooked the first fan you see and forced it to turn enough to break a mud dauber nest loose and then once it would start to turn, I just let the fan chew up the nest, rather than take it all apart while on trips. A fair amount of whang/banging but better than doing the job in a campground!

bjboles · 08-02-2021, 10:25 AM

OK. Thanks. Looking at it some more, the blue line is the air flow in to allow combustion on the first fan then through the blower fan over the heat tubes and out the duct work. The red is the combustion and exhaust out. So like you said, I don't think it really matters, but the top might give me a little more pressure to the fans. I plan on using a air compressor.

Morich · 08-02-2021, 01:04 PM

I really meant the blue line to show how the parts of the blower all line up on one shaft. Meant to show that getting one fan blad moving also gets the other moving, so if one moves they both should move but if there is something hanging the big one the moves air into the RV, it can also keep the small first one from moving, so we have to look at all the points on the blower shaft! Item 36 is actually inside item 37 but they draw it as way off, just as an easy way to draw??? Exploded drawings can get way to "exploded" to follow!

While a compressor may work, it takes large volumes, rather than high pressure so if something like a leaf vac is handy, it can work good.
But it's a cheap trick to try and if it doesn't, you are just back to taking it apart?/

Just assuming it's not easy, there may be some really good troubleshooting flow charts online that make a really logical point by point thing to follow. Not sure this is the same model, so check for matching but this is a chart/manual that I have stashed for info and may help:

http://techsupport.pdxrvwholesale.co...ice-Manual.pdf

Down about page 22 is what to do if "vent motor doesn't run" as a trouble??? Since it just blows a fuse right away, taking the wires off the thermostat might be a place to begin?

bjboles · 08-02-2021, 07:59 PM

Morich,
The leaf blower trick worked!! The blower turned on and then it lit. It does have a little fan noise when its powering down but not when running. It almost sounds like a contact noise more than a bearing squeal. I may have to take the cover off and take a look but for now it's working.

The heat pump works too. A question on that. Now let's say it gets down to 65degrees in the rv. I get up and turn the thermostat on and set it to electric. Then set the thermostat to 72 degrees. Since I'm over the 4 degree heat pump threshold will the LP furnace kick on first until 70 degrees is reached and then switch to heat pump?

Morich · 08-02-2021, 08:20 PM

Quote:

Originally Posted by bjboles

Morich,
The leaf blower trick worked!! The blower turned on and then it lit. It does have a little fan noise when its powering down but not when running. It almost sounds like a contact noise more than a bearing squeal. I may have to take the cover off and take a look but for now it's working.

The heat pump works too. A question on that. Now let's say it gets down to 65degrees in the rv. I get up and turn the thermostat on and set it to electric. Then set the thermostat to 72 degrees. Since I'm over the 4 degree heat pump threshold will the LP furnace kick on first until 70 degrees is reached and then switch to heat pump?

Good deal on getting it done!

But on the second question, I've never had the heat pump option, so best leave that to folks who will know better!

imnprsd · 08-03-2021, 12:30 AM

Great tip on using the leaf blower!

Note: I have never tuned-up my Suburban heaters, but maybe I should put them on my list of to-do's before next season.

I'm torn between doing some preventative maintenance, on a 2004 model furnace, and just leaving it as-is until one day I'm forced to learn more about yet another sub-system of this RV.

What do you recommend I do? What are a few good preventative measures to check when your Suburban 24 and 35 is working just fine, but is 15+ years old?

Or is this a case of: "If it ain't broke, don't fix it?"

Morich · 08-03-2021, 07:15 AM

Lube is always good on bearings but it is a pain to get to them, so it's a big one to think about. In my case, I knew that I had left a mess of mud dauber nest in the inside and that prompted me to think it bad enough to take it apart and clean enough, so oiling was just natural.
Some depends on how lucky a person is! If you get a hunk of mud built on the side of a bearing that doesn't seal too well, it can be bad to go without cleaning and oil but after tearing mine down, I found the nest was more just on the point where the blower wheel and frame met and it was not really fouling the bearing, so I probably was overly concerned about the bearings.
I think the bigger point might be to assure they could not get into that point in the future.
There are ready made screens sold to fit over the vents, but they tend to stick out and get knocked off, so I have made a point of looking at all the frig, furnace and water heater vents to see what I needed to do to get screen on each type BEFORE they got in!

This is one type but I find they don't seem to hang on too well and now drill out the rivets and place screen over the vent, flat so that I don't snag it and lose it. Pain to do but not like having to pull the furnace out!
https://www.walmart.com/ip/Stainless...E&gclsrc=aw.ds

The bearings are not a really well sealed type and I was able to get enough inside to make me feel better. I also never had trouble with that furnace again but I never seem to keep one RV long enough!

golden13 · 08-08-2021, 05:31 PM

Quote:

Originally Posted by bjboles

2004 Winnebago Journey 34H. Need some troubleshooting help. I went to use the furnace this weekend, slid the thermostat to gas heat, thermostat clicks, then pops the 12v circuit breaker under the fridge. The blower fan never spins. I unscrewed the circuit breaker panel and checked the connection and they looked good. The furnace worked last fall before storage. House batteries charged to 12.8. Next step is to pull the cover by the hot water heater?

The two most common issues with an RV furnace are a burned or wet circuit board inside the unit, or a fouled air sensor. Something as small as a human hair or a tiny dust mote can cause the unit to malfunction. If you decide to explore under the cover, do NOT touch that sensor inside that duct with anything metal. It's very soft metal, and even a gentle touch with a screwdriver, or whatever, can scratch it, and cause it to malfunction.

NeilV · 08-08-2021, 09:09 PM

A little caution to follow the flow when using a blower or vacuum since you really do not want to blow the sail switch paddle that detects air flow backwards and potentially damage the thin sheet metal sail or arm.

Mud daubers and other vermin do cause problems with the furnaces and other ported devices in the house and RV,

Radioflyer · 08-09-2021, 05:17 AM

Also have Journey (but 2009) with both propane heater and Mach basement heat pump. If you don’t want to trigger your Propane furnace in Fall look at the temp readout first and only initially set the thermostat to +2 degrees over. When it reaches that temp... move it up again +2. Helps to turn off (in my case) the ceiling vent(s) near the thermostat which allows rest of RV to warm higher before the control panel immediate area. This only works when outside temps are within the limits of the heat pump.

bjboles · 08-09-2021, 06:03 AM

Thanks everyone for the great info! Both the LP and heat pump are now working as intended.

Morich · 08-09-2021, 09:11 AM

Quote:

Originally Posted by NeilV

A little caution to follow the flow when using a blower or vacuum since you really do not want to blow the sail switch paddle that detects air flow backwards and potentially damage the thin sheet metal sail or arm.

Mud daubers and other vermin do cause problems with the furnaces and other ported devices in the house and RV,

I may have created some confusion on the way I drew the airflow on my previous snip as it is not as difficult as I may have made it appear. There is no problem, at least on this furnace, with the blower putting too much pressure on the sail switch.

One of the big features of all current model furnaces, is that the combustion air where we find the CO and hazardous fumes is ALWAYS kept separated from the room air which we breathe. Basic design, so that we don't get gassed?

But my drawing seems to have confused folks who have not actually looked at the airflow, so I have found a different exploded drawing which is a bit more clear and maybe I can show it better here.

The intake to the combustion air seems to be on top here and if we follow the red line, it goes in, across the smaller squirrel cage fan blade, into and through the combustion air chamber and then back out the exhaust. Item 36 is sandwiched and sealed inside item 37 which keeps any air from the burners from entering the room air which is on the other side of this seal where I've drawn the green lines.

Item 44 is the sail switch and it is shown as being in the larger chamber where the room air flows. Since the room air fan and combustion air fan are on the same shaft, it is assumed that they both move together. The heated room air is drawn in the RV intake vents, across the top of the heated furnace heat exchanger and back out into the room. No mixing with the gases in the combustion airflow!

It may not be true on ALL RV furnaces but on this specific design, the room air is where the big blower fan is located and the sail switch is in that airflow,
So damage to the sail switch is not likely if we use a blower on the combustion air.

I agree that it may be different on other furnaces but then designing it to put the electronics and switch in the heated air of the combustion air would seem to be a pretty poor idea.

The devil is often in the details and we do need to look close to sort out the solutions.

Journey39n · 08-09-2021, 11:24 AM

On my heatpump/propane heater, it can be a little hard to understand. But over the years I have learned, when setting to electric, the heat pump is going to come on and try to raise the temp to whatever the thermostat is set to. If it can not reach that temp in a given time, the propane heater will kick on to help.

If the propane is needed and kicks on five times in a row (like in low outside temps) the heat pump won't even come on for several hours, as the program assumes it is too cold outside for it to function properly.

If I want to nurse the heat pump along, in moderate outside temps without using propane, I only raise the set point temp by 1 degree at a time, and can raise the RV inside temp incrementally without triggering the propane heater to come on.

Similar to the air conditioner, if I run the temp setting down 1 degree at a time, I can trigger only one compressor to run, as needed sometimes with 30amp service.