2018 Hummingbird 17RB - Furnace problem

[ai2160]

Hello!

When we turn on the thermostat, the blower comes on and after about 30 seconds turn off again. From the research I did, it could be because the ignitor failed to light propane and there are a bunch of low hanging fruit to check eg., lighting arc at the right spot, reset switch, sail switch etc.,

However, in our RV, the furnace seems to be located under the bed. Is that accurate? Is there an easy way to access the furnace?

Cheers!

[Rustic Eagle]

Welcome to JOF

Originally Posted by ai2160

snip........the furnace seems to be located under the bed. Is that accurate? Is there an easy way to access the furnace?....snip

Based on the location of the 2018 17RB outside furnace exhaust it appears the furnace would be under the bed..., and there isn't an outside access panel with this model furnace.

My 2018 24RBS furnace is located under my jackknife sofa. I had to remove the sofa, then remove the 'wood box' covering the furnace in order to have an actual 'visual' of the furnace. The reset switch is located on top of the furnace.

Performing most of the repairs (sail switch, high temp switch, circuit board, ignitor, etc.) will require removing the entire furnace from the TT (been there, done it). I you plan to remove the furnace, first remove the outside chrome exhaust cover/pipe assembly.

My furnace location, jackknife sofa partially opened:



Sofa and wood box removed:



Furnace disconnected/removed from outside wall exposing electrical, ignitor, exhaust, etc..



NOTE: Your furnace model and/or configuration may differ from mine.

Bob

[ai2160]

Thanks for the welcome

I was really hoping for a different answer. Oh well. Thank you so much for your reply and the pictures.

[Jagiven]

Before digging in to deep! Is this a new to you TT? Has the furnace ever worked for you in the past?

If you are new to RVs. One thing that is important is to light the stove and let it run for a few seconds, to help purge most of the air out of the propane line. If I have not used my furnace all season, sometimes it take a few attempts to light before all the air is purged.

Before doing anything else, there is a reset switch, usually it is hard to see, but right in front, right behind the air return cover. On my unit, it is in the upper right hand corner. Black switch, dark spot, hard to see it, unless I am on my knees. But it is right there, and easy access once you know where to look.

#1 thing that tends to fail first is the sail switch (air flow monitoring switch).

Depending on the furnace you have, the control board might have a series of LED diodes, that will indicate a error code. Usually the control boards are buried and hard to get to. Hence you may have to remove the unit.

Edit: I was looking online at images of your TT. The water heater is right next to it (front corner of TT). There has to be an access point to it so you can set the water heater to winterizing mode.

Have you removed the mattress to determine if there is an access panel from above? Might have a few #2 square drive screws holding the platform in place.

If you can, could you post a few pictures of the furnace location with the mattress removed.

I think it would be very easy to access from above, even if Jayco stapled in the bed platform above it.

[ai2160]

Hello! Thanks for reply.

This TT is new to us and we are new to TTs/RVs. This is our first TT. Previous owner had it for two years. I removed the bed and there is a wooden box cover underneath that is screwed on. I figured that is where the furnace is.

I had the stove running before I turned on the thermostat. I will try it again to be sure. I didn't hear the ignitor click. I am not sure how loud those clicks are supposed to be and if the are audible especially with the blower running. I can certainly hear the fridge's ignitor click when I turn it on, but not the furnace.

RV is in storage now. Will post pics when I go to retrieve it and fix try to fix the furnace. Thanks again for your help!

[ALJO]

Any furnace without outside access door has to be removed and bench tested. It is most likely the sail-switch and that one is at front by the outside wall. Just bend the sail-switch fan slight for better airlift. We had many coming through our shop like that.

[ai2160]

Originally Posted by ALJO

Any furnace without outside access door has to be removed and bench tested. It is most likely the sail-switch and that one is at front by the outside wall. Just bend the sail-switch fan slight for better airlift. We had many coming through our shop like that.

Thank you. Do I need any special tools to turn the wall facing side of furnace around? Like in the picture above?

[ALJO]

Furnaces usually are pretty maintenance free, but are still mechanical an can fail. It use to be RV manufactures installed the outside access door (which I always recommend to our customers to buy). Most RV's have poor access for removal, so not user friendly.
Just some standard hand tools are needed. With install be sure the exhaust tube is installed correctly.

[Rustic Eagle]

ai2160,

If you do remove the wood box cover, I recommend cutting a hole through the top wood panel allowing access to the reset switch....., makes dealing with a future furnace 'reset' much easier.



Bob

[Phoenix PAL]

Sounds like the same problem we had this year. The problem is that you can't know the fault because you can't see the LED that displays the fault code.


Here's how I fixed ours.


https://www.jaycoowners.com/forums/f...fix-81657.html

[ai2160]

That is very clever!

[ai2160]

I am warming up to working on the trailer. I finally got a chance to expose the furnace. There are only two screws at the bottom where the duct is that keeps it in place. Once removed, the furnace seems to be loose. I also unscrewed the 4 screws outside on the exhaust. May be it is not needed.

I couldn't take it out or turn it around because I couldn't figure out a way to dettach the hot air duct either on the vent or from the furnace itself.

I am however able to verify that

1) Reset didn't work
2) The furnace tries to turn itself on 3 times before it shuts the blower off
3) I do see the red led flashing (green box in the picture). I just learnt about the fault codes. In retrospect, it feels like one flash every 3. I will double check next time.

Can someone tell me how I can separate the duct (red circle in the picture) from furnace or wiggle it around to get to the sail switch?

[JFlightRisk]

The exhaust on the outside sticks into the furnace, so you'll need to pull it straight out, than the furnace should lift up and allow you to get to that duct.

See post #6in this thread for what it looks like removed.


https://www.jaycoowners.com/forums/f...tml#post906814

[hummy]

My 2017 RB has a access panel on the outside, I know you you can see the front of the furnace and hot water tank with all the electrical showing and gas connections

[Rustic Eagle]

Originally Posted by hummy

My 2017 RB has a access panel on the outside, I know you you can see the front of the furnace and hot water tank with all the electrical showing and gas connections

If you are referring to the large hinged access panel on the outside (exterior) wall, that's for the HWH only......, unless your referring to an interior access panel on your 2017 model (?).

Bob

[hummy]

Now I'm not sure? I think your right! Hot water. When the weather gets nicer I'll look. I really didn't pay much attention when i winterize underneath the bed to see if the furnace was there! Hardly enough room for the hot water tank let alone a furnace. Kind of scary sleeping on top of a flame when the heater is running. LoL It has to be the same location in the picture. that stinks, I couldn't stand it! went out to look your right!!!

[ai2160]

Yep, Hot water tank is right next to furnace under the bed (closer to the front of the trailer).

[ai2160]

I should have been more clear. I was referring the air duct where the hot air comes from, not the exhaust. That is useful info nonetheless. I didn't know that exhaust vent is that long and sticks into the furnace. I have a couple of questions now

1) How do I detach the hot air duct (not the exhaust) marked with red circle in my picture from furnace?
2) As far as the exhaust vent goes, I removed 4 screws on the exterior of the trailer but the metal piece is firmly stuck. Should I just gently pry it out?
3) Once the furnace is loose, where is the sail switch located?

[Rustic Eagle]

ai2160,

1) Try removing the outside chrome/plastic exhaust pipe assembly first, then see
if the furnace will back away a little from what appears to be a foil air duct (may
be a slip fit ?). Isn't there an air duct vent cover on the wood panel underneath the
bed that can be removed?

2) I use a plastic putty knife to work the chrome flange/plastic pipe insert away
from the OEM Butyl putty tape.

3) Sail switch (blue wires) is located on the blower housing to the left of the
circuit board:



Bob

[Rustic Eagle]

Originally Posted by hummy

snip......Kind of scary sleeping on top of a flame when the heater is running......snip

I agree, mine is located under my jackknife sofa.

The Dometic/Atwood furnace installation documents state very clearly do not install under furniture.

Bob