Furnace kept blowing fuses... fix... (was mud daubers)

computeraces

GEAUX LSU TIGERS!!!
We have a 2010 Bighorn 3580RL. We didn't use the trailer for a few months and then camped at a place where it was cold. When we got setup, I turned the furnace on to heat it up since it was about 30 degrees when we arrived. You could hear the starter click and try to light a fire, but the fan never turned on. When I just turned the fan on, it works. I just filled up both propane tanks so that shouldn't have been an issue. After several attempts, I checked the 12 volt fuses and the furnace one was blown. It was a 20 amp. I replaced the fuse and tried again, and it instantly blew the fuse as it tried to turn on. I thought it was a grounded wire somewhere or bad circuit board. My dad and I took the cover off of the outside exhaust and we looked and didn't see anything at first. Then, with a flashlight, my dad saw some dirt dobber nests inside the top tube that goes to the squirrel case blower. The nests kept the blower from moving and blew the fuses. Once we knocked the nests loose and removed most of it, we replaced the fuse and it started right up. It was a little noisy at first, but after a few times of it kicking on, it sounded right. I think it still had a little of the nest in there. I didn't have a screen on the exhaust pipes. If so, this would have been prevented. I will now install a screen. I think this $5 part should be installed at the factory on new trailers. Or at least offered as an option or highly recommended by all dealers when they sell them. They'd make a few extra bucks and the new owners wouldn't have this issue. Hope this info helps someone with the same problem.

Cory
 

katkens

Founding Illinios Chapter Leader-retired
This is what Suburban Manufacturing say's about the screens, would imagine this is why they don't add them.

Question 6
Is it safe to install a bug screen over my furnace vent?

Answer:
No. Suburban does not approve - nor do we recommend - using the aftermarket screens being sold to cover the outside vent cap. This restricts the exhaust and intake air, resulting in improper burner operation and a potentially unsafe condition.


http://www.rvcomfort.com/suburban/service/furnaces_questions.php#Anchor-Question-5677
 

boatto5er

Founding VA Chap Ldr (Ret)
This is what Suburban Manufacturing say's about the screens, would imagine this is why they don't add them.

Question 6
Is it safe to install a bug screen over my furnace vent?

Answer:
No. Suburban does not approve - nor do we recommend - using the aftermarket screens being sold to cover the outside vent cap. This restricts the exhaust and intake air, resulting in improper burner operation and a potentially unsafe condition.


http://www.rvcomfort.com/suburban/service/furnaces_questions.php#Anchor-Question-5677

I'd really like to see their research notes on that statement. The small small change in air flow area with the screen cover is SO SMALL as to almost be inperceptable.
 

jmgratz

Original Owners Club Member
I was told by an RV Tech instructor during a class they do not recommend putting a screen on the exhaust ports because many people use a screen that has very small mesh openings. However it is okay to use one that is designed to that purpose that can be purchased at most RV Parts stores. These have a larger mesh which does not cut down on the airflow. We have been using them for over 10 years on our 5ers without trouble.
 

newbie

Northern Virginia
My dad had spiders build small webs in the venturi tubes for the propane water heater. Because the propane was burning too rich, it made ugly black soot up the side of his rig. Fortunately it was easy to clean off. Those little critters can reek havoc.
 
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