Furnace hi limit..

[Lawrosa]

I couldnt post to this thread, but its in response..

http://www.forestriverforums.com/for...ix-124810.html

Here is where im at...



Intresting thread. I too have a hi limit issue as talked about here.

I added a duct because I think the more the better. They only had 3 on my sf 30 suburban. One directly on opposite wall of furnace and the other two way down 10-15 ft away at buck area and bath..

I think my issue may be that I am testing the furnace when its 80 f in the camper.

Its a brand new 2018 261 coachmen..

The dealer sent me duct parts to add one at no charge..

I may add a 5th duct but may wait till winter... It may look hokey with two ducts coming out front of couch... IDK....


2017's had the duct but coachmen had sf 35's in them. Now that they put sf 30's suburban says 3 ducts required only..

[Lawrosa]

The two ducts were way down there. and one in bath.



The other is on other side in master bedroom. None on couch fascia.

That t stat would never satisfy IMO in the winter..

Now I have a duct there.






Now that I have one there under couch I may add another. Since I have room for one more on the plenum. Ill put it about 3-6 inches from this one on the couch..






As far as intake air?????

IDK I assume it comes in from the big space behind the back of couch. There is a big gap there. They have this big piece of luan over the furnace.

The Air flow in I assume is the channel where I ran the new duct through and air gets drawn in from behind the back of couch.

Maybe I should remove the piece of luan?

[SeaDog]

The assumption that more ductwork is better is not necessarily correct. To much air flow and the furnace will not have the proper delta T across the firebox. If the temp is 80* in the rig how do you know you need more ductwork? I think I would be testing the AC instead. good luck with your project.

[Lawrosa]

Originally Posted by SeaDog

The assumption that more ductwork is better is not necessarily correct. To much air flow and the furnace will not have the proper delta T across the firebox. If the temp is 80* in the rig how do you know you need more ductwork? I think I would be testing the AC instead. good luck with your project.

I did test when it was around 58f out when I first got the camper..

There was no way 3 ducts and their placement would heat that trailer up quickly.

The master bedroom most likely would be the room getting way overheated from my observation.

The whole issue too is the high limit on the burner going off. Im sure I have enough delta t of 90F.

[mwtracht]

Don't know if this helps but this is what happened to me. I posted originally using Heater rather than furnace but reading part of the link you posted I think there may be more problems like mine.

I have a 2017 2618 Ultra V that had a furnace problem that took months to get fixed because of Forest River's warranty program. When I took possession of my new trailer last year out first campout was Memorial Day on the Thompson River in Montana. It gets cool there at night and I thought the trailer took too long to warm up which is important when you are dry camping. I fought with FR and the dealer for a year before we finally reached a resolution which was to replace the air plenum below the furnace. The shape of the plenum was causing heat to be reflected back to the furnace and causing the overtemp switch to trip. The furnace would come on and the burner would be on for around 2.5 minutes and be off for 1.5 minutes while the furnace fan ran constantly using up my batteries. FR kept saying there was nothing wrong with the design and refused to warranty a fix. Suburban was very supportive and supplied another furnace for testing purposes and when that didn't fix the problem the dealer brought in a HVAC supplier who built a new plenum from the dealers design and now the furnace works properly. I just want to let other 2618 V owners know that if you don't think your furnace is heating your trailer as fast as you would like it may not be just your imagination. FR doesn't want to deal with this so you will have to do some testing yourself.
This is a sort version of a long story.
Best of Luck, dealing with FR you will need all you can get.
*

[Lawrosa]

So still having the issue. I did a temp test of return air vs supply.. At the furnace intake grate was about 100 f reading. This was with furnace running for some 5 minutes. The duct temp never got over 150f. So thats just a 50f temp rise.

I would think maybe its a faulty hi limit switch.

Oh I testing with a laser thermometer.

I think Ill just change out the switch to see what happens...