Cannot get furnace to kick in

[Mingy]

Greetings all,

 

Every month I check all the systems in the Oliver.  As usual, everything worked.  The surge suppressor shut down my AC intermittently because the line voltage was 110, not unusual on a 100 degree Florida afternoon with everyone's AC cranked.  But I was able to cool the interior into the low 80's to test the furnace, and nothing happened when the thermostat (furnace heat setting) was set to 90.

 

The gas works fine - fridge is running on it.  The water heater works fine.

 

The blower for the furnace did not come on, nor did it fire.

 

I pulled the furnace cover outside and all connections seemed tight and no trash was present.  No apparent burned spots on the board.

 

Now, am I unaware of some feature that requires a lower outside temperature for the furnace to work, or does this seem like a bug?

 

Any help would be appreciated.

 

Mingy

 

 

[SeaDawg]

Hey, Mingy, it's 90 degrees in my Florida backyard right now. Maybe try again after dark, when we plummet to the low 80s?

Not sure about your thermostat, as our older trailers don't have one, but some home tbermostats require a certain difference in temp before they will kick in...

I hope that's it.

Sherry

[John E Davies]

Fool the thermostat with a bag of frozen vegetables held up to it for a couple of minutes. They have to be organic baby peas or it will not work. It’s right there in the owners booklet. Sheeesh.... Kids these days know nothing.

 

John Davies

 

Spokane WA

[SeaDawg]

Great idea, John.

[Mingy]

I'll try the fuse first - pull out, crimp socket, reinsert.  No organic peas.  Hell, no organic anything.  But a blue ice flex pack should do the trick.

[permit bob]

Hey Mingy,

 

I'm still wondering about the furnace running on battery power. The furnace runs just fine when you're plugged into shore power. It'll run you out of the trailer if you let it!

 

Back in the day when I first picked up Oliver, Hull#68, the only issue I had was the furnace not kicking in. I picked it up in February and the campground down the road got very cold that night.

 

The factory went "over the top" and replaced the unit immediately before I left. We suspected that the amount of "return air" could of been an issue and increased that area, also. They were stellar! However, it still doesn't work off of battery power and I let it slide.

 

I just returned from boon-docking at 8500 ft. with two brand new Trojan 145, 6 volt batteries, replacing the two 12 volt batteries that came with the trailer. The nights went down to 41 degrees. Went to use the furnace and it still refused to ignite! Fan runs as if it's very hopeful that it will, but nothing. All gas appliances are working just fine.

 

I did call the manufacturer, a few years back, and they went through the ignition sequence and, long story short, explained that the units need 7 amps of power to complete ignition.

 

I was hopeful that with two new Trojan 145 batteries that it'd work. Granted, when you wire two 6 volt batteries in series you're not increasing the amps, but.....

 

As I say.... with shore power, the unit works like a champ!

 

Can someone smarter than me (probably quite a few folk!) come up with an answer? I have checked everything I can think of.

 

I have absolutely no issue with Oliver at all, but the unit still doesn't ignite on battery power.

 

What are we missing?

 

Best, Bob

[Landrover]

Just guessing maybe your igniter prob may have to much gap for battery ignition and shore power is able to make the gap?  Or I’m completely wrong.

[permit bob]

Hmmmmm.

 

Now there's a thought.

 

Thanks

[John E Davies]

So how many amps do you actually have, at the furnace itself? You need this or a similar meter that can read amps to a good accuracy

 

https://smile.amazon.com/gp/product/B00O1Q2HOQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

You can use it to check other stuff like your brake system or inverter without disconnecting or cutting wires.

 

 

You may have undersized wire(s) (which is not impossible - my brake wires were undersized by a lot) or a poor or corroded connection at the furnace or at the power source. It sounds as if it is something relatively simple, but you are going to have to play detective, or string new replacement wires from end to end. If it runs when the system voltage is higher (shore power) but fails when it is lower (batteries) then it’s all about how much current is getting there.

 

The fuse box terminals (under the dinette) are pure junk, they rely on soft metal “ears” to make contact with the fuse tabs. The ears are easily bent out of position if the fuse is inserted carelessly, or at an angle. You can carefully squeeze the ears closer together for a tighter fit. Use a pair of mini needle nose  pliers with tape or heat shrink tubing on the tips to insulate them, or disconnect the batteries first, or just be really careful with regular pliers...

 

 

My fridge twice wouldn’t run at all - the display went black -  and I had to go down there and tighten up the ears. Loose fit equals high resistance equals low (or no) voltage. That box does not meet standards we expect from a high end RV. Plus the door is hinged on the wrong side so you have to lie down curled up on the floor to even see inside. @#$&*  !

 

Good luck.

 

John Davies

 

Spokane WA

[Mingy]

Thanks for all the information.  As it turned out, I hadn't given the thermostat box itself enough time to cool down.  I set the thermostat to 90 (heat) and the ambient temp of the trailer was 82 but when I shot the temp of the thermostat control itself it was over 90, it is not blown on directly by AC.  Probably warm air inside the pantry too didn't help.

[permit bob]

John,

 

I knew you give me yet another excuse to buy a new tool and projects too!

 

Seriously, thanks for being so thorough. I'll start the investigative work today and see what I can find.

 

It has to be something simple, just a matter of finding it.

 

Best, Bob

[Jitters]

Thanks for this John.  I took delivery of #266 today and couldn't get furnace on.  When I remembered your post I grabbed a bag of ice and held it against the thermostat for a couple minutes  and bam....heater popped on.

 

Greg