Forced Air Furnace not lighting

[ice_it_06]

Any forced air techies out there Turned my attention to another fish house of mine today for season prep and like the first one found frustration.

Have a Suburban Model NT 20 SE in one of my fish houses.One year old and ran fine all last season.

Hooked up the deep cycle and newly filled 20# LP tank I used last year. Vent screens still in place and seems to be nothing inside furnace compartment as well.

Fan came on after thermostat was turned on and igniter clicked within (10) seconds. NOTHING The burner or even a pilot light was present.

Tried process numerous times along with reconnecting everything.

[BIG DS]

Just one idea. Eventhough the guy filling the tank has a scale, a lot of the time, they let to OPD valve tell them when the tank is full . Sometimes, the valve will stick shut and not let the fuel out of the tank just as it would not let anymore in. The easiest way to solve this problem is pick the tank straight up by the handles and smack it back down. This will dislodge the float and let the fuel flow . I have filled a lot of tanks and am guilty of filling them until the valve pops shut at times too. I have had to put the smack down on some of my own tanks from time to time because of it . If that doesn't do it I can not help you from there.

[ice_it_06]

BIG DS:

It definitely is getting fuel out of the tank.

Same tank I hooked to a heater that was putting out so much LP the other night it all but exploded. That was either a heater or regulator issue on the heaters supplied hose though. Still waiting for Northern Tool and the manufacturer allowing me to return the darn thing so I diverted my attention towards house #2.

Fuel might not be getting through the house line to the furnace, or lost @ the furnace somehow. I get the pilot click but no light or burner.

[Chad Halvorson]

You have to have a pilot before your burners will light. Your plugged up (small orifice). Im assuming you see a spark?

[ice_it_06]

Chad:

No I do not see a spark when the igniter goes off !!

Took the grill off so I could watch in sight window when it clicked and saw nothing.

[BIG DS]

Can you reach the pilot with a match or a grill lighter?

[ice_it_06]

No, there is a igniter assembly right @ the front of the heater. Sight window is right above it and everything is enclosed. The assembly has a gasket and (4) screws that mount it to the pilot area. Gasket looks good and screws are tight.

Usually the "fan" will start up and about (8) second later the pilot will ignite, and then the burner.

I've got fan, and pilot ignition attempt only.

[ice_it_06]

Well I hate to have to take it to a service center but seems like my only option. It's a smal 6 X 8 on a trailer and I know of a RV dealer/shop just minutes south of me on 35W in Medford.

Not familiar with anything maint related on these furnaces so I'm not sure how involved it is to try and solve the issue myself.Looks like it could get pretty complicated inside there.

Found a trouble shoot guide on-line for this model but there seems to be a host of possible reasons it will not ignite.

Thing ran perfect last year start - finish. Kind of bites now to have it fail.

[Pikeslayer]

Spiders love to build nests in propane,Tiny spider in the supply line if it was open all summer will plug it up,try tapping on the line and watch what falls out.

[ice_it_06]

This particular house has a quick connect 90 elbow on the outside of the wall. Very small opening but I did tap on it to see if anything was in there, and ran a long piece of wire up it for about 2 feet.

Burner area right in back of grill I removed sure seemed to have rusted alot for one years use.

Will try and find a owners manual for it and see if I can figure anything out before taking it in to a service shop.

[Surface Tension]

Are you giving it enough time for the propane to get to the valve block? Does the battery have a full charge.

[ice_it_06]

Surface Tension:

The Battery was full charged and I was trying to light it for over (30) minutes. Would let it cycle through the sound of the igniter and I would shut it down through the thermostat, and try again in a minute.

Fuel line has been hooked up and open now for almost two full days. Will hook battery back up soon and try it again.

[bbqhead]

i can probly help you, i am a recently layed off

rv tech.. do you have a stove in there to light

to see how strong the flame is? i have seen the

battery hooked up backwards, the fan will run but

wont light. do you hear a series of clicks when

the furnace tries to light?

randy aka bbqhead

[ice_it_06]

Randy:

There is no stove as it's just a small 5 X 8 custom made house by a RV dealer. The furnace is connected correctly as it's wired RV type Black/Pos White/Neg. Fan blows outward and igniter clicks on soon after blower.Thermostat functions fine as well.

I noticed the spark is present and pulsating for a couple seconds, but there is no gas apparently to ignite a burn.

Something is plugging it up apparently.

[bbqhead]

you should hear 1 louder click then the ignitor

should click for like 10 seconds. the louder click

will be the gas valve. i will check back. also turn

the valve off at the tank,loosen the gas line to

release pressure. then open the valve real slow,

some tanks have a real touchy safety valve and will

shut off the lp. will check back

randy aka bbqhead

[ice_it_06]

Randy:

I'm not getting anything beyond the LOUD click.

No repetitive clicks afterwards but I do see a flickering spark shortly.

Have done the tank thing a few times and even used a different tank.

[bbqhead]

pull the big orange wire off the ignitor and somehow

hold it 1/8 inch from a ground and turn it on to

see if you get any spark, with the lp turned off

of course.

randy aka bh

[ice_it_06]

The two prongs in the heaters front just below a sight window are of heavy wire. One that has a "orange" collar around it and both seem to be soldered to the prong.

Over by the gas valve I see a orange wire (clip connection)plugged in to the bottom of some small round device mounted on the housing wall by all the electrical.

[bbqhead]

ok what i would do is remove the ignitor, thats by

the window. try not to rip the white gasket, ground

the mounting and see what the spark looks like.

randy aka bbqhead

[ice_it_06]

This model has a plate screwed in under the window with (2) prongs, sitting right and left. Which one is the ignitor or are they both considered it ?

Gasket looks like it might be brittle but will be careful.

[bbqhead]

thats the ignitor with the thick orange wire, after

you check the spark look in the combustion chamber

for junk. clean the ignitor with sand paper.

will be back

randy

[ice_it_06]

Randy:

I've been wrapped up in work and getting trailer work done for my fish houses so I haven't had time to take another look @ that furnace until today. Thanks for your help but after deciding parts would be a issue to get and my knowledge limited I hauled it down to a RV dealer by Cabelas in Owatonna.

Although it appears to be a igniter issue that I see is only about $15, and a simple install, I'm feeling like taking it there will come back and bite me big $$$

Anything beyond that and a winter tune up I was suppose to get a call.

I'm sure I will (after the fact) and $200 or half a new furnace later.

[bbqhead]

well good luck! hopefully just the ignitor electrode,

never can be that easy!

randy aka bbqhead

[ice_it_06]

Problem was a plugged fuel line/regulator according to the service bill.

The line was connected to the tank and the other end has a quick connect on it so I'm not sure how anything was in that 6' section of line or how the regulator would plug up as well needing replacement. (was a new regulator already in the house sitting right next to the battery and 911 hose assembly)

Anyway a few lbs of air pressure and a unnecessary regulator later I was good to go for $95. It was bench tested and chamber cleaned out as well.

Thanks again

[bbqhead]

thats a good price! glad you got it going.

randy aka bbqhead