Suburban Propane Heaters - 1979 Newell

[blakestar]

I am going to start trouble-shooting two of the three propane heaters in our new 1979 Newell. Two of the heaters do not even "Kick on" or "click" when the thermostat is turned up. Does anyone have any suggestions on what to troubleshoot first?

Previous owner stated he never used the propane heaters so they may have not been used in a number of years (10 years or more).

I assume the voltage is from the 12volt house battery?

Thanks for any suggestions!

[HoosierDaddy]

Yep they run on 12V. First I'd make sure the thermostat is sending the proper voltage to the furnace to start. Check the ground wires on everything. On my '78 the vent blower starts first, runs for 20-30 seconds before it tries to light. If it doesnt light...(check the igniter and the vent to outside(wasps like to build nests in them)) the whole thing will shut down. If I remember correctly you then have to turn the thermostat off and then back on to restart.

[encantotom]

mine has duo-therm furnaces in it. they didnt work well when i got them and the igniter boards were bad.

they are really not very hard to troubleshoot.

you make sure you are getting power to them. there will be a 12v fuse/breaker somewhere for them as well.

dean is right, when the thermostat turns them on (the thermostat could be bad too), the fan comes on. when the sail switch verifies the fan is turning fast enough and after a certain time (20-30 seconds) then the ignitor will try and light the burner. it will try 3 times usually, then it will stop trying. if it is trying to ignite but do not (you can hear a gentle roar of the burner starting up) then it will stop trying and the fan will run until you turn it off at the thermostat.

then you have to turn the thermostat off and back on to get them to try to refire.

make sure you have propane, the tank is turned on.

some heaters switch the ground and some switch the hot. i replaced the control board with the Fan 50 plus from http://www.dinosaurelectronics.com/Fan_50_PIN.html.

i converted it from switching the ground to switching 12v so the fan control feature would work. now on mine, after 3 tries of lighting the burner, the fan will shut off. the reason you care about this is that if you were not home in the coach and running the furnace and dry camping, you would run the battery down running a heater that wasnt putting out any heat.

if you have more than one furnace, you can swap parts to troubleshoot them.

be very careful around the propane.

this place has a lot of manual of heaters. http://bryantrv.com/owners.html

you just have to determine which heater you have.

i will private message you my phone and you are welcome to call me. i have rebuilt all 3 of my furnaces in my coach. no expert, but i was able to get all of mine working great.

have fun!

tom

[fulltiming]

Blake, if the fan doesn't come on within a few seconds after turning the thermostat all the way up (assuming the temperature in the coach is below about 90 degrees), the thermostat is either bad, not getting 12 volts from the house batteries, mud dauber nests preventing the fan from turning, a bad fan motor or the motherboard is bad. If the fan comes on but it won't ignite it could be debris, such as mud duber nests keeping the fan from turning up to the proper speed, a bad sail-switch, a bad fan motor or a bad circuit board. If you hear clicking (which you indicated you do not) then the likelihood would be a bad igniter, a bad circuit board or no propane flow to the furnace (either shut off at the tank, very low level of propane, or the propane detector has shut down the propane flow in the coach).

Congratulations on your Newell purchase.

[blakestar]

Thanks for all the tips and suggestions!

Got one of the furnaces to work properly (center). The other two just make a "Click" noise when you turn up the thermostat. What do you think, could this be due to a bad igniter board????

Vents on the outside appear clean inside (has the fancy spring-loaded bug screens over them)

[encantotom]

i had 2 of my three do EXACTLY the same thing. if there is propane to the furnace, then it is a high likelyhood the ignitor control board is bad. what i did to confirm it was to swap boards between furnaces and the problem switched furnaces.

if you end up replacing them, from my humble opinion the ONLY ones to buy are the dinosaur electronics boards. they are much better than the stock ones and fairly priced.

i have had all three of my furnaces out, replaced boards, bench tested them and tuned them up.

like michael said, there is just a few things on them. if the fan is running fast enough, it will click the igniter and open the propane valve. the control board might not have enough spark, or open the solenoid controlling the gas valve.

the boards are about a hundred bucks apiece, so that is why swapping them is the sure way of knowing if the board is bad.

i took all three out and cleaned and rewired etc, just to be sure and used a propane bottle and hoses i adapted to work along with a 12v car battery.

i learned a ton on how to set the air adjustment to make them work right.

you shouldnt have to do all that though.

they are not the easiest things to get at, but not impossible.

i sent you my contact info if you need more help, call me.

later

tom

[fulltiming]

Although the bug screens are good to keep insects from building nests inside when not in use, furnace manufacturers recommend that you NOT operate the furnaces with the screens in place due to the restricted air flow. I have actually used propane furnaces with the screens attached without any problem but you might try removing them before further testing.

[encantotom]

proper air flow into the combustion chamber is a big part of making these things work right. i had to adjust the air mixture on mine. they have to be "under load" when bench testing them, meaning they cant be totally open and have to have all the tubing attached they have the same airflow dynamics that would be in the coach. makes a big difference. i learned that from talking to an old timer that has worked on these things for years.

that is why sometimes the screens can cause problems. not usually, but it is possible.

later

tom

[prairieschooner]

Our Center Heater, a Suburban model NT16L, was not working and actually making noises. I removed the Heater as an assembly by removing the Vent Cap (Outside Fitting with 4 Screws for the Base and 1 Screw inside the Round Part of the Outside Fitting and 4 Wires). I was then able to remove the Heater Assembly from the Housing and inspect the Combustion Air Box (Squirrel Cage Area). I found a Wasps Nest in there that had distorted the Combustion Air Wheel (Squirrel Cage). I have been able to order at least some of the Gaskets so that I can Complete Servicing the Heater Assembly.
Be careful guys, parts for these older units are getting hard to come by and some No Longer Available! The local Shop told me that the Combustion Air Wheel is one of those NLA parts. This Heater did not have a Screen installed when we got the Coach, I have found it in a Bay and will make sure that it is installed to keep this from happening again. I would think that as long as the Limit Switch that determines Proper Air Flow is working Properly then the Screen should not present a problem.
Just a "Heads Up".

[chockwald]

Steve, there is place in Montclair, CA called Green's Trailer Supply. They work on older RV's, and where able to find replacement parts in their inventory for the Suburban furnace in my old 1987 Fleetwood class c....specifically the squirrel cage......they may have "new old" stock that would work on yours.... (909) 983-1311.

[prairieschooner]

Clarke,
Just called Green's and they do not have the part. He said that it may be available as a Special Order from Suburban but no guarantees. I think that I will just straighten out the Wheel (using a Dial Indicator) and hope for the best right now since we are leaving in a week for the Sea of Cortez. I think that I will try to special order this part and others as spares after looking at all of my Heaters and the interchangeable parts.
Thanks for the source

[HoosierDaddy]

HHHHMMMMMM! I replaced a suburban furnace in my '78 ten years ago..I dont want to offer false hope but I may have the old furnace stashed out in the barn...I'm kind of a pack-rat.....("Dya know what these things sell for new??There's gotta be some good parts on it yet!!!!") I'll look for it ...
Dean

[folivier]

Hey Steve, don't foul your anchor!

[blakestar]

As a follow-up to this topic for anyone else who may experience similar issues.

Turns out the fan motors on my heaters were toast. They could "maybe" be rebuilt but instead I opted to go with new heaters. The NT-16F ducted furnace is no longer available (as are the fan motors).

I purchased a new NT-16S ducted furnace and with some very MINOR modifications to the ducts, the gas line and outside vent trim ring had it installed and operational in less than 1hr.

For the cost ($350.00 for a new NT-16S) I felt it the best way to go, knowing everything is brand new in the heaters.

More "Carefree" enjoyment in the Newell!!

[2dogs]

Does anyone else have a wood colored box with a red light and reset button with wires running to both furnaces front and mid? our front furnace will click sometimes sound like it fires then nothing the middle one wont even blow anymore aarg -------But on the bright side we are in yuma for the winter!!! beter than idaho!!!

Brian and Lana

[encantotom]

hi,

the furnace that clicks and then doesnt light is a common problem for the ignitor control board being bad. it usually will try 3 times then stop trying. it might even once in a while almost light, then not. i have posted in another post about repairing my 3 furnaces. i put in the dinsosaur boards and they work great.

the one that doesnt do anything could be anyone of a number of problems.

i hope you can find time to come to mesa, az to visit us while you are here for a while. it isnt that far from yuma.

tom

[prairieschooner]

I wanted to follow up on the repair of my NT16L Furnace.
I was able to get a replacement Fan Motor at SPANKY'S RV in Parker, AZ. The Replacement Motor came in a Kit, SUBURBAN #520949 with the new Gaskets for $74.99. I installed it a few days ago and we are using the Heater now.