Suburban furnace ignition boards

[zero]

Anyone here ever taken the time to figure out what components tend to fail on the ignition boards for Suburban furnaces? Obviously, I'm talking about the ones that do not use pilot lights. I got four furnaces here now (all pull outs from RVs) and not one of has ignition. All NT models. I've read many accounts of people buy new boards - but those things are very expensive. Seems when they fail, it's likely just a few bucks worth of components - but which ones?

[WME]

You know about these guys ??

http://www.dinosaurelectronics.com/index.htm

[zero]

You know about these guys ??

http://www.dinosaurelectronics.com/index.htm

Yes, I've seen their Website. They don't sell direct and all sales go though dealers. So I've got no idea what kind of prices they're charging. Seems obvious though they've mastered the art of fixing the boards.

[WME]

The universal boards run in the $80 range

[zero]

I ordered a Dinosaur board (I think) for $74 plus $6 shipping. I don't know if it will fit my furnace or not. I gave up trying to verify. It's a Suburban NT20SE with a 5-digit serial number (made in 1985). All the charts I found for retrofitting the universal boards show them for serial #s with 6 digits. I have no idea if it really makes a difference or not. Pacific RV Parts is sellingt the boards with a Suburban part # but it looks like a Dinosaur board to me. Part # 520741. NOT a "fan control" board.

I'm still wondering what key components tend to fail. I've got several here that do not make spark. They turn the gas valves on, and make a "charge noise" like a cap is charging - but never any spark.

[Maineah]

Yeah that's pretty much what fails or they don't light when it's 25* out and snowing at 3 in the morning. My guess is the spark transformer because like you say it goes through all the motions. The Dinosaur site has pictures of the boards and you can match the boards up mostly it's how the spark coil wiring mounts to the furnace wiring and size of course.

[zero]

I did a little more reseach and it seems the repair parts to actually fix the board are no longer available. I've got three boards here from 80s Suburban furnaces. All use a part # 230587 ignition assembly that was made by a company named Fenwall. It is now obsolete with no known replacement or cross-reference.

Seems the boards are classified by the type of connector. This uses what they call a UIB-L post. So, I guess the only easy fix is the new board from Dinosaur.

Their generic universal board fits these board numbers and mine is Suburban part # 05-152436-103.

:

Mark 10-12-2-5.5-5.5-E310, Mark 10-12-2-12-12-E310, 05-152435-003, 05-152435-103, 05-152436-053, 05-152436-103, 05-159003-253, 05-159003-255, 05-159006-753, 05-159006-755, 05-169005-123, 4322-321, 61525022, 61549522, FA7615 and MPD91731

[fred heath]

I did a little more reseach and it seems the repair parts to actually fix the board are no longer available. I've got three boards here from 80s Suburban furnaces. All use a part # 230587 ignition assembly that was made by a company named Fenwall. It is now obsolete with no known replacement or cross-reference.

Seems the boards are classified by the type of connector. This uses what they call a UIB-L post. So, I guess the only easy fix is the new board from Dinosaur.

Their generic universal board fits these board numbers and mine is Suburban part # 05-152436-103.

:

Mark 10-12-2-5.5-5.5-E310, Mark 10-12-2-12-12-E310, 05-152435-003, 05-152435-103, 05-152436-053, 05-152436-103, 05-159003-253, 05-159003-255, 05-159006-753, 05-159006-755, 05-169005-123, 4322-321, 61525022, 61549522, FA7615 and MPD91731

JD,

You can still get fenwal control boards. I purchased mine new last year. The company is located in Mass. (I believe).

They no longer make these parts but there's a company in the Midwest? That has all their surplus. They only sell to dealers and the part number has been changed. I got mine through a local plumb/heat supplier. It was expensive($125.00) but an exact replacement.

And mine did go in the middle of the winter.

[zero]

JD,

You can still get fenwal control boards. I purchased mine new last year. The company is located in Mass. (I believe).

They no longer make these parts but there's a company in the Midwest? That has all their surplus. They only sell to dealers and the part number has been changed. I got mine through a local plumb/heat supplier. It was expensive($125.00) but an exact replacement.

And mine did go in the middle of the winter.

Yes, I think I almost bought one. The Fenwal # for my board is 05-152435-103. Obsolete but it seems still for sale from a few dealers for $74. I decided to spend and extra $20 and get a Dinosaur board with the extra fan control feature plus the 3 year warranty. Seems to be a much better board then the original and I prefer having the fan-control feature.

[Maineah]

Another nice thing about the Dinosaur boards they fire 3 times before they give up the factory only once they are worth the extra money I have never had one fail to light. I replaced a board because some times it did not light most of the time it did but when I needed it the most it wouldn't.

[zero]

The ignitor module that I have circled is what I think failed and I gave up trying to find a replacement (to solder in).

[waiter]

I winder if you could wire in an old ignition coil from a car to replace that coil?

John Mc

88 Dolphin Auto

[Maineah]

I think they kind a work like a fly back transformer John.

[Vanman]

Maineah

I think they kind a work like a fly back transformer John.

I was thinking that when reading this post this morn and my DSL died. The old 12" black & white CRT monitor flyback might just do the trick.

JC

[zero]

I got the new Dinosaur board and put it in today. Now it works great but . . . I had a few problems along the way.

The older Suburban furnaces (this is a 1986) are not easy order a board for if you go just by serial #s and much of the info posted at various Websites like Dinosaur. Shortly after I ordered the first board - I found out if would not of fit unless I changed the high-tension wire (sort of like a spark plug wire on a gas engine). Some boards have a regular spark-plug terminal like a car engine - while others use a male 1/4" wide spade terminal.

After a few phone calls I ordered the Dinosaur "Fan 50 Plus" control board. The original board that failed was a Suburban # 520741. It is still available but would not of fit without some changes. Probably because mine is an older serial #.

The new "fan control" board has some added features the original did not. With the old board - if the heat stopped working, the fan would keep running forever until the battery went dead or someone shut it off. With the new board -the fan shuts off if the heat conks out. Nice feature.

Here were the slight issues I had along the way since I've never swapped in one of these boards before.

#1. The new boards are substantially smaller then the originals. So the bolt holes don't line up. I drilled two new holes and had to add spacers under the board to support it (two #10 hex nuts worked perfect).

#2 I had the sail-switch turned "on" all the time with a temporary jumper wire. The new board would not allow anything to work this way. Ends up it must "sense" an open circuit for the sail-switch before it does anything. I had it "closed" so nothing would happen.

#3 So, I reconnected the sail-switch as it would be normally. Hooked power to the furnace and the new power (indicator) light no longer turned on. Note -the new board comes with a replaceable 5 amp fuse and power indicator light. Now I had no light?? Well - ends up all was fine. Dinosaur says this added light is there to show when power is getting to the board. Ends up that is not true. It only lights when the board is in "furnace OK to run" mode. I waited a little bit and the furnace fired up and worked great.

After that I fixed a second furnace and it only took me 1/3 the time. Slight learning curve on my part.