[coldone]

Today I replaced the failing control board in my gas furnace with a new, universal one. Here is the info:

Furnace: Trane XE 80 (model: American Standard, TDD060C936C1, back from 1996)
Old control board: White-Rogers 50A50-471
Replacement: White-Rogers 50A55-843

After I installed the new board and powered the system up, the fan started and the board displayed 5 flashes, which indicated "open flame rollout switch". No gas, no ignition.

After some investigative work, I realized that my furnace has no rollout sensor switch; the RO1 and RO2 connectors in the big 12-pin connector that goes to the board had no wires in them at all.

According to the manual that switch is a NC (normally closed) switch. So I fooled the board by simply shortening RO1 and RO2 pins in the connector by using a jumper cable included in the kit. That did the trick, and the furnace started fine.

My question: is this an appropriate, safe solution? I could not find anything in the installation manual about doing a permanent shortening trick.

TIA!

[hvac1000]

Trane application - Jumper wire 151-2906 (provided with
control) must be installed on the furnace from R01 to R02 of the

12-pin connector.

SEE lower right page 3

http://www.white-rodgers.com/wrdhom/.../0037-6265.pdf

[coldone]

Doh! Can't believe I missed that. Spent 2 hours "troubleshooting" instead.

Thank you!

[hvac1000]

No problem. Those kind of things happen.

[hbsbtrouble]

Why would anyone want to bypass a safety feature like the rollout limiter which is supposed to shut down the furnace if the fan gets too hot?!

[hbsbtrouble]

I have a Trane gas furnace and it does have a circulator fan (blower) limit switch on it, but, the wires were left dangling, were not attached to the 12 pin plug. So if the fan overheated my house would burn down! Why would White-Rogers instructions for their controller model 50A55-843 state a permanent bypassing of the limit switch. Won't that open them up to a class action law suit?