I have changed all of the sensors and then I thought it was fixed. It ran and stayed lit for about 30 min and then went right back to the same problem. It will light and then the gas shuts off after a few seconds. If I let it cycle through this 3 times and then it should go to the " lock out" well it just turns the red light on once and then keeps on cycling, no lock out, no codes flashed, no solid red light, etc...

Try cleaning the flame sensor. It makes no difference if it is old or new just clean it. This will give a base line for the next test.

I just clened it with sandpaper and it lit and then died within 20 sec. I have checked and or regrounded all of the grounds as well. I am leaning towards thinking it is the HSI box. I have the white rogers / emerson electric 50E47-60. It doesn't give any trouble codes, ever...

Update, a little later I went back and switched the power on to the unit and it lit and worked for about 15 min. it was really cold in the house. After it shut down, it would not relight. But it did keep trying.

Strange that it would not run again.

Does the HSI glow during the start process?

Yes, it does. The only thing that does not happen during the ignition process "after it runs for a while and shuts off" is there is no gas flow. If you switch off the power to the unit for say... 30 min and flip it back on, it will light and run again for a bit. When the gas stopps the temp is not yet where the thermostat is set to and the his begins to glow again as if to try to relite it.

So it is an intermittent problem. Try jumping the R and W terminal on the low volt wiring strip in the furnace. This will eliminate the thermostat control and take that out of the line. This is just for testing purposes. See what it does.

Didn't help

Since you said you checked everything else I guess it is circuit board time.

Haha, yea, I think so. I have found two options the direct replacement : 50E47-60 or the one that they say has superseeded a number of older part numbers including the one I just listed. That new # is : 50E47-843. I have found either one for about $83 + s&h. the new # is supposed to be a complete conversion kit. Any advice on witch one to go with? They are White Rodgers brand controls

The conversion one is newer. Make sure to check it is the replacement for your old one.

50E47-843, Home Garden. Great deals on eBay!

Got one on the way now for $69 shipped, the -843 one. I will update once it comes in and I have a chance to install. Thanks for all of your help!

Mark all wires from old board. FOLLOW the instructions exactly on the document that comes with the new one.

Will do

Well I just installed the new unit. Now, the HSI will not glow. I am getting gas flow and everything seems to be fine. I am not sure if I should see a short across the HSI or some low impedance with the voltmeter.

The his igniter is good. I hooked up the old box and it will heat it up. The new box will not power up the ignitor. Any ideas?

Did you wire it exactly as in the instructions for the new board?

Look at this and read it over. It depends upon your system did you cut the wire or not ? The last two colums are your old board and the new one.

http://www.white-rodgers.com/wrdhom/...pg0274_277.pdf

http://www.white-rodgers.com/wrdhom/.../0037-6426.pdf

I assume you still are using a silicone carbide ignitor?

Read over and make sure purge time and all the other bells and whistles are set properly
Using your old board number as a reference.


I hate to say this but if it is wired correctly it is possible the board might be bad but I never had a bad one so??

It talks about cutting the "jumper wire" is it not good enough to just have the wire unhooked and left uncut? I didn't cut it just in case. We are only talking about 2 inches of wire that I would be cutting off, and one end is not even hooked to anything, the other end is protruding from the board of the new ignition control box. So I "DO" need to cut this and it really does matter? Haha

I also thought about trying this: the wiring right now is exactly like figure 1 on the pg0274_277.pdf file that you sent me. I thought about changing the wiring to resemble figure 3.

If you read the directions you will find out if you need to cut the wire or not. You are not cutting the wire completely out just one cut in the center of the wire is all it needs if you have to cut it to start with. It is a circuit jumper wire and if the board is used in a way that the instructions say it needs to be cut then you have to cut it.

I am not there to see your system or how it is wired but the instructions along with your OLD part number for the circuit board that was used is all you need to lookup the way to wire the new board properly. If you do not follow the directions exactly problem will happen.

You also have to set the timing of events and if you read the instructions you would see how that was to be done by using the old part number on the old board to look up exactly what to do.

Most of the time this type of repair is left to the professional HVAC person since it does require changes to the wiring but under normal circumstances anyone can do the job if they read and comprehend exactly what the instructions say to do.