raypak heater cfh, spk pilot lights, main burner doesn't

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J

jimburnetto

0
Oct 3, 2007
5
Hey guys,
Here's what I have:
The unit does CFH. Then SPK. It lights the pilot but the pilot assembly continues to spark. The main burner never lights. I'm trying to follow the troubleshooting guide. It says at this point I should be getting 24v across the MV-MV/PV leads. I tested this at the back of the pc board itself while all wires were plugged in. I get a jump up to like 300v according to my meter, then it drops down to zero or close to it. According to the manual, this means a bad board. Here's where I'm stuck--I'm not positive I'm testing this right & could use come help. As a sanity check, I tested across the PV-MV/PV at the back of the board in the same way. Because my pilot is lit, I figured this should be 24V, right? It spikes up to 300v or so, then goes back down to 4v.

I just feel like my testing is inconclusive & would like to know if I'm doing it right before I drop a few hundred bucks on a new board.

By the way, my first action was to just replace the pilot light assembly, so that is brand new. Replacing pilot light assembly did not solve problem.

So, am I testing this right?
Based on what you see here & your own experience do you think it's the board at this point?

Thanks for your help, I have not posted in a while, but always appreciate your guidance.

Hopefully this makes sense, let me know if I can help clarify my problem.
Jim
 
Not sure what model you have...

with what you are saying about the pilot lighting and the spark continuing, I would look into pulling the spark/pilot assembly and cleaning the flame sensor. The flame sensor needs to be satisfied that the pilot is lit before the gas valve will open. By it continuing to spark it seems that the flame sensor is not seeing the pilot.
 
So, that's what my first thought was too & I thought I took care of that when I replaced the whole pilot light assembly. My understanding was that it was all part & parcel in there. Is that not true?

It's an r206a.
 
OK, that should have taken care of it. Was there any work done on this unit prior to this problem occuring? Electrical wise, a good solid ground connection is needed for the flame sensor to function properly. Is the surface that the pilot assembly is mounted to in good condition? No rust, etc. The small milivolt current that flows thru this circuit is very sensitive to a weak connection.
 
fyi, I sent this email to raypak & they told me it was the board, too.


Unit goes through CFH, then SPK. Pilot light successfully lights, however pilot light assembly continues to spark and main burner never lights. I have replaced the pilot light assembly, but that did not fix it. Trying to determine if the problem is the PC Board or main valve. Following troubleshooting steps in manual. Tried to test for 24V across MV-MV/PV, but not sure how to interpret results. Would like a more clear explanation of test procedure please. I also tested across PV-MV/PV which should be 24v (pilot valve is opening & pilot lights), but that gave me 4v.


Their response:

You need to replace the board. It is not recognizing the rectification signal coming from the pilot.
 
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