You wrote (couldn't find it here so I copied it from the email notification):
Couple of things
You can have good flow through the SYSTEM, but have a problem with how the water is flowing through the heater.
Without getting too involved, all the water that enters the heater does not make it to the exchanger (to gather or absorb heat). A lot of it gets By-passed right to the outlet port. If either of your by-passes (you have 2) gets damaged or otherwise fails and lets too much, or not enough water by-pass, you can and will have flow issues through the heater resulting, in some cases, increased temps., long heat up times, exchanger erosion, etc.
The trouble with "guessing" if you need a board is, since it is an electrical component, almost everyone will not allow you to return it. So there's that...
If you are getting SPK with no re fire I would lean more towards the FENWAL. The board appears to be telling the FENWAL to spark or ignite and the FENWAL has locked out. But here we go again...
Has the FENWAL failed and has locked itself out? Or is the FENWAL reacting to a failure somewhere else. The board (directly upstream on the control river), seems to be giving the correct command because we have the SPK displayed. All of the safety devices have been satisfied. So a lot of what could go wrong is out of the equation at this point,
Lets back up...
The heater needs the right conditions to fire. Things like: is it turned on? Is the set temp higher than the inlet water temp? Is water flowing through the heater? Is the heater too hot to operate safely? All those things have to be right for the main board to say: OK lets heat.
So now when it does this, it tells the FENWAL(FW) to light the heater. It does this by doing a few things. It opens the pilot valve, then it sends a pulse to the pilot which arcs or jumps to ground. Hopefully, the pilot lights and the pilot sends a signal back to the FW that there is a flame at the pilot (flame rectification).
Now this is where (i think) your problem comes in...
When YOUR heater initially tries to heat, your FW is getting that signal, and the FW goes ahead and sends voltage to the main gas valve, valve opens, and the heater lights. Now what i think is happening is, the FW is at some point loosing the flame rectification, that barely detectable signal that the pilot sends back to the FW. And the FW thinks that the fire has gone out, and shuts the gas valve. Because you dont want raw gas pooling. The FW now tries to relight Because the board says everything is good. So now at this point, if you can hear the "buzz" of the FW trying to light the pilot, AND the pilot is lit, your FW is bad OR you have a ground issue (what i have been nagging about). If no pilot is lit AND no Buzzing, probably the FW.
See? i still wont say for sure. BTW, the FW is also one of those high dollar NONRETURNABLE parts...
My response:
I have never heard of FENWAL so I looked it up. Then I looked for parts. Not terribly priced. And returnable (on eBay). They allow returns on most stuff. Even on the control board. I always make sure that I can make a return before buying. I'm willing to buy it and try it. I have to refer to my manual to find where it is on the unit. The most I have to lose is return shipping. This has been quite the learning experience. Very interesting. I always want to know how things work. Before this, the heater was a just a big ol metal box.
Ok, I give. I cannot find a thing about a gas ignition control anywhere on my manual parts list. Is Fenwal a brand only? And does it go by another name? Yikes. My eyes hurt. lol
Last edited:
