Bradford White (Honeywell) Model # MI40T6FBN; HELP!

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NiceKaren

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Hello! New to forum, also may lose my mind if I can't fix my WH!

My pilot light went out randomly on Father's Day. No reason at all that I know of. I turn it to "OFF", waited a good 20 minutes or so then turned it to "Pilot" held that down for a minute or so then hit "Ignite" thirty times at least. Then nothing, no spark, no flame, nothing.

Open up the WH, took out the pilot assembly, cleaned the thermopile, cleaned off the grate that is on the very bottom under the burner because that had some crud on it. Put everything back together, noticed that I was able to "push in" the red button on the Resettable Thermal Switch (red-290 degrees). Pushed it in, no problem.

I then tried to light the pilot light again and was able to get a spark then after a few more igniter pushed I got a little blue flame. I held the pilot button down for what felt like a century and once I let it go the flame would go out, over and over again. It would not stay lit and from what I could tell, the flame was very weak.

I purchased a whole new pilot assembly and replaced the old one and I am still having the same issue. Go to light the pilot, get a little blue flame, let go of the pilot button, and it goes out.

The status light does "two blinks, 3 second pause".

I have read the service manual 300 times and I cannot figure out how to get this bad boy up and running again. It was installed in 2016 and is for residential use in my furnace closet. I am purchasing a new Resettable Thermal Switch, but other than that I have NO idea how to fix it.

Any suggestions?! Thanks!!
 

Tuttles Revenge

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I'm not a terribly good water heater diagnostics guy.. but did the pilot assembly come with a Thermopile? If that isn't sending the signal to the gas valve then the gas valve won't stay open on its own.
 

NiceKaren

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I'm not a terribly good water heater diagnostics guy.. but did the pilot assembly come with a Thermopile? If that isn't sending the signal to the gas valve then the gas valve won't stay open on its own.

Yes, the pilot assembly came with the igniter, thermopile, and another part all connected together.
 

Fitter30

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Two blinks bad / weak thermocouple. Thermocouples only put out between 20-35 mv. Disconnect thermocouple from gas valve inspect thermocouple end make sure that its clean and in the gas valve with a mirror reinstall tighten till snug 1/4 turn more. The hi temp switch pull electric spade clips off they should have resistance to pulling them. If you have a multi meter measure resistance cross switch should be close to 0 ohms. If not take a short piece of wire put it in the spade clips see if the pilot holds if it does switch is bad this is how to test it.
 

NiceKaren

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Two blinks bad / weak thermocouple. Thermocouples only put out between 20-35 mv. Disconnect thermocouple from gas valve inspect thermocouple end make sure that its clean and in the gas valve with a mirror reinstall tighten till snug 1/4 turn more. The hi temp switch pull electric spade clips off they should have resistance to pulling them. If you have a multi meter measure resistance cross switch should be close to 0 ohms. If not take a short piece of wire put it in the spade clips see if the pilot holds if it does switch is bad this is how to test it.

The thermocouple was replaced and now will spark & light. But it is a very weak blue flame and will not stay lit after I take my finger off the pilot button.
 

Fitter30

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If thermocouple circuit ( thermocouple, hi limit switch) putting 20-35 mv will not hold in the pilot. Are you sure the new pilot assembly was the same exact model number as the old assembly. Natural gas and lp have two different size orifices. Nat .022 lp .010 can vary in size few thousands.
 

NiceKaren

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Yes, I made sure to buy the exact part # listed in the manual. I ordered a new gas valve and red resettable thermal switch. Hopefully it is one of those because I am at a loss and I haven't seen anyone that's had the same issue as me. Thank you for your input!
 

Jeff H Young

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Actually that's a very common problem pilot wont stay lit. fitter 30 been very descriptive troubleshooting tips. I'd save my money on a complete valve for now till I knew
 

Weary_landlord

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Did you ever solve this? I am having a problem with the same unit right now. Not sure if it's the pilot light though. Heating greatly reduced. There's a steady blink of the green light every few seconds. There's a companion unit for the other floor that's working fine and has the green light blinking at the same rate.
 

Michael Young

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Did you ever solve this? I am having a problem with the same unit right now. Not sure if it's the pilot light though. Heating greatly reduced. There's a steady blink of the green light every few seconds. There's a companion unit for the other floor that's working fine and has the green light blinking at the same rate.

Yeah. Those Honeywell gas control valves suck balls. If you look up error codes. Damn near every single error code says the exact same thing (REPLACE GAS VALVE). I freakin’ hate those Honeywell valves. There are some guys who say you can reset them with a 9-volt battery. Yeah. maybe one in 20 you can reset with a battery. My experience is... just replace the freakin’ gas control valve. Cuz you know. it makes sense to replace a $150 valve than it does to replace a $12 thermocouple.
 
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