So I got a boiler that had not been used in a bit, maybe a couple of years but was working. The last time they needed to have some come light the boiler. My assumption there was the ignitor was going bad and needed to be replaced. I found a new one and replaced it, but it still wouldnt lite. I did the normal digging on the internet to test multiple things and see if I could come to a solution. I am no way certified to do this but figured Id give it the home owner try. So I took a volt meter and tested power through out the system and I am getting power everywhere. The only place I dont get a reading is from the MV connection to the gas valve which I assume is accurate because the PV sends power for the pilot to ignite. MV/PV also has power as well to the gas valve. When the furnace is powered on the damper goes from open to closed which I also assume is correct because if its not on why be open. The only thing here is it makes a buzzing sound when closed, but not all the time. When I set the thermostat to a temperature higher than what its reading, the relay kicks and sometimes that buzzing sound goes away. The recirculating pump gets power. Now if this is working or not I do not know. My lack of knowledge is the sequence it should turn on. I would think it would tell the pilot to turn on, then the pump kicks, then the MV to the gas valve gets power and allows more flow and then the damper opens. Again I dont have the education for this just the typical home owner stuff. There is a water regulator on the supply feed at 12lbs which I dont think is comprising anything. I am at a lost now and dont know what else to really test for. Another thing I noticed is when I set the thermostat higher, I dont get any voltage from the board that has the igniter plugged into. My assumption is to use a small lighter if that was the problem but I still get no flame from the pilot. My next guess is flame roll out sensor is bad, I added a picture. I ordered a new one to try since it was only 15$ so the test/fail wasnt that impactful. Please any advice or suggestions would be great, even if it is to just call someone. Knowing I gave it all I could is also satisfying. The pilot gas feed line was not clogged as well. I know gas is coming to the gas valve from checking the inlet tap.

Things that are currently new: Gas valve and the igniter

Make and model: Vaillant GA92-080-EIVD




  • What make and model is said boiler? Mar 6, 2021 at 22:29
  • 1
    That would be helpful lol, Vaillant GA92-080-EIVD Mar 6, 2021 at 22:37
  • hot surface ignitor or always lit pilot? Mar 6, 2021 at 23:47
  • I am going to guess the pipe coming out of the honey well gas valve is the thermocoupling and leads to the pilot. Are you able to light the pilot when the valve is on pilot mode? Mar 6, 2021 at 23:49

1 Answer 1


It was actually my thermostat. I have a new nest one and after jumping at the aquastat I realized the thermostat wasnt actually calling for heat and would just click the relay instead of staying down.

  • Thanks for coming back to post that answer! Please be sure to click the check mark so others know that this has been resolved.
    – FreeMan
    Mar 10, 2021 at 15:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.