UT 1003 - Boiler not lighting

bherrick71

Hi folks,

I have a boiler that doesn't light sometimes. It sounds like the gas comes on, it sounds like a spark is being made, but it doesn't light. Then it makes a high pitched whine that changes when you touch the spark ignition control. I can't figure out what is going on. The strange part--sometimes it lights, sometimes it doesn't. Sometimes it doesn't light then, 45 minutes later, kicks on. It makes no sense. Is it just a faulty unit? Would swapping it out solve the problem? If so, is it as easy as making sure there is not power and just plugging the cords into a new unit?

You can see/listen to it here: https://photos.app.goo.gl/xkJfU2nkt9xAarrp6

Any insight would be appreciated.

EdTheHeaterMan

The sequence of operation is that the damper opens, the damper open switch connects and sends power to the ignition control. The ignition control powers up the gas valve and the spark ignition. If there is no flame signal within a few seconds the control will close the gas valve. sounds like you may have one of 2 problems.

1. The spark is not positioned in the flow of the gas. This is corrected by cleaning the pilot orifice or burner position so the gas flows thru the spark
2. The burner is lighting but the flame sensor in not reading the flame on signal. This is corrected by cleaning the flame sensing rod or replacing the flame sensing rod if the existing one is beyond cleaning or adjustment.

I believe this would get you up an running but you need to understand how flame rectification works and what the sequence of operation of that ignition control is. If you ger the spark right and the signal correct and you still have problems, then you may have a bas control that is not opening the gas valve on every start cycle. you may also have a bad gas valve that IS getting the signal to open every time, but fails to open on occasion.

I have just offered you 4 different reasons why you have this problem. You can start by shooting the parts canon at your heater and hope you pick the correct part eventually. (flame rod, gas valve, spark ignitor, ignition control) Or you can call a professional that has experience with your system and get it fixed promptly. on the first try. at minimal parts cost.