Intermittent explosion when gas boiler ignites

KentnDC

For the past few weeks, about once every 48 hours, when the gas boiler ignites, rather than turning on quietly, there is an explosion (to shake the house/wake from sleeping) and the boiler ignites. There is a lingering smell... like something burnt.



2 weeks ago, the furnace company came by and cleaned it. It had been 13 months since the last cleaning. The explosions continued. A second service technician came out and could find nothing wrong. He suggested we get our flue checked. The flue man came out and all is well. But the explosions continue.....



It is a Peerless Boiler . The Model number is MI-04-SV (DE-03-SPRK) - it is about 12 years old with regular maintenance.



We had Central Air installed last spring but only cooling, no heat. New themostat was installed at that time.



The techician said he could not fix it if he doesn't see the explosion, but we can't recreate them. Any advice on what might be the problem and what can be done to fix this. It would be greatly appreciated. This all is rather unsettling.

Paul S_3

you must

call a professional.....it MAY BE a delayed ignition....which means that the gas valve opens on a call for heat and it does not ignite right away.....meaning the chamber fills up with gas then ignites.....when did this start happening AFTER the tech came to do the annual PM???....MAYBE he put the pilot assembly in the wrong place???....if it happens again, which more than likely it will....call the company back and ask for there most seasoned tech.....i am assuming he will know what to do.....for example check everything from gas pressure, combustion efficiency test, have them cycle the boiler a few times to see how it ignites...etc

                 PAUL S