Short-cycling

Tom_50

I have a steam boiler that short-cycles. It's a Weil-Mclain EG-45. I probably could have gone with a EG-40. It seems the boiler creates pressure too fast and goes off on pressuretrol. I've read that I can "down-fire" the burner. How do I accomplish this? Or can I lower the gas pressure on the gas valve. Also is it possible to just eliminate one burner from the rack and plug it off with a 1/8" plug. Thanks for your help.

Madghost

The best bet is to check with the manuf. prior to making any major mods. However by removing one burner or one from each side, removing the oriface and plugging off the gas train is a method called de-rating, and in atmospheric units is often beneficial it even extends the life of the refractory. Simply take the btu output of the boiler, divide by the # of burners giving you the ouput per burner, then subtract that number from the total output thus giving you the new de-rated rating.

A less drastic effort however may simply be to increase the differential on the pressuretrol it is often times a simple as that.

One more method would be to go with a two stage gas valve and a controller that would swing between low and high fire, it would be ill-advised to simply lower the fuel pressure to the train as the equipment is designed to operate a prescribed inlet pressure.

Hope this helps.

gerry gill

was your system a vapor system?

was it a two pipe, vapor, coal sytem, originally?..I'm asking for a particular reason, and you already figured it out I think..first make sure all air vents, system components work properly..the guys here would beat me up if i told you to down fire the boiler..but here is a hint from the Mouat vapor system countryside,,coal fires didn't rage, they simmered...I'm ducking :-) but dont make any adjustments without a combustion analyzer..

Tom_50

It's not an old house. Just a one pipe steam system. Orginally oil but now gas. All air valves checked out ok. Only 7 radiators, a two story A-frame house.

gerry gill

okay,

yup, I think I would do both, down fire some and remove equal amounts of burner tubes and plug their openings..probably start with one from each side..In the old days with the first gas boilers you could adjust on/off or in the middle for each and every burner tube, and you would open them up starting with the ones closest to the pilots depending on the weather..the colder it got the more burners you would open..shame we can't do that today..