intermittent pilot vs standing pilot

ChrisJ

I'm curious what everyones opinion is on intermittent pilot vs standing pilot.  I have to assume a standing pilot is far more reliable and cheaper to fix if it fails.



Is there anything I should know before making a choice on a new gas steam boiler?  Both options are available.

Tim McElwain

The typical cost

per year for a pilot using an .018 size orifice is around $100 to $130 depending on the cost of the gas per therm (100,000 BTU's). Thermocouples are very reliable and it is not unusual for them to last over five years and in some cases in my career I have had them last fifteen years.



If you add a vent damper to the boiler it will offset some of the cost by holding the heat in the boiler from the pilot. Just note that a small knockout has to be removed in the damper when using a standing pilot.



Intermittent pilot systems with spark ignition are not as reliable and parts are more expensive.

bill_105

Is it true..

that standing pilots will no longer be available, in 2012?

Tim McElwain

To the best of may knowledge that is

correct, in fact they are not allowed in some states now. I am just not sure which ones. The problem is when you increase efficiency requirements the standing pilot system even with the vent damper can't meet the standard.

ChrisJ

Why no high efficiency gas steam boilers?

The highest I can find so far is the Weil-Mclain EG series and even these are only 82.9% with intermittent pilot and damper.

Steamhead

Consider thermal efficiency as well

DOE output as a percentage of Input. Atmospherics like the EG are 80-82%. Wet-base power-burner units are 86%.