Is there an ideal cycling time for oil boiler run time cycle? What is short cycle?

CoachBoilermaker

What is a typical on/off run cycle for a well tuned steam system? Say it's 30F outside, and the thermostat is set for 67F. Should the boiler run for X minutes, and be off for Y minutes? Ballpark ranges? How does one dial this in? Vents?

EdTheHeaterMan

A good steam boiler cycle rate is one cycle per hour. That is what the thermostat sees.

What the burner sees may be quite different. During a call for heat, if your boiler is oversized, the burner may run for 10 minutes to make steam and pruge the air out of the vents. but if the thermostat is not satisfied by then, then the steam pressure increases and may trip the limit on the pressure control, 4 minutes later the pressure will drop and the burner will come back on. The pressure will build for some short time and pressure control will trip off again is a minute of two. And this cycle will go on until the call for heat is satisfied. So you need a proper size boiler to get your best oil burner or gas burner efficiency.

If you have got it just right, then the pressure limit control will never trip and the burner will stay on for 40 minutes and shut off for 20 minutes at 30°F

At 40°F the burner may run for 30 on 30 off.

AT 10°F the burner may run for 50 on 10 off.

Hope this helps

LRCCBJ

 During a call for heat, if your boiler is oversized, the burner may run for 10 minutes to make steam and pruge the air out of the vents. but if the thermostat is not satisfied by then, then the steam pressure increases and may trip the limit on the pressure control, 4 minutes later the pressure will drop and the burner will come back on. The pressure will build for some short time and pressure control will trip off again is a minute of two. And this cycle will go on until the call for heat is satisfied.

^^^^ THIS is short cycling.