Burnham MinuteMan II Short Cycle

John R Leny

I have a minuteman II boiler that short cycles because it is grossly oversized. The boiler is very reliable and I have never had a issues with it. My question is this. Is there a way to add an outdoor reset so I can get the boiler to turn off but keep the circulator running until the water temperature reaches 170. I want the boiler to fire at 170 and hit high limit around 190 or 200 and then relight at 170 etc. The board has a preset differential that cannot be changed. Anyone know if this can be done using a diffrent controller etc?

Unknown

Minuteman II Question

John,

Due to the fact that the supply and return water are actually exchanging to the system from the tank and not the boiler, resetting the temperature of the boiler water is really not possible. That tank water has to be hot enough at all times to be able to produce domestic hot water via the tankless heater.

I would suppose that you could seperate the system pump away from the boiler relay and use an Injection-Reset control to fire the boiler through the thermostat leads to the boiler relay and use the pump as an injection pump into a primary-secondary setup. The problem with this is that you will lose the priority functionality that is provided in the boiler circuitry to protect against taking a cold shower. My advice would be to leave it as is. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com