Pressuretrol vs. short cycling

John Shea

I was reading Dan's book last night and had a question about the Pressuretrol turning on during the heating cycle.

It is my understanding that during a heating cycle, it is normal for the Pressuretrol to cut the flame when the pressure reaches the "cut-out" point. Then as the pressure lowers from this point, the system fires up and the process is repeated. My question is, at what point do you classify the Pressuretrol cutting in and out (which is normal) as short-cycling (which is not)?

Have I confused the issue?

DanHolohan

It's the length of time between cycles, Jenny.

If the burner is kicking in and out every few minutes then it's short-cycling. If, on a really cold day, the burner comes on, runs for, say, 10 minutes, then shuts off for five minutes before restarting, I'd call that normal.

Short-cycling usually indicates an oversized boiler, or a piping system that lacks proper venting.

That help?

John MacGregor

That's the answer I was afraid of...

Hopefully my landlord will get a professional in here soon to take a look at it.

Thanks Dan!