Pressuretrol \"cut out\" Question

btc

My one pipe steam system is working well--in large part to the insight from The Wall and Dan's books. However, my system never seems to shut off on pressure--only tempurature. I have the Ptrol cut in at 1/2 psi and the differential at less than 1 psi (Honeywell 404). Typical cycle is 40 minutes or when 3/4 of rad sections are hot.

However, when the system runs longer (eg. 60-70 min. on cold start in am)and heat makes it to end of rads, rad vents (Hoffman 1A's)opening/closing for several minutes before temp cut off, I occasionally find that on the subsequent cycle, one or two radiators dont heat at all.

It seems like the longer cycle sends pressure above 1.5 psi which causes rad vents to stay in closed position.

Seemingly, boiler only kicks off on reaching temp, never based on pressure--I have observed boiler for entire cycle to check. Also, I do have main vents--Hoffman 75's on both runs.

Does this seem like a pressuretrol related situation? Any troubleshooting advise? Thank you. BT

ed wallace

pressuretrol

could be the pigtail has a slight blockage remove control than pigtail clean pigtail whith a piece of wire and flush with water than reassemble it could also be a t stat problem what makes you think its not going of on pressure the gauge might be bad

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Mark Hunt

I have seen


those controls let systems shoot well past the cut out limit on brand new installs.

You would be better off with a vapor stat control.

Unless you have a HUGE home, I can't imagine that you would need more than 1/2 lb of pressure to get the job done.

Mark H

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Dale

Temperature cut out

Have you put a digital temperature next to your thermostat? In an ideal world why would you ever want the boiler to shut off on pressure? It does on most systems since steam startup from a cold start produces lots of condensate but this isn't really desireable just the way it works.Sometimes the stat heat anticipator will produce so much heat to be satisified after a long call if the room heat isn't getting near it. I would just jump out the stat and see how the boiler cycles on pressure, If you want good numbers you'll need a 0 to 3 or 5 pound gauge along with the standard 30# one. A 0 to 3 PSI Dwyer magnahelic works great for a cycle test, just give it lots of pigtail as they are not designed for steam.