How much pressure

mel rowe

FWIW Since I downsized my oversized boiler by removing 4 of 16 burners and adjusting the gas pressure to get the recommended manifold pressure, normal steam cycles hardly ever show anything more than a couple oz. of pressure on my 5 psi gauge. All rads get hot and the system is operating best ever for me.

Techman

How much pressure

should I expect to see in a steam boiler in a one pipe system that utilizes T.R.V.'s on the radiators?

nicholas bonham-carter

1-pipe pressure

under 1.5 psi max. ideally 12 oz.--nbc

Brad White_203

Agreed

The use of TRV's is incidental and will not affect the pressure. Think of them has intelligent vents.

The Steam Whisperer (Formerly Boilerpro)

I have been finding that these systems can run about 6 ounces

or less. I have a system in Chicago that has an ounces gage on it and they heat the whole system at about 4 ounces. When the pressure starts running higher, they know to clean the boiler. I just calculated the pressure drop on a small commercial one pipe system and ended up with 4 ounces. Other systems end up about 6.

boilerpro




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Fred Harwood_2

Pressure

In an uncompromised one-pipe, the pressure need not exceed by a fraction the piping friction. I often find small boilers that develop only an inch or two of pressure (H20) and yet heat every room within two degrees and without cycling. Between the suction of collapsing steam in the rads and the heat of boiler, very, very little energy should be wasted on distribution. Cycling twice an hour helps.

Really.

The Steam Whisperer (Formerly Boilerpro)

Agreed!!..NM



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Techman

How much?

I thought the regular pressuretrol was not used on systems with TRV's ?And the regular T'stat was now the boiler controler.Something to do with theTRV's needing to "reset" to atmospheric press to work properly?

Fred Harwood_2

Pressure

The Pressuretrol ensures safe operation of your boiler. A properly working one-pipe matched to its load seldom trips it during normal cycling with the thermostat. Oversized boilers, or zoned steam systems, cycle against the Pressuretrol until the thermostat is satisfied.

TRVs are thermostatic vents and permit temperature regulation in individual rooms. They do little else.

The "reset" of radiator vents is needed only when pressures are relatively high and steam closes the vents. Normal cycling on the thermostat resets them when you cycle about two times an hour

Phil_17

Let me second that...

My system typically runs on 1 - 2 oz. of pressure. Never see any more than that unless all the vents are closed, which never happens under normal circumstances as the tstat is satisfied before some of the radiators are heated even half way across.

I think that a lot of boilers are overfired, especially if you're building more than 1-2 pounds of pressure before all the vents are closed.

To minimize the replies:
Yes I have a 0-32 oz. gauge,
yes the envelope has been tightened up significantly,
yes the house heats evenly,
no my pigtail is not clogged,
no there is no hammer,
no there are no spitting or hissing vents

I'm a happy camper! :-)

-Phil