steam boiler pressure

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Old 10-23-11, 07:21 PM
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steam boiler pressure

I have read that the pressure of steam heat need only needs to be high enough to push the steam to the furthest heat emitter is this correct?
 
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Old 10-23-11, 07:31 PM
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Generally yes but there are some installations that require the higher temperature of a higher pressure steam and there are some installations that require higher pressure steam to force the condensate back to the boiler or condensate receiver.
 
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Old 10-26-11, 02:49 PM
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for the most part that is correct. steam heating. proccessing is a different animal. your right on the money when it comes to a gravity system.
 
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Old 10-26-11, 07:17 PM
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The best operating steam system is one that never builds pressure but all radiators heat and satisfies the thermostat.
 
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Old 10-27-11, 01:36 AM
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The PROPER steam pressure is the pressure the system was DESIGNED to use. Most single family residential is DESIGNED to use very low pressure, about one-half psi. Multi-family residential MAY be designed to use this same very low pressure or it MAY be designed to use a higher pressure of maybe three to five psi. Large space heating systems MAY be designed to use higher pressures but this is rare.

Simply put, there is no blanket statement of pressure that covers all steam heating applications.

Long ago I worked in a facility that utilized high pressure steam (100 psi from a central boiler plant) in a building that had originally had its own low pressure boilers that ran at about 5-7 psi. The building had pressure reducing valves that dropped the 100 psi steam pressure to 3 psi yet there was a severe problem of overheating. Nobody, including the facility's Technical Services Supervisor could understand why it was overheating with 3 psi steam when the original pressure had been about 6 psi. I pointed out that they were now using superheated steam at a temperature near 338 degrees in a system that had been designed to use steam at 230 degrees. 108 degrees higher temperature meant a whole lot more BTUs being released into the building. I don't think that stuporvisor ever understood that simply reducing the pressure did NOT lower the temperature.

Along those same lines I volunteer at a historical museum where the steam heating system runs at about 50 psi for the simple reason that it was DESIGNED to run at that pressure and temperature. While it will run at a lower pressure it will NOT produce the necessary heat output needed for the extremely drafty 113 year-old building.
 
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Old 10-27-11, 05:58 PM
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Residentially the early steam systems (1841)were designed around 60 psi. There were just pipes no radiators. Later early rads were made of steel not cast iron.
In 1880 the government passed a law that the new residential steam systems had to be designed at 2 psi or less or the homeowner did not have to pay the contractor.
Go figure
 
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Old 10-27-11, 06:09 PM
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Thanks Wet side of. for the information
 
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