Commercial steam rooms 3

[skbutler]

I have a problem that pops up every now and then that seems like it should be easily understandable and easy to fix.
I work on the 18 kw electric boiler that supplies steam to the steam room in one of the first athletic clubs in the USA. I have the steam pressure set for 5 psig on the boiler. I have a temperature control set for 115 deg F. The steam room is in operation from 8 am till 6 pm. Occupied probably 50% of the time.

Problem: At times the boiler shuts down on temperature and doesn't turn back on for 45 min to an hour which results in the steam being hot but without steam. The steam room has no ventalation and the exterior walls are some 2 feet thick. The place was built around 1800.

I'm a boiler engineer, not a steam room designer.

Anyone have a simply control stratagy to keep the steam room full of steam and keeping the room temp below 120 deg F?

Thanks,

Steve

 

[Ziggypump]

Sounds like a humidity problem, not a temperature problem (if I am understanding your post correctly).

If I am understanding this correctly, then a thermostat in the room controls the boiler. In the event of heat loss, the boiler activates and supplies steam to the room. Now, when the temperature is satisfied (115 degrees?) then the boiler will remain off. The steam will condense and the room clears, while the room temperature is being maintained.

I believe a humidistat is what you would want as well as the thermostat. The humidistat will measure the amount of moisture in the air. When the amount of steam dissipates, to a level below the setpoint, the boiler will activate. The thermostat would still be desired so that the room isn't overheated.

I've never designed a steam room myself, so this may not be a complete idea, but when you want to maintain steam (humidity), temperature will not help.

 

[MintJulep]

Effectively the pressure setting controls how much steam enters the room.

So as the room approaches the desired temperature you want to decrease the pressure setpoint.

 

[Compositepro]

You must have some ventilation to bring in outside air. Steam adds both heat and humidity to the room. If you are controlling based on temperature, then your steam turns off when you reach set temperature, and a humidistat will not help.
People need ventilation, too. A low wall inlet register near where steam is added and a high register to let hot air out should be adequate. The high temperature in the steam room will drive convection.

 

[willard3]

You need a variable pressure controller to run the boiler, as MintJulep says.

Not inexpensive or simple.

 

[ChasBean1]

You say:
- I have the steam pressure set for 5 psig on the boiler
- I have a temperature control set for 115 deg F.
- At times the boiler shuts down on temperature and doesn't turn back on for 45 min to an hour.

If the boiler firing maintains a pressure in the steam header, tell me there is a control valve in the line that modulates to maintain room temperature? If not, the control might be very sloppy and problematic…