steam heat

[Deleted User]

i have a job with a #23 webster vent trap and a#23 webster boiler return trap can someone tell me there function and how they opperate

Adam_13

Webster System

Hi Mike, sounds like you have a webster two pipe vapor-vacuum system. One of the best steam systems ever built, but I'll stop getting sentimental here. The vent trap is a webster 20's series modulation vent trap. Despite it's fancy name it is an extremely simple device. All the system air is let out each cycle by the air vent at the top of the vent trap. Internally there is a float that is connected to a pin valve under the air vent. These systems were designed to run at extremely low pressure (usually not more than 8 oz. max.)The idea was that back in the coal era if someone wasn't paying attention to the fire and the pressure started to rise, the water would start to back out of the boiler and rise up in the returns. Thus, the float would rise in the vent trap closing the port to the air vent and preventing water from leaving the air vent to flood the bsmt floor, etc. Today make sure that the air vent is clear and run the boiler at low pressure and you won't have any trouble. Theoretically if you keep the pressure low nothing but air will come out of the vent. If water or steam is coming out of the air vent you have clogged return piping and/or steam traps that have failed elsewhere in the building. If this is the case find a good steam pro and they'll have everything straightened out for you in no time.

Now to the other device. In a two pipe steam system like yours, there should not be any steam presssure in the return piping as in a one pipe system. A one pipe system has "left over" steam pressure in the returns to help put the water back in the boiler. In your system normally there is no left over steam pressure to help put the water back into the boiler. This is where the return trap comes in. Basically a boiler return trap acts as a kind of condensate receiver. It also has a float in it like the vent trap. As the receiver fills with water, the float raises and opens a vave internally that admits steam pressure to the returns momentarily to push the water back into the boiler. The water is held back into the boiler by check valves. For more info or a clearer picture see Dan's book The Lost Art of Steam Heating under boiler return traps. Today these sometimes give problems if the check valves don't seat because of system crud, etc. Again, a good steam pro will be able to fully assess your trap to see if it's still functioning properly. If it's not the only choice is usually to replace the trap with a boiler feed pump (not condensate pump)controlled from the boiler.

Anyway, I'll end the book here. I'd love to see pictures of the system if you have any. Also, I've included scans from the original 1922 Warren Webster book of the vent trap installation details.

Can you tell I love steam heat! Hope I've helped, -Adam

PS- Sorry Mike, wasn't paying attention. When I wrote this I thought you were the home owner.