One-Pipe Steam has Water In It.

MarkR

Hello:

In the apartment I'm renting, there is a one-pipe steam system with water-hammer noise and air vents that occasionally sputter and spit. I attribute this problem to the fact that two of my radiators literally fill with water every 24 hours or so (I removed 5 gallons from one last night).

My landlord is not exactly a conscientious superintendent, and so I'm trying to do anything I can from aboveground before I need to wheedle him into the basement (at which point I will need to give him very specific instructions).

My presumption is that a) the system is overfilled, and b) the landlord set the automatic refill level too high (so even when I effectively drain the boiler (from the radiator end) the system just refills to that same too-high volume). The system pressure also may be too high (when I snuck in to look, the Pressuretrol says "on" at 1psi, "off" at 3, whereas most Google results suggest a two-story building should use no more than 1# of pressure).

Does my diagnosis sound correct? Can someone please give me some easy-to-follow instructions for the landlord? Or, if my diagnosis is incorrect, can anyone suggest anything else?

A few hopefully-helpful pieces of data:

1) The landlord has only owned the building for six months, and in that period, has removed and capped the steam pipes that ran to the upper floor. Assuming he made no adjustments to the boiler, might this explain the problem?

2) I have shimmed every radiator to ensure there is a slope back to the pipe.

3) One radiator had a thermostatic valve on the steam pipe (not the air vent), which I removed -- isn't that sort of thing intended for a hot water system, not steam, leading me to believe that whoever installed the system is not exactly a steam heating expert?

4) In the basement, there is a B&G "Watchman Condensate Unit" that makes a noise every five minutes or so, which I assume is some sort of vacuum pump; when the boiler was off, I would hear air being sucked *in* to the air vents every few minutes.



Thank you all for any help.

/m

John Shea

I would suggest....

picking him up a copy of "The Lost Art of Steam Heating" as a late Christmas present.

http://www.heatinghelp.com/shopcart/product.cfm?category=2-3

Hal

Sorry to post twice by accident.

Hal

Could be pitch

Warning: I am not a pro.
That said, I just solved the same problem in my house.

I had water hammer, gurgling, spitting, poor heating, all the way up the riser to the third floor. Very discouraging.

I discovered a horizontal pipe in the basement that had lost proper pitch, perhaps due to settling of the house. There was a puddle in the poorly pitched pipe that steam was sending up into the radiators. I had a plumber repitch the pipe. The problem is fixed.

This is only one possibilty that may be leading to your problem. Still it's worth looking into.

Thad English

one other thing...

I had a steam rad in my house fill with condensate last year. The cause was that the radiator supply valve was not open all the way and the condensate could not make it back down the pipe. I had the bright idea that closing it would "dial back" the amount of heat. Wrong. Instead, water eventually came out of the vent and damaged the ceiling of the room below. Make sure that valve is wide open.

patrick linhardt

water in rads

Hi Mark,

You are correct in suspecting the steam operating pressure. Two pounds of steam are usually enough for most systems. As Dan Holohan says about steam pressure, "Crank it down". Always operate at the lowest possible pressure for best system efficiency.


(1) Capping the upper floor radiators should not effect the system, except that the boiler might now be greatly oversized, which can cause some problems. Did this decrease the radiation by one half?

(2)Besides checking the pitch, have you verified that the radiator valves are completely open?

(3) You are right that you do not use a thermostatic valve on the supply valve for a one-pipe system. However they are used quite evectively on two-pipe systems. What did you replace it with?

(4)The Watchman unit is just for condensate transfer, it does not create a vacuum. As water fills the receiver tank, a float inside turns on the pump to move the water back into the boiler. The air sucking back into the radiator is natural.

Check the pressure, check the valves. Get the landlord to hire a professional.

Best regards, Pat