sudden imbalance in steam system

Hitzkup

i just found it at webb supply call them at 800-994-9322 and ask for danfoss #013g8250 and danfoss #013g0140 should be around $60 both together plus actual shipping.

use any straight air valve. i use a gorton c. if you have gortons on the other radiators neither the hoffman 41 nor the hoffman 1a will work. because of their venting capacity.

mark sch

shawn_11

One pipe steam question

After insulating the pipes in my building, and adjusting some air vents, I had the apartments balanced for heat. The apartment on the third floor was 71, when I set the thermostat on the first floor at 70--good enough for me.

Then last night, the weather was particularly cold outside, and that third floor apartment shot up to 77, while the first floor apartment (with thermostat) stayed at 70.

What might cause this to happen?

Although the system is balanced, the vents are smaller than ideal. (I have ordered replacement vents). I have had some short cycling in the past, which i attribute to pressure cut-out, but not sure if that would relate to this problem

Thanks for any thoughts you might have.

Bob W._3

You may need TRV's on the 3rd floor rads. My home has the same response. The boiler runs more often as the weather gets colder and the upper floors get more heat. When the weather is mild (above 25* or so) the boiler doesn't cycle as often and the 1st floor rads get the steam faster. The boiler shuts off on the thermostat before the upper floors get warm. I currently balance my system so the upper floors are cooler in mild weather and then warm up as the temp drops. I am planning on installing TRV's to cure this problem.

shawn_11

Where are you buying TRVs? I haven't found them locally (Wisconsin).

Also, did you ever consider venting the top of your steam risers? I'm wondering if that might help in my situation.

Bob W._3

Here is a link to a St. Paul supplier. I have bought from them in the past. Not the cheapest on some items.

http://www.statesupply.com/displayCategory.do?cuid=FP_VC_Therm_Rad_Valves

In thinking this through, however, I don't think I would use the Hoffman No. 41 vent in the TRV, since that is the equivalent of a Hoffman No. 40 with a straight shank. I'm thinking I would put in a 1/8" ell and nipple and use the 1A's or Gortons.