Poor Steam Pressure
I have a three family building with steam radiators and a Burnham boiler. Last winter, we really had no heating issues to speak of. Prior to this season’s heating, we had our local plumber do a tune up of the boiler and also replace most of the radiator valves, pitch the radiators and generally “balance…
I have a three family building with steam radiators and a Burnham boiler. Last winter, we really had no heating issues to speak of. Prior to this season’s heating, we had our local plumber do a tune up of the boiler and also replace most of the radiator valves, pitch the radiators and generally “balance the system”. I thought we’d preempt any trouble but since that was done, the house takes quite a bit longer to heat up. Unless we set the thermostat very high, the boiler usually kicks off before heat can even get to the last two risers at all. There is also one radiator that never gets hot. The plumbers tinkered and looked and looked and finally concluded that the boiler is undersized. It is a Burnham model 406b rated for 447 steam sq ft. The plumbers say I need something in the 600s. The building is four stories and 20 by 40. This diagnosis would make sense except that the building is the same as it was last year! The only difference I can think of is that they had noticed that two risers that run in the middle of the house that don’t have radiators attached to them had old valves attached. I think that last year one of them wasn’t getting hot at all. This year, with the new valves, that riser gets hot too. I wonder if the steam going to that extra riser could tip the scale and make the difference? Or could they have adjusted the boiler pressure in a bad way. On the boiler pressure gauage, it literally reads zero now, even when it is on. I’m not sure if it is broken or not. I don’t really trust the old plumbers who did the work so maybe I will get someone else in but any advice from anyone else that has seen their heating pressure (as I would describe it) drop would be great.
Yeah, a good plug could make all the difference! LOL, steam man.
Oops I forgot. Put a 1/4″ plug in the tapping instead of the vent.
-Steam Man
Absolutely do not remove any vents from the system! Steam will come shooting out of the tapping and cause any number of problems to people and your belongings (not to mention the entire room).
-Steam Man
Thanks again for all of the comments.
I looked at the valves they installed and they do seem to have been selected differently per floor.
The boiler says that it puts out about 103,500 btu of steam, if I am reading it right. Per Master Plumber, it is pretty old, from the late 80s. It does seem to fire up well though and plumbers who looked at it said we could probably get at least another five or ten years out of it, so we didn’t touch it during renovation.
Also to Master Plumber, we do not have the pipes insulated in the basement. That wasn’t an issue last winter but I guess we could consider that.
I’m not sure how to do the work suggested for the thermostat but will ask a neighbor who I think is more electrically handy – thanks.
I think i may close that interior riser, as suggested. Would i just remove the vent entirely, so air gets in?
Since someone asked, though the system was heating well last year, we did a renovation, during which a few of the radiators were removed and the old valves on them were removed and not reinstalled. Also one of the tenants had two radiators that were leaking. Also, while renovating, with many open windows, the boiler was on quite a bit last year and I thought could benefit from a inspection/tuneup. Last there was some particularly loud banging the system. The work this year was to address that. Otherwise I would agree with the “if it ain’t broke” motto.
Thanks all.
I just read in one of the other posts that someone suggested the boiler was undersized. Now I am thinking maybe it is and someone had raised the steam pressure setpoint to compensate. Then the recent plumber came along and set it back where it belongs and it doesn’t push enough steam.
Of course I am just speculating.
I would call the plumber back and ask him exactly what he did. If he doesn’t give you answers, you need another plumber.
Steve
I am not a plumber, but used to operate very big steam boilers. I also have not read all of the preceding posts, so someone may have addressed these-
You could have three things going on that could be causing this, I suspect it is one of them that brought this on:
1. the temperature in the room where the thermostat is located is reaching setpoint before the distant rooms have had a chance to heat up. In that case put new, larger vents on the radiators in the furthest rooms. You can put a smaller vent on the room where the thermostat is located.
2.they changed the setpoint on the thermostat. Check that and raise it if nec.
3. What I think they did was lower the steam pressure cutoff a little causing the burner to shut down before the steam has reached the far flung rooms. when this happens, it is not that you will get a little heat to those rooms, you get none (i’ve been through this in big buildings). They probably lowered this to save you $$, without realizing they went too far. have a real plumber (not someone like me) check the setpoint. raising it just a little could push the steam to the top floors. Do not attempt to locate the pressure switch yourself and try this –
Steve
http://www.thetinkerswagon.com
Lots of good advice here, not all of it easily comprehensible if you are new to one-pipe steam systems. These systems can be great but it is a delicate balancing act. Lots of variables to play with and hard to diagnose on a blog. I’m a homeowner, not a plumber, but here’s my advice:
1. If you are relatively handy and have a little bit of a head for these kinds of problems, take your query over to heatinghelp.com. Print out sizing charts for boilers and radiators, and get a sense whether your system is ballpark for your house. Post a query on their forum. Play with vents (larger ones — Gorton C or D for the top floor, smaller ones, Gorton 4,5,6 lower down — don’t forget the teflon tape) to balance the system. Read up on pressure settings. Lots of knowledge you can acquire and tinkering you can do to help you diagnose and maybe solve the problem or at least be knowledgeable if you need to call in a plumber.
2. If this is all beyond you, bring in a good, reputable plumber to assess all this for you. Two recommended here frequently are John Hlad (that’s who we use) and Gateway (that’s masterplvmber, who responded above). You can’t go wrong with either.
sounds like your vents are improperly sized… if you want a free consultation, email me at errol832000@yahoo.com
406b is an old defunct Burnham boiler number.
A Burnham IN6 (a very common unit in Brooklyn 3 to 4-story buildings) produces 450 square feet of steam and is a 175,000 BTU boiler.
If you think it may be close to your requirements or maybe slightly undersized, you can decrease some of your system’s EDR by insulating the distribution piping.
A proper EDR (equivalent direct radiation) calculation needs to be your first step in determining proper boiler size.
Me:
http://www.GatewayPlumbing.com