Two pipe steam heat troubles

Titus66

Hello all. I am new to this site but I read with great interest the dilemma of lostonLI. I have a two pipe steam heating system in a 1930 brick colonial home that I purchased almost a year ago. The boiler was replaced by the previous owner and converted to natural gas. Also the plumber installed two boilers. When I asked him why he did that he told me the second boiler was a backup to the first if it couldn't keep up with demand. I have never seen that before. What is puzzling is that each radiator in the house has a thermostat control with a dial on it and a sensor at the bottom of the radiator. Some of the radiators were cold during this last winter and some were very hot. Also when the boiler would go on there was banging noise on the first floor as if the radiators need to be bled, but as I'm researching a two pipe heat system I'm not sure you can bleed them. I don't think the contractor who installed the system is confidant in his steam heat ability because he wants me to consider changing to forced air heat. That's not happening. Can anyone give me advise or steer me to a knowledgable contractor. I am in Long Island. Thank you!!

ttekushan_3

It sounds to me like you have the makings of a good system but I'm going to go out on a limb and guess that you have a vapor system and the boilers' water lines are lower than the original. This exposes the loop seals between steam supply and dry return. So the return vents close and the radiators towards the end of the line lock up. Steam in returns will hammer.

Post a few pics of the boiler set up and we can give you a head start. Take a photo of the pressure control and its setting too.

Edit: if the original radiator valves were of the orifice type and replaced with standard TRV's then you need good radiator steam traps in addition to whatever else we find.

nicholas bonham-carter

Welcome to the wall!
For future postings, use the "strictly steam" category, to get the most eyes on your problem, and it's solution.
A correctly installed, and maintained steam system will be virtually silent, even, and economical, with no moving parts to make the electric meter spin around at top speed, so you are on the right track!--NBC

Danny Scully

Where on Long Island are you located? I'd be glad to help

Jamie Hall

Oy... well, two boilers can be used on a steam system -- Vaporvac has a lovely example of such a system -- but it has to be done right. Further, the rest of the work has to be done right -- and it does sound as though there is a good chance that it wasn't.

Danny -- the immediate previous post -- is very good at these things, and it might be a good thing to get him involved.

There are a few other things, though... tteckushan's comment on water lines is really important, but will take some work to check; you have to go through the entire system and figure out what is supposed to be below the water line and what isn't. Also, TRVs -- those valves with sensors -- can be used on two pipe steam, but shouldn't be necessary. And, in any event, it is very likely that you should have working traps on all the radiators.

Can you take some pictures and post them? The boilers and the way they are piped? And a typical radiator, showing both inlet and outlet? And maybe a sketch of the piping arrangements for supply mains and returns?

Titus66

Hi Danny Scully, Thank you, I am located in Glen Cove. I read a lot of comments about you and they all are good so I would like for you to come and see the entire system.

RobG

Smart move Titus66!

Titus66

Thank you RobG. And thank you to all for the feedback, I am really impressed with this site and the knowledge of all the people

vaporvac

I second and third looking at the new water level and redoing that near-boiler piping. If it's a two-pipe system, it may not have traps at the rads, but orifices at the inlets or outlets, or originally it may have had metered valves. The later would have negated the use of TRVs. You should look around your basement and see if any of that old stuff is lying around. Dan Scully can set you right, however and help de-knucklehead whatever needs it. Please continue posting as we love to see things set aright. I think it's part of my motivation, anyway.

Regarding two boilers.... You are very lucky to have that. Properly set up with a Taco relay and vaporstats, this makes for a VERY efficient system. I haven't studied the install, but the piping needs to be correct to work. It's not hard, but it needs to be right.
@Jamie , thanks for the kudos. I just love my little set-up that everyone here and at Slantfin helped design!

vaporvac

Also, I think HVAC people recommended ditching the steam because they have no idea how it works and don't want to learn. Just be sure it's them your ditch and not the system which one of the finest ever engineered. although you seem to be on it.

Titus66

Thank you for the positive feedback vaporvac. I am glad to hear that the two boiler system is good. I was very concerned about that. I will definitely keep posting the progress we make after i set up a meeting with Dan Scully

jumper

Too low is easier to fix than too high,so be happy.

vaporvac

Titus66 said:

I am glad to hear that the two boiler system is good. I was very concerned about that.

Definitely, no need for concerns on that axis. It's generally considered a premium install as one needs two of everything and there's more scope for getting the piping wrong. However, even I figured it out with the help of Slantfin, their manual and the folks here.
Two boilers provide more than redundancy, however, assuming they're sized correctly. They allow one to adjust the Btus to more closely match the heating load after the piping and rads are heated. Depending on the temperature differential, one or both will start up and when temp is reached only one will re-fire. The savings and added comfort are obvious as there are fewer Btus at play. It also helps when the venting is not up to snuff at it can allow for a slower burn, helping to simulate the old coal burn.

Someone is going to ask you, so it might as well be me!: Could you post the steam sq ft rating from the boiler plates and specify what exact boilers you have, in addition to pics? We'll then need the total edr of your radiators to see how well they match that output. This is info you want to know in any case, even if Dan is coming over.

Danny Scully

PM me and we'll try and figure something out.