do I need basement air vents or to balance the radiators- steam

Megan_2

Hello,

I have a steam heat counter-flow system with a very old and simple design. One drip line right off the main horizontal line drains the whole system. This is piped directly into the bottom of the boiler.

I have 2 boilers. One feeds the second floor; one the first. The one feeding the first floor works well; it has no main vents or basement vents at all. The rooms heat reasonable evenly.

The second floor on the other hand, has 3 radiators that heat at 1/2 or even 1/4 the speed of the other radiators on that floor, so those rooms are COLD. Coincidentally, the horizontal lines to those 3 radiators have a capped fitting. The external pipe dimension in all cases is 2" diameter; then there is a fitting with a protrusion and a cap, then the line drops down to 1 3/4 (external diameter).

I had a steam guy come by today and showed him these fittings, suggesting that these should be a basement air vent of some kind. He pointed out (correctly) that these are not located on the appropriate places for main vents- they are on the line for a single radiator, and not particularly near the vertical riser. They are 2-4 feet from a vertical riser.

He said what I need to do is replace all my radiator valves and use these to balance the system. I think that might work just fine, but a piece of me is still thinking that 3 cold radiators on the only 3 lines with capped fittings is a pretty good coincidence, and I ought to be paying attention to that.

Any thoughts?

Steamhead (in transit)

How long are the steam mains

and does the reduction in size occur on the steam main or on a run-out from the main to the riser?

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Megan_2

The steam mains are fairly short. The fittings are on run outs. The runouts are long- 20-40 feet in some cases.

This is assuming I understand what steam mains are correctly. To me a main is a pipe supplying more than one radiator, and runs horizontal. I am taking a runout to be a pipe serving a single radiator.

The fittings are on horizontal feeds to single radiators. The reduction in size is at the fitting, on these same horizontal runouts.

2 of the fittings are 2' from a turn in the pipe; approx a 45 degree angle but strictly a horizontal turn. Another 2 feet after that turn, the vertical run begins.

The other fitting is really in the middle of a runout; maybe 8 feet of pipe on either side of it. ??? That one I could believe goes to a disconnected radiator.

Captain Who

I'm not a professional or anything, but I'll see if I can help a little. First off, I think pictures of the "anomalous" fittings might help, but I'm thinking that 20 to 40 ft. runouts are extremely long. Have you checked the pitch of these runouts? I believe it should be at least 1 in. per 10 ft. in a counterflow situation and it should be even pitch (no dips). Also, I think insulation on these would be very important (should be on entire system). Maybe, the reduction fitting causes velocity of steam to increase here and a condensate issue there? Dry steam would be very important here and proper near boiler piping to insure this. Has the boiler been replaced at any time? If the old system had 3 radiators that were removed at some time, the system was presumably properly designed for that system and someone may have put too small of a boiler in as a replacement. I think you still have to size the boiler based on as if those old radiators were still there (Dan's book discusses this). I would definitely try replacing the radiator vents on the slow heating radiators - I have the Heat-Timer Varivalves and they seem to allow quite a bit of venting and are adjustable.

Perhaps if two of the fittings were for a vent of some sort someone may have removed these at some point because they were spitting water and you could try putting vents back there even though it is not typical to vent runouts. Again pictures or maybe a rough sketch would help.

Megan_2

Megan_2

I have some pictures of the 2 fittings on the long runouts.

I was looking to check my length description; 40 feet is probably an exaggeration but there are definitely 20+ feet runouts, not including the vertical portion.

I haven't checked all the pitches of all the pipes, but everything I have checked so far for pitch or size has been to standard as described by Holohan's book.

There is one radiator that has been removed from the system; no more. All the piping for that radiator has been removed from the heating system.

The system looks to have been coal orginally, then oil and now gas. The current boiler is quite old and is a low pressure boiler with minimal near boiler piping needs. None of the pipes in the basement were insulated when we moved in. We a few hours away from finished with that right now. We insulated some 250 feet of pipe. However, the system was able to heat the house (except for the cold room or 2) quite well overall even without insulation. So if anything, the boiler looks to be oversized now that we have insulated.

Thanks for the tip on radiator air vents. I have been wondering what would be the right types to get.

Steamhead (in transit)

Those plugged fittings

used to feed radiators, before the system was split in two. If there is one on the last runout attached to a Steam Main, you could use it for a main vent.

A Steam Main comes off the boiler and feeds several radiators. A Runout comes off the Steam Main to feed one or maybe two radiators. How long is each Steam Main from the boiler to the last runout?

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JohnG_3

So, do you vent mains or runouts?

"A Steam Main comes off the boiler and feeds several radiators. A Runout comes off the Steam Main to feed one or maybe two radiators."

Thanks, I was looking for that definition.

I have a similar situation, a one-pipe counter-flow system. There are two mains, one branching off the other, each one terminating in a reduced-diameter runout, with each runout feeding two radiators. As best as I can tell the mains have never been vented. What is the proper location for vents, at the main-runout junctions, or on the runouts just before they turn up into the walls?

Steamhead (in transit)

I'd put them

at the "main-runout junctions", that way the steam will be at each runout connection but no further when the main vents close.

"Steamhead"

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