Cold radiators, new steam traps, two pipe system

Dan Nibbelink

I discovered another item that might be a factor. The pressure gage has been reading 5 psi. I seem to remember that previous winters that it was reading 3 or 4. So I adjusted the pressuretrol from 2 psi to 1 psi. Now the gage is reading 6 psi. The gage is built into the front of the boiler which is 1920 vintage, so it's possible that it is not reading correctly.
The pressuretrol is a Honeywell PA404A1033, without a siphon loop. I haven't pulled the cover to check the differential setting.

Dan Nibbelink

Cold radiators, new steam traps, two pipe system

1920 Dunham Home Heating System, page 252 in The Lost Art of Steam Heating. Two pipe system. Three column radiators work fine. Seven thin tube radiators: some OK, most not. Two will only get to 80 deg at trap. The last one on the run (in my bedroom) gets warm at the top of the first three sections, the rest is COLD. Dunham steam traps - installed new Mepco cartridges which gave me new thermostatic discs and seats. Installed new air line valve at end of steam pipe. Installed new air vent at end of condensate pipe. Still doesn't heat properly. Any help is appreciated.

Steamhead (in transit)

What vent did you use

on the dry return? Also, what air-line valve did you put on the steam main? How long is the main and what pipe size is it? Are the problem radiators located toward the end of the steam main?

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Dan Nibbelink

more info

I'm not sure what you mean by "dry" return. On the return line, which might be "dry" of steam but would be wet with condensate, I put a Hoffman 75 Air Valve. At the end of the steam main I put a Hoffman p/n 401419 Steam Air Line Vent; the side connected to the steam main and the bottom to the return main. The main is probably 2-1/2" pipe (it's covered with insulation) and is about 120 feet long. The problem radiators are located in the middle and the end. A thin tube radiator in the middle of the line, and on the second floor, works great, the thin tube radiators on the first floor on either side are slow to heat. The column radiator that is next to last on the line, and has 7 foot long horizontal "risers" works excellently. The last radiator on the line, a thin tube, gets warm at the top of the first three sections; the other end of it is 50 degF.
I'm measuring temperature with a Raytek MiniTemp infrared unit. At the air-line valve the pipe on the steam side measures 150 and on the return side measures 90.
I'm wondering if the radiator valves are causing the problem. I will disassemble them this weekend.

Steamhead (in transit)

They might be

but you definitely need more venting on your steam main. Forget that little "Paul" vent- vent your main with three Gorton #2 vents at the end. Then see how your radiators work.

The overhead return line is "dry" since there is no water standing in it.

"Steamhead"

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Dan Nibbelink

more venting?

I don't understand how more venting can help. The steam gets to the end of the line, but it's not going to one radiator.
I tried to take apart the radiator valve but it is very tight. I'm getting a bigger wrench.

Steamhead (in transit)

The steam gets to the end of the line

but probably takes a while to get there. Proper main venting will get the steam to the end of the main in about a minute after the boiler starts sending steam out to the system. Then all radiator connections on the main will have steam available at about the same time.

Getting the steam TO the radiator connection is about two-thirds of the battle. Once that's done you can troubleshoot individual radiators. If the main takes a while to vent, it can be harder to see what's really going on.

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Steamhead (in transit)

Turn

the differential down to 1 if it's not already there.

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Mad Dog_2

Dan, you really need a steam pro on there

to help you decipher your system as you don't seem that familar with the terminlogy as it relates to what you have in your home or your customers...are you the contractor or HO. Mad DOg

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Dan Nibbelink

Culprit found

Your reasons for venting make sense. I will try it.

I got the radiator valve, a Dunham Packless, apart and found a culprit. It has a rubber seal that was loose from it's carrier. Because I don't need to shut this radiator off I removed the seal and put the valve back together. The radiator is now producing good heat. The seal was sitting on the seat so it was letting a very small amount of steam thru a labyrinth.
Do you know where I can buy parts for this valve; it has a patent date of Feb 16, 15. I need seals, handle grips and instructions.

Dan Nibbelink

Steam pro

I've been trying to fine a steam pro in Northern Colorado Front Range. I am the home owner, and have read Dan Holohan's books. I am a mechanical engineer, for what that is worth.
It appears that the main culprit is the radiator valves, which none of the troubleshooting guides I've read have suggested. However, I'm sure the steam traps, air vent and air-line valve were well in need of replacement.

Steamhead (in transit)

Dunham became

Dunham-Bush and then MEPCO. Try their web site:

http://www.mepcollc.com/main.htm

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