steam problems

mikeca

Looking for some input.

System info:

I have a one pipe steam system with a gravity wet return. The are 2 header runs which circle the basement and meet opposite the boiler and drip and join to the wet return.

The union is below the boilers water line and all returns have good pitch. The mains are vented near the end ~ 10 inches from the end. The boiler is 2 yrs old it is a Well McLain SGO4.



What I have done:

I have put new vents on all the radiators (vari valve) and replaced the main vents as well. (maid o mist) I have pitched all radiators toward the supply pipe. (1/4 inch)

I replaced the wet return lines. I installed a digital thermostat with 4 daily settings. Pressurterol looks to be set at 1 and .5 psi? Not sure how that works exactly, but the pressure is low. I haven't messed with that. Exposed basement piping is insulated.



Problems:

1) First thing in the morning when the heat kicks from 65-70deg the steam escapes from the valve stems. It is quite loud. Some water as well drips out. Later in the day this does not happen when the boiler engages.

2) The vents pant and hiss a bit and spit water before closing. After the boiler shuts and the vents have closed and things are quite some of the vents have a large air release that lasts about 15 seconds and then quite resumes. (What is that?)

3) The water in the glass does bounce, within a 1½ " range. The water is not dirty and the glass above the water line is clear. A local plumber claims the boiler is surging and needs to be skimmed?

4) I think the boiler near piping is wrong? The previous owners replaced the boiler 3 yrs ago. The near piping is copper, the pipe sizing matches the specs, but they did not pipe it with swing joints as recommended. the right header actually pitches back toward the boiler as it runs along the front of the house and then is correctly pitched toward the return along the remainder of the run. This doesn't seem good. 2 radiators condensate probably drain back the wrong way. In addition I think the Hartford loop is wrong. The wet return joins the equalizer ~ 8 inches below the boilers water line, and the fresh water and automatic filler are on the equalizer as well.



Overall the system heats the house well. All radiators get hot, there is no water hammer to speak of (except on the first rad (upstairs bedroom) off the left main, and there is no short cycling or anything like that. The mains heat at about the same pace, but I do not feel or hear the mains vent, should I? My guess is water is being pushed into the system with the steam, but I am no expert.



A bunch of info, Any suggestions would be greatly appreciated.



Much thanks,

Mike

Mark Hunt

For not being an expert

you came to a few correct conclusions!

Are you SURE that steam is escaping from the air vents on the radiators? You could just be hearing air.

If the near boiler piping is not correct, water can be pushed through the system. There should be at least 24" from the water line to the bottom of the header.

Your plumber is correct as well, the boiler probably needs skimming. This will settle the surging down.

Water in the piping can also cause the "panting and hissing". Steam comes in and pushes out the air, the water pools up behind it and the steam condenses and a vacuum is formed so the vent sucks air back in.

If you could post some pictures we could do a little better diagnostic.

Hope this helps!

Mark H

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mikeca

I have at least 3 ft of space between the boiler water line and the header. The valve stem leaks air and some water.
If you suspect water in the piping what can I do about that? I will post a picture on the near boiler piping.

Steamhead

Some more answers

The steam escaping from the radiator shutoff valve stems can be fixed by tightening the packing nut at the base of each stem. If you tighten it all the way and it still leaks, loosen the nut all the way, pull it up and wrap some string packing around the stem underneath the nut. Replace the nut and tighten it.

It's normal for vents to close, then open after a bit and close again. When the boiler shuts off, condensing steam forms a vacuum which is probably pulling air thru those loose packing nuts. This air must be vented on the next cycle. See if tightening the packing nuts helps this too.

The bouncing waterline can be caused by oil on top of the water in the boiler. Skimming will fix this.

That near-boiler piping sounds very wrong. I think you can download a PDF file of the proper piping diagram from Weil-McLain's site-

www.weil-mclain.com

which you can then give to someone from the Find a Professional page of this site to re-pipe the boiler. If you're in the Baltimore area, e-mail me!



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