Water Hammer, Radiators not heating, Quick cycling

DrDomm

Ok, I'm a newbie...just found this site.  My 86-year-old house has a steam system that has been a challenge for the 9+ years I've lived here.  The boiler is probably 30+ years old, but I can't see a manufacturer name on it.  It's a 2-pipe system.  We've had a lot of work done on the controls/valves on the front, and for the last few years it's worked pretty well.



We usually have to "reset" the control on the front 1-2 times weekly.  Yesterday I reset it after being off for a few hours.  When it restarted there was significant water hammer.  After the system heated, I noticed that radiators at the end of the system weren't warm.  These usually are.



I went to watch what was happening at the boiler.  It lights up, and builds pressure to 1.5 and then shuts off.  This takes about 3 minutes.  The water hammer starts, and the pressure starts to drop once the boiler shuts off.  After about 2 minutes, the pressure is back to zero, and the cycle starts over again.

I tried draining the system, but that didn't seem to work.  Any ideas?

Jamie Hall

Something is very wrong

but it will be hard to say what without a lot more information.



To start with, is this one pipe or two pipe steam?



When you say you have to "reset" a control on the front, just what do you mean by that?  There should be at least two and quite possibly three or more controls on the front, as well as the burner's own control box.  Can you take a picture of the front with all the controls, and be specific about which one it is you are resetting?



A boiler which builds pressure in only a few minutes is either WAY oversize, which seems highly unlikely, or is suffering from really poor venting or near boiler piping or some other problem which is preventing the steam from getting out to the radiation -- or some combination of these problems.



So... a couple of pictures, maybe, and whether we are coping with one or two pipe steam, at least for starters...

Hap_Hazzard

Do you have a camera?

It isn't clear what control you're talking about. Usually nothing needs to be manually reset, except for the occasional secondary low water cut-off, but these are rare on residential boilers, and you don't mention needing to add water. You also don't mention if the boiler is oil-fired or gas. A few pictures would help.

DrDomm

My pics...

It's 2 pipe.  Gas-fired.  Let me show some pictures...here's my baby...



The only vent that I'm aware of is that little silver one in the left upper corner on top of that rusty return pipe.



When I say "reset"...there's a little black button on that red "Fireye" box.  Every so often, and "alarm" light come on.  Push the button, it goes away, and fires up.



It's hard to explain the pipe layout, but most of the radiators come off of pipe that exits to the right of the boiler...to the front of my house.  The banging is to the left of the boiler...toward the back of the house.



I think it's the quick rise in pressure that just shuts the system off, and prevents steam getting to the radiators at the end of the run.  Just not sure why all of the sudden all the water hammer that is causing the quick pressure rise.



It has been super cold outside, fwiw.

DrDomm

Main pipes...

Here are the main pipes that come out of it.

DrDomm

Limited progress

My basement is finished, so it's a little tough to figure out the pipe layout.  I did find a valve on the opposite side of the basement diaganol from the boiler.  I opened it and let out about 1-2 gallons of water.  Now, the banging is gone.



The pressure still builds to about 1.6, and then cuts the boiler off rather quickly...just a few minutes.  The distant radiators are still cold, too.

nicholas bonham-carter

Fire eye giving you red eye

I think the fire eye box is a controller for the burner, and needs some service, along with the burner. Usually there is a device to monitor the start of burning, and if it does not detect all is well, then it will lock out, and good for it! Burner maintenance is not for the newbie, so find a pro.

Has the boiler been serviced by a competent professional regularly?

Regarding the vents, all steam systems need to have a means to allow the escape of air in the pipes, as the steam flows in. If the air cannot get out of certain areas, then the steam cannot get in, with the result of some cold radiators.

Post some pictures of your radiators, so we can see what sort of system you have, and we can advise.--NBC

DrDomm

Getting worse

I spoke to soon about the banging.  Within half an hour it started back up.  It seems like a couple of the radiators that were warming yesterday, now aren't.



The Fireye was replaced about 5 years ago.  It's actually been much better since then.  Our plumber has been here many times for different problems with the boiler and radiators since we bought the house almost 10 years ago.  They were last here about 2 months ago when they replaced pipe (which they had previously replaced) that was rusting on the front of the boiler.  In the picture I posted, you can see a cutout on the front of the boiler cover.  That's where they replaced that pipe.  I will call them today, but I don't think it'll be a quick understanding of what's going on.



It seems like the rapidly rising pressure is the problem...then short cycles that won't heat the whole house.  The thermostat stays on, and it starts again.  I'm not sure what the link between rapidly rising pressure and all the banging is.



Most of the radiators are covered...can't get pics right now.  Honestly, some have functional valves and some don't.  We had some replaced years ago, but the plumber didn't have enough to do all of them...system worked great...never thought to get the others replaced.

nicholas bonham-carter

When the plumber comes

Have him check the pressure. The regular 0-30 psi gauge, even if it is working cannot detect the several ounces of pressure needed to make your system function as it did when brand new. In this case, the pigtail, and opening to the boiler may be clogged, and the pressuretrol cannot do its job. A vaporstat would be a better choice for this system.

There is not much to go wrong with inlet valves , except for the disk which could drop off the stem, and cover the inlet hole. jmaenner@cbremega.com you have 2-pies, then there will not be the usual problem that you could have in 1-pipe (ie the rads filling with water which cannot flow out).--NBC

Other thoughts-

This may have been a vacuum system, in which there are still some parts holding water due to athe vacuum formed when steam condenses. There are differing opinions now about keeping the old systems running in a vacuum, but some have had great success, and I am planning to restore an old vacuum system, to see how it behaves. One thing is certain, it must be all or none developing a vacuum, or the water will have difficulty in returning.

Check the traps on the radiators to see they are holding back the steam from the returns.

Find out where the air is expelled as the steam is rising, and make sure it is clear.

DrDomm

Update

Called plumber first thing this morning, but haven't heard back.  Called again, and the owner (who knows my system) still isn't in.



I'm not sure what you mean by vacuum system, but I guess some are not supposed to be vented.  I believe that's what I have.  Years ago a plumber tried to put a vent in one of our attic radiators.  I was told by our current plumber that was wrong, and we just plugged it.  The only vent I have is the big one near the boiler at the top of the return line.  I heard it sputtering, but wasn't a real strong hiss.  I'll add a picture.



I've tried turning off our radiators that our working, hoping to "force" steam to the non-working ones.  My hope is that somehow fixes things.  Some of the cold radiators have gained a little heat.



The other thing I noticed was that the return on the boiler is quite rusty.  I hope that's not restricting the return.  I'll post a picture.



Thanks for all the advice.  Great resource here.