Steam boiler

Mike_h

I have a steam boiler. It  runs for about 5 minutes goes off on low water cut off because the water moves out of the boiler. Then after a few more minutes the water returns and boiler starts up. I'm thinking the water is pushing back out the return piping. Was thinking a check valve in the condensate return line Would help. Any thoughts on remedies

mattmia2

How stable is the water line while it is steaming? What does the near boiler piping look like? Much more likely it is being thrown up in to the mains because the boiler is making wet steam than being pushed out the return. Also possible that the return is partly clogged and that usually takes longer to empty the boiler but wet steam is the more likely culprit .

ethicalpaul

Matt has it. I think I've seen only one or two credible cases of actual verified "slow return" situations on this site, but that's where everyone thinks to go first. Far far more common is the near boiler piping sucking/throwing water up to the mains.

neilc

I will also ask / add , , ,
what pressure are you running?
and when did you service the pigtail last ?
pictures,
one or 2 distant showing the whole boiler, floor to ceiling, so we can see the piping above,
and a close up or 2 of the Ptrol, gage, sightglass, and LWCO

STEAM DOCTOR

Some history would also be helpful. Is this a new boiler? If not, when did problem start and was any work done to boiler or to heating system?

STEAM DOCTOR

A check valve is certainly one of the last things that you want to add to the system

Mike_h

I will take some pictures and post them. The pig tail for the pressure troll was cleaned recently. Also flushed And drained off top of boiler . And add some cleaning chemicals. The water level is normal 3/4 up in the glass at start. The boiler starts you can see some surging in the glass.  After running for a few minutes the water slowly reduces in the site glass until it disappears boiler goes off on low water cut off. After a few minutes off the water comes back. and it does the same short cycling over and over. Boiler there's about 10 years old. Boiler has 2" supply supply to a 3" main with equalizer and a heart for loop. It has had some condensate lines near the boiler replaced.  There is 2" and a 1/2 newer car newer copper condensate lines coming back to a 2" line At The Hartford loop and in 2" into the boiler .

mattmia2

Does to have a skim port? Surging is where your water is going.

Mike_h

It does have a skimming port which I used to drain about 20 gallons of water out. Added some chemicals to further clean. Still losing water After a few minutes of run. Although after off for a few minutes the water reappears . The water looks clean In sight glass and what was skimmed off the top.

Mike_h

I'll get pictures of the piping and the whole system in the next couple days Thanks for  The feedback

ethicalpaul

It would take a long long long time to boil away all that water into steam. If it drops while you watch it is surging.

also skimming isn’t draining…your use of the terms interchangeably might point to a factor in this, or might not

Mike_h

I skimmed it off the top. Though 11/2" tapping in front section towards top of boiler. I also drain an flushed out entirely boiler at bottom boiler drain. Added 1/2 quart cleaner. Sorry for any confusion. 

BobC

If to much cleaner is added that can cause problems like surging. Drain the boiler completely and fill it up with clean water - no chemicals - and let us know if things change.

Also skimming is a slow process, it takes and hour or two to fill a 5 gallon bucket. If you skim to fast it roils the water and you don't get all the oils that might be floating o top of your boiler water.

Bob

Mike_h

Here's some pictures of the boiler and the piping.

neilc

neilc said:

what pressure are you seeing while running?

jhewings

Is there an equalizer there?

kcopp

Its not piped right...
No equalizer to balance out the supply and return.
Additionally the Boiler may be oversized.
Flush out the boiler... then skim.

EBEBRATT-Ed

no equalizer is not allowing the header such as it is to drain.

drain flush and skim, the skim water should drain out slow the size of a lead pencil. get rid of the chemicals and then fill it and try it again

Mike_h

I will drain drain the system completely completely again and fill it up with water with no chemicals see how it works.

Mike_h

There is an equalizer up by the ceiling in the 3" pipe, it been there for 80 years or so. It may not be in the exact right spot but there's definitely a  2" pipe  connecting the supply to the return.

mattmia2

Oh my.

Is that pipe that will inevitably drip on the burner where you were skimming?

Steamhead

mattmia2 said:

Oh my.

Is that pipe that will inevitably drip on the burner where you were skimming?

You'd have to screw an extension nipple onto it. No big deal.

Steamhead

@Mike_h , what model SGO is that?

ethicalpaul

Mike_h said:

There is an equalizer up by the ceiling in the 3" pipe, it been there for 80 years or so. It may not be in the exact right spot but there's definitely a  2" pipe  connecting the supply to the return.

I can't identify the equalizer. It might be there, but 80 years doesn't mean anything to me--it could have been piped wrong for 80 years.

KC_Jones

There may be what you judge to be an equalizer, but when one looks at your piping it isn't where it's supposed to be, and given you are having water loss issues this is something to look at, in addition to what appears to be an undersized header.

I marked up the picture to show where the equalizer is supposed to be, while it's to equalize pressure it is also to make sure any water in the header is immediately returned to the boiler.



That boiler has 2 1/2" tappings in the block and I don't see a size increase at the header so the header is undersized as it's supposed to be 3", this can amplify the water sucking out of the boiler and being thrown out into the system.

I'm assuming everything there is 2 1/2", but can't always tell from photos, if it's only 2" the problem is even worse.