No water in sight glass. How do I know I dry fired?

Dooma00

1 pipe steam system. It is extra cold here lately and I was away. Went to basement and did not see much if any water in sight glass. Assuming it was just a little low I added water. Problem is it took a decent amount of water before appearing in the sight glass. Makes me nervous. I had my lwco replaced two seasons ago and I am pretty good about flushing. We had heat the entire time in the house.

The furnace showed no signs of distress. If I dried fired would it be more obvious?

Can I assume all is OK at this point?

Fred

If you had dry fired, chances are good you would have known by the time you got within a couple blocks of your house. Was the boiler running when you added all that fresh water? You are fortunate you didn't get hurt. Never add a lot of cold water to a hot, nearly dry boiler! Also, don't fire that boiler back up until you figure out why it was almost dry. You may not be so lucky next time.

Jamie Hall

I see you like to live dangerously. I hope the boiler had cooled when you added the water? I hope?

Since it didn't blow up on you, chances are that the worst is that it cracked when you added the water. That will show up either as a leak or a having to add a lot of water (a leak above the water line and steam up the chimney.

Now. Your LWCO apparently didn't shut the boiler off when it should have. That is really dangerous. You can check the LWCO when the boiler is firing by draining water; the boiler should shut down -- and it should do it before the water leaves the sight glass.

If it doesn't, the LWCO needs work. It may just need to be cleaned. It may need to be repaired. It may need to be replaced. Whatever, it is an essential safety device and my feeling would be that since it clearly didn't do its job you probably should not run the boiler unattended until you get it checked out.

And while you're at it, may I suggest adding a second, manual reset LWCO at a lower, but still safe, level?

Dooma00

Thanks for the info. I was told to flush weekly But did not realize that was supposed to be when the system was up and running. I will have the LWCO inspected ASAP.

When flushing the Lwco while the system is running at what point should I expect the lwco to shut down the system?

Fred

If it is a McDonnell Miller #67 LWCO, to test it, open the blow-off valve when the boiler is running. The boiler should shut off in maybe 5 seconds or so and re-fire when you close the valve. You should blow that valve down once every week or two. Allow water to drain until it gets clear, maybe a quart or two.

JUGHNE

You must have had your boiler blessed by the man in your profile/ID picture............if not, I would consider having it done.

JUGHNE

If you have been flushing the LWCO there is a good chance it is clean. It may be wired wrong. The installer should have checked it at least 2 X when he was done. FWIW

EBEBRATT-Ed

A boiler is safe to run when you can see the water level in the sight glass. The water level should be about 1/2 a glass when not running and will drop a little while steaming.

The low water cut off should shut the burner down when the water level is at the bottom of the gage glass

BTU

Here's how I can tell if the boiler was dry-fired. See pictures. Yes, LWCO failed. As well as the auto-feed. Miracle the thing didn't explode. Notice the blackened pressure gauge on the boiler front. Also notice the water pouring out the oil pump. And the tankless. Will try to post pictures of the take-down when this is replaced. Just in time for snow-pocalypse.

BobC

All is not lost, you might just be able to salvage the on/off switch.

Bob