No water draining from low water cutoff

Liem Tran

i believe that there is water in the boiler since the sight glass is 2/3 full with water. I ran the system and it seemed to work fine. the lwco is probably clogged like you said. how do i unclog it?

Liem Tran

No water draining from low water cutoff

Hi all,

I am a diy'er and am fairly new to steam heating. For the past three years, I have only been changing out the oil filter annually. Is there anything else that I should be doing such as cleaning or replacing the nozzle or cleaning the flue?

Secondly, no water is draining from the low water cutoff when I open the valve. Is this because the system has been off the entire summer? The water level in the sight glass is at 2/3rd's from the bottom of the sight glass. Will water enter the chamber (meaning the bulb of the low water cutoff) once the heating system is running?

Thanks in advance.

Steamhead (in transit)

Either the LWCO is plugged

or there's no water in the boiler. Have a pro look at it, if it goes wrong the boiler will crack.

Likewise the burner. Unless you have a digital combustion analyzer, you don't know if the burner is running safely.

Try the Find a Professional page of this site. Click Resources at the top of the page, then F.A.P. and follow the instructions.

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Liem Tran

i believe that there is water in the boiler since the sight glass is 2/3 full with water. I ran the system and it seemed to work fine. the lwco is probably clogged like you said. how do i unclog it?

tim smith

Liem, regarding no water from blow down on low water co

This is not safe to run, all it will take is for the feed water to not fill the boiler and you will dry fire the boiler very likely and the low water may be blocked up to such a point that it will not shut off boiler. This needs to be remedied now!! Just for safety sake. Tim PS, get a pro in for a short consult and he can show you the procedure if you really want to do it in the future and also he can check for clean efficient combustion.

Al Hendrickson_2

If the LWCO has a ball valve (1/4 turn lever-handle) at the bottom, you could possibly open it up with the boiler COLD and poke up through the valve with a short piece of wire to loosen up some of the the crud.

If the LWCO is so full of sediment that the valve is plugged up, it's probably time to have it taken apart and cleaned anyway . . . for safety's sake. I just cleaned my M/M 67 LWCO. I got the replacement gasket online from Patriot Supply. It's pretty easy to do, but it's an important safety item . . . so unless you're very, very sure that you'll do the job right, call a pro.