Removing probe type LWCO and plugging the hole

skimmer

I have dual LWCO on my steam boiler and the probe type doesnt work. I want to remove it completely and just stick with the one LWCO (MM 67)... I need to close up the tapping obviously so my question is: is there a specific type of plug made for closing up the hole where the probe was screwed into? I dont need this thing blowing out or cracking

ChrisJ

Off the top of my head I'd guess 3/4" NPT plug.
An NPT plug isn't going to make it crack anymore than screwing a new probe in it would.

skimmer

Hmm. Ok.. Was also thinking of making it a skim port with a valve too...

JUGHNE

Probably just a standard 3/4 or 1" tapping. Though a 3" long nipple with a cap would be preferred for the future.

Have you cleaned the probe? That could be the problem.

Steamhead

I'd get a new probe LWCO and dump the 67. Generally, the probe type is much more reliable.

STEAM DOCTOR

I would stick with the probe. Needs annual maintenance at most. Much less likely to fail. If you do abandon, you can just leave the probe in place

skimmer

Probe was never hooked up electrically, just sitting there doing nothing.. I kind of like the the MM 67 it gives me the excuse to blow it down every week or 2.. Even though now it doesnt shut the boiler off when I do the blow down.. I think the float is full of gunk.. I was going to clean or replace... Maybe I will just remove the 67 from the boilers circuitry and wire in the probe now..

I am guessing the probe will need to be wired as the first device in the circuit before all the other devices as I assume the 67 is wired...

JUGHNE

So right now you have no LWCO at all??

ChrisJ

I don't believe it matters where in the circuit the LWCO is wired, as long as it shuts the burner down.

Mine was originally wired before the thermostat from the factory but Jstar modified it so it's after the thermostat so my thermostat doesn't lose power.

What does matter is that you have a proper functioning reliable LWCO that shuts the burner off when necessary.

EBEBRATT-Ed

As far as being a low water cut off only it doesn't matter if the LWCO is first or last in the circuit.

If it is also being used as a water feeder control and a low water cutoff it should be first in the circuit so it can power the water feeder even if the boiler is off on pressure

skimmer

At the moment, no, the LWCO does not appear to be working when I flush it while the boiler is running it does not shut down... And no water feeder is attached, I manually fill the boiler

Fred

When is the last time that #67 was serviced? They get a lot of build up in the float chamber that clings to the sides and on the floor of the chamber, either can prevent the float from free movement. Less often but possible, the float itself can leak and fill with water but, typically, in that case, the boiler would shut down and not come back on as the float has settled towards the bottom of the chamber. The switches can go bad too but I've never experienced that in 25 years, on my boiler. Most likely it just needs cleaning. New gasket sets are available if you decide to go that direction.

skimmer

I just looked at it again today.. Opened the tiny port next to the blow down valve and stuck a pipe cleaner up there and wiggled it around.. Cleaned some junk out and water started flowing out nicely...

re-tested it and it worked (shutting down power when opened)

Going to keep my eye on it.. thanks!

gerry gill

sounds to me like that 67 needs to be taken apart and cleaned.