LWCO red light, no start but sight glass fine to overfilling

poetxpress

Hi all,

Oil steam single pipe system with a probe type MM LWCO. On cold start attempt I get a red light on the LWCO and no startup. After a little while the filler kicks on and keeps filling the boiler to overflowing. I've removed the probe and cleaned it but still getting the same results. No teflon tape or anything in the install.

Any ideas? It is about to get super cold here in New England and it would be great to have this sorted out. Thanks!!

poetxpress

When I pulled the probe it was wet, so it seems like the LWCO isn't recognizing that it is contacting water even when the boiler is full... Is there a good way to test that? A jumper of some kind?

Captain Who

Perhaps put it in a pot of water with a little salt in it and measure with a milliohm meter between the probe and the pot, with the threads touching the rim of the pot, and see if it is conducting. Maybe it isn't clean enough. Hydrolevel manual says to use scouring pad or steel wool.

poetxpress

Thanks! I don't have a milliohm meter handy but I'll try a more thorough scrubbing, reassemble, and if that doesn't work I might just go to the plumbing supply place and fork of the $ for a replacement.

Is it possible to just replace the probe, or do I have to do the whole unit?

Fred

Depending on the type/model,You may be able to get a replacement probe but it will depend on how well stocked yur local supply house is and then you still won't know that there isn't a problem elsewhere in the LWCO.

Captain Who

If cleaning the probe doesn't work it's probably a problem with the electronics in the unit

ChrisJ

To the OP. I'd replace the entire unit at this point. Like you said, it's about to get cold and you have no way of knowing which has failed. Depending on where you are supplyhouse.com could have one to you by tomorrow if you order soon.


While we're on the subject of probe type LWCOs I noticed Hydrolevel has a unit better than my model 400 which appears to allow you to do a test on it.

How does that work exactly? So far the only way I can see to test a probe type LWCO is to drain the boiler?

ChrisJ

Hatterasguy said:

ChrisJ said:

While we're on the subject of probe type LWCOs I noticed Hydrolevel has a unit better than my model 400 which appears to allow you to do a test on it.

HW boilers only.

What about this?
http://www.supplyhouse.com/Hydrolevel-Safgard-500-Electronic-Low-Water-Cutoff-24V-Steam


Or is that to test the manual reset and not the actual LWCO? I don't see how that makes sense though.

Fred

Looks to me like it is just a Burner Circuit test. Probably test it when the boiler is running and the test button will break the circuit and shut the burner down. Doesn't seem like much of a feature since it doesn't appear to test the actual probe.

ChrisJ

Fred said:

Looks to me like it is just a Burner Circuit test. Probably test it when the boiler is running and the test button will break the circuit and shut the burner down. Doesn't seem like much of a feature since it doesn't appear to test the actual probe.

So basically the only true test is to drain the boiler with the burner running.

That's a shame. With a float type a quick opening of the drain will shut it right down without the need to remove several gallons of water.

poetxpress

Fixed! I was too gentle the first time after reading "do not use a sharp tool to clean probe" in the manual . This time I scrubbed the heck out of it with steel wool (may as well since the next step is replacing it), reinstalled and I'm in business.

Thanks for all the help!!

Fred

ChrisJ said:

Fred said:

Looks to me like it is just a Burner Circuit test. Probably test it when the boiler is running and the test button will break the circuit and shut the burner down. Doesn't seem like much of a feature since it doesn't appear to test the actual probe.

So basically the only true test is to drain the boiler with the burner running.

That's a shame. With a float type a quick opening of the drain will shut it right down without the need to remove several gallons of water.

Yea, does seem like there should be a better way to test all of the circuitry and the probe in those units.