On cleaning the LWCO probe

04090

This is for a 19 year old Burnham steam boiler with a Honeywell RW700A Guard Ring low water cutoff device.



I think the probe needs to be cleaned because it's shutting the system off after 30 minutes or so. The water level remains fine. The probe has never been cleaned, and is not considered part of the annual maintenance by the oil dealer. So I'd like to try it.



Cleaning the probe seems simple enough; power off, loosen two screws holding on the box, remove it, unscrew the probe for cleaning and reinstall everything. Have seen the warnings online about use of teflon tape.



I have not come across instructions for cleaning the probe, and although it seems simple enough, would rather have something to follow.



Guidance appreciated.

Al Letellier_21

cleaning the probe

You are correct that it should be cleaned and we always included it in our maintenance and went as far as marking the boiler "Clean LWCO annually"

It is the most critical device in protecting your boiler. Usually a simple flushing with water and wiping with a rag is sufficient. Don't forget to check inside the probe location on the boiler for any build up of sediment. Anything wet contacting that probe will give a false signal that all is OK........make sure it gets done on a regular basis.

04090

response

The burner is stopping about 20 or 30 minutes into it's cycle. I tested the contacts inside the LWCO and see it is cutting power. The water level is above the probe, and bounces as expected within the glass gauge. Could that be a dirty probe?



I should add that the fuel is about 5 years old and the system has been off for the past three years. It provides heat to rooms rarely used so it's not critical that it's not working. But with the sub zero weather we've had the past few days I tried using it.

Charlie from wmass

Check the fittings that go

from the boiler to your sight glass. It may be clogged. I often find steady water levels that are quickly made to bounce by simply cleaning the sight glass ports and valves.