mcdonnell miller 67 series low water cut off

Unknown

Parts are available for these, but given the age it is, and looking at <A HREF="http://www.mcdonnellmiller.com/pdf/install_instr/MM-815C.pdf"> MM recommended maintenance </A>, I would replace-it myself.<BR>Do NOT fool around with an old unreliable LWCO! <BR><BR>Dave

Blackmajah

McDonnell Miller Series 67 Low Water Cut Off problem

Hello,

The mcdonnell miller 67 low water cut off valve on my steam boiler was receiving 120 V but only putting out 30 V. The BX switch had no continuity. The incoming hot is attached to terminal one and the "neutral" to terminal 2. However when I removed the BX switch and manually operated the lever on the back both of the circuits (terminal1 & 2 which relays the 120V to the 24V transformer), and (terminal3 & 4) tested positive for continuity.

The float lever didn't move but a little pressure freed it. Before that it was stuck in position so it kept the circuit(terminal 1&2) open. So I flushed it then filled it up a few times and the float raised and lowered properly with the water level.

I tried to remove the float assembly but it wouldn't budge.
Is the float assembly removable? If so do I need to remove it for inspection even though it worked during my test?

The blow down valve works but I could not get it out so I could better flush the float chamber? Does it come out and would I really need to do that?

Or did I solve the problem. The low water cut off is 10 years old.

Thanks

Matt

don_52

M&M 67

Matt, (wrote)

The low water cut off is 10 years old.

It has reached it's replacement interval, 10 years.

Replace or have replaced as whole assembly.

Linkage;

http://www.mcdonnellmiller.com/pdf/M&M/Product/Maint.pdf

HTH, db