Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Low water cutoff installations

dopey27177dopey27177 Member Posts: 276
I have seen many questions on low water cutoff installations and how to maintain them.

I am sending the installation guide from McDonnell and Miller for Steam and Hot Water Boilers.
This can be a refresher to Boiler a installer, technicians but more for the do it your self people. A do it your self person needs to know what the install looks like especially when hiring contractors.

A cautionary note to all do it yourself people is you are playing with fire. A dry fire can occur and you will lose your boiler. McDonnell Miller warrants it's products. Should the new lwcf fail you may not recover the cost of a boiler replacement.

Only a qualified boiler installing contractor will be able to recover your cost of a new boiler installation from McDonnell and Miller or his liability insurance due to a product failure.

Proper maintenance of LWCF's is required to protect the boiler from dry fires.

After reading the enclosures if you have questions about maintenance go on McDonnell Millers web site and reference the maintenance requirements.

I hope this discussion will answer some questions and impress on some people that LWCF's are a vital safety device. Additionally some jurisdictions require two LWCF's on small boilers.



  • retiredguyretiredguy Member Posts: 213
    A lot of the service tech's I dealt with were unaware of the risk or the potential disaster they could cause during a normal service check on a piece of equipment. I always stressed to any "would be" service tech the potential damage and bodily harm they could cause due to disregarding safety procedures on something they were servicing. When you are there for service or to correct a problem concentrate on the problem at hand. If you don't know or are uninsured about a particular control ask someone who knows and can instruct you on how to service or fix that device. A mistake could cause a disaster or change your life. I never found a fuel that had no potential risk or pressure vessel that was totally safe. If you want to be in this business you have to read and study everything you can get your hands on. It is much easier today than when I got into the business due to computers and instant access to just about everything.
  • BobCBobC Member Posts: 5,101
    Decades ago the primary control on my steam boiler failed, I was sick at the time so I called for repair instead of doing it myself. The guy came, diagnosed the problem and installed a new control - it didn't work.

    He called his boss who came over with a new control and found the new controller was miswired and thus failed. A new properly wired controller got the system back up.

    Mistakes happen, always inspect the last work done carefully. BTW that was the last time anybody else was called to fix my boiler. I'm perfectly capable of blowing things up on my own, no need to pay someone else.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!