Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Shutoff valve on return line of hot water furnace?

Frescard Member Posts: 5
Does it make sense to install a shutoff valve on the cold water return line that goes back into a hot water furnace?
I recently had to exchange a heating element, and I probably wasted 2 hours, first waiting for the water to drain, and then to fill up the system again. (In addition of introducing new rust-causing oxygen into the system with the fresh water.)
If I could shut off the water coming back, that should speed things up considerably, no?
Or am I missing something?


    JUGHNE Member Posts: 11,108
    The best set up is to have at least 2 isolation valves so that the boiler, pumps, tank, air vent devices etc can be serviced without draining the entire system.
    Then minimal water would be needed to be drained and avoid having to purge the entire radiation of air. And also introduce less fresh water into the system.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    It's actually in the code...Just had a commercial customer receive a violation notice on a 60 year old boiler not having them.
    Followed the code, and there it was... 'shall'...unless all the radiation and its associated piping is below the boiler.

    There was an error rendering this rich post.

  • Frescard
    Frescard Member Posts: 5
    edited December 2019
    My boiler is about 25 years old, but I had the regulator valve replaced about a year ago, and when they did that (and drained the whole system in the process) it was never suggested to install one.

    Only now, when I was doing work myself, did it occur to me that having some valves there might make work a lot easier.

    (But I suspect plumbers like to get paid for waiting around, so why would they suggest equipment that would cut into their billable hours...)
  • Intplm.
    Intplm. Member Posts: 2,083
    Isolation valves installed are always a good idea, as you have experienced recently.
    As to your comment of plumbers like to get paid waiting around.
    In my forty years in this business, I have never met one that likes waiting around for anything. They usually have too much to do and many customers to service.
    Often, customers do not want to pay for extras. Or, the original installer, ( possibly the former homeowner, hvac tech, plumber or mechanical contractor ) just didn't install the extra valve because they were too cheap to do so or were told by former owners not to.
    Alan (California Radiant) ForbesCTOilHeatJUGHNE
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,105
    edited December 2019
    Very few of the heating systems I work on have the ideal valve set ups. Just yesterday, a job in San Francisco had zero valves on the piping and no way to easily purge the system of air other than auto air vents at the manifolds.

    Pump isolation flanges with valves have made valving so much easier along with all the other valving options that you get from companies like Webstone. Pretty damn brilliant!

    It's a good idea to suggest upgrading the valving to the homeowner.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab