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gas hot water system will not fill with h20

ecobeing Member Posts: 3
kitchen redo forced move of cast iron radiator. did a pressure test of system to make certain no leaks. never let

pressure go above 20psi, would shut down compressor and let system

equalize. it finally settled out at about 13psi and all connections

passed soap test. hooray.

I cranked open the shutoff valve from the

main water line to fill system and ......nuttin'. so, methinks, maybe it

is the backflow preventer, which is next in line after the shutoff, it

might be frozen/blocked. two unions held the backflow in so I cracked

them, removed backflow, and with open pipes turned the water on


okay, deduction says that shutoff failed and it

looked as old as me (1952) so I replace it with a nice new shark valve

and union the 1/2" copper pipe feeding the boiler just in case. I turn on the water again and....nuttin'.

doesn't seem to be filling at all. I took out a radiator bleeder screw

to see if any air was being pushed out.....nuttin'.

there is that

bell shaped auto fill valve after the backflow and the little lever that

is supposed to let you allow more water flow just seems to flop around

and do nothing. the boiler is a weil mclain CG about 15 years old.

photos attached with culprits.

so, what am I missing? besides of course a few gray cells. ~:-)

many thanks!


  • Zman
    Zman Member Posts: 7,013

    Will water pass through the backflow or prv/fill valve.

    The fill valve will usually act like that if there is no pressure.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ecobeing
    ecobeing Member Posts: 3
    in response

    thanks carl! somewhat spooky though because my buddy who once lived here was also carl. I will disconnect the bottom union to the backflow tonite and see if water is passing through. may just be that these failures weren't evident until the system was disrupted. there was a lot of gook at the top of the backflow in the screen so maybe it is just clogged with pipe poop (technical term) as was the shutoff. plumbing is my nighttime recreation presently. guess I need a life.
  • ecobeing
    ecobeing Member Posts: 3
    just a little digging needed

    carl, solution was simple though not usual. all I needed to do was clean out the clogged tee connection that gave me quite the shower when the city's 80psi got a chance to escape. oh well, the new shark fitting is much more stylish. radiators filled effortlessly. never have seen brass pipe become occluded with iron buildup. if you need any tax advice, just holler!
This discussion has been closed.