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boiler valves extrol tanks

coalcracker Member Posts: 51
If you did not increase the amount of water in your system, you can use the same #30 that worked before. The tank is made to accept the increase in water expansion.


  • peter d_2
    peter d_2 Member Posts: 1
    extrol tank and boiler valve

    Iwent to service an 18 year old hydrotherm forced hotwater boiler .I replaced the pressure valve with the same one ,its a m1 watts valve.question does that also cover temperature?I also replaced the same extrol tank with the same one , that was a 30 this boiler out put btu is 145000 ,when i crossed refrenced it ,it said i should use a 90 ,mind you this boiler was workiing in this condition for 18 years will i be ok if i leave it like this?
  • Glenn Harrison_2
    Glenn Harrison_2 Member Posts: 845
    I'm confused?

    You said you installed a Watts M1 Valve on a hot water boiler.
    The only M1 valve I see on the Watts website is a steam rated relief valve set for 15 psi. If this is a hot water boiler it should have a 30psi relief valve on it, such as the Watts 374A

    Also, how well has the #30 worked over the last 18 years? Is it even the original. I'm assuming that you must have cast iron radiators if you calculated the need for a # 90 expansion tank at 145,000 BTUH. If so, you really should use the recommended tank, as I'm sure a fair amount of time was put into creating those numbers for sizing tanks based on different types of systems. There are more specific formulas out there for sizing based on the water content of a particular system, however the sizing charts are pretty accurate, unless the boiler is WAY over sized for the house/system.
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