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Right Angle Cast Iron Hot Water Radiator Valves 1/2 Turn

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rfriedman
rfriedman Member Posts: 1
in Plumbing
The 1/2 turn hot water radiator valves were common 100 years ago, but not today. They contained a sleeve with a cutout to allow water to flow. Why did they fall out of favor?

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  • DCContrarian
    DCContrarian Member Posts: 101
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    Those valves were for "balancing" the radiators, adjusting the flow so that each room got the right amount of heat. It was a fool's game because the heating load in different parts of the house depends upon conditions, and changing the valve on one radiator affects the flow in the entire system. Also, if you look at a curve of water flow vs. heat output it's not at all linear, so there are parts of the curve where minute movements of the knob cause big changes, and parts of the curve where big movements don't really change anything.

    They went out of fashion when thermostatic valves became available.
  • pecmsg
    pecmsg Member Posts: 4,871
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    DCContrarian said:
    Those valves were for "balancing" the radiators, adjusting the flow so that each room got the right amount of heat. It was a fool's game because the heating load in different parts of the house depends upon conditions, and changing the valve on one radiator affects the flow in the entire system. Also, if you look at a curve of water flow vs. heat output it's not at all linear, so there are parts of the curve where minute movements of the knob cause big changes, and parts of the curve where big movements don't really change anything. They went out of fashion when thermostatic valves became available.
    I respectfully disagree. 
    The small opening was to allow a small water flow to prevent Freezing. 
  • Big Ed_4
    Big Ed_4 Member Posts: 2,794
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    We use ball valves today.

    There was an error rendering this rich post.

  • mattmia2
    mattmia2 Member Posts: 9,703
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    Probably because machining the pieces to seal without some sort of gasket material is more costly than using a washer or other seal and is fairly prone to damage from minor corrosion.
  • DCContrarian
    DCContrarian Member Posts: 101
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    mattmia2 said:

    Probably because machining the pieces to seal without some sort of gasket material is more costly than using a washer or other seal and is fairly prone to damage from minor corrosion.

    The sleeve type valves were never meant to seal, they were meant to slow the flow of water.

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