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Looking for Mouat water seal traps

Does anyone out there have a stash of Mouat water seal traps? I need five.

I'm adding on to a Mouat vapor system with the graduated hand valves and the water seal traps. Its designed to Mouat standards, and reverse engineered for good measure. I'll use orifice plates instead of graduated hand valves, but I've come to the conclusion that dual inlet and outlet restrictions are the way to go. The trap's air hole is a greater restriction than the inlet valve restriction such that when air is being expelled from the supply piping, the air flow through the valve and the trap are equal. However, when steam begins to displace air in the radiator and condense, the steam flow through the valve becomes greater than the rate at which air is simultaneously being vented through the trap. At some point the condensation rate becomes equal to the inlet rate and the air venting through the trap becomes zero so long as supply pressures are low and consistent. This arrangement allows something that a simple orifice in the supply alone can't do. It can allow greater amounts of steam to flow into a cold radiator at a given air venting rate than it will to others that have warmed. This becomes important where TRV's must be used in areas with solar gain and skylights creating variations in heat demand while the rest of the house is fairly stable.

I want this feature to carry over into the new part of the house. If necessary I can make an effective vented water seal for the new 1st floor rads under the floor since they are accessible. The 2nd floor rads at least should have something above the floor since its been difficult enough to pipe up to and through the second floor while leaving the recent painting and redecorating untouched. Its been tricky to say the least. But at least two and preferably 5 water seal traps would be nice.




  • gerry gill
    gerry gill Member Posts: 3,078
    Terry- Dont forget about the drain hole..

    the mouat water seals are dry until steam starts condensing in the radiators..so i think there is no air restriction provided..if your using orifice plates you could in all reality get away with union elbows..if the steam can't make it to the end of the radiator you and i both know that no trap is needed..my 2 pennies.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

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