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ZONE VALVES, HEATING
Circulator assembly leaks on heating systems: here we explain how to find and fix the common points of leakage found at heating system circulator pump assemblies.
This article series discusses Circulator Pumps: how to find, inspect, diagnose, and repair problems with Hot Water Heating System Circulator Pumps or circulator pump relay switches and controls. This article series answers most questions about Heating System Boiler Controls on central heating systems to aid in troubleshooting, inspection, diagnosis, and repairs.
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[Click to enlarge any image]
Perhaps this is due to a failure to properly tighten the mounting bolts, or possibly because the flanges are supporting quite a bit of weight when larger (B&G type) circulator pumps are installed rather than the smaller (Taco type) pumps.
Because the heating distribution piping is normally hot you usually won't see water on the floor very often when there is a leak at the circulator pump mounting flange - only in extreme cases.
you will see a build-up of mineral salts and corrosion at the flanges.
In our opinion a good time to fix this leak is at annual service at the end of the heating season, when it will be less inconvenient to shut down, cool off, and possibly drain the heating distribution piping.
At below left is a little leak at the bottom circulator pump mounting flange [Click to enlarge any image] where you can see rust stains that do not appear on the sister circulators shown in the picture. At below right you can see things getting a bit uglier on a different circulator.
Why do circulator pump leaks go un-repaired?
Well the little leak at the red circulator at above left may not even be dripping onto the floor. Those hot heating pipes may be evaporating the small quantity of boiler water that leaks and runs down the pipe.
So nobody cares, right?
If you allow a leak at a heating system circulator pump to continue for too long, the plumbing and pump parts may be so damaged that the repair is both more difficult and more costly.
In the photo (left) we show a leak that continued at the Taco™ circulator pump mounting flange for long enough that the plumbing parts are badly corroded.
Instead of a "bolt-on" repair, additional plumbing work, and thus additional repair costs will be involved.
While the leak above appears to be due to poor sealing at pipe threads connecting to the circulator flange, most leaks occur at the circulator flange gasket itself.
I suspect it's because we notice these leaks during the heating season. It's cold outside.
Nobody wants to go to the trouble to shut down the heat and maybe have to drain the system just to install this little gasket.
If you do need plumbing repairs when replacing a circulator pump or pump flange assembly, this is a great time to ask your plumber or heating service technician to also install a service valve right at the circulator pump - if one is not already there. Having these isolation valves in place makes circulator repairs a breeze - well a comparative breeze.
Our next two photos (below) show a service valve added at a circulator pump (below left) - with a leak needing repair, and a leaking circulator pump at the mounting flange ( below right).
A working shutoff valve on the heating distribution piping at the circulator pump can reduce the repair time, trouble, and cost the next time that circulator pump assembly repairs are needed.
Also, if flow balancing valves are not already installed on the system, a valve at the circulator pump can permit balancing of hot water flow among multiple heating zones when all of the zones are calling for heat at once.
Our photo (above left) shows a valve at the inlet to a circulator pump on a hot water heating system. As the valve is leaking, this control valve will speed the repair process.
Circulator Pump Bearing and Circulator motor failures on hot water heating system pumps and what causes them: circulator pump mounting and support errors
At a heating system inspection we found a pile of five or six circulator pump motors in the corner of the boiler room.
The "beginner" heating tech had replaced each circulator pump motor after less than a year of service, thinking that s/he was simply getting "bad parts" from the supplier.
The root cause of the bearing and circulator pump motor failure in this case was that the bracket holding the circulator pump motor was not properly mounted and was slightly askew.
This out-of alignment of the circulator pump motor mean that the motor shaft was "torqued" through its sleeve bearing, leading to early circulator pump bearing failures, leaks, and noises.
Our photo (left) shows the mounting assembly intended to support the electric motor that operates a hot water heating system circulator pump.
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