The upstairs loop of my hotwate system is getting warm even though the
pump has not run for many hours. Seems like some sort of convection flow.
The thermostat controls the pump for the loop. (Tacopump about 30 years
old Weil boiler same age)
The basement loop (where the boiler is located) has it's own pump and
thermostat and does not show temp
when the pump is off. The boiler is off from late spring to fall and there
are no signs of water around it. Could the pump be so worn that water is
able to leak by the impeller and set up a convection Flow? The pump is in
the return line ( factory mounted position).
Sounds like a faulty (stuck open) flow valve on the loop, and the loop
is heating up by gravity. These flow control valves can stick open
(caused by rust and sediment) so try flushing the loop and tap on the
valve to "free" it up.
Chuck D wrote:
There are (in my system anyway) two check/flow valves that can be adjusted.
Assuming this is something new, I don't know if they can get out of
adjustment just sitting there. I had a similar problem on the upper floor
circuit many years ago and a half turn fixed the problem. YMMV, of course.
Flow valves are usually located on top side of the boiler and are red
with a "L" handle on the top. The pipe from the heating loop is going
into the side of it and the pipe from the boiler goes into the bottom
of it. Follow the pipe UP from the circulator or UP from the boiler and
you will find it.
Chuck D wrote:
Just looking around the system and discovered what looks like a big
valve body in the loop just after the expansion tank. Micht be the flow
valve. Wonder if is an anti backflow valve which needs pump pressure to
open. If so it must be stuck open as you say. Never even knew it was
there, pretty well hidden. I'll give it some percussive mantainence.
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