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baseboard heats without pump running

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).

Reply to
Chuck D
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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:

Reply to
chuckster

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.

Reply to
Edwin Pawlowski

Might be a dumb question but were would I find the flow valve. There are no zone valves in the system, just 2 loops, 2 pumps, and 2 thermostats.

Reply to
Chuck D

The type of pump used in a hot water heating system doesn't keep water from flowing when it is not running, whether it is worn or brand new.

Reply to
lwasserm

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.

Reply to
Chuck D

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:

Reply to
chuckster

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