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).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
--
No dumb questions, just dumb answers.

Larry Wasserman - Baltimore, Maryland - snipped-for-privacy@charm.net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.