Old Single Pipe heating system problem

[townfanjon]

Yes

Erm , possible blockage on your feed and vent where it joins the system

 

[Graham SW]

Erm , possible blockage on your feed and vent where it joins the system

Its really strange the pipe going into the pump gets hot but the output pipe does not but the pump seems to be working as I can feel it when it turns on

 

[Stigster]

The motor on the pump may be spinning but the spindle may not be turning the impeller giving the illusion of a working pump. As has already been suggested it may be air in the pump too. You can usually take out the slotted screw on the front of the pump to bleed air. On some pumps, older ones usually, you can also see the impeller under that bleed screw. Again, most impellers will have a slotted screw in the centre, with the system calling for heat you can give this impeller screw a quick twist with a screwdriver to get it going again if stuck. A small quantity of water will escape but nothing that couldn't be handled by a bucket or other container to catch the water.

If this works it might get your heating going again but the pump would want replacing sooner rather than later.