C.H. been off for 9months....

[planenut]

It must be here somewhere but I cannot find it......
that is a reference to starting up a gas fired central heating system that has been off for 9 months due to take over of house.
The boiler fired up but I noticed that a pump was feeling hot shortly after start up. Hot water did not seem to get passed the pump and I am sure the heat I felt in the pipe was from the pump as it was now feeling extremely hot, any ideas please?

 

[ban-all-sheds]

My theory, which I have, which is mine, is that the pump siezed up through not being used for 9 months and that now you've put power through it while it was stalled it's probably beggured.

 

[ChrisR]

To free off a pump:

undo the big central screw. Water will dribble out. Insert 6mm screwdriver, and try to locate in slot in end of shaft. Some slots are useless! Turn both ways until you feel it moving. You can try this with the pump turned on. If it's on but not turning it will get VERY hot.

On some pumps the screw is captive, if you pull out on the bit which unscrews, you should be able to turn the shaft.

Sometimes new pumps are so stiff you can't free them off this way. So Isolate the pump using the pump valves. Trouble here is that most pump iso valves are poor. The screwdriver-slot ones often leak, and the gate-valve type often don't shut off completely. Assuming you have done whatever was necessary (which may include draining the system) undo the 2 or 4 Allen head screws which hold the body of the pump to the end casting. Separate the parts. On some pumps the motor will stay stuck to the cast end. A tap should unstick it.

When you can see the impeller, hold the pump motor/body and turn the rotor to and fro. It may become surprisingly sloppy, especially endwise. Reassemble the pump. The pump shaft should be horizontal, and the plastic box with the wires should not be underneath.

While the pump is apart, check that the gap between the sides of the rotor is not full of gunge. If it is, clean it out with a nail file or similar.

If you run the pump while it's open (don't do it for long), you should need a strongish finger pressure to stop it turning, on full speed. If you can stop it easily, you need a new pump, though sometimes it's just the capacitor which has aged.

 

[kevplumb]

forgot the gentle tap with a hammer

 

[ChrisR]

Seen too many split castings! What I usually do first if access permits, is kick it! Quite often works.

 

[planenut]

Thank you chaps, I will try to have another go later today. I prefer the idea of kicking it, but alas it's up in the airing cupboard.
Thanks again.

 

[ChrisR]

Punch it then!

 

[kevplumb]

have tryed that (tends to make your eyes water )