C/H pump gets hot

[jrterror]

I have just drained my central heating system to make a repair to a leaking valve. I sorted the leak. I Filled up the system, added some Fernox, bled the rads and then switched on the pump without firing up the boiler. No leaks, no noise. Great. But then for some reason I switched off the pump, switched it back on and then the pump started to make a noise. I then placed my hand on the pump and it was red hot. Thinking that the inpellor may not be rotating freely, I then unscrewed the screw at the front of the pump. A little air came out, then water. But the noise continued. I switched everything off and then came to look on the web. So I have not left it running to see what happens. Does anyone have any ideas. Thanks D

 

[gas4you]

You haven't said if it was turning! Sounds like the bearings have stuck possibly to me and the motor is overheating. You didn't shut the pump valves for some unknown reason and forgot to open them again

 

[jrterror]

No, both valves are open. I think the blade was turning, but not entirely sure. What are the methods of determining this? Thanks for quick reply

 

[jrterror]

Also everthing worked fine before and its only been off line with no water in it for two days, three at the most.

 

[gas4you]

For how cheap they are I would put a new pump in. Thats the only 100% test and proof!

Edit; The electrics to the heating weren't left on whilst the system was drained so the pump has been coming on dry for the last 2 or 3 days

 

[Agile]

You put a screwdriver into the hole in the end of the rotor shaft and see if its free to rotate when not powered.

Then power it and see if the shaft rotates the screwdriver.

The fluid being pumped cools the motor so if its getting hot it usually means the pump is not pumping.

One of the valves may be stuck inside. To check that remove the pump and open a valve into a bucket.

Tony

 

[jrterror]

Again, no. I ensured that I swithch off the pump. I even switched it off at the main fuse board just in case my mrs got her fingers to it.

 

[jrterror]

Will water pour out of the shaft?

 

[jrterror]

Thanks for your help chaps. I'll look at it tomorrow. I'm off to bed

 

[Agile]

Chicken!

A little water may leak but that can be controlled with a medium size old towel or large sponge.

Tony