Pump very hot

GeorgeS · 24 Nov 2005

Folks,
first let me thank you all for the good tips i've used from this forum...saved me a lot of money!

hopefully you'll help me solve that one...
I have a Myson CP53 pump that is getting so hot I can't leave my hand on it more than a couple of seconds... even when the boiler is off, just the pump circulating cold water.
My upstairs rad are perfectly warm, but my downstairs are just hot at the top and barely tepid at the bottom. I've read on this forum that it could be some sludge problem in my downstairs rad but could it also be related to the pump?
Much appreciate your help.

G.

oilman · 24 Nov 2005

Your pump is probably stuck, or not running freely. Remove screw in the end and check shaft is rotating, and is free. Let the pump cool before doing this or you might get squirted with near boiling water.

GeorgeS · 24 Nov 2005

i've checked the impeller and didn't noticed any resistance. any idea?

oilman · 25 Nov 2005

Turn off upstairs radiators, and see if downstairs ones get hot.

GeorgeS · 25 Nov 2005

i tried that. it seems like downstairs rad are a bit warmer but they are still far from being as hot as upstairs, and still unevenly warm...the control valve is warm but the lockshield valve isn't.
One more thing...I noticed that all lockshield valves are completely open. is that the way they should be???

shaka · 25 Nov 2005

My advise change pump before it goes in cold period or christmas day b&q £32.00

blushy · 25 Nov 2005

I also have a Myson cp53 and a Potterton Suprema 30. Any idea what the pump should be set to? My house is a 3 bed semi and when the pump is on setting 3 it makes quite a row. On setting 2 it makes little noise but heating takes longer to reach required temp.

GeorgeS · 3 Dec 2005

Blushy- my pump is set to the fastest speed and the noise isn't a problem. maybe you should try turning the pump manually. You shouldn't feel too much resistance or hear any noise. turn off the boiler, unscrew the black cap in the middle of the pump until you feel the impeller spinning.if it makes noise or if hard to turn the screw, you might have a faulty bearing in which case the pump needs to be replaced.
Hope this helps.
out of interest, is your pump much hotter that the hot water pipe that goes into it?

JohnD · 3 Dec 2005

If the pump's hot when the water's cold, it must be blocked or jammed, and generating heat from using the electriciy in an unsuccessful attempt to push water round. You say the impeller turns freely, and that the downstairs rads get warm if you shut the upstairs ones, so that points to a blockage.

If it is a blockage (and not a pump valve closed by mistake) then you may be able to track it by feeling where the warmth in the pipes stops.

Or it could be a general sludge thing. Is this an old system with no inhibitor? I doubt it could be sludge in a single rad, because then the water would jut circulate freely through all the others.

GeorgeS · 3 Dec 2005

Hi JohnD- the house is about 8 years old. i'm not sure whether there's an inhibitor. the colour of the water is yellowish with a strong smell of chemical though...
unfortunately i can't track the warmth down the pipes as all pipes are hidden behind the plasterboards.
i'm gonna try balance the all system as explained in the sticky and see if it makes a difference downstairs. if it doesn't i guess i'll have to remove one of the rads and check if it's sludged...

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Pump very hot

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