Central Heating pump woes
Discussion
Chaps,
The pump for the rads on my heating seems to be reluctant to spin. It seems to have power going to it (according) to my tester but doesn't come on.
If I unscrew the silver cap and let a few dribbles of water out it springs into life and works perfectly. Doesn't always 'not work' but it seemed to start when the sparks put the new consumer unit in and the power was off for most of the day. Could be a coincidence though.
The heating was 'on' for an hour this morning and no heat in the rads at all before I did the above.
What are your thoughts? Picture below, not upside down but the pump is. It's a Grundfos UPS 18-60 Model D535.
The pump for the rads on my heating seems to be reluctant to spin. It seems to have power going to it (according) to my tester but doesn't come on.
If I unscrew the silver cap and let a few dribbles of water out it springs into life and works perfectly. Doesn't always 'not work' but it seemed to start when the sparks put the new consumer unit in and the power was off for most of the day. Could be a coincidence though.
The heating was 'on' for an hour this morning and no heat in the rads at all before I did the above.
What are your thoughts? Picture below, not upside down but the pump is. It's a Grundfos UPS 18-60 Model D535.
Get a new pump, £50, Turn valves off, prey they hold, undo unions, swap pumps over, redo unions, open valves, prey they open, job done...
You could just change the pump head, by undoing the 4 allen bolts, but looking at your pump, it looks very old and very likely not to seal properly...
You could just change the pump head, by undoing the 4 allen bolts, but looking at your pump, it looks very old and very likely not to seal properly...
Dave^ said:
Get a new pump, £50, Turn valves off, prey they hold, undo unions, swap pumps over, redo unions, open valves, prey they open, job done...
You could just change the pump head, by undoing the 4 allen bolts, but looking at your pump, it looks very old and very likely not to seal properly...
Out of curiosity why would it work when water is released from it? You could just change the pump head, by undoing the 4 allen bolts, but looking at your pump, it looks very old and very likely not to seal properly...
If you have isolator valves either side of the pump then it's a quick job. Disconnect power and undo the 2 big nuts. I needed to buy a big wrench (£6 at Screwfix, £21 at B&Q!!) as spanners were too small.
I didn't have 2 isolators so ended up draining/refilling the entire heating system. Which was a bigger job.
Never done anything like it before, took about 2hrs of which most time was working out how to drain the system. Helpful to have someone else around as well...
I didn't have 2 isolators so ended up draining/refilling the entire heating system. Which was a bigger job.
Never done anything like it before, took about 2hrs of which most time was working out how to drain the system. Helpful to have someone else around as well...
Have tried turning the spindle of the pump manually? If not, then with centre taken out and electric off, get a 5mm blade screwdriver and see if you can turn spindle. I have also with isolators/water turned off, turned the heating system on, must be very quick, since water has no where to go.
With pump back together, electrics on and isolators “open”, then with heating on, check there is water in header tank, also bleed the highest radiator, if still not working, then if pump is jammed try tapping the pump with a hammer. Sure sign of pump jammed will be pump hotter than pipes either side.
I would get a screwdriver,open thr front of the pump.round plug which undoes turning anti c/wise ,take it out,get a small screwdriver and see if its spinning,you will feel it if it is,if not turn it manually with a screwdriver
if the pump is jammed you will find the pump is hotter than the pipes round it (and may be too hot to keep your hand on)
I use Screwfix for my pumps, £80, but check distance between pump and isolator valves is same as your’s 130mm, get some WD40 and stilso
http://www.screwfix.com/
With pump back together, electrics on and isolators “open”, then with heating on, check there is water in header tank, also bleed the highest radiator, if still not working, then if pump is jammed try tapping the pump with a hammer. Sure sign of pump jammed will be pump hotter than pipes either side.
I would get a screwdriver,open thr front of the pump.round plug which undoes turning anti c/wise ,take it out,get a small screwdriver and see if its spinning,you will feel it if it is,if not turn it manually with a screwdriver
if the pump is jammed you will find the pump is hotter than the pipes round it (and may be too hot to keep your hand on)
I use Screwfix for my pumps, £80, but check distance between pump and isolator valves is same as your’s 130mm, get some WD40 and stilso
http://www.screwfix.com/
Wings said:
I would get a screwdriver,open thr front of the pump.round plug which undoes turning anti c/wise ,take it out,get a small screwdriver and see if its spinning,you will feel it if it is,if not turn it manually with a screwdriver
When I undo the silver plug water comes out - presumably I need to isolate it first?The pump is not turning though, using a screwdriver to the ear I can hear it spin up after I open the plug, let a bit of water out and then tighten.
Is it fair to say that if power is getting to it and there's water in the system, if it's not turning then it's the pump at fault?
When it's spinning all the rads get hot no problem, so I presume it doesn't need bleeding??
Yes isolate, then you should only get a trickle of water. When undoing isolating valves go back and foreward, clock wise and anti clockwise, this clears the scale etc. etc. that builds up.
Air in the system my affect the operation of the pump, causing pump to run dry. If you are getting intermittent operation from pump, then always best to replace pump. But check system for excessive air in radiators.
Air in the system my affect the operation of the pump, causing pump to run dry. If you are getting intermittent operation from pump, then always best to replace pump. But check system for excessive air in radiators.
Duke Thrust said:
Another pondering type question...
Would a slow running pump cause a higher gas usage? Ie the pump's slow and so the return feed has longer to cool and as such the boiler stays on for longer?
Or is that total pish?
The boiler switching on and off all the time because the water boils in it due to poor flow would use a lot more gas.Would a slow running pump cause a higher gas usage? Ie the pump's slow and so the return feed has longer to cool and as such the boiler stays on for longer?
Or is that total pish?
ThatPhilBrettGuy said:
Duke Thrust said:
Another pondering type question...
Would a slow running pump cause a higher gas usage? Ie the pump's slow and so the return feed has longer to cool and as such the boiler stays on for longer?
Or is that total pish?
The boiler switching on and off all the time because the water boils in it due to poor flow would use a lot more gas.Would a slow running pump cause a higher gas usage? Ie the pump's slow and so the return feed has longer to cool and as such the boiler stays on for longer?
Or is that total pish?
Yep, pump was screwed.
Was a total nightmare to change as the couplers that were on the isolators were seized. I had to drain the entire system, replace the isolators and re-fill. Shame as the isolators themselves were fine and it should have been a quick job just to swap the pump out.
Due to the horrible mess of pipes and radiators added over time draining, filling and bleeding took hours.
Come the summer the whole lot will come out and a well thought out layout will go in.
After I'd finished I took the old pump out to the workshop, got the joints cheery red using the torch and with it fixed in the bench vice and with a 2 foot stilson they still wouldn't shift.
Was a total nightmare to change as the couplers that were on the isolators were seized. I had to drain the entire system, replace the isolators and re-fill. Shame as the isolators themselves were fine and it should have been a quick job just to swap the pump out.
Due to the horrible mess of pipes and radiators added over time draining, filling and bleeding took hours.
Come the summer the whole lot will come out and a well thought out layout will go in.
After I'd finished I took the old pump out to the workshop, got the joints cheery red using the torch and with it fixed in the bench vice and with a 2 foot stilson they still wouldn't shift.
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