Pump problem.

[wolfinwales]

After a weekend away i have come back to find my heating or hot water not working at all.
I have checked the usual things i have problems with ie air in the system, header tank not filling etc.

This time there seems to be no circulation at all and the only thing getting (very) hot is the pump ( a 2 speed grundfoss super 4 V806) its making no sound at all to indicate movement, would this point to a broken pump ?
If so can a pump be replaced without draining the system ? i can see 4 allen bolts securing it to the pipework. How much would a pump cost ?

Other problems i have been having just lately are the header tank getting full of hot water. The main boiler is a Vulcan continental fitted around 25 years ago, is it time to look at complete replacement ?

All advice would be much apreciated, thanks.

 

[taydo]

yes it does point to the pump this would also explain the expansion tank getting hot no flow so escaping out of the safety expansion pipe.

there should be a valve either side of the pump so in theory you can replace pump without draining system. BUT they dont usually work.

dont no about any allen bolts unless its a flange type pump???

 

[oilman]

The main boiler is a Vulcan continental fitted around 25 years ago, is it time to look at complete replacement ?

No. It may go on for another 10 years, (or more). Wait until it starts leaking, or you cannot get spare parts.

 

[wolfinwales]

Thanks for your help, i think it must be what you call a flange type pump, the pump body is secured by 4 allen bolts, do you know if i would be able to change the pump without having to mess with the pipework at all ?
I have seen pumps that look similar in the Screwfix catalogue would they be interchangeable ?

 

[oilman]

Post the picture of the pump here using the format (img)...then the image address...(/img) but replace the () brackets with [].

 

[wolfinwales]

 

[renovator]

I have just replaced a Grundfos 15/50 using this sequence.

1) turn off central heating
2) locate and turn off power to pump
3) locate and close isolation valves either side of the pump
4) remove the pump
5) flip pump over, unlock baseplate, and disconnect power cable
6) take pump to Plumb Centre, and ask for a replacement
7) pay £37 + vat
8) refit power to pump
9) refit pump, replacing rubber washers and boss white on thread
10) open isolation valves, and check for joint leakage
11) turn on power to pump, check by hand for activity in pump
12) turn on central heating
13) check rads
14) reset central heating to correct time.

total time 2 1/2 hours

thanks to breezer for the isolation valve tip.

 

[renovator]

wolfinwales, the allen bolts hold the pump casing together personally I would'nt undo them.
from the pic you sent it appears that you have isolation valves, well at least one ( the red tap). Check for another at the other side of the pump.
Mine did function 98%, there was some fine mist produced but it did not cause any problems.

 

[AlanE]

Step 9 "refit pump, replacing rubber washers and boss white on thread"

The ONLY sealing on the pump is the two gasket washers.

Why boss white??? I pitty the poor bug**r that has to remove it in the future.

Alan

 

[oilman]

Pity I didn't read renovators thread properly. Agree with AlanE, the washers do the sealing, and the nuts don't have to be more than nipped. I now have a method for dealing with threads and jointing compound, but it took me 2 hours, 18" adjustable, hammer, blowlamp and a few choice words before I worked it out. Even then you will need room to swing a cat.

 

[AlanE]

Oilman the last of your requirements seems to be the one normally missing. Or at least in the majority of cases where I have had to replace pumps. Pumps not normally sited with any thought for future replacement.

I also smiled at renovators step 3. I have often found the need to have the trusty VAX running as the valves never quite seem to turn off the water compleatly!

Alan