What pump?

[barryplumb]

Hi all,

done some work in my sis in laws house last week, she lives in a 5 bed, 3 bathroom house.
There is a total of 21 radiators!! they have a big floor mounted oil fuelled boiler that works ok and the last gas engineer said it was 94% efficient.
The problem is they just have a standard size grundfos pump, so some of the rads are sruggling to heat up, any advice on a good pump to replace it with?

 

[Blackcatgas]

180mm port to port so it will fit in place of the 15/60, maybe a Grundfos ups 25 55 I fitted one a while back on a large 3 story 3m high cieling victorian detched house with 18 rads and the boiler in the cellar. Did the job nicely was £220 ish.

 

[barryplumb]

thanks Blackcatgas, was the wiring the same on the new pump?

 

[Blackcatgas]

edit Ive given the wrong port to port mm, yes its just earth live nuetral, let me just triple check Ive given you the right pump model number

 

[barryplumb]

ok thanks. ups 25 55 is a light commercial circulator

 

[barryplumb]

Also when i tried to drain down system via a small rad near the boiler downstairs, attached hoses ( two drain of valves on same rad) nothing drained off!
I flicked boiler on to start pump for a few seconds in case of an airlock and it pumped out of the hoses no problem, turned of boiler and flow stopped.
I then found 15mm feed to the boiler from header tank with a drain of valve , used this to drain down ok. So why would it not drain of from thge rad valves?

 

[PlumbBobBob]

did you open any bleed valves on the rads?

 

[barryplumb]

yep tried opening bleed valves on up and downstairs rads. even realeased nuts on the small rad and nothing came out . Could it point to a blocked vent pipe?

 

[PlumbBobBob]

yes probably there must be a restriction somewhere.

 

[barryplumb]

How can you check if a vent pipe is blocked? is there a procedure to test it?

 

[PlumbBobBob]

if you get a magnet and try it along the pipework not just the vent, wherever the magnet sticks or you feel a bit of resistance there is likely to be a blockage.

 

[barryplumb]

nice tip steveb, thanks.
Another tool I need to get! a magnet!