which pump do i require?

[bhm1712]

i am going to replace my Heating circulator as the Wilo Gold has become very noisy and vibrates through the whole system.

upstairs my rads are on 15mm pipe i believe without measuring, but downstairs they are on microbore pipe. i have been told that a standard pump may struggle with the resistance of microbore and so i should buy for example the Grundfos superselectric as opposed to the selectric. (15/60 instead of 15/50) is this correct? or will a normal 15/50 selectric handle it ok?

i only have 7 rads in all. 4 up and 3 down on microbore.

 

[oilman]

If it has been working with a 15/50, why change? Rubbish reasons are often given for changing to a 15/60. It is usually plumberspeak for "if I can confuse you with science, you are fair game for a larger bill".

 

[bhm1712]

it has been working, but it has to be on speed 3 to get the heat to the downstairs radiators

 

[gas4you]

This could be the old pump was 'getting tired', or even due to a slight sludge build up in the system.

Putting a 15/60 in may alleviate the symptoms, but not remove the main problem.

 

[bhm1712]

i will be having a power flush in the summer time when the central heating is not required so that incase of problems after, it wont be a heating emergency.

i will wait and see if the pump holds out till then. the old pump is 22 years old and i cant even open the bleed screw on it. not even with pipe grips on the end of a big screwdriver

 

[oilman]

i will be having a power flush in the summer time when the central heating is not required so that incase of problems after, it wont be a heating emergency.

Put some system flush in and run it for a fortnight then drain the system. You may not need a power flush. The down stairs rads may not get hot because the radiators aren't balanced. Try turning the upstairs ones off, and see what happens.

i will wait and see if the pump holds out till then. the old pump is 22 years old ...........

22 years with little maintenance, what more do you want?

 

[bhm1712]

the downstairs rads get red hot when i turn the upstairs ones off, which did lead me to believe tht they need balancing. however the pump is still very noisy. to add system cleaner do you just dose it into the F and E tank?

and to drain i presume you prevent the F and E tank from filling up and just drain from the last rad on the system?

 

[oilman]

the downstairs rads get red hot when i turn the upstairs ones off, which did lead me to believe tht they need balancing.

Turn the lockshield valves on the upstairs rads closed, then open 1/4 turn for a start. A little tweaking should sort it. Takes about an hour (or two).

however the pump is still very noisy.

22 years is not a bad endurance.

to add system cleaner do you just dose it into the F and E tank?

and to drain i presume you prevent the F and E tank from filling up and just drain from the last rad on the system?

Draining from any rad will do.