Noisy cylinder refill

[sai_2]

Hi,
is there anything obvious that could cause a cylinder refilling to be noisy sometimes and then not?

This is a fully pumped Potterton Profile 50e system with 7 rads and a shower with a pump to increase the low pressure. When a shower is taken (and this problem isn't consistent), there is sometimes a load of noise as it is getting refilled from the water coming from the loft down to the cylinder.

Any ideas why would this happen sometimes and not other times..?

Thanks.

 

[Gasman1015]

Probably incorrectly fitted pump supplies. They should direct from cylinder and cold water tank.

 

[sai_2]

OK thanks. Will get a pro to look at it and report back.