Tapping noise in central heating with Megaflo cylinder

[lokstok]

Hi all

We get a really annoying tapping noise in the central heating pipes when the central heating kicks in. The tapping is very frequent at first (5-10/second) but gradually slows down until it disappears.

As we have a Megaflo system I have read that the problem might be due to overpressurising the central heating. The pressure gauge only show about 1.7bar at the moment.

Therefore, my questions are:

1) Is it possible to reduce the pressure on the central heating only so that the taps are still at high pressure?

2) How do I reduce the pressure on the Megaflo system? I know how to put the pressure up, but not down

3) Could it be some problem other than an overpressured system?

Many thanks for any help you can give.

Brad

 

[linkyplumb]

Likely cause is that the pipe is expanding and rubbing against something- a joist or floorboard etc.