noisy system

[juliegg53]

Recently moved house. Got conventional boiler with microbore piping to rads c/w 3 port valve + pump + header tank.
Tested system. Get loud noise of rushing water (like when running mains tap) through rads. No sign of leaks. Tried notching down pump from 3 to 2 and turned boiler down to warm.
We\\\'re in a hard water area. Any inexpensive suggestions please ? Thanks.

 

[Bahco]

Check header tank see if water is present.
Your noise suggests plenty of air in system.

 

[juliegg53]

Hi Bahco, Thanks for reply.
Checked Header. Seems plenty in there. 2" above outlet. Lots of settled sludge in bottom and a bit scummy on top.
I also notched the pump down to 1 and it has improved but not cured. It kicks in every time the pump operates, whether boiler firing or not so must be a circulation prob.
From other threads i wonder if the pump could be on it's last legs ?
I did try bleeding the upstairs rads and no air present in them.

There is a Myson Aerjec 2 in the system (pump outlet side).