Spluttering cold water from direct supply

[GMitch2000]

Hi can someone please give me some advice as I have searched elsewhere on this forum (and several books) but previous problems seem slightly different from mine.

I have a mixer tap in the kitchen. The hot water (and taps elsewhere in the bathroom) are powered by a water pump but the cold water is a direct supply.

I keep getting extremely low pressure in the kitchen cold water. When I turn up the tap I then get a spluttering and then a very strong jet of water (soaking the kitchen). I have guessed that I may have an airlock and have tried covering the tap with my hand when running cold water. That seems to fix the problem for a little while but it then quickly comes back (sometimes ten minutes later).

Thank you very much to anyone who can offer advice!

 

[Softus]

Could be a water supply problem, but what type of mixer tap is it?

 

[GMitch2000]

I must say that I don’t know very much about plumbing, but I think it is a dual flow mixer, with two separate knobs for the hot and cold water.

Neighbours do not seem to have a problem so I don’t think it is a supply problem.

I had the same problem last summer, but after a few weeks it went away, but now it has come back again.

Can an airlock form in the cold water supply when the cold comes from straight from the mains and the hot from a boiler?