Possibly air lock

[Mkrob65]

When turning cold water on its spluttering but the hot is ok . Any suggestions great fully welcome

 

[DavidG58]

Try leaving to run, it may sort itself

on a caravan I had to blow up the tap to sort a similar problem

 

[TerryL]

Close all taps and switch on the pump - does it stop running? If not you've got a pressure leak somewhere. If it stops, open one tap at a time, closest to pump first, and run until it clears itself before moving on to the next. This is usually all you need to do. But!
I'd suggest checking the pickup pipe in the tank is actually underwater if you can get access. It could be the non-return valve in the pump is not closing properly (bit of grit) or has failed and is letting the water drain back into the tank.
The hot water is "buffered" by the boiler tank so is possibly not showing the same symptoms.
I'm assuming, of course, that you've got a pressurised system, rather than a submersible pump with microswitches on the taps, but I don't think you'd get the spluttering then.

 

[Mkrob65]

Hi . I only have a mixer tap for the kitchen sink . The cold tap head came off and there is a switch inside. My biggest problem is the water gauge isn’t working so I’m not sure if there’s water in the tank

 

[TerryL]

Never relied on gauges - I just fill ours until it overflows and know pretty well when we're going to need more through experience.

Okay, a switched system, but as you're getting something you know that the switch is working.

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