Cold water pressure in bath poor

[Evostance]

Looking at our system in the house, it would appear that every cold water tap in the house is fed from the mains, apart from our bath.

Looking at the pipework, the cold water pipe goes straight up to the header tank and has a gate valve that is currently fully open.. or at least I think it is.

When we open the bath tap, I can hear a gurgling/chugging noise around the gate valve. My assumptions here are that the valve is knackered and isn't fully opening.

A couple of questions here:

1. Does this sound like the valve is knackered
2. How exactly do I go about replacing this valve, as there is no isolator on the header tank. Turn off the water and drain the header tank?

 

[Simon F]

if you don't have bungs then yes.
turn of cold feed to tank and drain through the bath cold (then you keep your hot water)
when empty swap the valve.

but how slow is it?
how hot is the hot?

 

[Evostance]

if you don't have bungs then yes.
turn of cold feed to tank and drain through the bath cold (then you keep your hot water)
when empty swap the valve.

but how slow is it?
how hot is the hot?

The hot water when working is red hot, and the pressure there is fine.

Cold water is no more than a dribble. I could probably run marathon before that bath fills up!

 

[Evostance]

I think investing in a bung is the best option. I could run a marathon before the bath fills up as it is quite literally a dribble.

The hot is fine throughout the house

 

[Simon F]

try the valve swap,
but you could find that the pipe is furred up and needs replacing

 

[PhoenixServices]

Are you sure it's not the innards of the bath tap on the cold side that could of had it. If you can get to the pipe work easily, isolate it on the gate valve take the non live side off. Then put a bucket under it and open the gate valve into the bucket. At least then you know whether the problem is with the valve or not.

 

[Evostance]

Are you sure it's not the innards of the bath tap on the cold side that could of had it. If you can get to the pipe work easily, isolate it on the gate valve take the non live side off. Then put a bucket under it and open the gate valve into the bucket. At least then you know whether the problem is with the valve or not.

I'll give that a go, however I'm still convinced it's something else.

I say this because we had plumbers in who ended up cutting all the pipes in our house..

They then obviously shut down the isolation valves, and I reckon it's probably one of the few times they've been turned. Probably knackered it in the process.

Will try that though and see how it goes