Sudden drop in water pressure

[Paulus]

Hi Guys

I'm having real problems diagnosing problem with mixer tap. Customer says that the hot water pressure dropped suddenly to a dribble. I have replaced the ceramic valve with no effect.

I connected mains cold water to hot tail and it worked perfectly. I connected mains water supply to hot supply to get rid of possible air locks and checked the hot supply to hot water tail which is ok.

All I can think is that the water pressure is too low as the tap specs say minimum 4 bar which is just about what the customer has from an unvented system but the tap has been working for 3 years.

Any ideas why it would suddenly dry up so much?

 

[SafeGasInstall]

what about other taps in the house ,have they been changed any hot water there at all

 

[Paulus]

No problem with any other tap either upstairs or downstairs cloakroom although these all have proper valves, not ceramic.

 

[mickie]

and you've tryed water pressure and flow rate before the tap have ya ?

 

[WHPES]

Stuck check valve in the tap?

 

[Paulus]

Pressure and flow rate under sink is around 0.4 bar. The tap worked fine with cold water to hot tail so I can't see it being the check valve. How would I check this?

 

[PlumbBobBob]

is there any debris in the tap itself slowing flow down?

 

[Paulus]

Sorry, I don't see how there can be debris as it has been blasted out with mains pressure cold water. I'm glad others are struggling with this, I've been tearing my hair out all afternoon. I've just checked the cold water feed tank and found it only about half full,clutching at straws here but does anybody think this might have something to do with the problem. Unfortunately I have damaged the tail on the hot water feed and will have to wait until tomorrow before I can try out else.

 

[WaterTight]

mumble mumble...something mechanical failed..
mumble mumble...not uncommon...
mumble mumble...unfortunate i'm afraid...
mumble mumble ... price for supply and install of new tap

 

[Paulus]

Thanks everyone who replied, I have recommended a new tap which requires less water pressure.

 

[Nat]

Sorry, I don't see how there can be debris as it has been blasted out with mains pressure cold water. I'm glad others are struggling with this, I've been tearing my hair out all afternoon. I've just checked the cold water feed tank and found it only about half full,clutching at straws here but does anybody think this might have something to do with the problem. Unfortunately I have damaged the tail on the hot water feed and will have to wait until tomorrow before I can try out else.

water tank? You said it was unvented or am I missing something?

 

[AWheating]

All I can think is that the water pressure is too low as the tap specs say minimum 4 bar which is just about what the customer has from an unvented system but the tap has been working for 3 years.

never seen a tap needing a min of 4 bar pressure? most unvented systems have hot pressure reduced down to 3.5bar vai. PRV

 

[plumberdarren]

3 bar ;0