Low Hot Water Pressure

[AllLectric]

ok do this: run a hot tap now and see how quickly water enters the cold tank, on top of the h/w cylinder, through the float valve.

the kitchen will be low pressure as is only slightly lower than the tank!

for the bath, either the float valve is not filling quickly enough, the cold water tank is emptying quicker than it can re-fill, or there is a slight blockage in your cold feed pipe from the cold tank to the h/w cylinder.

the cold water tank is emptying quicker than it can re-fill

This seems to be the problem, the water in pressure seems fine, what can be done to correct it ?

 

[steved101]

if the cold tank is filling normally (ie float valve OK) then there is nothing easy that can be done...... except replace the unit...

 

[AllLectric]

Tried to find the inlet valve tap for the cold tank, cannot see anything. There is another tap fully open that goes straight into the top heater section, taht is fully open.

Theres a small screw on the cold tank inet (silver valve just before going into the cold tank). I haven't turned that yet, would this be for making sure cold water valve is fully open.

 

[seco services]

yes its a service valve.

 

[AllLectric]

if the cold tank is filling normally (ie float valve OK) then there is nothing easy that can be done...... except replace the unit...

Yes float works as nomal, it's right at the bottom when running hot bath tap. And takes ages to fill the small tank up to the top again. It must be not enough cold water coming in, to increase this would help i think. How would this be done, see above post also for info.

 

[AllLectric]

yes its a service valve.

Service valve as in increase - decrease water presuure valve. I cannot trun it to much and it pops out with lots of water can i.

Increase is anticlockwise or clockwise on these valves ?

 

[steved101]

is the float valve the correct type?? ie mains / high pressure.......

open the service valve FULLY, turn it anti-clockwise to the vertical position.

what is the cold pressure at the kitchen tap like??

 

[AllLectric]

is the float valve the correct type?? ie mains / high pressure.......

open the service valve FULLY, turn it anti-clockwise to the vertical position.

what is the cold pressure at the kitchen tap like??

Ok i got it its a quarter turn adjustment only, horizontal is fully open, virtical is closed (water stops). It was horizontal (fully open to start with).

Unsure if float valve is the correct type, wouldn't know the difference it's.
A red float attached to a BS1212 valve inside the cold tank.

Cold pressure at all taps is very high, so much at the bathroom sink turn to much i get soaked. But could be a modern type sink, that are not as high as the older ones.

 

[seco services]

you may be better with a full bore isolation valve rather than a service valve as they are resricted internal bore.

 

[AllLectric]

you may be better with a full bore isolation valve rather than a service valve as they are resricted internal bore.

Thank you.

Do you think the the float and float valve is of the needed high pressure type.

A red float attached to a BS1212 valve inside the cold tank.

I will shop for a full bore isolation valve at plumbing-diy shops. I have just looked at a compare site, and both screw valves look exatly the same style etc. Cannot tell them apart, or is there a way to be sure i have the restricted type, so not some other problem.

Top picture of each link.

http://www0.dealtime.co.uk/-full+bore+isolation+valve+15mm

http://www0.dealtime.co.uk/-restricted+bore+isolation+valve

 

[seco services]

look down the centre bore a restricted bore will start at 15mm but the centre will be only about 10mm.

 

[AllLectric]

Thanks i must take it off to find out. Shame there's no markings on the valve to say, full or restricted bore.

Thank you for both of your helps so far.