Extremely Slow hot water flow

[JanetF]

At the end of my tether on this problem. Daughter lives in an ex-council maisonette top floor. Her immersion heater was leaking badly so we had it replaced by a local plumber. Unfortunately he did such a bad job with the pipework and fitting of new immersion and the hot water flow was extremely slow making it impossible to run a bath within a reasonable time. We employed another plumber who re-did pipework and fitted immersion correctly but we still had problems with the flow but not as bad. He then fitted new taps which made this a little better but said we would never have great flow due to the placement of the tank which is very near the bathroom. Within a month the flow had got extremely slow again and now is just a little trickle out the immersion heater was replaced the water flow was good, she didn’t have a problem at all so what could the problem be now. We have spent in excess of £1500 so far for new pipework, immersion fitting, new taps etc., so really reluctant to pay out any further money, unless we know what the problem could be.

 

[JohnD]

I think when you say immersion heater, you mean hot water cylinder.

photo of the cold tank and of the hot water cylinder, and the pipes, would help.

Have you looked in the cold tank, and is limescale, dirt or a drowned mouse clogging the outlet? How high is the water level in the cold tank?

Look for any service valves in the pipework, and see that they are all fully opened, then back off a quarter turn (to prevent seizing).

immersion heaters
http://www.screwfix.com/c/heating-p...dredirect-_-plumbing-_-immersionheaterelement

hot water cylinders
http://www.screwfix.com/c/heating-p...6?cm_sp=managedredirect-_-plumbing-_-cylinder

 

[JanetF]

 

[JanetF]

The cold water comes from the mains outside the flat. Hope this helps.

 

[JohnD]

Have you looked in the cold tank, and is limescale, dirt or a drowned mouse clogging the outlet? How high is the water level in the cold tank?

The cold tank is the section on top of the hot cylinder. They are attached. There should be a round lift-off lid.

You say the cold water is off the main, so it will be high pressure, and not suitable for most mixer taps or showers, especially ones with a joystick.

Note the brass stopcock at the back near the low shelf, which controls the fill of the cold tank. The red wheel-valve on the insulated pipe controls supply of hot water to the tap. Are they both fully open, than backed off a quarter-turn? If they are noisy that can be dealt with separately.

The cylinder looks rather small. What size is it? You should find a label stating its capacity in litres. A bath holds about a hundred litres. Was the old cylinder the same size?

Run the hot tap into a bucket, time it to fill, calculate how many litres per minute it delivers.

 

[Aquaheat]

If it's a like for like replacement then I can't imagine you having great flow before either. That looks to be in the region of about 1.8m to the bottom of the cold water tank but lets say 2m just for arguments sake. That gives you only 0.2 bar pressure at ground level. Assuming that the bath is 500mm high then you only have 0.15 bar pressure at the taps. This is next to nothing.

It may just be the picture but the hot water draw off seems to have an incline so could be air locking there maybe.

For £1500 I would have converted you to an unvented cylinder so you had mains hot water to and a balanced hot and cold supply should you have mixer taps and you'd have had change.

Jon

 

[JanetF]

Many thanks for all your help and advice it is much appreciated. The old tank appeared bigger but it was square and would think years old. My daughter got the first plumber in who advised that it was adequate for the size of the property. The property has no gas and heating is underfloor. The second plumber who rectified the work also agreed saying the tank was adequate. Not sure where I go from here but need to have some resolution. I think it is a Wickes tank 900 x 450 117 litres tank

 

[JohnD]

Have a look in the top, and check the valves are open.