Radiators are hot, but water from hot tap is only warm..

[dpravo]

Hi everybody, I was hoping that someone can offer me some advice, I apologise in advance for any ignorance displayed as I've only been in the UK for a short time and I came from a hot climate where they don't have central heating so I am less familiar with central heating than most on this forum.. So, I have and indirect heating system with tanks in the roof, a (probably quite old) copper hot water cylinder in a cupboard on the first floor of the house and boiler down in the kitchen. The boiler seems to be working OK, with CH and HW or just CH switched on it heats the rads up to piping hot, but with CH and HW or just HW turned on the hot water to the taps is luke warm at best. The flow pipe from the boiler to the hot water cylinder is scalding hot down on the ground floor, but where it enters the hot water cylinder it is only warm and I guess it is not heating the coil very well and that is why we get luke warm water from the taps, its like it is losing loads of heat somewhere between boiler and cylinder - could this be possible? thank you so much in advance for any guidance on this issue!

 

[Simon F]

welcome to the forum.

if your understanding is limited then best to get a local plumber to take a look and advise.
is it gravity feed for hot water?
air lock, scaled pipes.

is it a y plan, splan?
problems with the valve

the heat could only be lost into the radiators,
or the boiler will just short cycle and keep turning on and off.

 

[dpravo]

Hi Simon! thanks for the quick reply. Don't worry, I have a plumber booked, but he can't get here for a week or so, so I thought I would reach out to the public in case it was a simple fix. It is gravity feed for hot water, and it is S plan, thank you. Both valves are less than a year old and I am pretty sure they are working ok as the pipework on the other side of the valves gets really hot depending on whether I have hw or ch or both on. Cheers!

 

[kris]

Are there airing points on the coil that you could bleed ? As if hw is on its own and isn't heating the coil either there's air or gunk in coil pipes or your zone valve isn't opening fully, is coil side of the zone valve roasting hot as far as you can trace? The cylinder stat maybe fauly closing the zone valve,

 

[dpravo]

Hi kris thanks for your enquiry! there are no airing point on the coil unfortunately. Coil side of the zone valve is roasting hot. thanks!

 

[dpravo]

Just in case anyone is wondering ( I know you all are ) I got this resolved...I drained down entire system, then connected mains powered hose to drain valve and blasted away for a few mins. A bunch of sludgy rubbish appeared in my F&E tank which I wet vac'd out, then I drained system again, refilled and everything is right with the world again.