Condensing boiler - CH working, no hot water

[Radders_23]

Hi all,

We have a Worcester Bosch Greenstar Ri boiler. For the past few weeks we have had no hot water from the taps. We have been doing a lot of ad hoc plumbing work like connecting new radiators, backfilling the systems, and at one point we connected the hot water taps upstairs to the cold taps upstairs to force out an airlock in the cold feed.

When I turn the hot water on and the heating is off, the heating turns on rather than the hot water. We can't understand whats wrong - as I understand it the boiler is not a combi so doesnt have a diverter valve. Any ideas/help is much appreciated.

 

[oldbutnotdead]

You'll have some motorised valves and a cylinder in the system? Is the cylinder getting hot as well as the radiators? Have the motorised valves been latched open (usually done when filling the system).
Pics of controller and valves will help

 

[Radders_23]

The 3 port valve was stuck on H regardless of heating only or hot water only selected. Now when I turn the boiler off from mains and on again it moves to W. There is still no hot water but the heating is still coming on when hot water only is selected (valve still at W). The boiler is making a sound and the blue thing next to the cylinder is warm. I attach pictures below.

 

[Radders_23]

Also, in response to your other question, when we backfilled the rads we did it with the garden hose using main cold feed

 

[oldbutnotdead]

Have you or anyone else working on the system been playing with the wiring? If the valve is moving from its rest position when you power up, that implies that it is working but not receiving the correct voltages at the various pins.

Again pics of the controller (cover on and wiring) and wiring centre wiring might be useful.
Is the cylinder stat set at a sensible temperature (50 deg C or higher)? Is the cylinder stat working (you need a multimeter to prove it)
Is there water in the hot water cylinder and header tank? Is there water in the feed/expansion tank? (If radiators are pressurised then there won't be an f & e tank. If cylinder is pressurised then there won't be a header tank & you shouldn't really be messing around with it)

 

[Radders_23]

Hi,

Thanks for your quick response. No one has touched the wiring of this. Silly question, but which controller and wiring centre are you referring to? By controller do you mean where I turn heating/hot water on/off?

 

[oldbutnotdead]

The controller being whatever you use to select heat, hot water or both. The wiring centre- usually a plastic box about the size of a small paperback book with a fair few cables entering it, often to be found in the cupboard where the cylinder is.
And answers to the other questions?

 

[Radders_23]

Hi,

Just been in the attic and there is water in both tanks which is refilling when the hot water tap is open. There is no wiring centre in the cylinder, unless you count a box that says DANGER. I did find some boxes near the boiler. I attach pictures of these along with the controller

 

[Radders_23]

Just found some paperwork from when we bought the house - apparently we have an Invensys British Gas WC1 Wiring Centre https://www.ebay.co.uk/p/1305392857

 

[oldbutnotdead]

Hmm. You say both tanks in the loft are refilling when you run the hot tap- should only be the larger one

Your controller- has someone been stripping wallpaper round it recently? With a steamer?

 

[Radders_23]

No the paper peeled away easily. Also, correction - it's the big tank only which was filling up.

Just been playing around and seems the hot water cylinder isnt hot at all. Could this be all due to an airlock?

 

[Deleted member 267285]

I would say your motorised valve is stuck in heating

 

[ianmcd]

Also, in response to your other question, when we backfilled the rads we did it with the garden hose using main cold feed

why did you do that ? was the system not filling on its own ? might be a blocked cold feed