Worcester Heatslave 20/25 Diverter Valve?

[dan_c]

Hi all,

This is my first post here and unfortunately it's ended up being about problems rather than optimistic queries about future plans for solar thermal and solid fuel with thermal stores....that's for another day.

My current boiler is a Heatslave 20/25 and this is in a house we purchased a couple of months ago. I am convinced the diverter valve is sticking as we've been having two different problems - the first is more common. I've read a few threads here and this has helped me believe the valve is my problem.

1. No heat from downstairs rads when heating is on - only a few upstairs.

When this happens I can give the body of the diverter valve a couple of light taps with the rubber handle of a chisel and there's a squshy/water flow noise and then the flow pipe for the central heating gets roasting hot and the heating works. A minute or so later the burner fires up and all is good.

2. Occasionally the boiler has been set to hot water only and we end up with heat pumping out of the rads - but still with some hot water. Tapping the diverter valve doesn't achieve anything when this is the case. This has only happened a few times and I ended up turning the CH and HW controls off to save oil

I had the boiler serviced a few weeks ago and the heating engineer didn't want to replace the diverter valve after I explained there was a problem. He said the boiler was just old (circa 1996/7) and not worth spending the money on. He suggested I change to a non combi with a unvented tank but I can't afford to do that right now. I also want to make a proper job of the heating system when funds allow and try to integrate solar thermal and maybe another log burner.

So.....does anyone think that the diverter valve could be the problem here based on what I have described? Is there anythig else I can do to diagnose the problem 100%?

Thanks very much
Dan

 

[SimonG]

Firstly welcome along

I would say it's definitely the diverter valve. It could be goosed but it could also be a lack of inhibitor in the system. I have had issues with diverters sticking and just the addition of some central heating inhibitor has been sufficient to solve the problem.
If this doesn't fix it then it needs changing. Depends on which valve type it is. If it's the cartridge type it's easier and cheaper, if it's the acl type it's expensive and a pain and the conventional honeywell somewhere in between.

 

[dan_c]

Thanks for the quick reply.

I recently had 7 rads replaced with a refill including inhibitor so I guess it is goosed! I'll have a look at it tonight and try to identify it by any numbers or maybe even a photo - at the moment all I could say is that the "lid" to the diverter control part looks like a rectangular piece of folded tin and the lever(?) exits the back face of this tin box which is facing slightly upwards and in towards the body of the boiler.

 

[SimonG]

Picture would be good, but sounds like acl or honeywell

 

[dan_c]

Thank you Simon - I'll report back tomorrow.

 

[kimbo]

Agree with simong but I would take the head off if the paddle is free I would just change the head, it sounds like the cogs are worn and are sticking.

 

[dan_c]

OK chaps - it is an ACL unit. A679B316-52L0 is the number I can see.

Any chance of explaining what you mean ref. the head and the paddle? Should I lever/clip off the metal cover to see what it's like underneath? Should I be able to see the cogs inside then or does it all need removing from the boiler?

Here are a few pics - as you can, she doesn't look like the most well loved boiler ever

 

[dan_c]

Anyone in the Gloucestershire area fancy fitting a new valve for me?

 

[dan_c]

Should the metal cover just lever/click off my valve so I can see inside?