Worcester Bosch 240RSF Hot Water Prob

[Graham81]

Dear All

Firstly just to let you know I have a Worcester Bosch 240 combi boiler.
Recently I have been experiencing reduced hot water temperature and also noticed that the radiators were getting warm when I used the hot water, even if the heating was off. I put this down to the diverter valve in the boiler and promptly replaced it. However this did not solve it. So as a test I shut off the central heating flow pipe then ran the hot water, and hey the water was at full temperature again.

I am at a loss as to what I am missing here, any ideas would be much
appreciated.

The only other thing I suspect is scale in the secondary heat exchange, reducing the the water that does the actual heating, so that it finds the easier route to be the central heating path. The reason I suspect this is that the diverter valve is only a hydralic valve and is not motorized.

If this is the case can it be cleaned, and with what?

Thanks in advance.

Graham

 

[ChrisR]

If the new dverter isn't diverting, it either already has a split in the diaphragm, or muck in the gubbins which is stopping it closing off. A blocked dhwhe wouldn't make the heating pipes hot.
Time to remove and dismantle.

 

[Agile]

"""I put this down to the diverter valve in the boiler and promptly replaced it"""

Now I wonder if he really changed the WHOLE diverter valve?

Some people fail to understand how these parts work!

Tony

 

[Paul Barker]

I think he changed the diaphragm without dissassembling cleaning silicone greasing and reassembling the pin.

Watch out there is an oring seal on opne of the brass pipes from the dv manifold to the dhw heat ex which leaks after you've had it apart and must be renewed with a freshly silicone greased new one. Silicone grease on ol;d one doesn't work. If you are a very patient man silicone sealer on old one and wait until it;s set might work, I don't trust that method but if you don't have o rings what else can you do?

Don;t get the pcb wet, that causes a lot of problems on this otherwise excellent boiler from Worcester's glory days.

 

[Graham81]

Thanks for the responses.

I have changed the whole diverter valve including the diaphragm, housing, both pins, shut off plates etc etc. I got the part from BES, very reasonable price.

I did grease it up before I put it in & cleared out the central heating loop by running cold water through it for about half an hour, with old part still in.

Also, your right, that o ring is now leaking. I was going to try and seal it.

I will dismantle and try again.

Also how do you guys rate this boiler?

 

[Paul Barker]

I can't understand why it's now sticking then.

I like the boiler and usually consider them worth repairing, but I have found that with their age they are often quite scaled up.

 

[Graham81]

I've striped it all out again and the valve seems to be moving as it should.

Can I get the o ring that you said would leak, and is, from a diy store or do I need a plumbing merchant. Also any idea how much?

Thanks

 

[chrishutt]

You can get various selections of O rings from DIY stores and plumbers merchants, but no guarantee that these will include the right one. You could order the correct spare part from a spares supplier like Parts Centre or many others.

 

[Paul Barker]

I'm fairly sure it comes with the Worcester DV but since you ordered the bes one (and well done for that) you now have to struggle to find o ring. Ring worcester for part number then phone parts suppliers to order it.

Could also try a motorcycle repair place they may let you have one if you take yours in.

Meanwhile why not try replacing it all dry with silicone sealant on the offending o ring and wait overnight before refilling.

Why hot water gets diverted to the rads is now a mystery it has to be inside the DV there is no other way.

 

[Graham81]

Thanks guys

I've removed the piece of pipe that joins the diaphragm to the DHW, as it was leaking from that small gap where the pipe size steps down a size. However I am not sure where this o ring goes, or indeed what I need to replace to stop the leak.

If I was to silicone it where do I put the silicone, I know this sounds stupid, just can't make sense of it.

Thanks

 

[Agile]

I dont understand why you should be having such a problem understanding such a simple part.

Its a "telescopic joint", one side is smaller and the other side is, wait for it, larger! The smaller one has a groove with a "O" ring.

If you take it apart and clean the INSIDE of the larger tube with wire wool you can sometimes get it to seal with the original "O" ring if you apply silicone GREASE. If you can fine a suitable size "O" ring then thats better though.

Why anyone should bother when the Worcester part is only about £8, I dont know ! I dont think Worcester sell the ring separately

Now to the fault ! The remote diagnosis is that the LOWER part of the diverter, which has its own actuating spring, is not moving and "following" the movement in the upper diaphragm section. Perhaps BES forgot to grease it with silicone during manufacture?

I suppose you should take it out and check it moves freely and grease the shuttle seals.

Tony Glazier

 

[ChrisR]

I think it's a horizontal DV.
Access to the diverting parts is through the back end.

 

[Agile]

Yes, its fittted horizontally but I described the manifold as the "lower" end because thats how they are pictured by BES.

To be more correct, its the "rear" rather than the "lower" but its definately not the "bottom" . Got it?

Tony

 

[Graham81]

Thanks again guys.

I will go to my local plumbing merchant tomorrow when they all reopen and see if they have the whole telescopic section, if not see if they have a suitable o ring. I will also get some silicone grease and give the valve a good dosing.

I will let you know the outcome. In the meantime I'm staying cold and thirsty!!

 

[Graham81]

Also does any one out there have a parts and/or service manual for this boiler as it is not longer available on the website?

Thanks