Worcester 24cdi: low hot water flow rate

[leonlikestrees]

Hi all,

I have a Worcester Bosch 24cdi. Earlier on this year I had the hot ware heat exchanger replaced, I honestly can't remember the problem now, but it was freezing cold, the boiler wasn't working, and we had plumbers on site already due to other building works, so I just let them get on with it!

Towards the end of the building project, we finally got our kitchen back and I noticed there was a definite drop in the hot water flow rate (or maybe pressure?). Basically, before I would get bubbles when filling a bowl of hot water to do the dishes, and now I don't.

I borrowed a weir cup and measured the HW flow at 7lpm. I didn't measure the cold (which was stupid), but basically it comes out like a rocket!

The only thing that has changed since then is that I've had the lead pipe coming into my property replaced, so the cold water flow rate will have increased. Could this cause the problem?

Finally, just in case it's relevant, I've also recently changed the diaphram on the diverter. This did not affect the flow rate at all, but did give me a chance to check the flow rate reducer on the heat exchanger, which seemed fine to me.

So...any ideas on what the problem is, and how to fix it?

Thanks!

Leon

 

[boilerdoktor]

check the filter which is on the cold water feed into the diverter valve. it may be full of carp.

also on the div valve is a small nut for reducing flow, make sure it is fully open

 

[leonlikestrees]

check the filter which is on the cold water feed into the diverter valve. it may be full of carp.

also on the div valve is a small nut for reducing flow, make sure it is fully open

I cleaned the filter on the div valve when I replaced the diaphragm, but I didn't touch the nut. In fact, I don't even remember seeing it

I'll give it a go and report back - thanks for the tip.

 

[leonlikestrees]

is the nut you refer to the one I circled in the picture below?

Untitled

• leonlikestrees
• 28 May 2012
• 1

Is it possible to take it all the way off and spit water everywhere?

 

[boilerdoktor]

no its the black nipple far right of your picture

 

[leonlikestrees]

Thanks!

 

[leonlikestrees]

I undid it several turns, and there was a click. My assumption is that there is a stop to stop you removing it completely, and I had reached "fully open" already.

I measerued the flow rate before and after (crudely with a 1l jug), and there was no difference - about 10s, or I suppose about 6l per minute. The jug is slightly more than 1l to the brim, so I will guess at no change from my 7l.

Is there a way to isolate the issue? For example, if I remove the flow reducer from the inlet to the DHW heat exchanger, and put it back together, if I get mains flow rate, that is the problem, right? Or will I just break it allowing full mains flow through the system?

Thanks,

Leon