Worcester 30CDI - hot water issues

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Hi all,

Just looking for some advice on my boiler. The issue I have is that for some reason my boiler (Worcester 30CDI) is providing only warm water even though the central heating is piping hot.

Situation I had yesterday was that from the shower the water was warm and when I switched the bath tub taps on the water was quite hot and was so for about minute.

The change in the temperature in the water has only happened recently.

On the actual boiler settings i have always had the water function set to off and the when hot taps are on you can hear the boiler kick in, granted it takes few secs for the hot water to pump through. Like I said I have not changed this in over 2 years so why the water is coming out warm now I dont understand.

I have though set the water settings on 'on' and taken off the eco mode, something i read else where on this forum. its helped a little but more or less same issue.

any advice on anything else i can try/ what the issue is? do i need new parts etc and how much am i looking at!?!?

Cheers

Mike
 
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Does the central heating flow pipe get warm , with heating off and hot water running?

If so then the diverter valve is on its way out.
 
Hi Linky.

Thanks for the reply.

Do you mean flo pipe to the actual heater? or is this in the boiler?

how much does this diverter value cost?

thanks
 
Sounds like a blocked plate HX, or backflow.

What's the hot water like at the kitchen sink.
 
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its just above warm. around 1 week ago i couldn't even put my hand under there and would have to mix in cold water.
 
Does the boiler switch on and off when you run a hot tap?
 
Yes but does it switch on and off in a cycle when the hot tap is on?
 
yes it does. just listened to it and when the tap was on the boiler was active and when turned off the boiler switched off. water is coming out little warmer now for some reason. not changed any setting though
 
I still think you have missed what i said, turn on the tap and leave it running, go to the boiler and watch what happens does the boiler switch on and off whilst the tap is open?

Now i am not an RGI or a qualified plumber, however i had a similar issue with my Worcester 28CDI, and that was a blocked plate exchanger, exact same symptoms, the other thing was i could get hot water, but only with the tap partially open, and still the boiler would cycle.

When was the boiler last serviced and is there any inhibitor in the system? If the plate exchanger is blocked you may have other crap in the system, so just changing it may only solve the issue short term.

I changed mine, then ran X400 in the system for 6 weeks before doing a mains water flush of the whole system, followed by a refill and new inhibitor. It now works like a dream. I also chnaged the diverter valve diaphragm at the same time as they are an absolute cow on the 28CDI.

I would get someone in to diganose the fault correctly, unless you have a multimeter with a contact temperature probe, in which case you could try and diagnose the fault yourself.

Here is my original post and the advice given, you need to measure the temp of the flow and return through the exchanger, any more than a 15 deg difference could indicate a blockage.

//www.diynot.com/forums/plumbing/worcester-28cdi-hot-water-problems.299152/
 
When the hot water tap is running and you have luke warm water as you describe, what is the primary temperature? This is shown on the display.

If it's very high (80+) you have a blocked plate heat exchanger.

If it's low (50-) there is either an electrical issue, sensors, PCB etc or crossflow from a faulty mixer tap orshower etc...
 
thanks for the replies everyone.

Andy- ok, my wife was washing the dishes for around 10-15mins. the digits on the boiler first showed 49. as the washing continued it crept up slowly to 55. By the time the mrs stopped washing it was on 61. When someone is having a shower its running at 69 and very slowly going up (on 70 now and shower finished). Hope this helps?


maxsys - the boiler remains constantly on when the tap is running. i will read your post and come back to you and i think you might be correct where you say i might need to get correct diagnostic on this.

again thanks for your help!!
 
Feel the mains hot water pipe as it comes directly out of the boiler and compare it with the temperature at the taps.

Also, turn off the cold mains into the boiler and open a near-by hot tap, there should be no flow of water from it except residual water in the tap.
 
an old thread I know but........
I returned from a weeks holiday and found the heating worked but i had no hot water and after trying to light 3 times would trip into fault.... after 3 hours of tinkering. googling, tinkering, reading the manual and tinkering some more I was already to admit defeat and was busy searching for a recommended heating engineer.
Then i remembered an old adage keep it simple stupid ( KISS )
I checked the gas meter and shut off valve and discovered the wife had thrown all the walking boots under the stairs and had inadvertently half shut off the gas thus limiting the amount of gas being supplied to the boiler.
opened it up fully
wooosh
hot water on tap.
Happy days.
 
start with the basics but don't worry everyone can gets caught out with that if they say different there fibbing , unless they cover the basics first of course .
 

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