Worcester 24cdi lukewarm water

[nabby68]

I have a worcester 24cdi com I boiler about 8 years old. The problem started in the summer when I noticed the hot water not getting as hot as normal but now in the winter it is only getting lukewarm .
The central heating side works fine
Any help or advice appreciated

 

[nabby68]

Any help???

 

[denso13]

Possible diverter fault. When the hot tap is running does the CH flow get hot (with the CH off)?

 

[Agile]

Probably more likely to be a partially blocked plate heat exchanger?

Tony

 

[nabby68]

Possible diverter fault. When the hot tap is running does the CH flow get hot (with the CH off?)

No the ch stays cold

 

[nabby68]

Probably more likely to be a partially blocked plate heat exchanger?

Tony

Is this easy to remove and clean?

 

[St0rmer66]

Possible diverter fault. When the hot tap is running does the CH flow get hot (with the CH off?)

No the ch stays cold

Has to be either a blocked plate or just unrealistic expectations of a 24kw boiler (but presumably you'd have realised this years ago).

 

[nabby68]

Forgive my ignorance but if the ch is hot how can the heat exchanger be blocked? Or does the heat exchanger only heat the Dhw

 

[St0rmer66]

Main heat exchanger does CH and DHW. Plate heat exchanger does DHW only (water from main heat ex heats one side, cold water goes in other side and comes out hot - the two not mixing at any point). If either main or plate was blocked you'd have hot water problems but the plate blocked only will not affect the heating.

 

[gigz]

Or it could be a DHW thermistor fault.

 

[nabby68]

Thanks for all replies. Do I need to drain central heating in order to clean plate heat exchanger?

 

[picasso]

Before you start to dismantle your boiler run a hot tap and put your hand on the hot water pipe coming out of the boiler and see if its hot, you may have a shower valve passing cold water into the hot water system.

 

[Jplumbing]

if your heating pipes arnt getting hot from under the boiler then it either blocked heat exchanger or hot water thermistor is on the blink (normally around £6) and takes 5 mins to fit, worth a try first

Change hot water thermistor (in pipe)
Turn boilers isolation switch off
turn water off
open hot tap where spout is lower then the boiler to drain the hot water out the boiler
find where the domestic hot water thermistor it located
take the two wires off it
with either a small socket set or spanner unscrew slowly and now you will find hot water tap starts to run a bit quicker
replace thermistor and repeat in reverse

Change hot water thermistor (clip on)
Turn boilers isolation switch off
find where the domestic hot water thermistor it located
take the wires of and unclip
clip new thermistor on
turn boiler back on

Simples

Thanks for all replies. Do I need to drain central heating in order to clean plate heat exchanger?

i would strongly suggest that you do NOT touch a 24cdi secondary heat exchanger unless you know what you are doing because they normally leak like a siv after

 

[St0rmer66]

You forgot the part where your hands get covered in white heat paste.

 

[Jplumbing]

You forgot the part where your hands get covered in white heat paste.

yer just after posting this i had a quick look at one and i remember the small little screw which you have got to bend open the clip, put it in, put some white paste on it , then try and bend it back round the pipe while getting covered in white paste and screwing the screw up without slipping and the screw pinging over the side of the room . Then you start again