Glow worm 30ci hot water problems

[swapz]

hi newbie here so please go easy....
have a gloworm 30ci over 7 years old
hot water has been patchy CH is fine
had a couple of plumbers in who say it will be 600+ to repair n might as well get a new boiler installed 2000+
am a bit reluctant as apart from patchy hot water its been perfect

already seen posts here looks like possible heat exchanger issues
the pressure reads consistently high at 5.5 to 6.5 when CH on but when turning on hot water goes down to 1.3-1.5 as long as hot water is running
goes back up immediately when hot water switched off
hot water varies between cool(not cold) to luke warm to warm
also has a very slight knocking noise when DHW is switched off
some posts here suggest diverter valve probs but manual only has follwoing options -three way valve head or three way valve actuater or bypass valve
which is it please
here is a link to manual
http://www.solvgroup.com/uploaded_files/File/GLOW_WORM_30_&_35ci_UIS.pdf
also found the new plate heat exchanger for 110 £ online within 2 mins
got quoted 300+ to buy n labor extra
also do combis have 2 heat exchangers ie one for CH in closed loop and plate heat exchanger for DHW
thanks a lot in advance and apologies for long post but considering that i am asking for ur time to answer this i thot it would b best to give all possible info

 

[elecguy]

Hi,
The pressure seems ver very high. Is the copper pipe (normally on the outside wall where the boiler is) dripping water?

once the pressure reached 3bar it should release its pressure. When running a hot tap, do you have any fault codes flashing on the front of the boiler?

cheers
Andy

 

[swapz]

What intially happened is one day the boiler started making a lot of noise and dumping a lot of water outside
In came local plumber and he fiddled with it to make it way it currently is
Problem is i wasnt home when this happened and i dont kno what he has done
Me thinks he may set the PRV to release only at really high pressure if thats possible at all (unlikely as that wouldnt b safe)
No fault codes sorry as this is not the 30ci+ version which shows codes
Just has a very small 1cm square window which shows pressure thats it

Could it b a prob with expansion vessel ie. pressure too high so when DHW starts it lowers becos the pressure is normal within seconds of starting DHW

 

[Agile]

It sounds as if you have several issues.

But they are all repairable and I would have expected the cost to be in the range £150-£300.

I dont rate them as one of the best boilers but properly maintained they are capable of reasonable service.

The bigest problemn is they are sold cheaply and so they are installed cheaply without properly cleaning the system.

Tony

 

[swapz]

Thanks Tony
What kind of symptoms woulda expansion vessel problem result in ie could it b high pressure
Anyways plan to get the gloworm guy in becos
Local guy just wants to sell a new boiler

 

[popeye2755]

the pressure reads consistently high at 5.5 to 6.5 when CH on

Read more: //www.diynot.com/forums/plumbing/glow-worm-30ci-hot-water-problems.310666/#ixzz1lIzcdg00

Are you sure that's not the central heating temperature?

 

[swapz]

Thankyou thanks many thanks popeye
Have some spinach on me
U r right
Its temp display not pressure
I am an idiot
So when Ch is on it shows temp which varies bet 5.6-6.6 and when u switch DHW on it shows press which is around .8 bar
That does mean my expansion vessel is ok
Right ????

 

[elecguy]

exapnsion sounds fine, a simple way to check is. with all demands off and the boiler cold note the pressure (in your case 0.8) pop the boiler on heating for 15mins half an hour turn the heating off and look at the pressure again, as a very rough guide i would not expect it to have exceeded 1.8bar.

back to your hot water then....

 

[elecguy]

you will still have fault codes in the display, while the hot tap is running check the display if it begins to flash alternatley between F & 14 then again i would suspect early signs of the plate to plate blocking. If the plate to plate is beginning to block you will have noticed the HW performance dropping of over time. if its just suddenly happened i would start to look else where and again if there is no fault codes.

pop the heating on and the display will show temperature, while the heating is on run a hot tap, check the display again and see if its showing temperature still or bar pressure. and let us know.

 

[Agile]

On a normal system the pressure should not increase by more than about 0.3 Bar.

If your "local guy" just wants to fit a new boielr then thats usually because he does not know how to do repairs and prefers the big money jobs like boiler installations.

You need someone who specialises in repairs and I expect there are probably 400-500 within 10 miles of you!

Tony

 

[swapz]

Hi guys
Thanks for all ur advice
I have run the DHW with heating on
Doesnt flash any codes even after running for 15 mins
Just shows pressure varies bet .8 to 1.1 bar
I have managed to find another guy who came n saw n said its either diverter valve or pcb
The old guy just wants to do a new boiler
There hasnt been any steady decline in DHW heat just all of a sudden
Only thing that was different was i switched the boiler off for a couple of days when i went away which i dont normally do
When i came bac it was ok but 2 days later sudden crash
And would have gone for new boiler but i have a strong gut feel its not major tho i am no expert
Slowly turning into one tho

 

[swapz]

Final update
Gloworm guy sorted it
Blocked DHW heat exchanger 2000802024
He also changed cartridge of diverter valve but it looked ok just a little scaly
Real happy with gloworm repair n 1 year cover at 300£
Great service n no exclusions on certain parts that my need repalcing
Only wont do it if beyond economic repair
Vs BGas which is £300 and quoted 350 extra for parts mot covered n stil wasnt sure whether he can fix it
Signing offf
Cheers for all ur help