Glowworm 38cxi how water problem

[FlameSafe]

Hi everyone,

Im a gas safe registered engineer who is kind of new to the whole gas industry. im having trouble with a boiler and wondering if anyone could throw some suggestions my way, i've got a few ideas but need a second opinion. Basically for example if i run the bath tap and fill up the bath, first nice hot water will come out until the bath is just under halfway full, then it goes real cold and stays that way for about 3 or mins, at times longer, then slowly the hot water will come back, but by the time the bath is full its kinda to cold. The same thing happens in the shower as it is not electric. i thought it may either be the diverter valve or maybe scale build up in the heat exchanger. ive heard about a washer somewhere in this boiler that may need cleaning also. but know no info on this, but i didnt want to check any of these just incase i end up having to replace it and the issue is still there, so thought id ask around on here first.

any ideas anyone? its my girlfriends parents boiler so trying to sort it asap.

looking forward to your replies,

Thanks.

 

[diamondgas]

:welcome: FlameSafe 🙂 .. Despite you being gas safe registered I thin you need someone more experienced to help you out 🙂 Seriously your post borders on my mum posting 🙂

 

[FlameSafe]

thanks for your help, just what i need to hear. i know all that already hence why im on here asking for help otherwise i wouldnt be, and i wrote it that way to make it clear and to be polite!

 

[M.Joshi]

Possibly an overheat cut-out is activated after a few minutes. I would have thought that if there was scale build-up in the secondary heat exchanger, you'd continuously see a reduced hot water flow?

 

[desrob]

Hi everyone,

Im a gas safe registered engineer who is kind of new to the whole gas industry. im having trouble with a boiler and wondering if anyone could throw some suggestions my way, i've got a few ideas but need a second opinion. Basically for example if i run the bath tap and fill up the bath, first nice hot water will come out until the bath is just under halfway full, then it goes real cold and stays that way for about 3 or mins, at times longer, then slowly the hot water will come back, but by the time the bath is full its kinda to cold. The same thing happens in the shower as it is not electric. i thought it may either be the diverter valve or maybe scale build up in the heat exchanger. ive heard about a washer somewhere in this boiler that may need cleaning also. but know no info on this, but i didnt want to check any of these just incase i end up having to replace it and the issue is still there, so thought id ask around on here first.

any ideas anyone? its my girlfriends parents boiler so trying to sort it asap.

looking forward to your replies,

Thanks.

your first sentence says it all ,the industry is verging on been a joke.nothing personal

 

[diamondgas]

thanks for your help, just what i need to hear. i know all that already hence why im on here asking for help otherwise i wouldnt be, and i wrote it that way to make it clear and to be polite!

So why say your gas safe registered ?

 

[desrob]

Hi everyone,

Im a gas safe registered engineer who is kind of new to the whole gas industry. im having trouble with a boiler and wondering if anyone could throw some suggestions my way, i've got a few ideas but need a second opinion. Basically for example if i run the bath tap and fill up the bath, first nice hot water will come out until the bath is just under halfway full, then it goes real cold and stays that way for about 3 or mins, at times longer, then slowly the hot water will come back, but by the time the bath is full its kinda to cold. The same thing happens in the shower as it is not electric. i thought it may either be the diverter valve or maybe scale build up in the heat exchanger. ive heard about a washer somewhere in this boiler that may need cleaning also. but know no info on this, but i didnt want to check any of these just incase i end up having to replace it and the issue is still there, so thought id ask around on here first.

any ideas anyone? its my girlfriends parents boiler so trying to sort it asap.

looking forward to your replies,

Thanks.

try gas pressures,i've just had thread not approved,for pointing out ops first sentence

 

[desrob]

goodnight.

 

[JAP&H]

Is the appliance located in a known hard water area?

Could be fouled primary and/or DHW heat exchanger.

If water not free to circulate the primary thermistor can close the gas valve, pump and fan continue.

Once cooled, burner relights.

System cleanse may be in order.

 

[FlameSafe]

Because i am, and it would look stupid if im trying to fix someones boiler and im not gas safe as that would be wrong, surely everyone knows that.

fairly simple really!

thank you everyone for all of your more sensible answers, youve helped alot. 🙂

 

[jtsplumbing]

Hello Flamesafe and :welcome: The early CXi range had a problem with flow sensor, check that when water starts to run cold do's the LCD display show bar pressure insted of temp if so sticking flow sensor, easey part to change also wile water is off remove & clean inlet filter on cold water.

 

[FlameSafe]

thanks for the reply, i will defo check everything everyones said, the flow sensor did come to my mind, but now you have said it i shall check it along with everything else.

thank you

 

[jtsplumbing]

Hi Flamesafe do you have installation / fault book that came with boiler ??

 

[FlameSafe]

Hi Jtsplumbing, i have just this minute got the installation book. so im planning to take a look at the fault finding section.
Anything else i should be looking for?

 

[jtsplumbing]

No it explains it all quite well in book, Good luck with it.

 

[FlameSafe]

great, thank for your time and help. very much appreciated.