Greenstar 28i junior constantly resetting

[ChunkyD]

Hi

I have a greenstar 28i junior that I keep ha ing to reset when running hot water, it's fine with heating but when I demand hot water it will run for 30 seconds or so then will cut out and need a reset

If I reduce the flow on the hot water tap the hot water will run for longer and sometimes enough to fill a bath before resetting

It also works better in eco mode but again needs resetting after a while

Any ideas

 

[MeldrewsMate]

It sounds like the secondary heat exchanger may be severely restricted. Have a registered gas fitter check and remedy it.

 

[ollski]

Agreed, does the hot water tend to go hot cold hot cold before it overheats?

 

[ChunkyD]

Hi,

Yes, I get hot, cold, hot, cold then just cold

I replaced the flow turbine a few months ago and the old one was pretty disintegrated, I thought I got all the bits out but looks like there maybe some bits from that in the plate heat exchanger

 

[ollski]

No it won't be anything to do with the crumbling adaptor...that's just standard. It's a really long plate heat exchanger and they block on the primary side with fair regularity on a dirtyish system.

 

[ChunkyD]

Thanks guys,

I replaced the heat exchanger about 5 years ago so it is probably due (old rads but new boiler 10 years ago)

Can it be cleaned/flushed out or am I better replacing again

 

[muggles]

They can be cleaned if you have the right kit but it's easier to just replace them. Worth noting that you shouldn't be removing the cover on this boiler unless you're Gas Safe Registered and competent to carry out the 26.9 checks on completion

 

[ChunkyD]

Thanks muggles, I am lucky enough to have a next door neighbour who is gas safe registered so I do the work, he then checks and services that way I save a bit of money (unless I make a complete balls of it)

 

[AGAS]

Hi,

Yes, I get hot, cold, hot, cold then just cold

I replaced the flow turbine a few months ago and the old one was pretty disintegrated, I thought I got all the bits out but looks like there maybe some bits from that in the plate heat exchanger

Doubt it but the way

 

[ReganAndCarter]

If HEX is blocked it will be rust particles from inside rads. You can clean plate heat exchangers with Spirit Of Salts (acid) - just be careful and use gloves/eye protection. 15 mins in with the acid, then flush out. If done properly, it should be good as new. Sounds like you also need to clean your system and fit something like a Magnaclean magnetic filter on the return pipe to boiler. Then dose system with corrosion inhibitor.

 

[ChunkyD]

Hi guys

I have replaced the plate heat exchanger but I am still experiencing the same issue, heating runs fine but hit water runs from 30 secs up to 2 mins but then the boiler needs 're setting , any other ideas?

 

[ChunkyD]

Just another update on this, don't know if it makes a difference to the diagnosis,

The boiler stays active for longer with reduced flow, e.g. tap on half way it will fill a bath, if it's full on it needs 're setting within a few seconds

 

[AGAS]

Thought I was in cc