REMEHA 28c advice/comments please

[TechnicallyZero]

My Remeha 28c had a E5 error called an engineer who said it needs service. Had the service done for £75. It stopped working after few hours. Engineer came again changed electrode and burner gasket cost £100. It stopped working after 27 hours. This time called a different engineer who changed siphon tube cost £75. It worked for 15 hours and heard a bang and it stopped. Another engineer came and said that gas valve need replacing as the last person had set the settings for LPG gas (CO2 10.5 & O2 5.1) where as it should have been for ordinary gas (8.8 & 5.2) change the gas valve cost £320 but now the Engineer is saying it needs new parts costing £800 as CO2 ratio is not safe.
My question are:-

1.As the boiler is just 0ver 5 years 9 months old should I get it repaired or get a new one.
2. What part/s been damaged by LPG settings.

3. Has the engineer by setting LPG has caused the irreparable damage.

Would appreciate any advice or comments please.

 

[lame plumber]

seems the first chap may not have clean the ionization probe when he serviced it or did but it then failed. so he popped the burner out completely to check it and then needed a £20 seal and the new probe some £15-20.

second lad may have found a split in the syphon tube (fairly common), may have leaked over gas valve or something else and shorted it out. as far as settings for lpg killing a gas valve, I dont think so, just readjust it back to normal setting, not hard.

Now for new parts costing £800, forget it, you will be better off calling baxi out to repair it for a one off fee or get a new one from another firm altogether as the first few are taking the mick a bit in my opinion

 

[TechnicallyZero]

Thanks
Boiler ran under LPG setting for over 15 hours If that has not caused the damage why they are asking for £800 for parts. I think will try Baxi for one off repair. Thanks again