Aluminium or Stainless heat exchangers

[Peterhampshire1]

Hi,
I am about to buy a new combi boiler perhaps more than one for rental properties. I have listened to the merchants, sometimes the odd plumber at the counter and the salespeeps. I already have two Vaillaints with BGas maintenance agreements in rentals, now I know tennants are hard on equipment and most problems occur on change of tennant(a good indicator of pilot error), but will never buy Vaillant again just because fed up with seeing the engineer every two months. So looking for new Brand and cutting through the rubbish talked. Some have Aluminium heat exchangers and others Stainless. Seems brand/price has no bearing on this fact. Now as an old Engineer I understand all about corrosion and have a car in Portugal which has little use but Ally head, Copper rad. and steel block. Major problem and takes a lot of work to maintain. I have even changed the exhaust for stainless. So BIG QUESTION is Aluminium Heat exchanger in a hard water area a sensible solution for me and not the supplier. Seems suicide to me but consistantly recommended expensive units with Ally Heat Ex and told you get what you pay for !!! Peter PS. I have a Potterton Profile at home with traditional system plenty of fresh chems in system and is 20years still going. Your experiences appreciated Please

 

[gazdaz36]

Maybe you should question the bg engineers competance to repair the boiler than blame the boiler itself???????

Anyway back to your original question.....

It depends on the state of the water in your system and whether it is going to get flushed out properly. Aluminium heat exchangers usually have larger waterways through the heat exchanger so less likely to block.

Majority of stainless heat exchangers are manufactured by gianonni but are very sensitive to sh*t in systems.

IMO if the new boiler is going onto a correctly flushed and cleaned system with a magnetic filter on the return I'd choose stainless everytime.

 

[Peterhampshire1]

Maybe you should question the bg engineers competance to repair the boiler than blame the boiler itself???????

Anyway back to your original question.....

Thanks for input re stainless, must explain, I have open mind re BG as first call was fixed price deal from man in Valliant van. Interesting, never had a problem that was not boiler related. Good news is the cabinet and the badge are about the only original parts and can confirm never the same problem repeated. Just glad they renew the agreement every year.

However, do take point that the scrap heat exchanger is stainless but very small bore not leaking but blocked. So how do I get any reliable statistics on failures does anybody hold them???

 

[Tibbot]

. So how do I get any reliable statistics on failures does anybody hold them???

Yes, Vaillant and most other manufacturers will hold all the statistics on their failures. You could ask them kindly for a list.