vaillant 837 and 937 discontinued?

[jedi]

Aluminium is an excellent conductor of heat, plus its light weight so no torn mussels for installers...

Jedi, do you know all Worcester current model are using Al hexs?

Among current models from all manufacturers, I am impressed by Viessmann stainless steel heat exchanger, similar to Giannoni but with bigger water ways.

But prices for Viessmann spares are dear!

I am aware yes, do all aluminium hexs corrode in this way? With using the correct inhibitors does this stop?

I've read that SS hexs also suffer from condensate and can crack?

 

[ScottishGasMan]

Most aluminimum mixtures will suffer corrosion at different rates, from system water and from condensate over time.

Most stainless steel do not show any notable issue with condensate and wont crack either, very very very rarely there might be one that is deffective and can pin hole causing an internal leak, but I have to say, after working on literally thousands of em, ive never seen it for myself

 

[vulcancontinental]

First Veissmann with ali now Vaillant. Both metals will continue to be used and be generally OK.

There are loads of alloys ad the Icos Isar one wasn't even listed on the register of aluminium alloys that I could find.

Not seen an ally radiator pinhole yet and it has the same water running through it. Someone is going to say they have I'm sure.

If ali fades out it will be because it is too good at condensing. You have to service them more thoroughly because they condense better (in my opinion) if there are no oxides on them they aren't condensing. Lee services them properly by clearing the drain, that's one of the things you're supposed to do on a service but often isn't. Blocked outlet and the condensate doesn't drain quickly leaving the acidity time to work.

If all this low temp running takes off big time the 15 minute FGA safety check just isn't going to cut it and you'll be lucky to get 7 years from a boiler IMO