heat exchangers on high efficiency boilers

[AlaskaFrank]

I'm replacing an old hot water heating system with a new "high efficiency" system. Weil-McLain offers a cast aluminium heat exchanger; others are stainless steel. Apparently there may be corrosion issues with aluminium, but the heat transfer is much better than with stainless steel. Is this a no-brainer?

 

[D_Hailsham]

I'm replacing an old hot water heating system with a new "high efficiency" system. Weil-McLain offers a cast aluminium heat exchanger; others are stainless steel. Apparently there may be corrosion issues with aluminium, but the heat transfer is much better than with stainless steel. Is this a no-brainer?

Hi AlaskaFrank.

This is a UK based forum, so names like Weil-McLain mean nothing to us.

The majority opinion this side of the pond is that stainless steel is preferable as it is not prone to corrosion.

I suggest you also ask your question on a US site such as Heating Help

 

[ianniann]

The thermal conductivity of stainless steel is awful, but I assume this is taken into account by making the heat exchangers sufficiently thin or suitably shaped. There doesn't seem to be any consistent difference in efficiency between boilers with heat exchangers made from different materials.