On 2007-11-30 16:25:58 +0000, said:

How safe is it to fix a boiler of about 45Kg to a breeze block wall?
The manual states simply to fix it on a strong wall.
Breeze blocks are widely used for external wall (on the inner leave at
least), so I'm assuming it is safe.
Perhaps it is better to use suitable plugs...

Any suggestions?

Yes you can.

Keep in mind that the weight is predominantly in a downward direction.

You can use heavy duty long fixings suitable for the material.

I used polyester resin fixings for mine. This technique involves the
use of threaded studs of a diameter suitable for the holes in the
boiler mounting bracket, and of a length of (say) 100mm. Holes are
drilled into the wall 2mm oversize for the studs and cleaned out.
A special two part resin with one part containing mortar is injected
into the holes and the studs inserted. After a suitable time
(minutes to hours depending on resin and temperature, the bracket can
be fixed to the wall.

This method is ideal for heavy weights on breeze blocks because there
is not the risk of crumbling around the fixing.

Screwfix among others sell the materials