Outdoor hotwater pipe insulating advice

[aido]

Hi

I have a hot water tank outside my house in the boiler house. The hotwater pipe and in a concrete block channel about 22 foot long, 6 inches deep and 9 inches wide. The pipes have regular insulation on them and the channel is covered with concreate slabs. I was going to fill the channel with sand. Before I do so could anyone offer advise on how best to approach insulation these pipes?

Help would be appriated.

[Unregistered]

25mm of a foam based pipe insulation such as armaflex should do the trick.

Seal well and bury with sand.

Note that any un-insulated pipe (such as the cold feed to the tank) must be burried with 900mm of sand to prevent freezing under all conditions but insulating it reduces the cover required.

Make sure your hot water cylinder is also well insulated.

[Unregistered]

25 mm insulation is a joke I suppose.For your issue B&Q , and other DIY shops as well ,offer 100 mm pipe lagging.This in turn has to be packed in a casing-usually ridgid plastic- because mice and other creatures love it warm and cosy as well.And if the insulation is sqeezed (by the weight of the compacted soil)it does not insulate anymore.And if it is soaked it won't insulate neither.
A boiler outside a house is a wastefull idea anyhow.Why do you go for that?Modern condensing boilers are so small and quiered that they fit under the kitchen sink,into the cupboard resp.into the attic.They fit practically everywhere.
See http://www.sedbuk.com/ for the boilers available.
Good luck!