Expansion tanks - how high?

[Steth]

I'm flooring the loft and will take the opportunity to replace the two lidless uninsulated scum filled 16 litre expansion tanks (one for the boiler, one for the Aga).

At present, they're perched on a rickety tower. Is this necessary or can I just stand them on the loft floor? Aga and boiler are on the ground floor, loft is above the first floor. The overflows are long pipes which go up to the ridge and then double back. Again, is this necessary? Main cold water tank sits on the loft floor.

Many thanks for any info.

 

[chrishutt]

What you call the overflows are the vent pipes. The overflow pipes are the 22mm plastic ones. The vent pipes would normally extend about 200mm above top of tank.

The feed and expansion tanks only need to be higher than the highest part of the system they serve, so if you have no rads above floor below they can both sit on the attic floor.

 

[Steth]

Many thanks - that will look much neater

 

[oilman]

You don't need to replace them un less they're damaged, I just scrub them with a stiff brush, and syphon all the crud out. Block the outlet before you do though, you don't need all that stuff in the system.

 

[Softus]

The overflow pipes are the 22mm plastic ones.

To be pedantic, aren't they 21.5mm?

 

[chrishutt]

I knew someone would say "but they're 21.5mm" and I should have guessed who it would be. I thought 22mm was a reasonable approximation.

 

[Softus]

 

[Softus]

Any word from the fat b*stard yet Chris?

 

[chrishutt]

No, nothing. I expect they've got their hands full with the last minute adjustments to the new BRs for next week.

 

[Softus]

Fair point. I should have realised earlier that, judging by the tiny amount of thought that goes into them, a lot of work is being done at the last minute