Lobster wrote :
Ron Lowe wrote:

To do so, I'd have to bring the existing tundish down from about 1m high
to 30 cm off the floor (is that in itself allowed?), and add a tee into
the 22mm copper below the tundish, connected to a short vertical run
into which the 0.5" plastic drain hose from the dehumidifier would be
tucked. Diagram below.

ISTR there's regulations about the distance from the PT relief valve down
to the tundish.

tundish should be* vertical,
located in the same space as the unvented hot water storage system and be
fitted as close as
possible and *within 500mm of the safety device* e.g. the temperature
relief valve.

OK, so if I moved the tundish downwards, it'd fail the above spec, so that's
out.

Harry's suggestion about the a/c pump is interesting though - I know nothing
about them but if that worked it would mean I could leave the tundish where
it is, and interpose my tee below it. (But wouldn't the dehumidifier object
to the head of pressure on its output?)

Given that the dehumidifier spec is 10L/day, that's 7 ml/min which could
potentially already be trickling down the discharge pipe at such time when I
have my proverbial catastrophic failure, and end up with mains-pressure
boiling water (20 L/min?) pouring down the tundish (ie, ~3,000 times as much
as produced ny the dehumidifier) - ie the presence of the dehumidifier output
is totally trivial, right?

So it looks to me that providing I don't alter the height of the tundish, my
idea should be OK...???

The amount from the dehumidifier is trivial by comparison, a slow drip.
The pipe from a pump could be simply clipped onto the tun-dish.

There are various types of condensate pump with differing methods of
them being turned on...

Some simply pump all the time they have a supply, some sense when a
probe senses water (in a tray), some have a built in float switch and
require the water to be able to fill up their chamber with water
-gravity feed, some can self prime - pump situated higher than the
water level.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk