If you part with £500,000 you can own a brand new good sized 3-bed room
2 reception mansion flat in North London.
You would of course expect that the whole building was built well with a
high specification of fittings and fixtures.
The specification on paper is fine: Gas powered CH and unvented mains HW.
For that money I would have wanted underfloor heating but what the hell.
1) All the radiators are fed from 10mm plastic micro bore which emerges
through the plaster-board behind each rad. The pipes are fed from the
ceiling void. No problems with this except the radiators are not under
2) The boiler is a Potterton Suprima. Architects usually specify these
since they have not updated their estimation from the old days of
Neataheats and Profiles, anyway they are fixable (its supply pipes are fed
from the inaccessible ceiling void also).
3) The airing cupboard has all the rest of the gear in it.
The controls are S-plan but the resistance through the HW coil relative
to the 10s of metres of 10mm microbore is zilch so effectively the system
is HW priority. Is this a feature or a short coming?
There is a drain point on the HW indirect coil which is the lowest point
(except for each of the rad valves).
4) The designer/installer has obviously bought into the 'self-balancing
properties of Microbore' school. No probs, the TRVs will likely come to the
rescue to cure the luke warm rads at the ends of the flat. :-;
5) The 'smart' bypass valve is fitted in the wrong direction (so no water
will flow through it no matter what it's set to). Which will tes tout the
boiler overheat function :-;
6) The filling point is out of reach above the HW cylinder (Santon) and them
some. To add any water requires taking out the airing cupboard shelves and
then using some steps. The customer asks me to make it easier for them.
No problem I think. Here begins my downfall.
The draining and the plumbing went exactly to plan. The problems came on
refilling. The pump pumps downwards and air rises upwards, if the
installer had done any of the following I might have spent a bit less time
trying to refill the system.
A) Put the pump so that it pumps upwards (air/water would get pumped into
the rads and the air would get out somehow).
B) Add auto air vents above the boiler or the airing cupboard.
C) Add manual vents accessible through a little hatch to bleed the air.
After struggling with it for somewhile (trying to get the pump to feed 1
rad at a time) I ran out of time and had to go back later. I was tempted
to reverse the pump ( but the boiler and zone valves would have probably
In the end I had to take the pipe above the pump and cut out a section and
replace it with 3 sides of a square (see below). The outside top corner was
a T going up into a piece of pipe with a manual air bleed at the top. This
worked just well enough to let me get home.
! x Bleed
Please reconcile "You get what you pay for" with "Price is no indication
Ed Sirett - Property maintainer and registered gas fitter.
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