Re: [OT] ishh central heating controls

["Gary Jenkins" <gjenkins@xxxxxxxxx>]

Just my 2ps worth :)

1) the pump. Usually the nut in the middle is used to bleed air from
the pump, as it will need priming before you use it. Let the water
in, bleed it then run the pump. Check the pump instructions, but the
ones i've used you can do an additional bleed whilst the pump is
running, but be ready for a lot of water coming out

2) The boiler- afaik only modern direct heating boilers will detect
the flow of water in order to fire (in fact its a drop in input
water pressure that it spots) but this only occours on hot water
where it is heated on demand by the boiler, i.e. no hot water tank.
Your water valves should have microswitches that report that the
valves are open to the boiler which then fires as a mains voltage
has been applied to it.

3) the valves. Personally i dislike 3 way valves ever since i spent
ages trying to work out why my cousins central heating turned off
for an hour or so when someone had a bath. the valve was both plumed
and wired incorrectly causing the system to shut off the heating
until the water tank was hot again! any way- id say you are best to
swtich to two way valves, expecially if from a Home automation point
of view- it give the maximum control. You can also use a two way
valve to shut off large areas of the house - for example i will
eventually put one in to stop heating the lounge in the mornings on
weekdays when its not used.

Word of warning though, most CH/HW systems are different- if you do
replace your 3 way for 2 two ways you'll need to review the
appropriateness of the wiring configuration. Some systems will use
a "pump run on" system to keep the water flowing round for a few
minutes once everything is shut off so the water in the heart of the
system cools down a little- and if this is the case you need a
length of pipe bettween the pump output and the return pipe with a
gated stop  cock in it. Otherwise the pump will pump against two
closed valves and the water will have no where to go- damaging the
pump.