Re: Manifold/TRV actuators - 24V or 240V?

["Simon Coates" <simon@xxxxxxxxxxxxxxxxx>]

Simon,

I used manifolds for all UFH and standard radiator circuits - controlled
vi=
a HV-IO board and 240V actuators with DS1820s in each room.  One important
=
point is the positioning of the temperature senor.  My criteria was to
posi=
tion them at standard light switch height, away from doors, on a wall that
=
doesn't get any direct sunshine (ie. prevent solar gain on the sensor) and
=
not above an a source of heat (obviously not over a radiator but also not
d=
irectly above lighting).  Hope this makes sense!

I got 240Vac actuators because that's all I could get at the time (9 years
=
ago).  If I was to do this today I think I'd go with 24V actuators from a
s=
afety point of view.  Although the 240V actuators are IP67 rated ( totally
=
waterproof)  making a waterproof connection at the other end of the flying
=
lead can be more difficult.  Note that when you fill your system you might
=
have to flush out the manifold and UFH/radiator circuits to remove air
usin=
g a hose pipe.  Water is likely to spray everywhere!

HTH

Regards,

Simon
----- Original Message -----=20
From: simon_haslam=20
To: ukha_d@xxxxxxx=20
Sent: 05 November 2010 08:57
Subject: [ukha_d] Manifold/TRV actuators - 24V or 240V?


=20=20=20=20
I'm nearly at the point of finishing off my CH installation and have to s=
ort out the actuators for the 7 port manifold that will run my radiator
zon=
es.

I will be controlling the zones using a HobbyBoards 1-wire 8 channel I/O =
board (http://www.hobby-boards.com/catalog/product_info.php?cPath=3D24&prod=
ucts_id=3D1554) which has 8 relays on it, each rated at up to 60W
(0.25A@24=
0V).

I can get both 24V and 240V actuators for my manifold. I was originally g=
oing to use 24V ones as they would be low voltage within whatever
enclosure=
I find for the relay board. The 24V actuators are AC so I was planning to =
drive them from Maplin power supply (Maplin 1.5A L55BR http://www.maplin.co=
.uk/Module.aspx?ModuleNo=3D96964&OrderCode=3DL55BR).

However I am now thinking I'll need at least one 240V relay (to control t=
he boiler demand) so maybe I should have all the actuators as 240V too?
Tha=
t would be about =A333 cheaper (actuators + PSU), plus if a future owner
wa=
nted to use some other controls later (1-wire isn't very
plumber-friendly!)=
I suppose 240V is far more common and could be easily rewired. A 24V AC PS=
U would be another thing to go wrong too.

Note: power consumption is about same - 24V supply uses about 4W when idl=
e & according to spec the 24V actuators is 3VA whereas the 240V is
3.45VA. =
So for 7 valves open that's ~25W for 24V actuators and 24W for 240V ones.

What do people think? Stick to 24V and know everything is low voltage (an=
d no Part P concerns) or go for the much more common 240V?

Simon (procrastinating again!)
PS. I've posted this on Navitron too and will report back any response.



=20=20

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