In an earlier contribution to this discussion, Richard
wrote:
On 07/05/2010 23:36, Roger Mills wrote:
In an earlier contribution to this discussion, Richard
wrote:

There is a manual/automatic lever on those HP2A actuators. I wonder
if the actuators motor for heater should be disconnected, and the
lever set to manual. If that means permanently open.

You can certainly keep the valve open with the lever, independent of
the motor, but you can't rely on it moving far enough to operate the
auxilliary contacts.

Anyway, I'm just taking out the cylinder, leaving the rest of the
plumbing alone, and just have the boiler run the radiators. What
that calls for in wiring changes and any lever selection on the HP2A
actuators, I'm not 100% sure.

You still need a way of having the room stat control the boiler. If
the auxilliary contacts are not doing it as the valve opens and
closes, you'll need to connect the stat output directly to M7/3 as I
said earlier.

I think what I will do, is remove the connection at pin 1 in the SET
3E timer. Then no live will ever get to the water actuator via the
cylinder thermostat. You don't want a demand for heat and the valve
closed on the cylinder pipe circuit.

Setting the switch to water of course will do nothing. But that is
okay.
So, when the room thermostat closes, the heater actuator will open,
and close the auxilary contacts, producing a demand for heat, as is
normal.
I think that is the solution.


Yes, that will work. But you originally said that you wanted to remove the
valves altogether. Then you changed that to leaving the CH valve in place
but jacking it permanently open - and I was responding with how you could
achieve either of these from a wiring point of view.
--
Cheers,
Roger
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