Wiring diagram for central heating.

I have a ACL Lifestyle LP241 central heating controller and I am using three outputs, CH-on, HW-on and HW-off.

CH-on is connected through a Salus RT500RF roomstat to the CH on terminal of the Honeywell three port valve.

HW-on is connected through a Honeywell L641A1005 tankstat to the HW-on and HW-off terminals of the three port valve.

HW-off is connected to the HW-off terminal of the three port valve.

All these connections are routed through a 10 way connecting block

I am having trouble seeing how I connect the boiler and pump so they are both running when either/both hot water and heating are called for.

If I directly connect the boiler and pump, to the CH-on and HW-on terminals of the three port valve, I will not be able to control the heating and hot water independently as they will be connected together.

At the moment I have the boiler and pump connected to the heating terminal so i can only heat the water whilst the heating is on.

The three port valve is pre-wired with five wires, Neutral, Earth, CH-0n, HW-0m and HW-off.

Can anyone point me to a suitable wiring diagram?.

http://content.honeywell.com/uk/homes/systems.htm scroll down to Y plan

There is no hot water on as far as the the 3PV is concerned, there is a hot water satisfied wire though.

You should wire the NO wire from the cylinder stat to run the boiler and the pump. The orange wire from the 3PV should also be connected to this terminal.

Your NO wire from the Salus receiver should be connected to the white wire of the 3PV.

The NC and HW-OFF should both be connected to the 3PV grey wire.

Then it will work.

Thanks to both of you for your very valuable help.

My problem, apart from advancing senility, was to misunderstand the wiring of the three port valve.

Now I fully understand what each wire does I can now understand the wiring diagram.

I now have one further problem - the frost stat.

If I wire it into the connector holding the orange wire the boiler will fire and the pump rotate. However if the controller is off there will be no power to the white and grey wires the 3-port valve will be set to hot water.

Hoe can I get the frost stat to work with the 3-port valve set to central heating

Wire it to the terminal for ch on the 3 port valve rather than the orange wire, the one that comes from the room stat.

By the way you should also have a pipe stat in series with a frost stat so the boiler will only fire when the temp drops AND the return pipe is cold enough to maybe cause a problem.

Thanks gas4you, I understand the need to only have the frost stat firing the boiler if the water in the pipes is below a minimum temperature.

My questions are these.

1. What pipe (frost) stat do you recommend to switch on when the water temperature falls below a certain critical value?
2. What is the critical minimum value for the water temperature?
3. As it is the water temperature that is critical and not the air temperature in the garage why do I need a conventional air frost stat? Could i simply replace it with the pipe stat?

I will have a roomstat in the house which will fire the boiler st some (low) preset value.

What is a reasonable safe minimum temperature to set the roomstat in the house?

I fit the Honeywell, I think the lowest setting is around 10C. If you only have a pipe stat this will kick in the boiler etc every time the heating goes off and the water temp drops, possibly even in the summer

Thanks to the advice i have received here I now have a fully working system that does all I require and I now understand fully how it works.

regards

David