gas boiler control wiring query--2 port valve

[thomaspatton]

Hi all. I have googled in vain regarding my wiring problem. I am converting a solid fuel system to gas. It requires the installation of 2-2 port valves usual 5 wire set up-a CH/HW 7 day programmer and a cylinder stat. Unfortunately the wiring instructions for the gas boiler are vague in one vital area-----------connecting the programme controller to it. The boiler is a Glowworm Energy Saver 40 it must be supplied with its own power supply on connectors L and N and it needs earthed. There are 4 other connectors 1-PN-PL and SL. The instructions state---------Any external controls must only be connected to interupt the Red Link between terminals 1 and SL------I am baffled. The control power is fed by the permanent live grey wire through the microswitch? on one/both of the two port valves via the orange wire to the boiler when one/both of the valves is opened.

Am I correct in thinking the Red Link must be removed and the control power be applied via the orange wire{s} to either 1 or SL--------if so which one?.

The pump is fed power from the boiler-but-the two port valve wiring shows the pump powered from the valve[s] also---------is this necessary---the boiler has a pump over run circuit. Looking forward to enlightenment tam

[dennis]

Without a diagram I would say that you remove the red link and connect the end switches on the valves in parallel where the link was. It is probably a low voltage control circuit but without a diagram its hard to tell.

[David Hansen]

On Thu, 14 Feb 2008 07:47:34 -0800 (PST) someone who may be [e-mail] wrote this:-

I would be inclined to disregard the valve diagrams.

When on the programmer should send electricity to the thermostats for the hot water and heating. This allows the programmer to turn things on and off, either under programme control or when the manual controls are operated.

If the thermostat(s) are calling for heat then this should send the electricity on to the motor for the appropriate valve. This allows them to switch the things they control on and off as necessary.

The auxiliary contacts on the valves should send electricity to the boiler, so it will only fire if one or both valves are open.

The boiler should power the pump, provided there is somewhere for the water to go if both valves are shut such as a differential bypass valve or towel rail. The boiler can then turn the pump on and off as it sees fit.

Older Glowworm boilers did have a link in their terminal strips. In essence removing this meant one had to have a permanent live supply to the boiler. With the link in place it took electricity from the switched live terminal to the permanent live terminal. With the link in place the boiler would not control the pump, which would be activated by other means and thus there was no pump over-run. No idea if modern ones are like this.

[Roger Mills]

What you are installing is essentially an S-Plan system - but with some modifications which I will detail later. Your starting point should be the S-Plan wiring diagram shown in

Unfortunately the wiring instructions for the gas boiler are vague in

L, N and E are pretty obvious. PL and PN are the live and neutral connections for the pump - which must *only* be connected to the boiler, and not as shown in the Honeywell diagram. SL is switched live - which is the demand for the boiler to fire. I assume that '1' provides a live output. With a link between 1 and SL, the boiler will fire all the time. If you replace the link with a switch, the boiler will only fire when the switch is closed - which is what you want. The 'switch' in this case is the two secondary microswitches in the zone valves, wired in parallel. So the grey wires from both valves need to go to '1' on the boiler rather than 1 in the wiring centre. The orange wires need to go (via 10 in the wiring centre) to SL on the boiler, rather than L. As noted earlier, there must be no direct connection between 10 and the pump.

Yes, as described above.

Yes, as above. [It doesn't matter in absolute terms which is grey and which is orange - it's just a switch, but it's easier to understand if you stick to the way I suggested]

Covered above.

HTH!

[ARWadworth]

plan is the diagram you need to get started.

The PL and PN terminals on your boiler are to supply the pump (pump live and pump neutral) as opposed to the diagram (where the pump and boiler run together) as this will allow the boiler to have pump overun.

A quick look at the online manual of your boiler confirms that it states "Any external controls must only be connected to interupt the Red Link between terminals 1 and SL."

Easy.

Use the grey and orange wires from the 2 two port valves to do this. Connect grey wires to 1 on the boiler and orange wires to SL. Remove the grey wires from permanent live.

Adam