2 port motorised valve question and manifold for microbore q

stuarthall · 11 Sep 2008

2 basic questions please if any of you have any advice?

1) what is the best way to clean a blocked/partially blocked microbore manifold?

2) a 2 port motorised valve (HONEYWELL) has grey as permanent live (unlike a 3 port mid position does). why is this?

am i right in thinking that with the same valve, if a room or cylinder thermostat calls for heat, the 2 port valve BROWN wire becomes live (from the stat closing/calling) which then makes the valve motor motor across, which then in turn puts power on to the ORANGE wire, which then start up the pump and boiler respectively?

I am nosey but curious as to how it actually works.

gas4you · 11 Sep 2008

Back flush the manifold, it may help.

The grey permanent live is to supply the microswitch that has the orange wire connected on the other side. This microswitch is made when the valve opens so telling the boiler/pump to work.

The valve motor is supplied via a switched live on the brown wire.

stuarthall · 11 Sep 2008

right, so the grey wire needs to be live (or the valve will not work). so when the brown wire is live (when the stat is calling), the motor motors across, and closes the auxiliary switch which puts power on to orange (to start pump/boiler). but the auxiliary switch needs the grey wire to be live to for it to open?

D_Hailsham · 11 Sep 2008

stuarthall said:
right, so the grey wire needs to be live (or the valve will not work). so when the brown wire is live (when the stat is calling), the motor motors across, and closes the auxiliary switch which puts power on to orange (to start pump/boiler). but the auxiliary switch needs the grey wire to be live to for it to open?

The auxiliary switch connects the grey to the orange. If the grey wire was not live, the boiler would not run. The auxiliary switch is not connected to the brown or blue motor wires.

gas4you · 11 Sep 2008

stuarthall said:
right, so the grey wire needs to be live (or the valve will not work). so when the brown wire is live (when the stat is calling), the motor motors across, and closes the auxiliary switch which puts power on to orange (to start pump/boiler). but the auxiliary switch needs the grey wire to be live to for it to open?

Yes, you've got it in 1

D_Hailsham · 11 Sep 2008

gas4you said:
stuarthall said:

right, so the grey wire needs to be live (or the valve will not work). so when the brown wire is live (when the stat is calling), the motor motors across, and closes the auxiliary switch which puts power on to orange (to start pump/boiler). but the auxiliary switch needs the grey wire to be live to for it to open?

Click to expand...

Yes, you've got it in 1

The implication of the bit which I have highlighted is that the grey wire needs to be live for the valve to open. This is not correct, as I pointed out earlier.

stuarthall · 12 Sep 2008

ok - a bit confused here!!!

so from what i have read and understand this is how it works:

the stat (cyl or room) calls, and the brown wire becomes switched live.

this then puts power on to the valve motor which motors across and makes the grey wire close the auxiliary switch when then puts power on to the pump and boiler.

basically, the grey wire NEEDS to be live for the valve to opne (and therefore the pump and boiler will not run/fire without the grey being live).

Also the orange (which sends the power on to the pump and boiler directly) is a switched live from the grey wire/motor?

D_Hailsham · 12 Sep 2008

stuarthall said:
the stat (cyl or room) calls, and the brown wire becomes switched live.

Correct

this then puts power on to the valve motor which motors across

Correct

and makes the grey wire close the auxiliary switch

NO! The switch closes because the motor has run and opened the valve.

then puts power on to the pump and boiler.

Correct. The closing of the switch connects the grey wire to the orange wire

the grey wire NEEDS to be live for the valve to open

NO! The motor runs and the valve therefore opens because power has been supplied to the BROWN wire. The grey wire has nothing to do with the motor working.

therefore the pump and boiler will not run/fire without the grey being live.

Correct If there was no power on the grey wire, the orange wire, connected to the boiler and pump, would not become live when the switch closed.

the orange (which sends the power on to the pump and boiler directly) is a switched live from the grey wire/motor?

Just from the grey wire NOT from the motor

Got it?

stuarthall · 14 Sep 2008

got it now !!!! thanks!

the grey wire is a permnanent live which allows the orange to become live when the switch is made (switched live) (thus putting power on to pump and boiler)!

i suppose another fault is the valve not shutting properley as the return spring may seize up or not return fully allowing the valve to not fully close and to let by?

gas4you · 14 Sep 2008

As a general rule of thumb, if something is getting heat when it shouldn't the valve body will be at fault (stuck open to some extent) and if something is not getting heat when it should it is the microswitch.

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2 port motorised valve question and manifold for microbore q

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