Glow-worm Flexicom 18 sx 'No demand for water/heating'

[Mark Coverdale]

Hello there,

I have a Glow-worm Flexicom 18sx boiler which has stopped working while we were on holiday.
I.E. everything seems fine with the controls & bolier but there is no longer hot water or heating on demand.

Now, as we were away, obviously nothing has changed, so I've tried to diagnose the problem myself and have got so far:

There is no error code message on the boiler.
A 'status' report shows s30, meaning there is 'no demand' for heating or hot water.
The 3 port valve seems to move as it should.
I had a quick look at the diagnostic reports and could see nothing wrong other than the 'no demand' problem.
All heating controls are on and seem to work as normal.
I have changed the 'Assembly housing' unit for a new one for no effect.
The pump seems fine, i.e. I turned the screw on the front and clean water started to seep out.

The only thing that seems strange to me (though I can't see how it would change just by being away for 2 weeks) is that if I test the room stat with a circuit tester, it appears that there is no power to the unit, which doesn't make sense to me, not being a plumber. However, that doesn't explain the lack of hot water on demand...

Can anyone help?

Thanks in advance.

 

[mogget]

Have you got a multimeter that you can use safely?

If so check between the orange wire from the 3port valve and neutral, when your timers are on and stats on maximum.

If there's 240v then the problem is toward the boiler side of the test point, if 120v or lower problem is on the controls side.

Bear in mind that the colours of the wires at the thermostat do not necessarily correspond with the functions of the wires. It's quite common for the earth core to be used as a switched live for example.

You could also remove the wiring plug from the bottom of the boiler and check for 240v switched live - neutral there. Bear in mind these plugs are a little fragile though and need to be removed carefully.

 

[Mark Coverdale]

I have. Could I get a clue which setting to put it on?

Thanks though mogget, that is very helpful. I shall try that first and let you know how I get on.

Much appreciated.

 

[mogget]

Any ac voltage setting above 240v, mine I use 600v-ac for checking mains voltages.

Be sure that the leads are in the voltage connectors on the multimeter, not the current (a) ones if it has unpluggable leads!

Be careful as it's mains voltage and can kill if you let it go through you.

 

[Mark Coverdale]

Thanks, I shall proceed with caution...

 

[Mark Coverdale]

Hi, I followed you instructions, putting the leads to the orange and neutral as indicated on the picture with those helpful blue arrows:

But there is no reading, even if I change from 500 to 200...

 

[Mark Coverdale]

When I slide the switch on the 3 port valve then turn the power off, the switch moves backwards of it's own accord, so there must be power to it, right?

 

[mogget]

How did this fault start? Was it just sudden loss of heating and hot water at the same time?

I will assume that you have a two channel programmer, a room stat and a cylinder stat.

If so, do you have 240v at the programmer supply and does the programmer appear to be working as normal? It would be unusual for both stats to fail at once.

Either way, could you please tell us which controls you have,

By the way when you call for hot water only, the output from the programmer passes through the cylinder stat and energises the orange wire directly. Hunch says programmer failure at this point, but need to confirm.

The valve is spring loaded so the lever will move back if no power, unless hooked in the slot.

 

[mogget]

By your last post do you mean that the valve is holding position while the power's on and springing back when power is switched off?

 

[Mark Coverdale]

We went away on holiday, so the heating or hot water wasn't used for 2 weeks. My parents stayed at the time, but only used the immersion for hot water. When we came back, neither hot water or heating worked.

Here are my stats:

 

[Mark Coverdale]

Yes, when the power is on, the switch is at the back, then I can move it and 'lock' it forwards and it stays. When the power is off, it moves to the back.

 

[mogget]

That would suggest that the grey wire shoud be live.

You could take the programmer off its back plate, and bridge L-hw off and L-heating on. This should bring the heating on provided that the valve and room stat are working correctly. There'll be a wiring diagram on the back of the programmer.

I probably don't need to tell you there'll be 240v in there unless the power's turned off.

Hw off should energise the grey wire (hold in last position)

Heating on should energise the white wire via the room thermostat (motor valve to heating position and in turn, energise the orange wire).

 

[Mark Coverdale]

Just to clarify, when you say bridge, you mean connect the two accross inside the programmer with a piece of wire? (sorry for the stupid question)

 

[mogget]

Yes, sorry for not being clearer. Just about any piece of cable or flex will do for this purpose, providing it will fit in the terminals.

Alternatively you could make a note of where the heating on and hw off wires are (or take a photograph) and pop them both in the live terminal with the live.

 

[mogget]

BTW don't put the programmer back on with the bridges in place!