Vaillant ecotec plus 438 no heating or hot water
- Thread starter noddy997
- Start date
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Yes it does, already checked.
See post #79. and all tests carried out prior to that.
I keep asking what does the brown wire in the PCB terminal 3 do??
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At the moment it's working fine. So I can't test.
When it hasn't worked, I have heard the valve click to heating and also hot water, whichever is selected. It's a new valve head and the the spindle moves freely on the body hence I didn't do a full swap.
When it's running (heating or hot water or both) it doesn't randomly turn off.
The issue is at times, randomly, neither heating or hot water would work despite the facts stats are turned up.
Maybe prudent to connect in that indicating bulb between the PLB terminal 4 and N, at least if thats illuminated and the boiler is not firing it means that the SL is receiving 230V which logically then means a "boiler" problem.
I have got 130-150v on switch live sometimes
And I have also got 0v on the pump wire on the green terminal
In both instances the heating was turned on at programmer and stat calling for heat. At other times I got 240v but pump and boiler did not fire up.
Multimeter did flicker from 240-500v a few times too.
Spoke to a gas guy who's been on the job for 45+ years he said there must be a break in a wire somewhere.
Rads were fitted 2 months ago and pump changed then, I checked under floorboards of one room were pipes were altered and cables too far for any damage.
Checked at the wiring centre several times and everything fine and tight.
This may not be be unusual under certain circumstances.
"When this Heating demand is satisfied, during a Heating ON period, 50V to 150V (voltage can vary according to the supply) will remain on the orange wire and the valve will continue to be energisedand warm to the touch. Switching Hot Water ON or turning OFF at themains will de-energise the valve and it will spring return back to the Hot Water only position until thenext demand."
I know it may be causing no problems and (if) doesn't seem to be required but can you just disconnect the brown wire at terminal 3 on the PCB.
I can't see any reason for it based on this schematic, the * is just saying no link.
When the water goes off in the morning the heating goes off too despite the heating timing is until 930am and water 8am.
But in the evening when the water goes off at 730pm the heating stays on as it should until 9.30pm
But in the evening when the water goes off at 730pm the heating stays on as it should until 9.30pm
Multimeters are high impedance, they can measure voltages induced onto wires which are near them - so they can basically tell lies.
A test lamp connected between SL and the Neutral, will not lie. If lit, the SL is live, if not lit, then SL is not live.
Possible, but unlikely.
Heat from pipes, is very unlikely to damage cables.
Thank you.
Heating came on more than an hour later of requesting it.
It worked for 3 hours then gone off.
The bulb is lit, the switch live isn't coming on in the boiler, the one on the green terminal.
John I removed brown wire from terminal 3 and then the stat and programmer had no power. It's there to provide power to them. I appreciate the schematics say otherwise, but it has been like this for 15 years.
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So for hot water it isn't supplied? And sl would be 0v?
I was getting it before with CH only it was off, then it came on as did the boiler
No, there must all ways be 230V to the SL when the boiler is required to fire.
On HW only the valve is doing nothing, its spring loaded to the HW position only, port B, and the 230V comes from (we now know) a PL, ter.3 to the programmer and back to ter.4 the SL, via the cylinderstat, if the stat is satisfied then 0V to the SL and the valve stays where it is. When CH only is requested the valve moves fully the other way, via the cylinder stat ter.2, if not calling and a grey? wire or with HW OFF if the HW is timed off until port A only is opened, it is only in this position that the 3 port valve then supplies the 230V via the orange wire. So, if it only appears that the boiler is tripping regularly only while calling for CH only, to check this, that you atually have 230V even with a lit lamp. If the voltage is 230V then looks like a boiler fault even though strange if its only happening in the CH only mode.
The fault happens in both HW and CH, together or independently
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