Giff wrote:

I've just replaced the timing unit for my Vaillant combi boiler as its
never worked properly since I moved in. What I expected to happen is
that when the timer is set to ON, the heating/hot water will come on
(providing its selected on the boiler itself), when the timer is set
to OFF, only the hot water will be available.
Unfortunately, this isn't the case. It looks like the zone valve isn't
working in the boiler. (I've checked and made sure that the timer
works correctly).I do know that when the Vaillant engineer came to
look at it prior to me moving in, he couldn't get the timer working
and therefore "wired it direct" whatever that means.
I assumed that this meant he'd bypassed the timer although now I
suspect he also bypassed this within the boiler.

Does anyone know how I get round this? Is it safe for me to go delving
around inside the boiler itself?

1) You don't happen to have a wall mounted thermostat anywhere?

2) All vaillants require a connection between terminals 3 and 4 to run
the heating.
This applies to Sines, VCWs, & Turbomaxs.

It's mains powered electrical appliance no more dangerous (less
actually) to delve into (electrically) than a toaster.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Giff wrote:

Ed Sirett wrote in message ...


Generally there is LN&E and another three terminals marked 3,4&5.
Heating 'go' is done by connecting the mains on terminal 3 to terminal
4, terminal 5 is an extra neutral for devices that need it.

External timers go in series with the thermostat.

Just opened it up. Looks like the guy who came to fix it actually
disconnected the wires from the timer that would control the on/off
heating. What he's done is put a loop between pins 3 and 4. I assume I
could remove that loop, add the L from the heating control into 4, the
N into the same mains N connection. This should mean that the power to
the heating should only come on when the switch is made on the timer.
Is this right? I know I'm probably asking some daft questions but I'm
a bit of a first timer at boilers.
Thanks for your help

The 3,4 link should mean the boiler runs the heating all the while (when
the summer/winter switch is put to

This is very basic electrics really: if 3 is connected to 4 the boiler
runs the heating.
You might well find that simply connected the mains to 4 will also do
the same, but is best avoided since you might get odd effects.
If you want thermostat as well you will take the switched output from
the timer and connect to terminal 4 via the thermostat.

The timer should get its power from the L&N direct from the mains and it
should conect 3&4 togther to make the heating run.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Thanks for you help. I've wired it all up and the heating is now switched by
the timer.

The only strange thing I've found is that when I switch the heating on with
the timer, I can hear the boiler fire up and you can see it light. When I
switch it off, the heating switches off but the boiler is still making a
noise. Sounds like a fan but the fan isn't on. If I switch the heating off
using the switch on the boiler then the noise goes likewise if I turn the
hot tap on and then switch it off, the noise goes.

I know I didn't add this earlier but is Vaillant is a Turbomax if thats any
help.

Anyone out there know what the problem might be?

Andy

"Ed Sirett" wrote in message
...
Giff wrote:

Ed Sirett wrote in message
...


Generally there is LN&E and another three terminals marked 3,4&5.
Heating 'go' is done by connecting the mains on terminal 3 to terminal
4, terminal 5 is an extra neutral for devices that need it.

External timers go in series with the thermostat.

Just opened it up. Looks like the guy who came to fix it actually
disconnected the wires from the timer that would control the on/off
heating. What he's done is put a loop between pins 3 and 4. I assume I
could remove that loop, add the L from the heating control into 4, the
N into the same mains N connection. This should mean that the power to
the heating should only come on when the switch is made on the timer.
Is this right? I know I'm probably asking some daft questions but I'm
a bit of a first timer at boilers.
Thanks for your help

The 3,4 link should mean the boiler runs the heating all the while (when
the summer/winter switch is put to

This is very basic electrics really: if 3 is connected to 4 the boiler
runs the heating.
You might well find that simply connected the mains to 4 will also do
the same, but is best avoided since you might get odd effects.
If you want thermostat as well you will take the switched output from
the timer and connect to terminal 4 via the thermostat.

The timer should get its power from the L&N direct from the mains and it
should conect 3&4 togther to make the heating run.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Giff wrote:
Thanks for you help. I've wired it all up and the heating is now
switched by the timer.

The only strange thing I've found is that when I switch the heating
on with the timer, I can hear the boiler fire up and you can see it
light. When I switch it off, the heating switches off but the boiler
is still making a noise. Sounds like a fan but the fan isn't on. If I
switch the heating off using the switch on the boiler then the noise
goes likewise if I turn the hot tap on and then switch it off, the
noise goes.

Our combi (not a Vaillant) does this too, and the noise is from the central
heating pump. Even if we switch the CH off, the pump keeps on running.
Using a hot tap will always shut off the CH and the pump on our system, and
this is why the noise stops if we turn a hot tap on for a second or so.
Maybe your system has the same logic.
--
Richard J.
(to e-mail me, swap uk and yon in address)

Known as overrun & takes away residual heat from the core while the burners
and body cool down.

Steve


"Richard J." wrote in message
...
Giff wrote:
Thanks for you help. I've wired it all up and the heating is now
switched by the timer.

The only strange thing I've found is that when I switch the heating
on with the timer, I can hear the boiler fire up and you can see it
light. When I switch it off, the heating switches off but the boiler
is still making a noise. Sounds like a fan but the fan isn't on. If I
switch the heating off using the switch on the boiler then the noise
goes likewise if I turn the hot tap on and then switch it off, the
noise goes.

Our combi (not a Vaillant) does this too, and the noise is from the
central
heating pump. Even if we switch the CH off, the pump keeps on running.
Using a hot tap will always shut off the CH and the pump on our system,
and
this is why the noise stops if we turn a hot tap on for a second or so.
Maybe your system has the same logic.
--
Richard J.
(to e-mail me, swap uk and yon in address)

Steve Moore wrote:

"Richard J." wrote in message
...
Giff wrote:
Thanks for you help. I've wired it all up and the heating is now
switched by the timer.

The only strange thing I've found is that when I switch the heating
on with the timer, I can hear the boiler fire up and you can see it
light. When I switch it off, the heating switches off but the boiler
is still making a noise. Sounds like a fan but the fan isn't on. If I
switch the heating off using the switch on the boiler then the noise
goes likewise if I turn the hot tap on and then switch it off, the
noise goes.

Our combi (not a Vaillant) does this too, and the noise is from the
central
heating pump. Even if we switch the CH off, the pump keeps on running.
Using a hot tap will always shut off the CH and the pump on our system,
and
this is why the noise stops if we turn a hot tap on for a second or so.
Maybe your system has the same logic.
--
Richard J.
(to e-mail me, swap uk and yon in address)

moved from top post
Known as overrun & takes away residual heat from the core while the burners
and body cool down.

Steve


The length of time this happens for is adjustable. See the installation
and servicing guide.

ON Turbomax+ models (leds + digital temp display) its done by changing a
setup number in the control computer.
On plain Turbomaxs (ladder of Leds) the manual simply says it is
automatic (and gives no indication whether it is adjustable or not).

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html