Vaillant ECOmax VUW 236 EH Instructions For Installation And Servicing page 31

•
S.17 - pump overrun
(display duration: 20 secs to
80 secs)
•
S.0 - no water demand
By stepping correctly through these
codes the boiler has demonstrated
correct functioning for DHW.
To exit from status mode push the right
hand button once. (The display will
now show the primary flow temper-
ature).
5.11.3 Functional check of CH
operation using built in
diagnostics
•
Set the boiler central heating con-
trol to the `Heating and Hot Water'
position.
•
Enter status mode by pushing the
right hand diagnostic button once,
e.g. with the tip of a ballpoint pen
(1, fig. 43). The display should
now show `S.0'
•
Turn on all external controls (room
thermostat, timer etc.) and turn
maximum radiator temperature
control to `9'
•
The display will now step through
the following codes:
•
S.1 - fan running and proving
(display duration: 4 -5 secs)
•
S.3 - ignition
(display duration: 10 secs max)
•
S.4 - burner operation CH
(display for duration of CH opera-
tion)
•
Turn the external heating controls
off. The burner should be extinguis-
hed and the display will now step
through the following codes:
•
S.5 - pump and fan overrun
(display duration: 5 secs)
•
S.7 (pump overrun)
(display duration: 20 secs to
5 mins)
•
S 30 (external controls satisfied)
•
Turn the external central heating
controls on. The following code will
now be displayed:
•
S.8 (anti-cycling `economiser'
engaged)
(display duration: 5 mins)
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