Worcester 26CDi XTRA Installation And Servicing Instructions page 38

If heat
demand has
occurred in
last 30
minutes
Within four
minutes of
last hot water
demand
AND
AND
primary
temperature
If heat
above 80°C
demand has
NOT
occurred in
last 30
minutes
No demand
and primary
temperature
below 8°C
Internal
Run pump for
"Autofrostat"
four minutes
demand
OVERRUN FUNCTION
Run pump
until primary
drops to
80°C
Run fan
until primary
drops to
80°C
AUTOFROSTAT FUNCTION
Wait in normal
off state for
30 minutes
Monitor
central Below
heating 5°C
sensor
Commence normal
central heating mode
until temperature
reaches 30°C
38
If primary
temperature Run pump for
still increases two seconds
above 90°C
5°C Return to
Above
to normal off
9°C
9°C state