Worcester 35CDi II User Manual

29
18. Operational Flow Diagrams
MAIN SWITCH
ON
Green Light
On
Room
thermostat
and/or mains
programmer
(or link) On
AND
Electronic
facia
programmer
(if fitted) On
AND
ST13 link in
AND
CH control
knob On
CENTRAL
HEATING
DEMAND
CH light On.
Pump On.
Fan ON High for 2
sec then Low speed -
28CDi.
Fan ON High for 2
sec then Low speed -
35CDi II.
Ignition Sequence.
Burner Light On.
Three minute
wait
Gas valve Off.
(CH light still
on. Pump still
On)
Over tempera-
ture shut-
down if flow
temperature
5°C above set
value
Two minute mini-
mum burner
(30 seconds -
35CDi II)
pressure then
ramp up
pressure over
next one minute
Modulate gas
to maintain
flow
temperature
set by control
knob
DEMAND
END
Pump
continue four
minutes.
Fan continue
fifteen
seconds
CENTRAL HEATING FUNCTION
AND
AND
AND
DOMESTIC HOT WATER FUNCTION
MAIN SWITCH
ON
Green Light
On
Flow switch
On
(Tap open)
DOMESTIC
HOT WATER
DEMAND
(Priority over
CH demand)
HW light On.
Pump On.
Fan ON High speed -
28CDi.
Fan ON High for 2
sec then Low speed
- 35CDi II.
Ignition Sequence.
Burner on
Four second
ramp to max.
gas pressure.
Fan speed
changes at mid
pressure
35CDi
II.
Modulate gas
to maintain
delivered
water
temperature
at value set by
control knob
Ten second
wait
Gas valve Off.
(HW light still
on. Pump still
On)
Over
temperature
shut-down if
water
temperature
8°C above set
value
Burner shut-
down if
primary
temperature
94°C
(until 84°C)
DEMAND
END
Fan continue
fifteen
seconds
Possible
overrun
condition
within next
four minutes
(See next
section)

Worcester 35CDi II Specifications

General

Model	35CDi II
Output	35kW
Mounting	Wall-mounted
Max. DHW Output	35kW
Efficiency Rating	A
ErP Heating	A
ErP Water	A
Warranty	5 years
Fuel Type	Natural Gas