51
Henrad CC FF
- Installation
FAULT FINDING
81 CH but no HW
Unplug the lead from the sensor
and connect it temporarily to a
replacement sensor, if available.
(Alternatively, see footnote)
Does the flashing stop ?
Is the HW light on PCB 40
flashing ?
Is there a flow of at least 3.5 litres per
minute (or about 1 pint in 10 seconds) when
a hot tap is turned on ?
Change the flow switch
NO
YES
NO
YES
NO
YES
NO
Adjust the restrictor ball valve to
give the required flow.
If this is not possible rectify a
system pipework defect or a
supply pressure problem.
Check the flow restrictor for
blockage
Switch off the boiler.
Unplug the flow switch lead at
the inline connector.
Measure continuity between
the switch leads and turn a
hot tap on.
Does the switch close ?
Reconnect the flow
switch.
Unplug the lead from the
HW sensor and transfer
temporarily to a
replacement sensor.
Will the boiler operate ?
Fit new HW sensor (which has
failed 'low resistance')
Check all connections to
PCB 40.
Check for moisture on
PCB 40.
If no fault found check
PCB 40 by substitution.
WARNING.
When panels are removed for service, live parts are exposed so caution should be exercised when fault-finding.
YES
Checking CH and HW thermistor sensors
The sensors can be checked by measuring their resistance,
using a suitable multimeter connected across the sensors'
terminal pins.
At room temperature expect
9,000 to 11,000 Ohms
At 60°C.
expect
2,000 to 2,500 Ohms
At 85°C.
expect
1,000 to 1,500 Ohms
YES
NO
Check - and
repair or
replace the
sensor
lead.
Does boiler
operate ?
Fit new HW
sensor
NO
Check all connections
to PCB 40.
Check for moisture on
PCB 40.
If no fault found check
PCB 40 by substitution.
F
AUL
T FINDING
Summary of Contents for CC 100 FF
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