Hamworthy Sherborne Series Installation, Commissioning And Service Manual page 36

Figure 12.1. Fault Finding Procedures.
Initiate Start Procedure
Is the fan running?
Yes
Continued
Ref. Fig 12.2
* Condensing models only
HAMWORTHY HEATING LTD
No
Is mains power on?
Yes
Is the on/off switch on?
(Fascia power on indicator
illuminated)
Yes
Is the temperature limiter
reset? (Fascia overheat
indicator illuminated)
Yes
Is the condensate trap
blocked* (Red LED on
main PCB illuminated)?
Yes
Is there a demand from
the temperature control?
Yes
Is the remote on/off control
link (R1-R2) closed?
Yes
Is there a demand from the
Milton sequence control?
(If installed)
Yes
Is rotary switch 'SW1'
on boiler main PCB set
correctly?
Yes
Has the ignition controller
reset? (Fascia lockout
indicator illuminated)
Yes
Is there power to the fan?
Yes
Is there a control signal
to the fan? (24V dc across
pins 1 & 5 of 5way fan
control connector)
Yes
Replace fan
SHERBORNE
No
supply connections
No Check on/off switch position
and wiring connections
Reset temperature
No
No
No
Check and turn temperature
control knob to maximum
No
Check and generate
No demand from Milton
(Refer also to Milton
installation manual)
No
Check and reset ignition
No
controller (red lockout
reset button on fascia)
No Check fan power supply
wiring connections
Check fan control wiring
No
connections, replace
30
Check fuses and
limiter (Limit Stat)
Check and clear
blockage
Check and close
remote circuit
Check and adjust
rotary switch
boiler main PCB
500001103/E