Halsted Ace GC 47-333-15 Sequence of operation
Sequence of Operation
Control fascia contains main selector/ignition lockout reset switch, heating & hot water potentiometers, 5 function LEDs and pressure gauge.
Overheat thermostat with manual reset. Situated bottom left on the underside of boiler activating at approximately 106 ° C ± 6 ° C.
Single speed Grundfos pump (head replacement required only). Note: If pump fails this could lead to the fan venturi melting.
Primary and DHW flow switches are mounted onto the Diverter valve, both having clear plastic housing allowing the operation to be checked.
Hydraulic Diverter valve at bottom left of the boiler which is at rest in CH mode and drives to the left to DHW mode.
NOTE: When there is no demand, there is approximately 180 Vac to both connections on the fan and all connections on the APS!!
DHW Operation
- Demand for DHW.
- Diverter valve moves to the left and makes DHW flow switch (continuity).
- PCB checks primary flow switch for open circuit. If primary flow switch is closed circuit no
demand will be recognised or displayed.
- DHW light illuminates.
- PCB sends 240 Vac via the neutral wire to the pump, which runs.
- PCB checks both Central Heating (primary) and DHW NTCs are in range.
*** If either NTC is out of range DHW light goes out within 1 second of being illuminated, pump stops, boiler will not operate in either DHW or CH mode until the NTC is back in range (no lockout occurs).
- Primary flow switch goes to continuity. If primary flow switch doesn’t go to continuity within 6
seconds, sequence stops, pump ceases to run, power on light flashes (burner may ignite
within this 6 seconds).
- PCB checks APS for open circuit. If closed circuit sequence stops, pump continues to run.
- PCB sends 240 Vac to fan which runs.
- Fan operation proved by APS (closed circuit). If APS doesn’t go to closed circuit sequence
stops, fan and pump continue to run (no lockout occurs).
- PCB checks overheat stat for continuity. If open circuit fan stops, pump continues to run and
lockout light illuminates.
- PCB sends approximately 130 Vdc on grey and black wires and approximately 60 Vdc on
purple and red wires to the gas valve, which then energises.
- PCB commences spark ignition.
- Burner lights and rectification takes place within 8 seconds.
*** If flame rectification fails, the gas valve is de-energised and the lockout light illuminates.
- Gas valve modulates in conjunction with the temperature as sensed by the DHW and primary
NTCs by altering the voltage on the purple and red wires.
- End of demand, diverter valve returns to rest position, flow switch goes to open circuit.
- Fan stops, gas valve is de-energised but pump continues to run for a limited period.
CH Demand
- Demand for CH from external controls (230 Vac on X9 pin 3).
- PCB checks primary flow switch for open circuit. If primary flow switch is closed circuit no
demand will be recognised or displayed.
- PCB checks both Central Heating and DHW NTCs are in range.
*** If either NTC is out of range Central Heating light goes out within 1 second of being illuminated, pump stops, boiler will not operate in either DHW or CH mode until the NTC is back in range (no lockout occurs).
- If NTCs are in range Central Heating light illuminates.
- PCB sends 240 Vac via the neutral wire to the pump, which runs.
- Primary flow switch goes to continuity. If primary flow switch doesn’t go to continuity within 6
seconds, sequence stops, pump ceases to run, power on light flashes (burner may ignite
within this 6 seconds).
- PCB checks APS for open circuit. If closed circuit sequence stops, pump continues to run.
- PCB sends 240 Vac to fan which runs.
- Fan operation proved by APS (closed circuit). If APS doesn’t go to closed circuit sequence
stops, fan and pump continue to run (no lockout occurs).
- PCB checks overheat stat for continuity. If open circuit fan stops, pump continues to run and
lockout light illuminates.
- PCB sends approximately 130 Vdc on grey and black wires and approximately 30 to 60 Vdc
on purple and red wires to the gas valve, which then energises.
- PCB commences spark ignition.
- Burner lights and rectification takes place within 8 seconds.
*** If flame rectification fails, the gas valve is de-energised and the lockout light illuminates.
- Gas valve modulates in conjunction with the temperature as sensed by the primary NTC by
altering the voltage on the purple and red wires.
- End of demand.
- Fan stops, gas valve is de-energised but pump continues to run for a limited period.
Data
Fan: 1 Speed 230 Vac Coil Approximately 50 Ohms
Thermistors: Central Heating & Hot Water 19Kohms@ 10 ° C
Gas Valve: Honeywell Twin Solenoid (Softlight) 1 Coil Grey & Black Wires Approximately 130 Vdc Modulating Coil Purple & Red Wires Up To 60 Vdc Aps: 2 Wire, Switching At 1.5 Mbar
