Heater Sequence of Operation
If all limits are satisfied and there is a call for heat:
1.The heater pump is powered and begins circulat- ing water through the heat exchanger.
2.The blower is powered and goes through a 15 sec- ond prepurge beginning when air flow is proven by closure of the blower suction air pressure switch.
3.The igniter is powered, and once proven, heats up for 20 seconds.
4.The gas valve is then energized for a 4 second trial for ignition period. Trial for ignition is fixed at 50% input. The heater is allowed to modulate once flame is proven and the firing rate will adjust to match the load based on the configuration and set- tings of the temperature control or external input.
5.Once the heat demand is satisfied the gas valve will close and the blower will run a 30 second post purge. The heater pump will continue to circulate water for 0 to 10 minutes depending on the pump delay setting on the Raypak modulating tempera- ture control.
Ignition Module
When additional heat is needed, the combustion air blower starts to purge air from the combustion cham- ber for 15 seconds. On
The optional
Code |
| Condition |
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On |
| System OK; No faults present |
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Off |
| Possible control fault; Check power |
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1 Flash |
| Low air |
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2 Flashes |
| Flame in combustion chamber; |
| No call for heat | |
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3 Flashes |
| Ignition lockout |
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4 Flashes |
| Low HSI current |
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5 Flashes |
| Low 24 VAC |
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6 Flashes |
| Internal fault; Replace control |
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| Table U: Ignition Module |
| Diagnostic LED Flash Codes |
High Limit—Manual Reset
This heater is equipped with a fixed setting manual re- set high limit temperature device as standard or it may have an optional adjustable setting manual reset high temperature device.
The fixed setting manual reset high limit is located on the In/Out header of the heat exchanger on the right side of the heater (accessible through the front door for reset as necessary).
The optional adjustable manual reset high limit is lo- cated inside the heater junction box. Push the reset button and adjust the setting to approx. 40°F (20°C) above desired outlet temperature.
Fig. 38: Ignition Module | 37 | Fig. 39: High Limit (Manual Reset) |
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