Armstrong World Industries 243, 302, 242, 122, 123, 203, 182 Specifications, Magic-Pak HW/HWC, Fan On

SPECIFICATIONS

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FAILED FLAME SENSE/TRIAL FOR IGNITION

When the pressure switch closes and a 24-volt signal is sent to pin 5 of the 6-pin ignition wire harness, the spark ignition cable terminal and pin 4 of the 6-pin ignition wire harness energize.

1.As spark voltage is supplied to the ignitor elec- trodes, the gas valve opens and this causes the burners to ignite.

2.The ignition control continues to energize spark voltage until a flame sense signal is supplied to the flame terminal on the ignition control.

3.If a flame sense signal is not received at the flame terminal on the ignition control, the spark igni- tion cable terminal remains energized for 10 seconds.

4.After the 10-second trial for ignition, the ignition control de-energizes the spark ignition cable terminal and pin 4 of the 6-pin ignition wire harness. This causes the gas valve to close and the elec- trode spark to stop.

5.Once the 24-volt signal is sent to pin 4 of the 6-pin ignition wire harness, a 30-second circulating air blower “on” delay starts. After the delay is timed out, the circulating air blower starts.

6.After the spark ignition cable terminal de-ener- gizes, the ignition control initiates a 30-second combustion blower inter-purge delay.

7.After 30-second inter-purge, the ignition control energizes the spark ignition cable terminal and pin 4 of the 6-pin ignition wire harness. If the flame sense signal is received at the flame terminal of the ignition control, the unit continues heat call.

8.If the flame sense signal is not received, the system goes through three trials following the above sequence.

9.After three trials, the system goes into lockout and only the limit switch circuit and pressure switch circuit remain energized during the 60-minute lockout period.

10.If the flame sense is lost during the heat cycle, the gas valve de-energizes immediately and the system goes into the trial sequence.

FAN ON

1.When the thermostat is switched to the “FAN ON” position, the R-Gcircuit sends a 24-volt signal to pin 4 of the 5-pin thermostat harness.

2.The 24-volt signal energizes the cooling speed relay, sending L1 power to the ACB COOL terminal of the ignition control.

3.L1 power is sent to the circulating air blower terminal block, causing the circulating air blower to run in cooling speed.

Magic-Pak: HW/HWC

4.The circulating air blower continues to run in cooling speed until the thermostat is switched to “AUTO”, interrupting the R-Gcircuit.

Note: With the thermostat in the “FAN ON” position during heat call, ignition control will not energize the heat speed relay. The circulating air blower continues to run in cooling speed unless the limit switch circuit opens, which would cause the heat speed relay and the induced draft blower relay to become energized. This would de-energize the cooling speed relay until either the limit switch circuit is closed or the thermostat is switched to the “AUTO” position.

SRM-HW/HWC

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