Assessments - 4, GPA: 3.5
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Facilidade de uso
PRE-PURGE The control board monitors the low pressure switch and ensures it remains closed during pre-purge. If the pressure switch opens, the control goes back to pressure switch proving mode. The control waits for a 15 second pre-purge period, then begins the ignition trial IGNITION TRIAL PERIOD The control board energizes the pilot gas valve and spark outputs for an 85 second Ignition trial. The control de-energizes the spark when flame is sensed and enters a flame stabilization period. If flame is not established within the ignition trial period, the control de-energizes the spark and gas valve and begins an inter-purge period before attempting another ignition trial. If the call for heat is lost during an ignition trial period, the control immediately de-energizes spark and gas. The control runs the inducer motor through a post purge period before de-energizing. If the pressure switch is lost during an ignition trial period, the control immediately de-energizes spark and gas. The control begins pressure switch proving before an inter-purge and re- ignition attempt. PILOT FLAME STABILIZATION PERIOD The control board de-energizes the spark output, and waits for a 2 second flame stabilization period before energizing the main gas valve. If flame is lost during the flame stabilization period, the control board counts it as a flame loss and retries ignition or locks out flashing a "5" on the LED. HEAT BLOWER ON DELAY The control board waits for 30 seconds and then energizes the indoor blower heat speed. Blower on delay time begins at the start of flame proving period in the trial for ignition. If the thermostat demand for heat is removed, the control de- energizes the gas valve, energizes the blower on heat speed and initiates a post-purge and heat blower off delay. MAIN BURNER OPERATION High heat warm-up Two stage models run high heat for the first 60 seconds following Pilot Flame Stabilization period regardless of W2 demand. If W2 is not energized at the end of this 60 second period the control de energizes the high gas output and steps the inducer to low speed. If W2 is energized the control remains on high heat. There is no high heat warm-up on single stage models Low heat The control board keeps the pilot gas valve, main gas valve and induced draft motor energized while continuously monitoring the call for heat, low pressure switch, and flame status. If the call for heat (W1) is lost, the control de-energizes the gas valve and begins post purge. If low pressure switch opens, the control de-energizes the gas valve and begins pressure switch proving mode. If flame is lost, the control de-energizes the gas valve within 2.0 second and counts the flame loss. If flame has been lost more than 16 times within the same call for heat, the control board locks out flashing "5" on the LED. If flame has been lost less than 16 times, the control attempts re-ignition after a 300 second inter-purge period. High heat If the W2 terminal was energized more than 1 second before W1 at the start of the call for heat, and remains continuously energized through the call for heat, the control considers it to be connected to a single stage thermostat and implements a 10 minute Auto staging feature. The 2nd stage thermostat call is ignored until 10 minutes into steady heat (9 minutes after high heat warm-up ended). Johnson Controls Unitary Products 340968-XIM-A-0108 The control recognizes a call for 2nd stage heat when W2 is energized (connected to "R"). The control energizes the high gas output and induced draft motor on high speed. If the call for 2nd stage heat goes away and the 1st stage call remains, the control de energizes the high gas valve, drops inducer speed to low, and returns to low heat operation. Response to loss of W1, low pressure switch, and flame are identical to low heat operation. POST PURGE The control board runs the induced draft motor for a 30 second post-purge period, and then de-energizes the inducer. If a call for heat occurs during post-purge, the control finishes the post-purge, drops inducer out to re-prove open pressure switch before continuing with the heat cycle. HEAT BLOWER OFF DELAY The control board de-energizes the indoor blower motor after a delay time as selected by movable shunt (60, 90, 120 or 180 seconds). Blower timing begins when the thermostat is satisfied or heat cycle was interrupted. The control returns to standby when the blower off delay is complete. If the thermostat call for heat returns before the blower off delay is complete, the control begins an ignition sequence with pre-purge while the blower off delay continues. LOCKOUT While in lockout, the control board keeps the pilot gas valve, main gas valve and induced draft motor de-energized. Lockouts due to failed ignition or flame losses may be reset by removing the call for heat (W1) for more than 1 second, but less than 20 seconds, or by removing power from the control for over 0.25 seconds. The control will automatically rese...