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PROBLEM
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PROBABLE CAUSE
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REMEDY
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Heater will not start. Flame monitor shows message 3-P INTLK OPEN.
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One of nine switches in limit circuit is open.
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See discussion of limit circuit in separate Tec-Note on control functions.
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Heater will not start. Flame monitor shows message LOCK OUT PTFI-FLAME FAIL (PTFI means Pilot Trial For Ignition)
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1. Bad flame scanner.
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1. Check the flame scanner per separate Tec-Note on service and replace it if defective.
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2. Igniter improperly set.
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2. Reset per manual on Power Flame burner.
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3. Bad ignition transformer.
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3. Check for 120 vac at primary. If ok check ignition wire for break. If ok check for spark. If no spark replace transformer.
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4. Bad ignition wire.
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4. Check wire for break. Replace if broken.
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5. Bad pilot solenoid
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5. Check for click when energized. If no click check for 120 vac at solenoid terminals. Replace solenoid if there is no click when voltage is applied.
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6. Pilot gas regulator improperly set.
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6. Check regulator and reset if necessary per separate Tec-Note on service.
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| 7. Bad amplifier card in flame monitor. |
7. Replace card. |
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Low media flow/pressure indicator light off.
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1. Low media pressure switch out of adjustment.
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1. Re-adjust low media pressure switch per applicable Tec-Note on setting pressure switches.
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2. Strainer clogged.
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2. Remove and clean strainer.
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3. Level of media (thermal fluid) in expansion tank is too low.
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3. Check sight gauge on expansion tank. Confirm that sight gauge is correct by using measuring stick through top of tank.
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4. Air in circulating pump.
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4. Bleed air from pump per separate Tec-Note on service. |
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Low combustion air (limits made indicator light is off, but all other lights in limit circuit are on.)
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1. Line to low combustion air switch is clogged.
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1. Disconnect air line and blow compressed air through the line.
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2. Street elbow in low combustion air switch is clogged.
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2. Remove cover with burner sight glass. Remove street elbow and blow compressed air through it.
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3. Fan blades of combustion air blower clogged with dust.
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3. Clean blades to remove dust.
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| 4. Low combustion air switch out of adjustment. |
4. Readjust low combustion air switch per separate Tec-Note on service. |
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High media temperature indicator light is off.
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1. Strainer is clogged.
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1. Remove and clean strainer.
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2. Maximum temperature setting of UDC2300 is too low.
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2. Re-set maximum temperature in UDC2300 to a temperature 80 degrees (min) higher than set point on UDC 3300. Press MANUAL RESET to clear alarm.
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| 3. Inadequate flow of thermal fluid in system piping. |
3. Check for closed or stuck valve in system piping. |