Troubleshooting Instructions. LB White L.B. White Therma Grow Greenhouse Heaters HW120

Troubleshooting Instructions

READ THIS ENTIRE SECTION BEFORE BEGINNING TO

TROUBLESHOOT PROBLEMS.

WARNING n

This heater can start at any time.

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Troubleshooting this system may require operating the unit with line voltage present and gas on. Use extreme caution when working on the heater.

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Failure to follow this warning may result in personal injury or death.

The following troubleshooting guide provides systematic procedures for isolating equipment problems. This guide is intended for use by a QUALIFIED GAS HEATER SERVICE

PERSON. DO NOT ATTEMPT TO SERVICE THESE HEATERS

UNLESS YOU HAVE BEEN PROPERLY TRAINED.

TEST EQUIPMENT REQUIRED

OPERATION SEQUENCE:

-- Line voltage is sent to transformer

-- Terminal at transformer branches off line voltage to . . terminal L1 on ignition control.

-Transformer reduces line voltage to 24 VAC.

-24 VAC is sent to thermostat.

-Thermostat closes and returns 24 volts to terminal W on ignition control.

-Red light on ignition control is illuminated.

-- Ignition control sends flame sense current to flame sensor.

-Ignition control module performs self safety check.

-- Internal components are tested.

-- Air proving circuit is tested

-- Control sends 24 VAC from terminal PSI to air . . proving switch.

-Ignition control module begins ignition trial sequence.

-Ignition control sends 115 volts from terminal IND to motor.

-- Motor starts.

-Air proving switch closes and 24 volts are returned to terminal PSO of ignition control.

The following pieces of test equipment will be required to troubleshoot this system with minimal time and effort.

• Digital Multimeter - for measuring voltage and resistance.

• Low Pressure Gauge - for checking inlet and outlet pressures at the gas control valve against dataplate rating.

INITIAL PREPARATION n

Visually inspect equipment for apparent damage.

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Check all wiring for loose connections and worn insulation.

The ignition control module is self-diagnostic. The red light located on the control will flash a specific pattern depending upon the problem which is diagnosed. To use the flow charts, t identify the problem by the light pattern of the L.E.D. (light emitting code) diagnostic light. If the light is flashing, the flash pattern will be followed by a pause and then a repeat of the flash pattern until the problem is corrected. The light will only be on when the selector switch is positioned to HEAT and the thermostat or controller is calling for heat. The light will not be on when the selector switch is positioned to VENT.

Heating Mode Problems Page

L.E.D. light is not on during a call for heat. . . . . . . . . . . . . . 19

L.E.D. diagnostic light is flashing:

A. Rapid flash. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

B. Long flash ( 2 seconds on-2 seconds off). . . 20

C. One time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

D. Two times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

E. Three times. . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

F. Four times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

G.Five times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

H.Six times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

-Ignition control module sends 115 volts to hot surface igniter.

-- Igniter reaches ignition temperature in 17 seconds.

-Ignition control restarts the fan motor while sending 24 VAC to air proving switch.

-- Switch closes and 24 volts are returned back to control.

-Ignition control send 24 volts from terminal GV to high limit switch.

-- If limit switch contacts are closed, limit sends 24 volts to gas control valve

-- Gas control valve opens

-- Ignition occurs.

-Flame sense current is passed through burner flame back to ignition control.

-- Igniter stays powered until ignition control proves flame sense

-- Igniter then shuts down.

-- Gas control valve stays open

-Room warms to desired temperature.

-- Thermostat is satisfied.

-- Heater shuts down.

-Process starts again on a call for heat.

IGNITION TRIAL SEQUENCE:

-First trial for ignition takes approximately 30 seconds

-- Two more ignition trials occur

-- Second trial immediatley follows if first trial failed.

-- If second trial fails

-- Ignition control starts a 15 minute waiting period

-- Allows the ignition interruption to pass

-At end of 15 minutes

-- Ignition control attempts third and final ignition trial

-- If igntion control does not prove burner flame after third trial, the control goes into safety lockout ( 3 flash)

-- Gas valve closes.

-- Hot surface igniter shuts down

-- Fan motor stops.

-To retry for ignition, turn the heater off and then on.

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