Empire Comfort Systems DVP42FP, P)-2 Ignition System Checks Check ignition cable. Make sure

Important

1.The following service procedures are provided as a general guide.

2.Meter readings between gas control and ignition module must be taken within the trial for ignition period. Once the igni- tion module locks out, the system must be reset by setting the thermostat down for at least one minute before continuing.

3.If any component does not function properly, make sure it is correctly installed and wired before replacing it.

4.The ignition module cannot be repaired. If it malfunctions, it must be replaced.

5.Only trained, experienced service technicians should service intermittent pilot systems.

Perform the CHECKOUT steps on page 53 as the first step in troubleshooting. Then check TROUBLESHOOTING GUIDE to pinpoint the cause of the problem. If troubleshooting indicates an ignition problem, see Ignition System Checks below to isolate and correct the problem.

Following troubleshooting, perform the CHECKOUT procedure (page 53) again to be sure system is operating normally.

Ignition System Checks Step 1: Check ignition cable. Make sure:

A.Ignition cable does not touch any metal surfaces.

B.Ignition cable is no more than 36 inches long.

C.Connections to the ignition module and to the igniter-sensor are clean and tight.

D.Ignition cable provides good electrical continuity.

Step 2: Check ignition system grounding.

Nuisance shutdowns are often caused by a poor or erratic ground.

A.Acommon ground, usually supplied by the pilot burner bracket, is required for the module and the pilot burner/igniter sen- sor.

•Check for good metal-to-metal contact between the pilot burner bracket and the main burner.

•Check the ground lead from GND (BURNER) terminal on the module to the pilot burner. Make sure connections are clean and tight. If the wire is damaged or deteriorated, replace it with No. 14-18 gauge, moisture-resistant, thermoplastic insulated wire with 105 C (221 F) minimum rating.

•If flame rod or bracket are bent out of position, restore to correct position.

•Replace pilot burner/igniter sensor if insulator is cracked.

Step 3: Check spark ignition circuit. You will need a short jumper wire made from ignition cable or other heavily insulated wire.

A.Close the manual gas valve.

B.Disconnect the ignition cable at the SPARK terminal on the module.

WARNING

When performing the following steps, do not touch stripped end of jumper or SPARK terminal. The ignition circuit generates 13,000 volts at 25 pf load and electrical shock can result.

C.Energize the module and immediately touch one end of the jumper firmly to the GND terminal on the module. Move the free end of the jumper slowly toward the SPARK terminal until a spark is established.

D.Pull the jumper slowly away from the terminal and note the length of the gap when sparking stops. Check table below.

ARC LENGTH	ACTION
No arc or arc less than 1/8	Check external fuse, if provided.
inch.	Verify power and module input
	terminal.
	Replace module if fuse and power
	okay.
Arc 1/8 inch or longer	Voltage output is okay.

Step 4: Check pilot flame current.

A.Turn off furnace at thermostat.

B.Disconnect main valve wire from the TH or MV terminal on the gas control.

C.Disconnect ground wire from GND (BURNER) terminal at module.

D.Connect a meter (dc microamp scale) in series with the ground lead.

•Disconnect ground lead from GND terminal on ignition module.

•Connect the black (negative) meter lead to the ignition module GND (BURNER) terminal.

•Connect the red (positive) meter lead to the free end of the ground lead.

E.Set thermostat to call for heat. The spark will light the pilot but the main burner will not light because the main valve actuator is disconnected.

F.Read the meter. The flame sensor current must be steady and at least 1.0 uA.

G.If the reading is less than the minimum or unsteady,

•Make sure pilot flame envelopes 3/8 to 1/2 inch of the flame rod.

•If necessary, adjust pilot flame by turning the pilot adjustment screw on the gas control clockwise to decrease or counter- clockwise to increase pilot flame. Following adjustment, always replace pilot adjustment cover screw and tighten firmly to assure proper gas control operation.

•Check for cracked ceramic insulator, which can cause short to ground, and replace igniter-sensor if necessary.

•Make sure electrical connections are clean and tight. Replace damaged wire with moisture-resistant No. 18 wire rated for continuous duty up to 105 C (221 F).

H.Remove meter and reconnect all wires. Return system to normal operation before leaving job.

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