Installation and Maintenance Manual

Diagnostics
GLND-SVX01B-EN 41
U. No Spark. 1. Thermostat not calling for heat. 1. Close thermostat contacts.
2. No low voltage. 2. Check for 24V across 24V terminals of S8600.
3. Spark gap closed or too wide. 3. Set gap to 0.1.
4. Broken or cracked ceramic on
spark electrode.
4. Replace pilot assembly.
V. Spark present but pilot does not
light.
1. Loose S8600 connections. 1. Check all connections, term. PV feeds 24V to pilot valve.
2. Improper gas pressure. 2. Check pressure—pressure that is either too high or too low
may cause a problem.
3. Is spark in pilot gas stream? 3. Spark should arc from electrode.
4. No pilot gas — do not use match to
test - presence of gas is easily
detected by the odor.
4. Check pilot line for kinks. Ensure there are no drafts.
W. Pilot lights — Main valve does not
energize.
1. Loose S8600 connections. 1. Check connections-term. MV feeds main valve.
2. Cracked or broken sensor
ceramic.
2. Replace pilot assembly.
3. Check sensor/spark lead for
continuity.
3. Replace if needed.
4. Measure 24 volts from term. MV to
term. MV/PV.
4. If present, replace main valve; if not, replace S8600 Igniter.
X. Hi-Limit switch tripping 1. Vertical run of flue is too short.
(Standard unit only—as Category
I.)
1. Lengthen vertical run of flue pipe (see “Installation:
Venting,” p. 18).
2. Unit is overfiring. 2. Manifold pressure too high; adjust. Burner orifice may be
too large: verify/replace if required.
3. Air flow too low. 3. Increase air flow; check fan size. Check for proper voltage.
4. Defective switch. 4. Replace.
Table 9. Troubleshooting guide (continued)
Symptoms Possible Cause(s) Corrective Action