TABLE 11—TROUBLESHOOTING — HEATING
SYMPTOM | CAUSE | REMEDY | |
| Water in gas line | Drain. Install drip leg. | |
|
|
| |
| No power to furnace | Check power supply fuses, wiring, or circuit breaker. | |
|
|
| |
| Miswired or loose connections | Check all wiring and wirenut connections. | |
|
|
| |
| Replace thermostat. | ||
|
|
| |
Burners will not ignite. | Broken thermostat wire | Run continuity check. Replace wire if necessary. | |
|
| ||
Misaligned spark electrodes | Check flame ignition and sense electrode positioning. | ||
| |||
| Adjust as necessary | ||
|
| ||
|
|
| |
|
| 1. Check gas line for air. Purge as necessary. NOTE: | |
| No gas at main burners | After purging gas line of air, wait at least 5 minutes for | |
| any gas to dissipate before attempting to light unit. | ||
|
| ||
|
| 2. Check gas valve. | |
| Dirty air filter | Clean or replace filter as necessary. | |
| Gas input to furnace too low | check gas pressure at manifold. Match with that on unit | |
| nameplate. | ||
|
| ||
| Unit undersized for application | Replace with proper unit or add additional unit. | |
Inadequate heating. | Restricted airflow | Clean or replace filter. Remove any restriction. | |
Blower speed too low | Use faster speed tap if available, or install alternate | ||
| |||
| motor. | ||
|
| ||
|
| Check rotation of blower, thermostat heat anticipator | |
| Limit switch cycles main burners | settings, and temperature rise of unit. Adjust as neces- | |
|
| sary. | |
|
| 1. Tighten all screws around burner compartments. | |
|
| 2. Cracked heat exchanger. Replace | |
Poor flame. characteristics | Incomplete combustion results in: Aldehyde odors, car- | 3. Unit overfired. Reduce input (change orifices or ad- | |
| bon monoxide, sooting flame, floating flame | just gas line or manifold pressure). | |
|
| 4. Check burner alignment. | |
|
|
|
