SolarAttic Troubleshooting
SolarAttic Troubleshooting for PCS4, PCS3, PCS2, PCS1, and Controls
Use this complete troubleshooting guide to diagnose common SolarAttic solar pool heater issues, including power, blower or fan operation, water flow, valve operation, sensor warnings, insufficient heating, short season, vibration, filter pressure, and circulation problems.
- Current PCS4 support for today’s SolarAttic solar pool heater.
- Legacy PCS3, PCS2, and PCS1 support for older SolarAttic systems.
- Control and wiring guidance for GL235, LX220, sensors, valves, and automation.
Start Here First
Basic SolarAttic Troubleshooting Checklist
Many SolarAttic issues are caused by simple operating conditions. Before assuming a failed part, confirm that water flow, airflow, power, controller mode, sensor placement, and attic heat are all correct.
Confirm Water Flow
- Pool pump is running.
- Filter is clean and pressure is normal.
- Valves are positioned to route water through SolarAttic.
- Bypass valve or actuator is not sending water around the unit.
- Pool cleaner flow is not stealing flow from the heater loop.
Confirm Airflow
- PCS4 blower, PCS3 blower, or PCS2/PCS1 fan is operating.
- Air intake and discharge are not blocked.
- Unit is not too close to an attic wall or obstruction.
- Discharged cooler air is not recirculating back into the intake.
- Unit is located high enough in the attic to collect useful heat.
Confirm the Heat Call
- GL235 or LX220 controller is in AUTO mode when automatic operation is intended.
- Attic or solar sensor is warmer than pool water.
- Desired pool temperature is set above current pool temperature.
- Sensor service or check sensor lights are not active.
- Water flow and blower or fan power are operating at the same time.
Important Safety Warning
Some Troubleshooting Requires a Qualified Professional
SolarAttic systems can involve electrical power, pool plumbing, attic access, valve actuators, temperature sensors, float circuits, and moving fan or blower components. Do not perform electrical, attic, plumbing, or internal component service unless you are qualified.
PCS4 and PCS3 Systems
PCS4 and PCS3 Troubleshooting Guide
PCS4 and PCS3 automated systems commonly use GL235 solar controls. These troubleshooting items cover power, blower, valve operator, sensor, heating, vibration, pressure, and circulation symptoms.
PCS4 and PCS3 Symptoms and Checks
| Symptom | Check These Items |
|---|---|
| GL235 power light does not light | Check main breaker, blown 2-amp GL235 fuse, timers, loose power wires, and 120 VAC power inside the GL235. |
| PCS4 or PCS3 blower does not turn on | Check GL235 wiring, attic outlet power, unit plug, thermostat setting, 2-amp fuse, GL235 relay, thermal cutoff, power cord, starting capacitor, motor, controller, and 120 VAC at the attic outlet. |
| Motor hums but blower cage does not rotate | Turn power off for 15 to 30 minutes for possible thermal overload reset. If still humming, have the starting capacitor and motor checked by a qualified person. |
| PCS4 or PCS3 does not turn off | Confirm the unit is wired for automatic operation through the GL235 internal relay at terminals 5 and 6. Review the wiring diagrams before changing wiring. |
| Valve operator rotates in the wrong direction | Valve may have been staged incorrectly. Switch valve operator from ON1 to ON2, or the reverse, as appropriate. |
| Valve operator does not rotate to proper stop position | Check internal limit switch, cam, mechanical stop, and valve operator condition. |
| Valve operator rotates in one direction only | Reverse the VOR switch from ON1 to ON2 or vice versa. If it still fails, check valve operator limit switch, mechanical stop, and internal circuit. If it reverses correctly, check GL235 wiring or controller. |
| Valve operator rotates slowly | Check for incorrect 12 VAC versus 24 VAC valve output, defective valve operator, or incorrect GL235 voltage wiring. |
| Valve only rotates when the valve switch is flipped | Check whether the GL235 is wired for 220 VAC operation but supplied with 120 VAC. |
| Check sensor light is on steady | Check for shorted pool water temperature sensor, open pool water sensor, cable problem from GL235 to water sensor, or loose screw at GL235 water sensor terminals. |
| Check sensor light is flashing | Check attic temperature sensor wiring, loose solar sensor terminals, cable problems, upside-down unit mounting, leak detection float condition, defective float switch, shorted attic sensor, or open attic sensor. |
| Insufficient heating | Check solar weather, pump timer schedule, restricted valves, bypass valve routing, pool cleaner interference, controller AUTO mode, controller power to unit, synchronized water flow and blower power, sensors, float circuit, attic sensor location, blower motor, airflow, unit location, airflow recirculation, and waterfall cooling. |
| System turns on at night, too early, or too late | Check whether the pool water temperature sensor is exposed to wind, rain, sun, or false temperature conditions. Insulate and weatherproof the sensor area as appropriate. |
| Short swimming season | Confirm AUTO mode. Use a pool cover when nights are cold. If seasonal heat loss exceeds solar gain, a backup heater downstream of SolarAttic may be needed for late-season extension. |
| Excessive vibration | Check unbalanced or loose squirrel cage, loose motor or cabinet hardware, lack of foam base, rigid building mounting, contamination on squirrel cage, motor bearings, and unsupported rigid attic pipes. |
| High pressure at filter | Backwash or clean filter, check support-system valve positions, and contact pool service if pressure remains high. |
| Poor circulation or cloudy pool water | Clean filter, check valve positions, check pump flow rate, check pump sizing, and contact pool service. This is often not a SolarAttic unit problem. |
| High electric bill | Check filter pump runtime, filter pump size and condition, pump relay/timer strategy, and overall home energy use. The older manuals note that the pool pump is often the larger energy factor. |
Legacy PCS2 and PCS1 Systems
PCS2 and PCS1 Troubleshooting Guide
PCS2 and PCS1 systems often used LX220-style control logic, fan motors, valve operators, water sensors, solar sensors, and older automation wiring. Use the correct manual before servicing legacy equipment.
PCS2 and PCS1 Symptoms and Checks
| Symptom | Check These Items |
|---|---|
| LX220 power light does not light | Press reset if applicable, check main breaker, timers, loose power wire nut, and 120 VAC power inside LX220. |
| PCS2 or PCS1 fan does not turn on | Check thermostat setting, attic outlet power, unit plug, LX220 wiring, LX220 relay, internal motor thermal cutoff, power cord, starting capacitor, motor, solar controller, and 120 VAC at attic outlet. |
| Motor hums but fan blade does not rotate | Turn power off for 15 minutes for possible thermal overload reset. If still humming, have the starting capacitor and motor checked. Do not run unsafe capacitor tests without qualified help. |
| PCS1, PCS2, or filter pump does not turn off | Legacy LX220 relay wing nut may be too tight, causing relay contact problems. Dangerous power may be exposed near the relay, so turn power off and use qualified service. |
| Valve operator rotates in the wrong direction | PCS1 older systems may have an upside-down valve operator plug. PCS2 systems may need valve operator switch moved to the other ON position. |
| Valve operator does not rotate to proper stop position | Check internal limit switch, cam, mechanical stop, and valve operator condition. |
| Valve operator rotates in one direction only | Reverse plug or operate VOR switch depending on model. If valve still does not rotate, suspect valve operator limit switch or internal circuit. If it reverses, suspect controller wiring or controller. |
| Valve operator rotates slowly | Check for reversed transformer plug or incorrect voltage causing 12 volts at the valve operator instead of required 24 volts. Also check for defective valve operator. |
| Valve only rotates when VOR switch is flipped | Check whether LX220 is wired for 220 VAC operation but supplied with 120 VAC. |
| Water sensor service light is on | Check for shorted water sensor, open water sensor, cable problem from LX220 to water sensor, or loose screw at LX220 WTR terminals. |
| Solar sensor service light is on | Check attic temperature sensor wiring, loose LX220 SOL terminals, cable problem, upside-down unit mounting, leak detection float, shorted attic sensor, or open attic sensor. |
| Insufficient heating | Check poor solar weather, pump timers, shut water valves, bypass valve routing, pool cleaner interference, LX220 Automatic mode, controller power to unit, water flow and fan sync, sensors, float circuit, attic sensor location, fan motor, airflow, coil direction, unit location, airflow recirculation, and waterfall cooling. |
| PCS2 fan set to medium or low | PCS2 troubleshooting notes include fan speed as a possible heating-performance factor. Confirm fan speed and airflow setup. |
| Turns on at night or too early | Pool water sensor may be exposed to cooling wind, rain, or sun heating, causing false temperature readings. Insulate and weatherproof sensor area. |
| Short swimming season | Confirm Automatic mode, use a pool cover to reduce night heat loss, and consider backup heat downstream if seasonal conditions exceed solar heating capacity. |
| Excessive vibration | Check unbalanced fan blade, loose fan blade, loose motor or cabinet hardware, missing foam base, rigid building mounting, fan contamination, motor bearings, unsupported rigid piping, or need for isolation dampening. |
| High pressure at filter | Backwash and clean filter, check valve positions, and contact pool service if pressure remains high. |
| Poor circulation or cloudy pool water | Clean filter, check valve positions, pump flow rate, and pump sizing. This is often a pool circulation issue rather than a SolarAttic unit issue. |
| High electric bill | Check filter pump hours, pump size, pump condition, controller relay strategy, and minimum runtime timer. The legacy manuals state the unit itself is usually not the main electric load when operating correctly. |
Controls and Sensors
GL235, LX220, Sensors, Valves, and Automation Troubleshooting
Many SolarAttic issues trace back to controller mode, sensor readings, voltage wiring, actuator position, fuse condition, or pump synchronization.
GL235 No Power Indicator
- Check main power circuit breakers.
- Check the GL235 fuse.
- Use the correct 2A ATO-style fuse when replacement is required.
Heating Always On
- Check whether recirculate freeze protection is enabled.
- Confirm the switch is in AUTO.
- Disconnecting sensors for testing should only be done by qualified service.
- If control logic fails testing, the control may require repair or replacement.
Heating Never Comes On
- Confirm AUTO mode.
- Set desired pool temperature higher than actual pool temperature.
- Confirm solar or attic sensor is warmer than pool water.
- Confirm valve actuator switch is not OFF.
Check Sensor Light
- Steady light generally points to pool sensor circuit issues.
- Blinking light generally points to solar or attic sensor circuit issues.
- At about 77F, a good 10K sensor should measure approximately 10,000 ohms.
- Use the manual sensor table for other temperatures.
Valve Actuator Issues
- If the valve turns the wrong way, switch actuator output or ON position as the manual directs.
- If it only moves one direction, check actuator limit switches and controller wiring.
- If it creeps slowly, confirm correct valve voltage.
Sensor Wiring Rules
- Do not run sensor wires with 120/240V wiring.
- Protect outdoor sensor wiring from weather.
- Use shielded cable for long runs or runs near electrical wiring.
- Keep pool sensor insulated and weather-protected from false readings.
Heating Performance
If the Pool Is Not Getting Warm Enough, Look at the Whole System
SolarAttic heating performance depends on attic heat, sun exposure, pump schedule, water flow, blower or fan airflow, sensor placement, pool cover use, night heat loss, wind, waterfalls, and whether water flow and fan power are synchronized.
A system can be operating correctly and still have reduced heating during poor solar weather, cold nights, uncovered pool conditions, high evaporative loss, or when a waterfall continuously cools the pool.
Prevent Repeat Problems
SolarAttic Installation and Maintenance Notes
Several older SolarAttic documents repeat the same prevention rules. These help avoid poor heating, noise, vibration, water damage, freeze damage, and service problems.
Place the Unit High
Heat rises in the attic. Locate the unit as high as practical and avoid placing it on the floor of a large stand-up attic.
Do Not Block Air
Do not obstruct air entering or leaving the unit. Avoid short-circuiting cooler discharge air back into the coil intake.
Support Plumbing
Rigid pipes should be properly supported in the attic. Poor pipe support can contribute to vibration and service problems.
Protect From Freezing
In freezing climates, winterize correctly. Water left in attic piping or the unit can cause serious damage.
Manuals and Support
Use the Correct Manual for Your SolarAttic Model
PCS4, PCS3, PCS2, PCS1, GL235, and LX220 systems do not all use the same controls, wiring, fan assemblies, or troubleshooting steps. Match the manual to your model before servicing.
Document Downloads
Troubleshooting Source Documents
Use these original documents for detailed service procedures, wiring diagrams, and model-specific information.
PCS4 Manual
Open PCS4 ManualPCS3 Trouble Guide
Open PCS3 GuidePCS2 Trouble Guide
Open PCS2 GuidePCS1 Trouble Guide
Open PCS1 GuideGL235 Control Manual
Open GL235 ManualAll Manuals
Open Manuals PageNeed Help Troubleshooting?
Contact SolarAttic Before Rewiring, Disassembling, or Removing Equipment
If you are unsure which model you have, which controller applies, or what a warning light means, contact SolarAttic support before performing service work.