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🔧 Troubleshooting
Troubleshooting matrix
| Symptom | Likely cause | First check |
|---|---|---|
| Cloudy water | Poor filtration, high pH/TA, low FC | Pressure, runtime, FC vs. CYA |
| Green water | Algae, low effective chlorine | FC/CYA ratio, phosphates, circulation |
| Scale on tile or heater | Positive LSI, high CH/pH | LSI, temperature settings |
| Metal stains | Corrosive water, copper/iron | Source water, heater, LSI |
| Pump losing prime | Air leak, lid o-ring, low water | Lid gasket, suction fittings, skimmer level |
| High filter pressure | Dirty media, closed valve | Baseline psi, valves, flow |
Troubleshooting equipment
Diagnose in this order: 1) Power and breaker, 2) Water flow and filter pressure, 3) Chemistry and temperature, 4) Controls and sensors, 5) Components. Most "dead equipment" calls are flow, power, or a safety switch doing its job.
🔧 Plumbing tips and tricks
- Leak or evaporation? Run the bucket test: compare the pool and a bucket on the first step over 24 hours, with the pump on and then off.
- Air in the system: check the pump lid o-ring, drain plug, unions, and suction-side fittings. Bubbles in the basket usually mean an air leak.
- Dye tests at suspected leak points show water movement. Pressure-test lines with plugs and a gauge to find a bad line.
- Low flow? Check baskets, skimmer weir, impeller, clogged fittings, and partly closed valves before replacing the pump.
- For clogged lines, try a drain-clearing bladder or a controlled blowout. Don't overpressurize old pipe.
- Prime and cement PVC properly and respect cure times. Use PTFE tape on threads, and don't overtighten threaded fittings.
- Check valves and 3-way valves are a common hidden cause of flow issues. Check orientation and operation.
🔥 Gas heater diagnostics
If you smell gas, shut it off, ventilate, and call the gas company. Don't troubleshoot a suspected leak.
- Confirm the heater calls for heat: thermostat setting, pool pump running, error codes.
- Check flow: a pressure or flow switch will block ignition on low flow. Look for a dirty filter, closed valves, or a failing switch.
- Verify gas supply and pressure at the heater, and that the gas valve is on.
- Ignition: listen for the igniter or pilot sequence. Clean or replace a dirty flame sensor and check the igniter.
- Check venting and combustion air for blockage, and the high-limit and over-temp switches.
- Inspect the heat exchanger for scale or corrosion, which usually points back to unbalanced water (LSI).
- Use the manufacturer's fault code chart and wiring diagram, and test components before replacing them.
⚡ Electric heater and heat pump diagnostics
- Lock out power before opening panels. Verify supply voltage, breaker, and contactor operation under load.
- Electric resistance heaters: check the flow switch, high-limit, and element resistance and amp draw.
- Heat pumps: check airflow, a dirty or blocked coil, fan operation, compressor start, and the pool temperature rise across the unit (follow the manufacturer's range).
- Low output in cool weather or low humidity is often normal. Check the defrost cycle and ambient temperature limits first.
- Refrigerant work requires proper certification where law requires it.
🎛️ Setting variable speed pumps
- Priming: set a higher speed and a short priming time so the pump can pull water, then drop to normal.
- Filtration: pick the lowest speed that still gives enough daily turnover and good skimming. Many pools run roughly 1,200–1,800 RPM, but verify flow.
- Cleaner and features: give booster-less or suction cleaners, waterfalls, and spa jets their own higher-speed schedules.
- Heater, salt cell, and flow switches need a minimum flow. If they fault, raise the low speed or add a schedule to cover heating or chlorine production.
- Backwash and high-demand tasks: use a temporary high speed, then return to schedule.
- Use a pressure gauge or flow meter to confirm real flow, and set up a scheduled run profile (and freeze protection if relevant).
🧂 Troubleshooting salt systems
- Low or no output: check power and the flow switch, then verify salt with an independent test and compare it to the cell's minimum.
- Water too cold: many cells reduce or stop output below a set temperature. Check the manual.
- Scaled or dead cell: inspect plates, clean per manufacturer, and check hours of use and warranty status.
- Low chlorine despite output: check stabilizer, high demand (algae, heavy use), run time, and the output percentage setting.
- Persistent errors: check cell cable and connections for corrosion, then the control board and power supply.
- Check pH and alkalinity too, since salt systems push pH up over time.
📱 Understanding automation panels
- Know the parts: power supply, control board with relays, user interface, temperature sensors, valve actuators, and the communication bus to pumps, heaters, and chlorinators.
- Start with the basics: power, fuses, breakers, voltage, and a good ground.
- Communication faults: check bus wiring, polarity, and terminations. Many setups use RS-485 style connections.
- Valve actuators: confirm wiring, rotation direction, and position feedback if the system uses it.
- Sensors: temperature faults come from thermistors, so check readings against the manufacturer's resistance chart before replacing parts.
- Heater control: use relay or low-voltage control as the manual specifies, and confirm cool-down delays are set.
- Before a factory reset or firmware update, back up or photograph all settings and schedules.
Fault message reference
| Message type | Usually means | First checks |
|---|---|---|
| Low flow / flow switch | Not enough water moving | Filter pressure, baskets, valves, pump speed |
| High limit / over-temp (heater) | Heat not carried away, or scale | Flow, heat exchanger scale, thermostat |
| Ignition failure | No flame detected | Gas supply, igniter, flame sensor, venting |
| Low salt / no flow (salt system) | Salt below minimum or flow lost | Independent salt test, flow switch, cell scale |
| Overload / over-current (pump) | Motor strain or supply issue | Amp draw, voltage, impeller, bearings |
| Communication error (automation) | Bus or wiring fault | Wiring polarity, connections, power, board |
| Sensor fault | Open or shorted sensor | Resistance vs manufacturer chart, wiring |
Exact codes differ by brand and model, so confirm against the manufacturer's manual. I can add verified code tables for the specific brands you service.
⚠️ Professional note
Local codes, licensing, and manufacturer specs govern. Verify ranges against current standards (e.g., your health department, ANSI/APSP/ICC-11, and equipment manuals).
Local codes, licensing, and manufacturer specs govern. Verify ranges against current standards (e.g., your health department, ANSI/APSP/ICC-11, and equipment manuals).