Pump symptoms and what they mean
The pump is the heart of the system, and it fails loudly and predictably. Learning to match the noise to the cause tells you whether you have weeks or hours.
- Rising screech or metallic grinding: motor bearings are failing. It gets worse until the motor seizes. Replace or rebuild before it takes the seal with it.
- Humming but not spinning: usually a failed start capacitor or an impeller jammed with debris. Both are far smaller repairs than a seized motor.
- Bubbles in the pump basket or streaming from the returns: a suction-side air leak. Check the lid, the lid O-ring, water level at the skimmer, and the baskets.
- Losing prime repeatedly: same family of causes as air bubbles, plus a possible crack in the fitting between skimmer and pump.
- Water dripping under the motor: the shaft seal has failed. Keep running it and water reaches the motor windings, which turns a cheap part into a new pump.
- Tripping the breaker: stop and call. This is electrical, and pools and improvised electrical diagnosis do not belong together.
Filter pressure: the one gauge worth watching
The pressure gauge on the filter is the single most useful diagnostic on the equipment pad, and most owners never establish the number that makes it useful. Right after a filter cleaning, note the reading. That is your clean baseline. Everything afterward is read against it.
When pressure sits 8-10 psi above baseline, the filter is loaded and flow is restricted. That restriction is not merely a filtration problem: it starves the heater, strains the pump, and is behind a surprising share of "my heater is broken" calls. Pressure that is unusually low instead usually means flow is blocked before the filter. A clogged basket, a closed valve, or a failing impeller.
- Sand: backwash at 8-10 psi over baseline; replace the media every 5-7 years
- Cartridge: clean several times a season; replace elements every 2-3 years
- DE: backwash and recharge at 8-10 psi over baseline; inspect grids annually for tears
When the heater will not fire
Heaters are the component most often blamed for someone else’s failure. Before assuming the worst, work the checks in this order. The first two resolve a large share of calls at no cost.
- Clean the filter. Low flow trips the pressure switch and the heater refuses to fire by design.
- Confirm gas supply: check that the valve is open and that other gas appliances are working.
- Check the thermostat setpoint against actual water temperature. A heater will not run for a one-degree difference.
- Look for a fault code on the display and write it down before cycling power; many heaters clear the code on restart.
- Inspect for nests. Mice and wasps overwinter in Illinois heaters constantly, and the debris blocks burners and sensors.
- Everything past this point (ignition, flame sensors, limit switches, heat exchangers) is a technician’s job. Gas appliance diagnosis is not a DIY project.
Salt cell problems
A salt system that reports low output usually has a scaled cell rather than a chemistry problem. Fox Valley water is hard, and calcium builds on the cell plates until they cannot produce chlorine. Inspect the cell periodically and clean the scale off according to the manufacturer’s instructions. That one habit is most of the difference between a cell that lasts three years and one that lasts seven.
Also check the obvious before replacing anything expensive: salt level in range, water temperature above the cutoff (most cells stop producing in cold water by design), and the cell not simply at the end of its 3-7 year life. And every fall, the cell comes out, gets cleaned, and is stored indoors. A cell left plumbed in over an Illinois winter cracks.
Spring startup failures are winter failures
The equipment problems that surface at opening were almost always created the previous fall. Water left in a pump housing, filter, heater, or chlorinator expands when it freezes and cracks the housing. You simply do not find out until April. Cracked pump housings, split heater manifolds, and ruptured filter tanks are the standard consequences of an incomplete winterization.
This is the practical argument for professional closing: a blown-out, plugged, and fully drained system has nothing left in it to freeze. If you opened this season to a cracked component, the fix is not just the part. It is making sure the closing that caused it does not repeat.
What is safely DIY, and what is not
Homeowner territory: emptying skimmer and pump baskets, backwashing and cleaning filters, replacing a pump lid O-ring, checking water level, resetting a tripped GFCI once, and noting fault codes before you call.
Not homeowner territory: anything involving gas connections, opening a heater’s combustion area, electrical work at the equipment pad, breakers that trip repeatedly, and pressurized plumbing repairs. Beyond the safety issue, a misdiagnosis at this level tends to cost more than the service call would have.