Replace an old controller when it has a fault that cannot be repaired, when it has fewer stations than your system needs, or when it lacks scheduling capability you would genuinely use — independent programs, multiple start times for cycle-and-soak, or seasonal adjustment. Do not replace a working controller simply because it is old. A twenty-year-old unit that can be programmed sensibly is doing its job.
The capability question is the real one
Set aside faults for a moment. The honest argument for replacing a functioning older controller is capability, and there are only a few capabilities that matter enough to justify it.
Multiple start times per program, which is what makes cycle-and-soak possible. On Piedmont clay this is the single most valuable scheduling feature there is, because clay cannot absorb water as fast as most systems apply it, and splitting one long run into two or three shorter cycles with soak periods between converts runoff into infiltration. On a sloped lot the difference is substantial.
Independent programs, which matter on any system where turf, beds and drip zones need genuinely different schedules — and on large systems that have to be split to fit inside the legal watering window at all.
Seasonal adjustment as a global percentage, which lets you scale every zone proportionally as the season changes instead of rewriting every run time and losing the relative balance someone worked out originally.
Enough stations. A system that has grown beyond its controller’s capacity has usually had zones doubled up, which means two areas with different needs share one run time.
Reasons that are not good reasons
- Age on its own. Controllers do not wear out from switching zones; they fail from surges, heat and moisture. An old unit in a dry basement may have decades left.
- Wanting lower water bills, without fixing the system first. The savings people attribute to a new controller mostly come from correct scheduling, which an old controller can often deliver too.
- A dead display. That is frequently a tripped GFCI, an unplugged cord, a blown fuse or a failed transformer — all cheap, and none of them mean the controller has failed.
- One zone not working. That is almost always a valve, a solenoid or a station wire, and the controller is a bystander.
- Wanting phone control while the system has a broken head, a seeping valve and two mis-aimed zones. Automating a system with hydraulic faults automates the faults.
Want this looked at rather than read about?
Diagnostic-first visits across North Georgia. Call 770.335.8595 or request service — you get an estimate before any work begins.
Fix the hydraulics first
This is the point we make most often and it is worth being blunt about it. A controller decides when water is applied and for how long. It has no idea where the water goes.
A smart controller cannot detect that a head is misaligned and watering a driveway. It cannot tell that a lateral line is leaking, that overlap has been lost between heads, or that a valve is seeping continuously. It will schedule beautifully into a system that is wasting water, and the homeowner will conclude that smart controllers do not save anything.
So the order is: inspect the system zone by zone, fix leaks, correct coverage and alignment, address pressure, then choose a controller. Done in that order a good controller earns its keep. Done in the other order it disappoints.
What a replacement visit should include
- Identify every field wire before disconnecting anything. Labelled wire transfers quickly. An unlabelled bundle has to be traced station by station so the zone numbering still means something afterwards.
- Test each station electrically during the changeover. Resistance readings on every station while the wires are accessible catch marginal solenoids and developing wire faults before they surface as callbacks.
- Reconnect and test accessories. Rain sensor, master valve, pump start relay — each verified rather than assumed.
- Fit a weathertight enclosure for outdoor locations. Moisture and insects are what kill outdoor controllers, and the enclosure is the defence.
- Fit surge protection and ground it properly. Surge is the leading cause of controller death, and protection is cheap relative to the unit.
- Program it for the season and the soil. Inside the 4 p.m. to 10 a.m. window for publicly supplied water, with cycle-and-soak where the soil and slope call for it, and realistic run times rather than factory defaults.
- Document what each station operates. Written inside the door. This makes every future repair on the system faster and cheaper.
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Services that fix this
Controller Repair
The brain of the system: no power, dead stations, lost schedules and surge damage diagnosed and repaired.
Read more →Smart Irrigation Controllers
Weather-based watering that adjusts itself — set up properly for Georgia clay and the legal watering window.
Read more →Irrigation System Inspection
Every zone run, every head watched, every fault written down — before it becomes an expensive repair.
Read more →Where we work
Irrigation Medics repairs irrigation systems across Hall County and the Lake Lanier communities, the Gwinnett corridor through Duluth, Suwanee and Buford, and North Fulton and Forsyth — Johns Creek, Alpharetta, Milton, Roswell and Cumming. Same rates throughout. See the service area.