AC not turning on in Casselberry, Florida
A system that is completely dead is almost always a power or safety-switch problem rather than a broken air conditioner: a tripped breaker, a pulled disconnect, a blown low-voltage fuse on the control board, a tripped condensate float switch, or a thermostat with dead batteries.
What is most likely wrong
| # | Cause | How common | What it looks like |
|---|---|---|---|
| 1 | Tripped breaker or pulled disconnect | Very common | Nothing runs at all, indoors or out. |
| 2 | Condensate float switch tripped | Very common | The most common 'dead system' in Florida. Everything looks fine; nothing runs. |
| 3 | Thermostat batteries or settings | Very common | Blank or frozen display, or set to heat, or set above room temperature. |
| 4 | Blown 3A or 5A low-voltage fuse on the control board | Common | Blower and condenser both dead, thermostat unpowered if it is not battery-backed. |
| 5 | Failed contactor or transformer | Common | 24V control power absent. Needs a meter, not a guess. |
| 6 | Blower door safety switch | Less common | The air handler cabinet door has been left off or not seated after a filter change. |
| 7 | Failed control board | Less common | Usually diagnosed by elimination after the above. |
What you can safely check yourself
- Thermostat: batteries, set to cool, set below room temperature.
- Both breakers. Reset a tripped one once. If it trips again, stop and call — a breaker that trips repeatedly is telling you about a fault, not about itself.
- The outdoor disconnect pull-out is fully seated.
- The air handler cabinet door is properly closed and latched.
- The condensate line and secondary pan. A tripped float switch is a safety device doing its job; clear the blockage rather than bypass the switch.
- Any service switch on the wall by the air handler — they look like light switches and get flipped by accident.
Refrigerant, capacitors and the inside of an electrical panel are not homeowner jobs.
A run capacitor holds a lethal voltage after the disconnect is pulled. Refrigerant handling requires EPA Section 608 certification. And in Florida the work itself is regulated: an air conditioning contractor licensed under Chapter 489 may replace, disconnect and reconnect the power wiring at the dedicated disconnect, and repair or replace disconnects, breakers and fuses on dedicated HVAC circuits — s. 489.105(3). That scope exists precisely because this work is not general-purpose electrical work.
Verify any Florida licence, including ours, at the DBPR licensee search.
Why this happens in this housing stock
The float switch deserves special mention here. In a climate where the evaporator coil condenses water for most of nine months, the condensate system is the part most likely to shut a healthy system down — and it is supposed to. The float switch exists to stop the alternative, which is water in a ceiling. Drain line clearing is a researched $80–$250 and it is a routine call here in a way it is not in a dry climate.
Older Casselberry houses add a wrinkle: in much of the 1970s–80s stock the air handler sits in a garage or a hall closet with the drain running to an outside wall, and forty years of that line has usually accumulated a slope problem as well as a biological one. If yours blocks every single year, the line is the problem, not the algae.
Seminole County Property Appraiser CAMA extract (Parcels.csv, dated 2026-09-05). Improved residential parcels — single-family, townhome and condominium — in city tax district C1, City of Casselberry. n = 8,563.
What the fix typically costs
| Job | Researched range | What drives it |
|---|---|---|
| Diagnostic visit | $75–$150 | Usually credited. |
| Drain line clearing | $80–$250 | The most common cause of a dead system here. |
| Contactor or relay | $100–$450 | A wear item. |
| Thermostat repair or replacement | $100–$500 | Spans a $20 stat to a matched communicating control. |
| Capacitor replacement | $150–$400 | If the condenser is dead but has control power. |
These are researched market ranges, not our prices and not a quote.
The dollar figures below come from published third-party cost guides — named and linked at the foot of the page — and from the City of Casselberry’s own published permit fee. They are here so you can tell whether a quote you have been handed is in the ordinary range for this work. They are not an offer, and no two houses in Casselberry cost the same to do.
Not getting anywhere?
Tell us the symptom, the build year of the house and roughly how old the equipment is. That usually narrows it to two candidates before anyone drives out.
Phone: (689) 308-3675 · Monday-Friday, 8:00 AM - 5:00 PM
Where the facts on this page come from
Every figure above is either a primary-source document or a named third-party cost guide. All of it was checked in September 2026. Fee schedules, rebate amounts and market prices change without notice — if you are about to spend money on one of these numbers, open the source and check it.