Evaporative (swamp) cooler repair & service
Still running a swamp cooler?We still service them.
Pads, pumps, float valves, motors, belts and the mineral scale our water leaves behind. Repaired by a licensed HVAC contractor rather than whoever answered the ad, and with an honest answer about whether it is worth keeping.
CSLB #999179 Licensed & insured Spring startup service
Worth knowing
Most swamp cooler work here is done by handymen
That is not a criticism of every handyman, and plenty of them change a set of pads perfectly well. But an evaporative cooler is a piece of mechanical equipment with a water supply, a 120-volt motor and a mounting on your roof, and there are real differences between a licensed contractor and a general handyman doing that work.
If you are happy with your cooler, we will fix it properly and leave. That is the entire job.
Briefly
How yours actually works
An evaporative cooler pulls outside air through wet pads. Water evaporating off those pads absorbs heat from the air passing through, and the cooled air is pushed into your house. There is no refrigerant, no compressor and no sealed system — which is why they cost so little to run and why every component on the list below is repairable.
It works best when the outside air is dry, which is exactly what a Fresno summer delivers for most of the season. That is why they are everywhere here and rare in humid parts of the country.
Pads
Aspen fiber or rigid media. The surface where evaporation actually happens, and the part that needs replacing most often.
Pump
A small submersible pump lifting water from the pan to the distribution lines at the top of the pads.
Float valve
Controls the water level in the pan. Stuck open floods, stuck closed leaves the pads dry.
Motor and blower
A squirrel-cage blower moving air through the wet pads and into your ducts or ceiling vent.
Belt
On belt-driven models, connecting motor to blower. Stretches, slips and eventually breaks.
Bleed or purge system
Continuously discards a little water to stop minerals concentrating. Critical with Fresno water.
The mistake we see most
A swamp cooler needs windows open
This is the single most common reason we get called to a cooler that "stopped working" and turns out to be fine. Evaporative cooling pushes a large volume of air into the house, and that air has to leave somewhere. Close everything up the way you would with refrigerated air conditioning and the cooler is fighting the pressure it created itself.
Worse, the moisture it adds has nowhere to go either. Humidity inside climbs, evaporation becomes less effective, and the cooler that was working perfectly last week now feels like it is blowing damp warm air.
Getting it right
- Open windows on the far side of the house from the cooler, not next to it.
- Two to four inches across a few windows is usually enough. It is about a path for air, not a gale.
- Open more in the rooms you want cooler, less elsewhere. That is how you direct the airflow.
- Run the pump a few minutes before the blower so the pads are properly wet before air starts moving.
What goes wrong
Seven faults that account for most of the swamp cooler calls we take, in roughly the order we find them.
Pads that are spent, scaled or dried out
The most common by a distance. Pads collapse, clog with mineral deposits or dry into a hard mat that air passes straight through without evaporating. They are consumable, they get replaced at least annually here, and a fresh set often resolves a cooler that seemed dead.
A failed or clogged pump
No water reaching the pads means no cooling, just a fan. Pumps fail outright, seize after a winter dry, or clog with scale and sediment. The tell is a cooler blowing air that is moving but not cool, with dry pads.
A stuck float valve
Stuck closed and the pan runs dry, so the pump has nothing to move and burns itself out. Stuck open and it overflows continuously, which on a roof-mounted cooler means water going somewhere you would rather it did not.
Blocked water distribution lines
The tubes that spread water across the top of the pads scale up and block, so parts of the pad stay dry. You get partial cooling and an assumption that the whole unit is failing when it is a cleaning job.
Motor, bearings or belt
Squealing, grinding or a blower that will not turn. Belts stretch and snap, bearings fail after seasons of humid operation, and motors eventually give out. All repairable on most units.
A rusted or leaking pan
Years of standing water eventually rusts the pan through. On a roof-mounted cooler this shows up as staining down a wall or a wet patch in a ceiling, and it is the point where the economics of repair start to get discussed honestly.
A musty or unpleasant smell
Stagnant water in the pan and biological growth on old pads. Draining, cleaning and fresh pads resolve it. If the smell returns quickly, the bleed system is usually not working. More on swamp cooler symptoms.
They need two visits a year, not one
Evaporative coolers are more seasonal than refrigerated systems. Skipping either end of the year is how a working cooler becomes a broken one.
March to May
Spring startup
- Pan drained, cleaned and scale removed
- New pads fitted and seated correctly
- Pump tested and distribution lines cleared
- Float valve set to the correct water level
- Belt tension checked or replaced, motor lubricated
- Water line reconnected and checked for leaks
- Bleed system confirmed working, and run tested
October to November
Fall shutdown
- Water supply shut off at the valve
- Supply line drained so it cannot freeze and split
- Pan drained completely and dried out
- Old pads removed rather than left to rot in place
- Unit covered, and the ceiling damper closed
- Condition noted so spring startup is not a surprise
Closing the ceiling damper matters more than people think. An uncovered cooler with an open damper is a hole in your roof all winter, and it will show on your heating bill.
The local factor
Fresno water is hard on these
Evaporative cooling works by leaving the water behind and sending the vapor into your house. Everything dissolved in that water stays put — on the pads, in the pan, inside the distribution lines and through the pump.
With hard water, that accumulates fast. It is why pads here need replacing more often than the packaging suggests, why pumps clog, and why a cooler that was cleaned properly last spring performs noticeably better than one that was not.
The bleed system exists specifically to manage this by continuously discarding a small amount of water. When somebody plugs it to save water, scale builds several times faster and the whole unit suffers.
What we do about it
- Descale rather than rinse. Pan, lines and pump housing properly cleaned rather than hosed off.
- Confirm the bleed is running. A blocked or deliberately plugged bleed is a common find.
- Set the water level correctly. Too high wastes water through the overflow, too low starves the pump.
- Tell you the honest pad interval for your water and your run hours, rather than the number on the box.
Being straight with you
What a swamp cooler can and cannot do
Evaporative cooling is genuinely good at what it does. It costs a fraction of refrigerated air to run, it brings in continuous fresh air rather than recirculating the same air, and in dry Fresno heat it produces a real and meaningful temperature drop.
Its limits are physics rather than a defect. It cannot cool below what the outdoor humidity allows, so as moisture in the air rises — late summer, or a monsoon push — effectiveness falls exactly when you need it most. It adds humidity indoors. And on a genuine 108-degree afternoon it will not hold the temperature refrigerated air conditioning will.
Whether that is a problem depends entirely on you. Plenty of Fresno households run a swamp cooler happily for decades and have no interest in changing. If yours is one of them, we will keep it running properly and say nothing further about it.
If it has stopped being enough, that is a separate conversation and we are happy to have it when you raise it.
What it costs
Most of these are small jobs
Swamp cooler repairs sit at the inexpensive end of what we do. Pads, pumps, float valves, belts and distribution lines are all modest parts, and most visits are resolved in one trip. We quote the specific job after diagnosis rather than publishing a range, because the spread between a set of pads and a motor replacement is wide and the honest number depends on what we find.
Spring startup and fall shutdown are priced as set services, and you will hear the figure when you book rather than when we arrive. If a repair does not make economic sense on an older unit, we will tell you that plainly instead of doing it anyway.
Swamp cooler questions
Do you still service swamp coolers in Fresno?
Yes. Pads, pumps, float valves, motors, belts, distribution lines, pan repairs, and seasonal startup and shutdown service. Most evaporative cooler work in this area is handled by handymen, and we are a licensed HVAC contractor doing the same work with insurance, a written warranty and CSLB accountability behind it.
Why is my swamp cooler blowing warm air?
Usually because the pads are not wet. That points at a failed or clogged pump, a stuck float valve leaving the pan dry, or blocked distribution lines. Spent or scaled pads produce the same result even when water is reaching them. It can also happen when the house is closed up, because the cooler needs windows open to move air through and let humidity escape.
How often do swamp cooler pads need replacing?
At least once a year in Fresno, and sometimes mid-season on a cooler that runs heavily. Our water is hard, and evaporation leaves those minerals behind on the pads, so they scale up and stop evaporating efficiently well before they look worn out. Fresh pads are frequently the whole fix on a cooler that seems to have failed.
Do I really need to leave windows open?
Yes, and it is the most common reason a working cooler appears broken. Evaporative cooling pushes a large volume of air in, and that air needs a way out. With the house sealed, pressure builds, humidity rises indoors and cooling performance collapses. Two to four inches across a few windows on the far side of the house is usually enough.
How much does swamp cooler repair cost?
These are among the least expensive repairs we do, since pads, pumps, float valves and belts are modest parts and most visits are resolved in one trip. We quote the specific job after diagnosis rather than publishing a range, because the difference between a set of pads and a motor replacement is substantial.
Why does my swamp cooler smell?
Stagnant water in the pan and biological growth on old pads. Draining, cleaning and fitting fresh pads resolves it. If the smell comes back quickly, the bleed system that continuously discards a little water is usually blocked or has been deliberately plugged, which lets minerals and growth concentrate.
Should I replace my swamp cooler with central air?
Only if it has stopped meeting your needs. Evaporative cooling costs far less to run and brings in fresh air continuously, and plenty of Fresno households are perfectly happy with it. Its limits are that it cannot cool below what outdoor humidity allows and it will not hold temperature on a genuine 108-degree afternoon. If that has become a problem, conversion is worth looking at. If it has not, we will simply keep yours running.
Let's get it running
Diagnosed properly, repaired by a licensed contractor, and warranted in writing.
Repairs are quoted after diagnosis and approved by you before any work begins. Roof access is subject to the roof being safe to work on; where it is not, we will tell you before booking. California Heating & AC Repair is operated by Craftline Renovations, Inc. · CSLB License #999179 · Licensed and insured.