MasterCool Swamp Coolers: A Reno Owner's Reference

You are most likely to find a MasterCool on a Reno roof when the cooler up there went in within the last fifteen years or so. It is the rigid media brand from Essick Air Products and Champion Cooler Corporation. Below: how to read the model number, the catalog names for the parts, and the order things wear out on Truckee Meadows water. What any of the work costs is on the pricing page.

Reading the data plate

Every MasterCool residential unit is single-inlet, and the prefix tells you which way the air leaves:

The digits after the prefix give cabinet and media. A 51 is the smaller cabinet and a 71 the larger, and a trailing 12 means 12 inch media rather than 8 inch. An ADA5112, for example, is a 51-size down-draft carrying 12 inch media.

The Contractor Line uses its own prefixes, AS1C for 115 volt and AS2C for 230 volt, and arrives fully assembled with motor, pump, pulley, purge system, and thermostat. Most installs get those units with two-speed motors, and in Reno that pairing earns its keep after dark: the July normal low at the airport is 60.4 against a normal high of 93.9, so the low speed and the thermostat get used every evening. The too-cold-at-night page explains why.

Airflow, motors, and belts

MasterCool rates the residential line from 1,370 to 5,024 CFM, and its published table is candid about ductwork. An ASA71 with a 3/4 horsepower motor moves 3,619 CFM at 0.1 inches of static pressure but only 2,978 at 0.5 inches. That drop is the reason one model can cool a single-story Sparks ranch nicely and leave a two-story Spanish Springs house warm upstairs.

On the standard line the motor and pulley are bought separately. Motors come in 1/3, 1/2, 3/4, and 1 horsepower; pulleys in 3-1/2 by 1/2, 4 by 1/2, or 4 by 5/8 inch bore. A 51 cabinet takes a 57 inch belt and a 71 cabinet a 67 inch belt.

Parts by their catalog names

Getting the right piece starts with calling it what MasterCool calls it:

• Water distribution system. PVC tubing inside a protective housing that spreads water over the top of the media. The distributor tube, the distributor housing, and a distributor filter pad are each sold on their own. When the top of a pad is wet and the bottom dry, look here first.
• Float. Sold as a float valve assembly: an adjustable brass arm with a splash guard.
• Pump. A submersible pump, thermally protected and UL recognized. The basket, retainer, screen, and receptacle are separate parts.
• Purge pump. An optional kit on its own bracket, sold by MasterCool as a way to cut mineral build-up and make media last longer.
• Media. Munters CELdek rigid media, UL Greenguard certified, under a five year limited warranty.
• Wet section and reservoir. A thermoplastic reservoir that will not corrode, carrying a limited lifetime warranty, plus a non-metallic moisture shield that keeps water off the steel cabinet.
• Cabinet and blower. Bolted galvanized steel finished in polyester powder coat, a machine-balanced blower wheel, and a mesh prefilter screen.

Truckee Meadows water and the purge kit

TMWA’s river water is soft most of the time, 2 to 5 grains per gallon across most of Reno and Sparks in its own area reports. The catch is that it does not hold still. Southwest Reno read 13.9 grains in the first quarter of 2026 and 2.6 in the second; West Reno went from 10.4 to 6.7. TMWA itself says the groundwater wells it brings on from mid-April through October can and do shift the chemistry somewhat. Pan concentration climbs fastest when the supply turns hard, so a cooler seeing 3 grains one quarter and 14 the next needs a purge more than one on a steady supply. Scale is what seizes pumps, sticks floats, and crusts pads until air blows through without cooling, the most common warm air call of a Reno summer.

Rigid media helps on the same front. The corrugated sheets slow the air down, which MasterCool says raises saturation and delivers cooler air, and by the same physics they hold water longer and shed scale better than shredded aspen, provided the pan is bled or purged.

On rebates: utilities in Colorado and New Mexico pay for evaporative coolers, but we could not find an NV Energy rebate for them, so choosing 8 inch or 12 inch media here comes down to comfort and lifespan rather than a rebate tier. The permits and licensing page shows what we checked.

Failure order on a MasterCool

1. Pump, $150 to $400 installed. Scale on the impeller, or a burnout after a stuck float let it run dry. A packed screen looks just like a dead pump, so check it before buying anything; the pump-not-pumping page has the two-minute test.
2. Float valve assembly, $100 to $250. Stuck closed it starves the pads; stuck open it sends water over the roof edge, which is the leaking water call.
3. Belt, $40 to $100 with the visit. A 57 or 67 inch belt by cabinet, and the cheapest repair on the roof.
4. Distribution tubing and filter pad. Inexpensive, easy to overlook, and the usual cause of a pad that wets unevenly.
5. Media, three to five years, less without a working purge. A rigid set runs $300 to $700 against $80 to $200 for aspen.
6. Motor, $300 to $700, with two-speed at the top of that range. Test the capacitor and the blower bearings before writing one off.

The pan is where this line is strong. The thermoplastic reservoir carries a limited lifetime warranty and does not rust through the way the older galvanized pans on the 1950s Sparks ranches do. It also changes what a missed shutdown costs: a MasterCool left full into Reno’s October freeze tends to crack a pump housing rather than open a pan seam, which is the cheaper mistake, though a fall winterization is still the right call. With a sound pan, nearly every repair on the pump and float page is worth making.

Related pages: the aspen side of the same family is on the Champion and Essick page, the other rigid media line common in the West is on the AeroCool page, and the repair cost calculator prices a repair on your unit from the published ranges.