| WATTS | VOLTS | Hot Zone MM/IN. | Overall MM/IN. | 304SS 316SS | Titanium | Ship Wt. Lbs./(Kg) |
| 3000 | 240 480 | 180(7) | 280(11) | S3SP3211 S3SP3241 | S3TP3211 S3TP3241 | 21(9.5) |
| 6000 | 240 480 | 330(13) | 430(17) | S3SP6217 S3SP6417 | S3TP6217 S3TP6417 | 30(13.6) |
| 9000 | 240 480 | 460(18) | 585(23) | S3SP9223 S3SP9423 | S3TP9223 S3TP9423 | 33(15) |
| 12000 | 240 480 | 610(24) | 735(29) | S3SP12229 S3SP12429 | S3TP12229 S3TP12429 | 39(17.7) |
| 15000 | 380 480 | 760(30) | 890(35) | S3SP15435 | S3TP15435 | 45(20.5) |
| 18000 | 380 480 | 890(35) | 1040(41) | S3SP18441 | S3TP18441 | 51(23) |
| 24000 | 380 480 | 1040(41) | 1195(47) | S3SP24447 | S3TP24447 | 65(29) |
| 27000 | 380 480 | 1195(47) | 1350(53) | S3SP27453 | S3TP27453 | 70(32) |
| 2400 | 240 480 | 180(7) | 280(11) | S3SP2.4211 S3SP2.4411 | S3TP2.4211 S3TP2.4411 | 21(9.5) |
| 4800 | 240 480 | 330(13) | 430(17) | S3SP4.8217 S3SP4.8417 | S3TP4.8217 S3TP4.8417 | 30(13.6) |
| 7200 | 380 480 | 460(18) | 585(23) | S3SP7.2423 | S3TP7.2423 | 33(15) |
| 9600 | 380 480 | 610(24) | 735(29) | S3SP9.6429 | S3TP9.6429 | 39(17.7) |
| 12000 | 380 480 | 760(30) | 890(35) | S3SP12435 | S3TP12435 | 45(20.5) |
| 14400 | 380 480 | 890(35) | 1040(41) | S3SP14.4441 | S3TP14.4441 | 51(23) |
| 16800 | 380 480 | 1040(41) | 1195(47) | S3SP16.8447 | S3SP16.8447 | 70(32) |
Electric heaters made with resistance wire
Traditional immersion heaters use “resistance wire” as the source of heat. Resistance wire is commonly used in toasters and electric water heaters and is usually a nickel/chromium alloy. It will typically heat to around 900°F.
When an electric immersion heater using resistance wire operates in air or becomes covered with solid buildup (such as fish waste), the heat is not able to dissipate quickly enough. This results in a rapid increase in operating temperature. Elevated temperatures shorten the heater life and can damage surrounding plastic materials including pond liners.
To protect these materials from high-temperature damage, electric immersion heaters often include a built-in heater over-temperature cutoff device – called a “protector.” The protector senses the surface temperature of the heater and trips if it gets too hot. This shuts the heater off. While the protector is a necessary safety device, a heater that is shut off may threaten the pond or tank inhabitants.
As Don Campbell, First Ascent Fish Farm, explains, this is one of his primary concerns with his current equipment. *“We train our customers in both programming and care of the heater/controller. However, too frequently the folks we train are not the folks cleaning the tanks between deliveries and the heater is not unplugged, leading to a blown fuse [protector].*”
After a protector has tripped it must be replaced. If there is no protector onsite, the tank or pond may suffer a loss of heat. For a supplier or keeper of live fish, this can result in increased mortality.
Electric heaters made with PTC chips:
Electric heaters using PTC chips do not use resistance wire as a source of heat. Instead, they use PTC (Positive Temperature **Coefficient) chips. When the chip temperature increases, its electrical resistance also increases, resulting in decreased heat output. As the PTC chips heat up, they will reach a designed temperature at which they cannot get any hotter. Thus, PTC chips have a predetermined temperature limit.
No protectors to replace
Thermal protectors are not necessary with PTC electric immersion heaters. Their self-limiting capability offers the safety of a protector built directly into the heater core. This eliminates downtime caused by a tripped protector and the need for replacements.
PTC heaters will not damage tanks or liners.
PTC immersion heaters have a maximum surface temperature of 518°F when in air and manufactured with ½-inch spacers so they will not damage tank or pond liner materials. They will not damage tanks made from polyethylene (PE), high-density polyethylene (HDPE), fiberglass, polypropylene (PP), CPVC or PVC as well as other materials (see chart).
PTC heaters can operate in air or with solids buildup
A resistance heater will overheat if operated in air, covered by scale or solid waste. This elevated temperature can shorten the life of the heater by several months. With PTC heaters the potential for burnout is eliminated, thereby increasing service life. (Removing the material from the surface of the PTC heater or putting it back in water will raise the heat output accordingly.)
According to Campbell, the advantages offered by PTC heaters, *“could pay for themselves in both labor savings and fewer mortalities in less than one year.”
