| Models | Serial # Range | Years |
| Classic | F 151001 to F 4B9999 | 1995-2000 |
| Classic (230volt only) | FH-151001 to FH-469999 | 1995-1996 |
| Classic | FQ 151001 to FQ 4B9999 | 1995-2000 |
| Grandee | G 151001 to G 2D1251 | 1995-2002 |
| Grandee | GQ 151001 to GQ 2D1251 | 1995-2002 |
| Highlife | K 151001 to K 469999 | 1995-1996 |
| Jetsetter | J 151001 to J 2D1257 | 1995-2002 |
| Jetsetter | JQ 151001 to JQ 2D1302 | 1995-2002 |
| Landmark | S 151001 to S 2D1110 | 1995-2002 |
| Landmark | SQ 151001 to SQ 2D1226 | 1995-2002 |
| Prodigy | H 151001 to H 2D1249 | 1995-2002 |
| Prodigy | HQ 151001 to HQ 2D1334 | 1995-2002 |
| Sovereign (230volt only ) | IH-151001 to IH-469999 | 1995-1996 |
| Sovereign | I 151001 to I2D1473 | 1995-2002 |
| Sovereign | IQ 151001 to IQ2D1554 | 1995-2002 |
| Sovereign Limited | ILE 1D1001 to ILE 2D1344 | 2002 |
| Vanguard | V 1C1001 to V 2D1315 | 2001-2002 |
| Vanguard | VQ 1C1001 to VQ 2D1363 | 2001-2002 |
 |
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| Models | Serial # Range | Years |
| Khyber / Siberian | L 151001 to L 2D1354 | 1995-2002 |
| Manora / Bengal | M 151001 to M2D1942 | 1995-2002 |
| Sumatran | N 171001 to N 2D1530 | 1997-2002 |
| Tondi | P 151001 to P 469999 | 1995-1996 |
Note: Symptom of this part failing is a flashing red "Power" light on the Hot Spring & Tiger River control panel or on the control box of the 1995-1996 Tiger Rivers. This thermistor is smaller in diameter than the Control Thermostat Thermistor (78969). It screws into the port (hand tight only) marked "outlet" on the PDR replacement heater. Typically, when one thermistor needs replacing the other is close to failing as well and should be replaced at that same time. Thermistors have a reliable lifespan 6-8 years or so.
