O-ring for the outlet side of a Watkins No-Fault Heater. It is the smaller of the two o-rings. This o-ring is for the part number 38416 thermistor, and the part number 39204 thermistor.
| Item | Decription | Serial Numbers Uses | Part # |
| 1 | Screw | All 1E1001 - Current | 35162 |
| 2a | Heater Titanium 6kw | All 1E1001 - Current | 76227 |
| 2b | PDR Heater Retro Fit 6kw | All 1E1001 - Current | 73790* |
| 2c | Heater Titanium 6kw | All 1E1001 - Current | 76228 |
| 2d | PDR Heater Retro Fit 4kw | All 1E1001 - Current | 73791 |
| 3 | Clamp 3/4" | All 1E1001 - Current | 300055 |
| 4 | Tubing 3/4" | All 1E1001 - Current | 70315 |
| 5 | O ring Hi Limit | All 1E1001 - Current | 34879** |
| 6 | High Limit Thermistor | All 1E1001 - Current | 39205 |
| 7 | O Ring Control Thermistor | All 1E1001 - Current | 34878** |
| 8 | Control Thermistor | All 1E1001 - Current | 39204 |
| Item | Description | Part # |
| 1 | T-stat Control Thermistor | 38415 |
| 2 | O-ring Control Thermistor | 34878 |
| 3 | Hi-limit Thermistor Assy | 38416 |
| 2 | O-ring Hi-limit Thermistor | 34879 |
| ITEM | Description | Serial No Used | Part No |
| 1a | Thermistor Assy Hi- Limit | see below matrix | 38416 |
| 1b | Thermistor Assy Control | see below matrix | 38415 |
| * | O- Ring Control Thermistor | All-151001-current | 34878 |
| * | O- RIng Hi- Limit Thermistor | All-151001-current | 34879 |
