Raypak 009577F Water Temperature Sensor, 3-Wire, for Digital 206A-406A, 207A-407A, 408A, 156A and Avia (Inlet)

Raypak 009577F Water Temperature Sensor, 3-Wire

Part # 009577F | Genuine Raypak replacement part | For digital 206A to 406A, 207A to 407A, 408A and 156A heaters and the Avia water inlet

This is the water temperature sensor Raypak uses on its digital gas heaters with electronic ignition. It is a 3-wire sensor holding two 100K thermistors. The control board reads both, shows the water temperature on the display and calls for heat when the water falls below the set temperature. On the Avia it is the inlet water sensor.

✅ Fits these Raypak models:

• 206A, 266A, 336A and 406A digital heaters with electronic ignition (Raypak's 2019 parts list also names the 266 and 399)
• 207A, 267A, 337A and 407A digital Low NOx heaters
• 408A Professional Series heater
• 156A digital above-ground heater (the analog 106A takes the 2-wire sensor 011587F)
• Avia 264A and 404A, water inlet sensor only (the Avia outlet sensor is 019043F)
• 84 Professional 259B and 409B Low NOx heaters, built 2016 to 2018
• RP2100 R185B, R265B, R335B and R405B with electronic ignition, built 2003 to 2004
• Not for millivolt heaters, which use a mechanical thermostat

🔧 Details:

• Raypak part names: Temperature Sensor IID Units; Temperature Sensor Digital (3-Wire); Kit-Temperature Inlet Sensor on the Avia. IID is Raypak's short form for its electronic intermittent ignition device
• 100,000 ohm (100K) dual thermistor, as stated in Raypak's Digital Tool Box Guide and Avia Tool Box Guide
• 3-wire sensor. The manuals have its wiring checked at control board terminal P1
• Raypak's Tool Box Guide shows it on the inlet/outlet header. The sensor adapter (006714F on the 206A to 406A) is a separate part

📌 Good to know:

• On the digital 206A to 406A, Raypak's manual ties three display messages to this sensor: Sensor Failure (the two thermistor readings disagree by more than 2°F), Sensor Open and Sensor Short. It says to inspect the thermistor, wires and connector, check the resistance against the chart in the manual, and replace the sensor if it is more than 10% off.
• Electrical diagnosis on a gas heater is for a qualified technician.

Check your heater's model and serial number before ordering.