Heat Controller Water Source Heat Pump manual 6, Supply & Return Water Temperature Sensors

Section 2 WattMaster WHP

Supply & Return Water Temperature Sensors

Sensors for monitoring supply and return water temperature are available in two main types, fluid immersion temperature sensors (See Figure 2-6) and strap-on sensors (See Figure 2-7). Both are 0-10000 ohm thermistor type sensors. The fluid immersion sensor generally has better accuracy than the strap-on type but either is suitable for typical water source heat pump temperature requirements. The fluid immersion type sensor requires that a thermowell be installed in the pipe and the strap-on type, as its name implies, simply straps around the outside of the pipe. The fluid immersion sensor requires that the pipe be at least 4” in diameter in order to accept the thermowell. The strap-on type sensor is adjustable for use on 1/2” to 6” or larger diameter pipe.

The fluid immersion sensor is provided with a 4” long stainless steel thermowell. It has ½” MPT external threads and ½” FPT internal threads. A ½” FPT fitting to accept the thermowell must be provided by others in the pipe to be monitored, for connection of the thermowell. The thermowell is screwed into the ½” FPT fitting installed by others in the pipe and the sensor probe is then screwed into the ½” FPT fitting on the thermowell.

Leads Are Non-polarized.

Butt Splice Leads To 24 Gauge

Wire Minimum. Connect Leads

To "Analog In" And "Ground"

At Controller.

OE230 Duct Sensor

The OE230 Duct Sensor Threads Into The OE291 Stainless

Steel Thermowell. The OE291 Thermowell Threads Into A 1/2”

FPT Elbow or Tee in the Water Piping1/8-27of theNPT5.Water50ExternalCoilThread 1/8-27OE291NPSMStainlessInternal4.941/2"5Thread.13NPTSteelExternal3.25ThermowellThread0.

Where You Wish to Measure the Water Temperature. The Pipe must be a minimum of 4” Diameter or an Extended Tee and Bushing Configuration Must be Used to Accommodate the Length of the Thermowell Assembly.

Duct Sensor with Thermowell

Figure2-6:

2-10 Installation and Wiring