Crown Boiler PHNTM080 - Temperature Sensor

120
Combustion Fan–Thecombustionfanpushesair-fuelmixtureintotheburnerandthespeedofthisblowerdeterminesthering
rate. There are two electrical connections at this fan:
 • 120VPlug–Supplies120VACPowertotheFan
 • SpeedControlPlug - Delivers a PWM (speed control) signal from the boiler control to the fan. This plug also includes
` tachometer connections so that the boiler control can monitor the actual fan speed.
In the event that there is 120volts at the boiler, but no signal at the speed control plug, this fan will run at its maximum speed.
Speciccausesofthisinclude:
 • Disconnectedspeedcontrolplug
 • Blown24Vfuse.
 • LooseJ2Plug
 • LooseP8plug(P8isonbacksideoflowvoltagePCB)
 • LooseL2orL3Plug
Gas Valve – The gas valve used on this boiler has either one or two 24VDC coils (the gas valve used on all boiler models is
redundant).Thegasvalveoutputfromtheboilercontrolis24VAC.Arectiermoduleisinstalledbetweenthegasvalveandthe
wiringharnessonthe80,100and120models(Figure11.4a).Therectierisbuiltintothegasvalveplugitselfonthe150and
180.
Table 14.6a: Supply, Return and Flue
Temperature Sensor
Temperature versus Resistance
Temperature Ohms of
Resistance
°F °C
32 0 32624
50 10 19897
68 20 12493
77 25 10000
86 30 8056
104 40 5324
122 50 3599
140 60 2483
158 70 1748
176 80 1252
194 90 912
212 100 674
230 110 506
248 120 384
Table 14.6b: Outdoor Air Temperature Sensor
Temperature versus Resistance
Outdoor Temperature Ohms of
Resistance
°F °C
-20 -28.9 106926
-10 -23.3 80485
0 -17.8 61246
10 -12.2 47092
20 -6.7 36519
30 -1.1 28558
40 4.4 22537
50 10.0 17926
60 15.6 14356
70 21.1 11578
76 24.4 10210
78 25.6 9795
80 26.7 9398
90 32.2 7672
100 37.8 6301
110 43.3 5203
120 48.9 4317