CleaverBrooks CFC-500 Operation, Service And Parts Manual page 22

Section 2 — Installation
2-8
21.Route return water sensor (the 2-wire sensor) to the lower pipe on back
of boiler, and install lower panel. Coat sensor with heat-conductive
compound P/N 872-00631. Insert sensor into return pipe sensor well
and secure with mounting clamp (Figure 2-13).
Figure 2-13
22.Coat outlet feed water temperature sensor (the 3-wire sensor) with heat-
conductive compound P/N 872-00631. Insert sensor in sensor well
behind the burner (Figure 2-14).
B
A
Figure 2-12
Part No. 750-263