A.O. Smith 100 Series Service Handbook page 26

MCB - SECTION E
See Figure 12 on page 19 for location of this section on the MCB.
• J6 Socket (Not Used)
• Pin 1 - N/A - not used
• Pin 2 - N/A - not used
• Pin 3 - N/A - not used
• Pin 4 - N/A - not used
• J7 Socket (Outlet Temperature Probe, Manual
Reset High Limit)
• Pin 1 - 24 VDC manual reset high limit
• Pin 2 - 24 VDC manual reset high limit
• Pin 3 - Not used
• Pin 4 - 5 VDC Outlet Temperature Probe
• Pin 5 - 5 VDC Outlet Temperature Probe
• Pin 6 - Not used
† J9 Socket Pins 3 & 4 - the Remote Temperature Probe or the optional Quad Thermistor Probe connects
to this socket. Two yellow wires from this socket are routed to the junction box on the back of the Boiler.
Dedicated field wiring and conduit must be installed between the Remote Temperature Probe or the optional
Quad Thermistor Probe and the junction box. The Remote Temperature Probe is factory supplied with all
VF Boilers. Either the Remote Temperature Probe or the optional Quad Thermistor Probe is used as the
"Controlling Probe" on VF Boilers, see Boiler Controls on page 6. The SW1 dip switch #4 must be turned on
to activate one of these two probes after installation, see Table 4 on page 23.
24
E
2 1
J8
4 3
1 3
J9
2 4
Figure 17
Servicing should only be performed by a Qualified Service Agent
3 2 1
2 1
J7
4 3
6 5 4
• J8 Socket (Inlet Temperature Probe)
• Pin 1 - Not used
• Pin 2 - 5 VDC Inlet Temperature Probe
• Pin 3 - 5 VDC Inlet Temperature Probe
• Pin 4 - N/A - not used
• † J9 Socket (Remote Temperature Probe or
Quad Thermistor Probe)
• Pin 1 - N/A - not used
• Pin 2 - Not used
• Pin 3 - 5 VDC remote/quad temperature probe
• Pin 4 - 5 VDC remote/quad temperature probe
J6