A.O. Smith VF VB 1000 Service Handbook page 30

MCB - SECTION C
The upper right corner of the MCB contains the following sockets/components:
J2 Socket (Pump relay coil; IRI gas valve)
• Pin 1 - 120 VAC switched hot wire to pump relay coil
• Pin 2 - 120 VAC neutral wire to pump relay coil
• Pin 3 - 120 VAC hot wire to IRI gas valve - N/A on VF boilers.
• Pin 4 - 120 VAC neutral wire to IRI gas valve - N/A on VF boilers.
J15 Socket Not used on VF boilers
J1 Socket (MCB power supply from PDB)
• Pin 1 - 120 VAC hot wire
• Pin 2 - 120 VAC neutral wire
• Pin 3 - Ground
J18 Socket (Silicon Carbide igniter power)
• Pin 1 - Igniter 120 VAC hot wire
• Pin 2 - Igniter 120 VAC neutral wire
F2 Fuse - N/A on VF boilers - if fuse is removed or blown it will not effect operation of VF boiler
JP4 Jumper - Should be on - removed during manufacturing only
J16 Flame - Flame sensor connection (single wire connect on MCB - split wire serves two flame sensors)
JP2 Jumper - Set jumper on pins 1 & 2 for 2.7 amp igniter
JP3 Jumper - Should be on - removed during manufacturing only
The MCB circuit board is mounted upside down on VF boilers compared to the illustrations below.
J2 Pump / IRI Gas
AOS WPC - Tech Training
VF BOILER SERVICE MANUAL
J15 Not Used
4
3
2
1
Servicing should only be performed by a Qualified Service Agent
J1 Line Pwr
4 3
3 2
2 1
F2 Fuse
1
not used on
VF boilers
J16 Flame
29 of 72
J18 SiCar
2
3
2
1
1
JP4
C
1
JP2
2
3
JP3
Ashland City, TN © 2007