A.O. Smith VF VB 1000 Service Handbook page 70

TECHNICAL SPECIFICATIONS
Input Specifications (cont):
†
High Blower Prover Pressure
Switch
†
Low Blower Prover Pressure
Switch
†
Blocked Flue (Exhaust)
Pressure Switch
†
Low Gas Pressure Switch
†
Water Flow Switch
†
Low Water Cut Off Switch
†. Signal level passed through switches: 24 VAC @ >7ma. (Does not require low-level con-
tacts).
†
Output Specifications:
High Speed Combustion Blower
Low Speed Combustion Blower
Hot surface igniter - Silicon Carbide
Gas Valve
Low Water Cut Off
Alarm
Spare
IRI Gas Valve
†
Pump
†. Field installed boiler circulation pumps (VB models): For outputs up to 120 VAC 5 FLA
use on board remote pump relay connected to TB1 terminal board on the PDB (page 36).
For 120 VAC outputs between 5 and 20 FLA, use an external relay/starter and supply 120
VAC pump power through the 20 amp F2 pump fuse on the PDB (page 37). For outputs
above 120 VAC or 20 FLA use an external relay/starter and a separate dedicated power
supply for the pump, use the on board pump relay Com and N.O. contacts to initiate the
field supplied starter/relay coil only.
†. Total currents are limited by the input circuit breaker and fuses on the PDB and MCB. See above
AOS WPC - Tech Training
VF BOILER SERVICE MANUAL
Normally Open, closes on a pressure fall at -4.8" W.C. ± 0.01
Normally Open, closes on a pressure fall at -0.12" W.C.± 0.01
Normally Closed, opens on a pressure rise at 1.0" W.C. ± 0.1
Normally Open, closes on a pressure rise.
Natural Gas Activation Pressure: 4.0" W.C. ± 0.4
Propane Gas Activation Pressure: 6.4 " W.C. ± 0.5
Normally Open, closes when flow rate exceeds an adjustable
setting (approximately 22 GPM)
Normally Closed, opens when water level is low
120 VAC, 50/60 Hz, 3A (MCB J15 Socket)
120 VAC, 50/60 Hz, 3A (MCB J15 Socket)
120 VAC, 50/60 Hz must prove 2.7 AC amp minimum.
24 VAC, 50/60 Hz, Switched 3.5 A
24 VAC, 50/60 Hz, Not Switched, 1 A
24 VAC, 50/60 Hz, Switched 1 A
24 VAC, 50/60 Hz, Switched 1 A
N/A on VF boilers.
120 VAC, 50/60 Hz, maximum 20 FLA
Servicing should only be performed by a Qualified Service Agent
69 of 72 Ashland City, TN © 2007