A.O. Smith VF VB 1000 Service Handbook page 19

START UP PROCEDURE (CONT)
Start Up Procedure
1. Before starting the boiler, please review the boilers Instruction Manual supplied with the
boiler. Ensure the water piping, gas line, controls, and venting have been installed per
the instruction manual. Further information on water piping and controls is on pages 61 -
67 in this service manual.
2. Ensure the gas train shut off valve (see the image on page 23) in the boiler's gas train is
open.
3. Purge all air from the gas line to the boiler and ensure there are no gas leaks. Ensure
the main supply gas valve is open.
4. Be certain that the system is full of water, that all air has been purged from the boiler,
storage tank (s), and the water lines. Open both the supply and return water valves to
the boiler. Ensure there are no water leaks.
5. Ensure the power supply meets the minimum requirements on page 68 in this manual.
Ensure all control wiring (remote Tank/Loop probe - external Enable/Disable control) is
run in a dedicated conduit per requirements on page 68.
6. Perform the power supply test outlined on page 40; correct any problems detected.
7. Prior to turning on the gas, proper sequence of most of the system can be verified.
Close the manifold gas shut off valve (page 23), start the system and allow it to run
through a heating cycle. It should stop when it checks for the flame and declare a fault.
This will verify that the pump, flow switch, igniter, VFD (variable frequency drive), gas
valve, blower and low/ high blower prover switches are all functioning.
8. Drill a 7/16" hole in the side of the boot tee approximately 8" from back panel to insert
the gas analyzer probe. The hole must be sealed upon completion of the start-up.
9. Open the main supply gas valve to the boiler.
10. Turn the boiler's on/off switch on. Ensure the Operating Set Point is set high enough to
activate a call for heat (page 8). If an external control is using the boiler's Enable/Disable
circuit (Aquastat, Boiler Sequencing Controller, EMS) ensure the external controls
contacts are closed (page 65). If there is no external control using the boiler's Enable/
Disable circuit ensure the two wires provided for this circuit are wire nutted together in
the junction box on the back of the boiler. Review the controls section beginning on page
61 and refer to the wiring diagram on the boiler.
11. Allow the unit to run for at least 15 minutes before proceeding with the combustion
analysis. Take a combustion sample and record CO and CO
12. Attach a U tube manometer to supply gas pressure source at the boiler. Measure the
supply gas pressure with a U tube manometer with the boiler firing in Max Mode. Set the
boiler to Max Mode (Firing Modes - page 17). Ensure a minimum supply gas pressure of
4.0 " W.C. for natural gas or 11.0 " W.C. for propane is present with the boiler firing at
100%. Maximum supply gas pressures are 11.0 " W.C. natural gas and 13.8 " W.C.
propane gas. Adjust supply gas pressure at the supply gas regulator as needed to
maintain these supply gas pressure requirements.
AOS WPC - Tech Training
VF BOILER SERVICE MANUAL
Servicing should only be performed by a Qualified Service Agent
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or O readings.
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