U.S. Boiler Company INDEPENDENCE IN3PV, Installation & Operating Manual

25

VIII. Service Instructions

A.

  General  

 Inspection and service should be conducted annually. 

Turn off electrical power and gas supply while 

conducting service or maintenance. Follow instructions 

TO TURN OFF GAS TO APPLIANCE. See Figure 21.

CAUTION

Label all wires prior to disconnection when 

servicing controls.  Wiring errors can cause 

improper and dangerous operation.  Verify proper 

operation after servicing.

B.

  Low water cutoff

Clean probe.
1.  Drain boiler to point below Tapping "L".
2.  Disconnect the (3) wire multipin connector from the 

control and disconnect the control's black wire from 

the probe's screw terminal. 

3.  Remove control from probe.
4.  Unscrew probe from Tapping "L".

NOTICE

Carefully remove, clean, and reinstall probe. 

Platinum guard ring must not be exposed to 

rough treatment, or useful life of probe may be 

shortened.

5.  Remove deposits from probe using diluted 

phosphoric acid (H

2

PO

4

) solution, 3 parts water to 1 

part phosphoric acid. Normal operation will occur 

with up to 0.2 inch of contamination. If scale or 

contamination exceeds 0.2 inches clean probe more 

frequently.

6.  Reinstall probe in Tapping "L". Mount control on 

probe. Attach control's black wire to probe's screw 

terminal and reconnect the (3) wire multipin 

connector to the control.

C.

  Water Feeder and Additional Low Water Cut-Off

Refer to manufacturer's instructions.

D.

  Vent System 

 Inspect for obstructions, soot 

accumulation, proper support, and deterioration of pipe, 

fittings, and joints.

1.  Clean vent terminal screens. Vent terminal must be 

free of obstruction, undamaged, with screens 

securely in place.

2.  Vent terminal and wall thimble (if used) must be 

weather-tight.

3.  Vent pipe must be full round shape, and show no 

damage from impact or excessive temperature.

4.  Vent pipe must be supported at minimum 5 foot 

intervals and must not sag.

5.  All joints must be secure and watertight.
6.  Condensate drain must have minimum 6 inch trap 

and allow condensate to flow freely. To clean:
a.  Disconnect condensate drain from drain fitting.

b.  Flush condensate drain with water. Fill trap with 

water.

c.  Securely fasten condensate drain to drain fitting, 

providing gas-tight and watertight seal.

7.   If vent pipe must be disassembled for removal of 

obstructions or resealing of joint, see Venting 

Section.

E.

  Boiler Flue Passages.

 Inspect for blockage or soot 

accumulation.
1.  Remove Main Burners.

a.  Disconnect Pilot Tubing from Gas Valve.
b.  Disconnect Igniter/Sensor Wire and Pilot Ground 

Wire from Ignition Module.

c.  Disconnect (2) wires to Flame Roll-out Switch.
d.  Remove Burner Access Panel.
e.  Mark manifold with location of Main Burner 

with Pilot Bracket.

f.  Hold Main Burner on throat. Lift slightly to clear 

orifice. Pull Main Burner from combustion 

chamber. Main Burner with Pilot Bracket can 

only be removed by lifting at 45° angle after 

adjacent Main Burner to right is removed.

2.  Disconnect Junction Box to Vestibule Wiring 

Harness from Blower.

3.  Remove (4) locknuts securing vent connector. See 

Figure 7. Disconnect vent connector and vent pipe 

from blower outlet. 

4.  Remove Jacket Top Panels.
5.  Disconnect Silicone Tubing from Canopy. Pull 

tubing through Blower Access Panel into vestibule.

6.  Remove Blower Access Panel.
7.  Loosen (4) carriage bolts. Remove Canopy/Blower 

Assembly.

8.  Remove Gasket and Flue Gas Baffles. Inspect Flue 

Baffles for deterioration.