Servicing; Checking And Adjusting The Gas Manifold Pressure; Checking, Removing And Reassembling Of The Vent Air Intake System; Lubrication Of Moving Parts - Williams 1773512 Installation Instructions And Owner's Manual

All servicing activities must be performed by a qualified service technician or a service agency. The home owner may not service
the furnace. The home owner must read this section to be informed of the periodic maintenance and checks that are required.
All servicing (except on vent system) must be performed with the external casing removed. After any servicing, the external
casing must be reinstalled properly.
The furnace comes set from the factory at the correct HI and LO gas manifold pressures as shown in "Technical Data". It is
recommended to check the pressures periodically (minimum once a year). If adjustment is required, this can be done by
adjusting screws "C" and "D". (Figure 8) A test gauge must be connected as explained in "Checking the Gas Manifold
Pressure".
Proceed as follows:
1. Place the unit in the HI mode.
2. Adjust the HI pressure by turning screw "C" (pressure regulator) to the value given in "Technical Data". Turn clockwise to
increase the pressure, turn counterclockwise to decrease it.
3. Turn the control knob clockwise until the gas control switches to LO mode. The position in which this occurs depends on
the actual room temperature.
4. Loosen screw "D" until the correct value for the LO pressure is achieved. Turn clockwise to decrease the pressure, turn
counterclockwise to increase it.
5. Switch the unit from LO to HI mode to check that both the HI and LO pressures are correct. A tolerance of plus or minus
0.1-inches w.c. on the pressure value is acceptable. Readjust if needed.
6. Disconnect the test gauge and firmly tighten the screw of the gauge connection, then check for gas leaks from it.
The HI and LO pressures must be adjusted as instructed above. Never adjust them independently of each other.

Checking, Removing and Reassembling of the Vent Air Intake System

It is essential that the vent air intake system is examined periodically (minimum once a year) to verify it is clean from dust and
deposits of solid materials such as leaves or nests. The vent air intake system is checked from outside. Proceed as follows:
1. Remove the vent cap by removing the three outer screws. (Figure 7)
2. Remove the inner flue pipe. Do not use tools; the pipe can be extracted by hand.
3. Remove dust and deposits from the vent cap and flue pipes. Deposits in the air pipe must be taken outside. Do not push
them inside the furnace. The outer air pipe may not be removed from outside.
4. Reinstall the flue pipe from outside. Do not use glue or sealants.
5. Reinstall the vent cap on the flue pipe. Do not use glue or sealants. Tighten the three outer screws.
This furnace does not require lubrication. Do not try to lubricate any part of the furnace such as motors bearings, keys, knobs,
screws, etc.
Correct and proper operation may be checked by examining the burner flame. The flame may be examined through the front
flame viewer. The flame must be stable and have blue colour. Some small yellow tips are acceptable with propane gas. If the
flame is yellow or has excessive turbulence, check the gas manifold pressure and the vent air intake system. If these are not
acceptable, call a qualified service technician for a complete check of the furnace. Call also your gas supplier to check the
composition of the gas in use.

Checking and Adjusting the Gas Manifold Pressure

Lubrication of Moving Parts

Flame Visual Check

Servicing

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