4.Take garden hose and wash heat exchanger, mak- ing sure soot is removed from between fins. (Avoid excessive water against refractory).
5.Reassemble; when heater is fired, some steam will form from wet refractory. This is normal.
NOTE: In extreme cases it may be necessary to remove the heat exchanger completely for cleaning. The simplest method is steam cleaning at a local car wash. DO NOT WIRE BRUSH!
CAUTION: Soot is combusti ble, so exercise extreme care.
Unitherm Governor
Replacement
1.Shut off water, gas and electricity, close valves, relieve pressure.
2.Drain heat exchanger.
3.Remove Unitherm Governor.
INLET/OUTLET HEADER
OUTLET
INLET
GASKET
UNITHERM GOVERNOR
WITH POWER ELEMENT
Fig. 38: Unitherm
To test operation of Unitherm Governor, place in hot water (110°F or higher) and watch for movement against spring. If no movement, replace.
MAINTENANCE AND CARE
To be followed one month after initial
1.Inspect top of heater and
2.Clean main burners and pilot burner of dust and lint.
CAUTION: Soot may be combustible. Wet com- pletely when cleaning.
3. Inspect and operate all controls and gas valve.
4. Make visual check of burner and pilot flame. Flame pattern on main burner and pilot is indicat- ed on page 26. Yellow flame means restriction of air openings. Lifting or blowing flame indicates high gas pressure. Low flame means low gas pressure.
5. Clean room air intake openings to ensure ade- quate flow of combustion and ventilation air.
6. Remove header opposite inlet pipes when clean- ing and inspect internal tubes for scale deposits. If scale does not form within first quarterly inspec- CAUTION: Combustion air must not be contaminated by corrosive chemical fumes which
can damage the heater and void the warranty. tion, then inspect annually thereafter.
7.Keep heater air clear and free from combustible materials and other flammable and corrosive vapors and liquids.
8.Keep moving parts lubricated.
9.Manual operation of pressure/temperature relief valve at least once a year.
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