Reznor HRPD (Outdoor Duct Furnaces) Unit Installation Manual - Manual (Page 26)

Form I-RP/HRPD, P/N 132210 R14, Page 26
2) With the manual valve turned off to prevent flow to the gas valve, connect a
manometer to the 1/8” inlet pressure tap in the valve. NOTE: A manometer (fluid-
filled gauge) with an inches water column scale is recommended.
3) With the field-installed manual valve remaining closed, observe the manometer
for two to three minutes for an indication of gas pressure. No pressure should be
indicated on the manometer.
If the manometer indicates a gas pressure, the field-installed manual gas valve
must be replaced or repaired before the combination gas valve can be checked.
4) If the manometer does not indicate gas pressure, slowly open the field-installed
manual gas valve. After the manometer's indicated gas pressure has reached
equilibrium, close the manual shutoff valve. Observe the gas pressure. There
should be no loss of gas pressure on the manometer. If the manometer indicates
a loss of pressure, replace the combination gas valve before placing the heater in
operation.
NOTE: Operational pressure settings and instructions for checking pressure settings
are in Paragraph 6.1.
CAUTION: DO NOT bottom out the gas valve regulator adjusting screw.
This can result in unregulated manifold pressure causing excess
overfire and heat exchanger failure.
10.0 Maintenance
and Service
(cont'd)
10.2.3 Cleaning Pilot
and Main Burners
In the event the pilot flame is short and/or yellow, check the pilot orifice for blockage
caused by lint or dust accumulation. Remove the pilot orifice and clean with air pres-
sure. DO NOT REAM THE ORIFICE. Check and clean the aeration slot in the pilot
burner.
Clean the metal sensing probe and the pilot hood with an emery cloth and wipe off the
ceramic insulator. Check the spark gap; spark gap should be maintained to 7/64". After
the pilot is cleaned, blow any dirt away with compressed air.
Clean main burners and burner orifices using air pressure. Use an air nozzle to blow
out scale and dust accumulation from the burner ports. Alternately blow through the
burner ports and the venturi. Use a fine wire to dislodge any stubborn particles in the
burner ports. Do not use anything that might change the port size.
Clean the burner rack carryover systems with air pressure.
10.2.2 Burner Rack
Removal Instructions
1. Turn off the gas supply.
2. Turn off the electric supply.
3. Remove control access side panel.
4. Disconnect the pilot tubing and flame sensor lead.
5. Mark and disconnect electric valve leads.
6. Uncouple the union in the gas supply.
7. Remove sheetmetal screws in the top corners of the burner rack assembly.
8. Pull "drawer-type" burner rack out of the furnace.
To disassemble the burner rack:
1. Remove Carryover System --
Natural Gas - remove the flash carryover system from the "manifold end" of the
burner rack
NOTE: Natural gas burner racks manufactured prior to 3/95 have a lighter tube
carryover system. Break the lighter tube connection at the orifice and remove the
supply tubing, the drip shield and the lighter tube.
Propane Gas - break the lighter tube connection at the regulator and remove the
lighter tube orifice supply tubing; remove the retaining screws in the drip shield and
the shield; remove the retaining screws and slide out the lighter tube.
2. Pull main burners horizontally away from injection opening and lift out.
3. Remove manifold bracket screws and remove manifold.
4. Remove the main burner orifices.
5. Remove screws and lift out pilot burner.
Follow the instructions in Paragraph 10.2.3 to clean. To re-assemble and replace,
reverse the above procedures being careful not to create any unsafe conditions.
10.2 Maintenance
Procedures
(cont')
10.2.1 Gas Valve (cont'd)