Johnson Controls RL18 User Manual

Contents
Contents
General......................................................................................5
Certification.............................................................................. 5
Safety.........................................................................................5
Specific safety rules and precautions.............................. 6
Safety requirements.......................................................... 7
Combustion air quality (list of contaminants)................7
Codes and standards.........................................................8
For furnaces installed in the Commonwealth of
Massachusetts only............................................................8
Inspection........................................................................... 9
Ductwork.................................................................................10
Ductwork general information.......................................10
Duct flanges......................................................................11
Ductwork installation and supply plenum
connection - upflow/horizontal......................................11
Floor base and ductwork installation - downflow........11
Coil installation.................................................................12
Downflow duct connectors.............................................13
Residential and modular home upflow return
plenum connection..........................................................13
Side return application....................................................13
Bottom return and attic installations............................ 13
Downflow application......................................................13
Horizontal application..................................................... 13
Attic installation................................................................13
Suspended furnace or crawl space installation........... 14
Filters....................................................................................... 16
Filter installation...............................................................16
Side return........................................................................ 16
Gas piping...............................................................................17
Gas safety..........................................................................17
Gas piping installation.....................................................17
Gas orifice conversion for propane (LP)....................... 18
High altitude gas orifice conversion..............................18
High altitude pressure switch conversion.................... 19
Electric power.........................................................................19
Electric power connections.............................................19
Supply voltage connections............................................20
Low voltage control wiring connections....................... 20
Accessory connections.................................................... 21
Electronic air cleaner connection...................................21
Humidifier connection.....................................................21
Twinning and staging............................................................21
Furnace control twinning wiring....................................21
Twinning duct system......................................................22
Vent system............................................................................ 22
Vent connections..............................................................22
Category 1 - 450°F maximum vent temperature......... 23
Venting.............................................................................. 23
Venting into an existing chimney...................................23
Fan-assisted combustion system...................................23
Ambient combustion air supply............................... 23
Dampers, louvers and grilles (Canada only)...........25
......................................................................................25
Ventilated combustion air.........................................26
Vent and supply (outside) air safety check
procedure....................................................................26
Start-up and adjustments.....................................................27
Removing NOx screens (Lo-NOx models only)............ 27
Gas piping leak check...................................................... 28
Ignition system sequence...............................................28
Calculating the furnace input (natural gas)..................28
............................................................................................29
Adjusting the manifold gas pressure and input
rate.....................................................................................30
Airflow settings.................................................................31
Safety controls........................................................................34
Control circuit fuse...........................................................34
Blower door safety switch...............................................34
Rollout switch controls.................................................... 34
Pressure switches............................................................ 34
Limit controls....................................................................35
Sequence of operation..........................................................35
Troubleshooting.....................................................................35
Furnace control diagnostics........................................... 36
Diagnostic fault code storage and retrieval................. 37
Replacement parts list...........................................................38
Replacement part contact information.........................38
Wiring diagram...................................................................... 39
Start-up sheet.........................................................................41
Johnson Controls Ducted Systems
Installation Manual: RL18 Single-Stage Standard ECM Residential Gas Furnaces (Non-condensing Multi-position Standard Low
NOx)
3

Johnson Controls RL18 Specifications

General

Brand	Johnson Controls
Model	RL18
Category	Furnace
Language	English