Ignition Controls - Robertshaw Thermostats

Acronyms GND = Ground IGN = Ignition LP = Liquid Propane MV = Main Valve NO = Normally Open NC = Normally Closed PV = Pilot Valve V AC = Voltage Alternating Current V DC = Voltage Direct Current

Definitions Sensors - Senses the variable change in temperature and sendsa signal to the controller. Transmitters - Interprets signal from sensor to displaycondition of temperature variable. Transformer - An electromagnetic device that either raises orlowers the voltage of an alternating current electrical system. Voltage - The electrical potential pressure behind the flow ofelectricity, measured in terms of Volts. Current - The movement of an electrical charge through acircuit, measured in terms of Amps. Hertz - A unit of measurement for frequency in cycles persecond of a waveform. Relay - An electromechanical device that opens or closescontacts when a current is passed through a coil.

Gases Liquid Propane tends to hover at ground level Natural Gas rises, goes up the Flue Manometer measures Gas Pressure– Inches of Water Column

Ignition Control Applications with Gas ValvesFurnacesHearth ProductsWater Heaters – Pool heatersBoilersSpace, Roof-Top and Industrial Infrared HeatersCommercial DryersCommercial CookersDeep Fryers

Ignition Control System1. Thermostat requests for a call for heat2. Ignition controller requests for a spark to the electrode which ignites the gas3. Control uses flame rectification or sensor to identify if flame is present4. Ignition controller sends signal to open Gas Valve5. When thermostat is satisfied, gas valve closes to shut off main burner gas

Feature List for Ignition ControlsApprovals– CSA– ULEase of Use– Local vs. Remote Sensing• Some use Jumper– Diagnostic LEDs• Flashing Red, Green, AmberApplication Timings– Trial Attempts (1, 3, infinite)– Ignition Timing (seconds)– Pre/post/inter-purge settingsPhysical– 24V AC @ 50 / 60 Hz– SMT - Surface Mount Technology– Conformal coating– Installable in NEMA-3R boxes– Quick connects or plugsSafety– Hard Lockout– Auto-Restart Lockout• Eliminates service calls

ManufacturersJohnson ControlsWhite RogersHoneywellRAMFenwalRobertshaw®

Why Are There So Many Part Numbers for IgnitionControls? Robertshaw® commonly used in Furnace Applications– Direct Spark - DS series• 24 V, 1 Attempt, Non pre-purge• 24 V, 3 Attempts, Pre-purge– Intermittent Pilot - SP series• 24 V, Standard• Lockout model, flame rectification, 60 sec lockout– Hot Surface - 780 series• 120V, Local, 6 sec trial• Universal kit, 24V, Local & Remote, Natural or L.P. Furnaces, Commercial Laundry, Space Heaters, & Pressure Washers– Direct Spark• RAM I Series 120V, Non-pre-purge, Local• RAM 2 Series 240V, Non-pre-purge, Local• RAM 3 Series 24V, Non-pre-purge– Intermittent Pilot• RAM 4 series 120V, Infinite attempts• RAM 5 series 24V, Enclosed, Molex connector– Hot Surface• RAM H Series 24V, Pre-purge, Remote, 3 Attempts

Fenwal Uni-Line® Products Direct Spark– 35-53 Series, 12V– 35-72 Series, 120V• Lockout reset with Thermostat• Multi-pin connector and Remote– 35-61 Series, 24V, Local Sensing• Combustion Blower Relay• Results in lower costs on blower Intermittent Pilot– 35-63 Series, 24V Hot Surface– 35-65 Series, 24V– 35-66 Series, 24V• Combustion Blower Relay

Ram Existing Uni-Line Product RAM mostly used for following applications:– Furnaces - Commercial Laundry - Space Heaters - Pressure WashersDirect Spark– RAM I Series 790-001: 120V, non-pre-purge, Local– RAM 2 Series 790-200: 240V, non-pre-purge, Local– RAM 3 Series 790-300: 24V, non-pre-purgeIntermittent Pilot– RAM 4 series 790-400: 120V, infinite attempts– RAM 5 series 790-500: 24V, enclosed, Molex connectorHot Surface– RAM H Series 790-015: 24V, pre-purge, Remote, 3 tries

Ignition Control KitsKits are for Contractors and Service Professionals Intermittent Pilot Uni-Kits Direct Spark Kits Hot Surface Kits Non-Lockout Universal Kits Lockout Kits Lockout with Pre-Purge Kit Replacement Kits Automatic Pilot Relight Kits780-001780-002

Custom Ignition Control Products Robertshaw® Custom Part for Rheem is 695-200 Hot Surface Igniter Ignition Control ModuleCustom Printed Circuit Board

Aftermarket Opportunities Original Equipment Manufacturers (OEMs):– A.O. Smith– Rheem– Trane– York– Lennox– Amana / Goodman– Bradford White– Modine– G.S.W.– Viking Range– Henny Penny

Electronic Fan & Blower Controls The 695-101 Series Fan Control Designed for Carrier Air Handlers Exact replacement requiring no modification Electronic Blower Motor Controls Used with Heating and Cooling Equipment On a call for heat, circulating and induced draft blowers areenergized

Igniter Types1. Direct Spark– Spark Rod acts as a Flame Sensor2. Hot Surface– Silicon Carbide (fragile)– Silicon Nitride• Requires Flame Sensor– Mini-Ignitors• Faster Heat Time• Gas Furnace ApplicationsNEW3. Intermittent Pilot– Requires Pilot Valve

Hot Surface Igniters – Silicon NitrideWhat is Silicon Nitride? A light, hard material with low thermal expansion coefficientTypical characteristics of Silicon Nitride include: High Mechanical Strength Fracture resistance – stronger than Silicon Carbide Good thermal shock resistance Good chemical resistance Resistant to deformation at room and elevated temperaturesSelecting Exact OEM Replacement parts in the Robertshaw family: Add an “N” to existing silicon carbide part numbers (41-410 41-410N)

Hot Surface Igniters – Silicon NitrideLonger Usable Life Unlike Silicon Carbide which has a porous construction,Silicon Nitride is non porous and does not oxidize with age. Silicon Nitride igniter elements can be cleaned with toughcleaners and can withstand strong alkali’s and acids. Due to its outstanding performance, Silicon Nitride offers apiece of mind to the home owner when the temperaturesdip into the low teens during the winter months.

Quiz Question What allows silicon nitride igniters to work in HVACHeating applications?□□□□Low thermal expansion coefficientHigh Mechanical StrengthFracture toughnessAll of the above Silicon Carbide has a porous construction, SiliconNitride is non porous and does not oxidize with age.□ True □ False

Transformers Transformers change AC voltage levels Select VA Power Rating– Ranges from 20 VA to 75 VAPower (VA) = Volts * Amps Input Voltage– 120, 208, 240, 408, or 480V AC Output Voltage– Mainly 24V AC Inquire about fuse protection Transformer 620 Series 620-403

General Purpose Switching RelaysRelay - An electrically controlled mechanical devicethat opens and closes electrical contacts when avoltage (or current) is applied to a coil.Used to control Blower on and off.

Air Pressure Switches The 2374 Series are used to sense positive, negative, ordifferential air pressure– Max pressure 0.5 psi They are relatively insensitive to temperature changes– Range includes -40° F to 190° F Adjustable air sensing actuates an internal SPDT switch Applications include detection of fans and blowers, staticpressure drop across filters

Questions to Ask When Selecting Module1. What are you heating? What is OEM Factory Number?2. What is the supply voltage?3. What is the control voltage?4. Do you want to clear gas before, during, and/or after heating cycle?5. How many trials for ignition would you like?6. How many seconds between trials?7. What style of heating (direct spark, hot surface, or intermittent pilot)?8. Do you want remote or local sensing of flame (dual rod or single rod)?9. How do you want to handle lockout? How long?10. Do you want board enclosed or open?11. What type of connectors do you want?12. Do you need to change voltage levels, switch machine on or off, detectair, replace parts, or need a kit?

Trouble Shooting Tips Problem # 1: Hot Surface Igniter Does Not Glow Red Possible Causes:– No main power– Faulty Transformer– Faulty Thermostat- check call for heat– Faulty Limit Switch– Faulty blower interlock switch– Faulty hot surface igniter– Faulty ignition control– Remember to wait for purge time, 17 or 34 seconds Trouble Shooting:– With power on and thermostat at its highest position, checkvoltage between “TH” and “TR” on HS780 module.• If 24 Volts is not present, check transformer output• If no 24 Volts present on secondary side, change transformer– Check for 120 Volts at the igniter across “IGN” and “GND”• If voltage present, change igniter.• If no voltage present, change module.

Trouble Shooting Tips Problem # 2: Igniter Glows Red but Main Burner Will Not Light Possible Causes:– Improper Igniter or Sensor Alignment– Faulty Ignition Control– Faulty Gas Valve– High Inlet Gas Pressures– Polarity Reversed– No Earth Ground Trouble Shooting:– Check availability of gas at gas valve. Make sure valve upstream isin the Full On position. Check pressure ok.– Check “GRD” and “PV/MV” by reversing wires• If reversed the gas valve will not open.– Check proper ignition position and properly grounded– Check for 24 Volts at gas valve terminals– “1” and “2” on a 7200 series, “TH” and “TR” on a 7000 series• If Yes, check wire resistance or change gas valve• If no, change the 780 series module

Trouble Shooting Tips Problem # 3: Main Burner Shuts Off before theThermostat is Satisfied Possible Causes:– Improper Igniter or Sensor Alignment– Faulty Ignition Control– Contaminated Igniter and/or sensor– Bad burner ground Trouble Shooting:– Check polarity– Check for proper igniter position– Check for proper ignition control grounding– Visually inspect igniter and remote sensor for anycontamination. Clean and replace.– Check main burner ground– If above steps are ok, replace igniter

Trouble Shooting Tips Problem # 4: Main Burner Does Not Shut Off WhenThermostat is Satisfied Possible Causes:– Faulty Gas Valve– Faulty Ignition Control Trouble Shooting:– Check thermostat to make sure contacts are open, checkfor 24 Volts between “TH” and “TR”.• Should be Zero, if gas valve is stuck open, replace valve– Check for 24 Volts between “PV/MV” and “GND” .• If 24 Volts present, replace ignition control• If 24 Volts not present, replace gas valve

When you have Questions? Technical Service 1-800-445-8299 Fax 1-630-260-7243 Customer Service 1-800-304-6563 Fax 1-800-426-0804 Uni-Line® Catalog Website: www.Uni-Line.com Cross Reference Website:www.uni-line.com/Templates/xrefsearch.aspx General Information WebsiteRobertshaw®, Paragon®, FireX®, Eliwell, Ranco®, and Publication Zone®www.InvensysControls.comwww.RobertshawTstats.comwww.ToolBox.InvensysControls.com/templates/Login.aspx