CAMBRIDGE M-SERIES Technical Manual Download Page 1

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M-SERIES

DRAW THRU

DIRECT GAS-FIRED

MAKE-UP AIR HEATERS

TECHNICAL MANUAL

M-TM1-0915

M110-M115 (3HP) REV. G

M115 (5HP) REV. H

M118-M136 REV. C

M140 REV. A

WARNING:

Improper installation, adjustment, alteration, service or maintenance can cause property dam-

age, injury or death. Read the installation, operating, and maintenance instructions thoroughly

before installing or servicing this equipment.

FOR YOUR SAFETY

The use and storage of gasoline or other flammable vapors and liquids in open containers in

the vicinity of this appliance is hazardous.

FOR YOUR SAFETY

If you smell gas:

1. Open windows.

2. Don’t touch electrical switches.

3. Extinguish any open flame.

4. Immediately call your gas supplier.

Made in the USA

90.1

ASHRAE

COMPLIANT

Summary of Contents for M-SERIES

Page 1: ...ad the installation operating and maintenance instructions thoroughly before installing or servicing this equipment FOR YOUR SAFETY The use and storage of gasoline or other flammable vapors and liquids in open containers in the vicinity of this appliance is hazardous FOR YOUR SAFETY If you smell gas 1 Open windows 2 Don t touch electrical switches 3 Extinguish any open flame 4 Immediately call you...

Page 2: ...ards Manufacturer does not warrant Products if they are abused improperly operated or maintained subjected to abnormal wear and tear damaged due to improper gas or electric service damaged in transit or that have been repaired or modified by others without Manufacturer s written authorization Buyer shall have no right to enforce this Warranty unless it has complied with all of its obligations unde...

Page 3: ...d Mount Configuration 13 Horizontal Mount Thru Wall Configuration 16 Vertical Mount Outdoor Configuration 19 Vertical Mount Indoor Configuration 23 Gas Piping 26 Electrical 27 Start Up Instructions 28 Operating Instructions 35 Operating Sequence 35 Electronic Thermostat 36 TSS Controller 38 Maintenance Instructions 47 Reference 48 Heater Roof and Wall Openings 48 Heater Discharge Dimensions 48 Gas...

Page 4: ...is to be interlocked to open inlet air dampers or other such devices If the heater is installed such that an inlet duct is uti lized the duct system must be purged with at least four air changes prior to an ignition attempt IMPORTANT Installation in Aircraft Hangars Refer to the Standard for Aircraft Hangars ANSI NFPA 409 for specific information on the installation requirements for these heaters ...

Page 5: ... the Remote Heat Adjust control face based on the setting of the override temperature dial which is visible from the top of the control MAXITROL SERIES 44 The Maxitrol Series 44 modulation controls maintain a constant space temperature by increasing or decreas ing the discharge temperature The Space Temperature Selector is set to maintain the space temperature of the heated space by controlling th...

Page 6: ...RIM BY OTHERS UNIT DP Vertical Mount Indoor Configuration Vertical Mount Outdoor Configuration DD Discharge Duct DE Discharge Elbow DP Discharge Plenum DRH Dual Rainhood w Inlet Screen Filter Rack FS Filter Section V Bank FSID V Bank Filter Section Inlet Damper Combo HBDD Horizontal Blast Discharge Diffuser IC Inlet Collar IE Inlet Elbow MC Mounting Curb MDD Motorized Discharge Damper MID Motorize...

Page 7: ... 250 280 Discharge Damper internal N A N A N A 30 30 35 45 55 75 Discharge Plenum 4 way 100 150 200 250 300 400 470 930 1480 Discharge Plenum 3 way 80 130 175 220 260 360 430 500 795 Discharge Splash Pan 40 40 40 60 60 60 80 80 80 Curb 14 60 70 80 100 120 180 210 230 270 Curb 24 100 120 140 170 200 270 310 340 445 Model M118 M120 M125 M130 M136 Base Heater 1800 2300 2900 3200 3600 Rain Hood Single...

Page 8: ...filtration Heater operation is typically electrically interlocked with mechanical exhaust fans manually operated switches programmable timers or other process control sys tems The discharge temperature of heaters with fixed discharge temperature controls is typically set 10 F to 20 F above the desired space temperature The enter ing air thermostat acts as an economizer by deactivat ing burner oper...

Page 9: ...he heater If upon review of the proposed installation a problem is discovered which may be considered detrimental to the performance of the heater or restricts its serviceability or deviates from the instructions or drawings which may be provided it is the responsibility of the installer to communicate that information to the person or persons responsible for pro viding the installation instructio...

Page 10: ...CTIONS HORIZONTAL MOUNT MOUNTING CURB M110 M136 Shown for Roof Top Configuration Downblast Application Model A B C M110 32 38 27 12 48 M112 32 38 27 12 48 M115 32 38 40 31 60 M118 32 38 44 10 60 M120 32 38 50 26 72 M125 37 88 63 12 84 M130 37 63 84 81 96 M136 37 88 84 81 96 ...

Page 11: ...n See pages 10 12 for roof opening dimensions for your specific heater The gas and electrical connections must not penetrate the unit base or mounting curb Cambridge Engineering recommends using pitch pockets or decktite to seal the penetrations IMPORTANT Accurate measurements are critical and will affect in stallation process 2 Assemble and secure the roof curb to the support structure per the re...

Page 12: ... Series Technical Manual TYPICAL INSTALLATION HORIZONTAL MOUNT ROOF TOP CONFIGURATION M110 M115 Typical Curb and Discharge Duct Model W L M110 19 25 19 25 M112 20 75 20 75 M115 23 5 23 75 Roof Opening Typical Curb and Discharge Duct ...

Page 13: ...M136 48 48 Roof Opening GAS CONTROL ENCLOSURE DUCT DISCHARGE LIFTING EYES HANGING BRACKET VENT w SCREEN VENT PIPE INLET GAS PIPE HIGH PRESSURE SHUT OFF VALVE HIGH PRESSURE SUPPLY TAP HIGH PRESSURE REGULATOR HPR SEDIMENT TRAP BY OTHERS INCOMING POWER CONTROL WIRING CONDUIT ELECTRICAL CONTROL ENCLOSURE HPR RCS LOCATE MIN 10 FT FROM INTAKE BY OTHERS 7 9 WIRES REQ D BY OTHERS OPTION CURB MOUNTING DISC...

Page 14: ...een Locate Min 10 Ft from Intake Incoming Power RCS Discharge Plenum Hanger Bracket Discharge Duct Mounting Curb Lift Eyes Gas Control Enclosure Rainhoods Control Wiring Conduit 7 9 Wires Req d By Others HPR Option Typical Curb and Discharge Duct TYPICAL ROOF TOP INSTALLATION Typical Curb and Discharge Duct Model W L M140 55 55 Roof Opening TYPICAL INSTALLATION HORIZONTAL MOUNT ROOF TOP CONFIGURAT...

Page 15: ...the structural engineer s recommendations IMPORTANT The support structure should be installed such that the heater will sit level 3 Use a crane or comparable lifting device to raise and position the equipment Block the heater where necessary Use a spreader bar to prevent damage and connect slings to the lifting brackets IMPORTANT Cambridge Engineering recommends mounting the heater a minimum of 24...

Page 16: ...4 M Series Technical Manual TYPICAL INSTALLATION HORIZONTAL MOUNT OUTDOOR PAD MOUNT CONFIGURATION M118 M136 Typical Curb Typical Duct Interface Model W L M118 25 5 25 5 M120 29 5 29 5 M125 35 35 M130 41 41 M136 47 47 Wall Opening ...

Page 17: ...M Series Technical Manual 15 Cambridge Engineering Inc TYPICAL CURB TYPICAL INSTALLATION HORIZONTAL MOUNT OUTDOOR PAD MOUNT CONFIGURATION M140 Model W L M140 54 54 Wall Opening Typical Duct Interface ...

Page 18: ...se and position equipment Block the heater where neces sary Use a spreader bar to prevent damage and con nect slings to the lifting brackets IMPORTANT Cambridge Engineering recommends mounting the heater s rainhood a minimum of 24 off the ground or other surfaces 4 Apply washers and double lock nuts to secure equip ment on hanging rods Note The discharge end of the heater should be raised slightly...

Page 19: ...M Series Technical Manual 17 Cambridge Engineering Inc TYPICAL INSTALLATION HORIZONTAL MOUNT THRU WALL CONFIGURATION M110 M115 Model W H M110 32 35 25 M112 32 35 25 M115 46 35 25 Wall Opening ...

Page 20: ... Engineering Inc 18 M Series Technical Manual TYPICAL INSTALLATION HORIZONTAL MOUNT THRU WALL CONFIGURATION M118 M136 Model W H M118 50 55 M120 56 55 M125 68 71 75 M130 89 75 71 75 M136 89 75 96 75 Wall Opening ...

Page 21: ... eyes The Vertical Mount heaters may be shipped in sections due to shipping constraints Review the Accessory Identification drawings see page 4 to identify the locations of these sections IMPORTANT Cambridge Engineering recommends mounting the heater a minimum of 60 off the mounting surface in areas where snow accumulation could impact the heater operation 4 Attach each mounting leg to the inlet a...

Page 22: ...color of the heater acces sories at the joint between the top discharge duct and outside wall surface Make certain this is a continu ous bead and that it runs the entire width of the duct Caulk all other exposed joints 11 Install the discharge plenum by screwing the plenum to the discharge duct Install hanging rods from ceil ing supports to the plenum s support brackets DETAIL A DETAIL B ...

Page 23: ...9 5 29 5 M125 35 35 M130 41 41 M136 47 47 Wall Opening VENT w SCREEN LOCATE MIN INLET GAS PIPE HIGH PRESSURE SHUT OFF VALVE HIGH PRESSURE SUPPLY TAP HIGH PRESSURE REGULATOR HPR SEDIMENT TRAP HPR OPTION BY OTHERS CONTROL WIRING CONDUIT 7 9 WIRES REQ D BY OTHERS RCS INCOMING POWER EXTERNAL WALL WALL FLASHING BY OTHERS BRACKETS LIFTING 10 FT FROM INTAKE VENT PIPE BY OTHERS ...

Page 24: ...GE DUCT UNIT ROOF DUCT OPENING COLLAR TEK SCREW OUTER PERIMETER INSULATION WALL FLASHING BY OTHERS DISCHARGE DUCT LIFTING BRACKETS POWER INCOMING CONTROL WIRING CONDUIT BY OTHERS 7 9 WIRES REQ D RCS BY OTHERS SEDIMENT TRAP INLET GAS PIPE HIGH PRESSURE REGULATOR HPR HIGH PRESSURE SHUT OFF VALVE BY OTHERS VENT PIPE LOCATE MIN 10 FT VENT w SCREEN HIGH PRESSURE SUPPLY TAP OPTION HPR DISCHARGE DUCT W T...

Page 25: ...s rain hood a minimum of 60 off the ground or other surfaces in areas where snow accumulation could impact operation 4 Attach each Mounting Leg to the inlet elbow using the 1 2 13 x 1 1 2 bolts The bolts install down ward through a clearance hole in the accessory into a threaded insert in the Mounting Leg Install all four legs on the accessory and then attach the inlet collar to the inlet elbow us...

Page 26: ...the color of the heater accessories at the joint between the top inlet collar and outside wall surface Make certain this is a continuous bead and that it runs the entire width of the collar Caulk all other exposed joints 11 Install the discharge plenum by screwing the plenum to the heater Install hanging rods from the ceiling supports to the plenum s support brackets DETAIL A DETAIL B ...

Page 27: ... INSTALLATION VERTICAL MOUNT INDOOR CONFIGURATION HORIZONTAL BLAST M118 M136 VENT w SCREEN LOCATE MIN VENT PIPE BY OTHERS INLET GAS PIPE HIGH PRESSURE SHUT OFF VALVE HIGH PRESSURE SUPPLY TAP HIGH PRESSURE REGULATOR HPR SEDIMENT TRAP HPR OPTION BY OTHERS BRACKETS LIFTING 10 FT FROM INTAKE INCOMING POWER 7 10 WIRES TYP CONTROL WIRING CONDUIT BY OTHERS RCS ...

Page 28: ...ed will not restrict or block the access door from fully opening 5 Install gas piping to the make up air heater in accordance with local codes or in their absence in accordance with the National Fuel Gas Code ANSI Standard Z223 1 or the CAN CGA B149 Installation Codes IMPORTANT A 1 8 NPT tap is supplied with the heater for measuring the gas supply pressure If the gas supply pressure exceeds that i...

Page 29: ... air can affect the sensor when the door is closed and may not adequately sense the tempera ture when the door is open In dock areas the sensor should be located on the first column in from the outside wall IMPORTANT Observe the special notes and instructions on the wiring diagrams including the following The wiring for the space temperature sen sors must be shielded twisted pair wiring and must r...

Page 30: ...y void the warranty 1 VISUAL INSPECTION OF EQUIPMENT a Check for any physical damage from ship ping or installation that could render the heater inoperable b Verify all heater accessories and filters if applicable have been properly installed c Check for loose components belts plugs ter minal screws etc d Verify the access doors and controls enclosure are free from obstructions such that they can ...

Page 31: ...nt Only experi enced technicians with knowledge and respect for live power should proceed beyond this point b Turn the blower service switch to the LOCAL position The blower motor will start after the motorized inlet damper opens Then turn the blower service switch to the OFF position and verify the blower is rotating in the proper direction See the directional arrow on the blower housing IMPORTAN...

Page 32: ...range needle is set to the Minimum setting and the right orange needle is set to the Maximum setting from the table above IMPORTANT Call the Cambridge Engineering Customer Service Group at 800 473 4569 if unable to obtain the required pressure drop across the burner profile plate o 6 MOTOR AMP DRAW CHECK IMPORTANT The heater access doors must be closed for this test a Check the motor current at th...

Page 33: ...rs with a filter section or filters in the rainhood The pressure drop must not fall below 0 75 inches WC for LP gas heaters without filters or 0 79 inches WC for LP gas heaters with a filter section or filters in the rainhood If the pressure drop is below these values it is an indica tion of low airflow or burner overfiring To correct this condition either adjust the manifold pressure regulator to...

Page 34: ...as leak detected must be repaired before the make up air heater is placed into service 10 MINIMUM FIRE SETTING IMPORTANT All access doors must be closed during this procedure a Reinstall the 3 wire previously removed from the amplifier b Connect a meter set to read DC micro amps mA in order to verify the minimum fire flame signal during the adjustment process Connect the meter by removing the red ...

Page 35: ...e port Turn the blower service switch to the LOCAL position and the burner service switch to the OFF posi tion and measure the burner static pres sure c Connect a DC voltmeter to terminals MV OUT on the multi functional PC board d Turn the burner service switch to the LOCAL position and monitor the modu lating valve voltage flame length manifold differential pressure and the time required to estab...

Page 36: ...e Maxitrol Series 44 control system set the MIN and MAX setting of the amplifier to the application specifications e Verify the blower and burner service switches are in the REMOTE position f Return the Technical Manual and Wiring Diagram to the manual holder g Perform a visual inspection of all wiring and gas valve plugs to ensure they have been properly replaced h Replace and fasten all covers a...

Page 37: ...s to run until turned off HEATING MODE 1 Mode switch in HEATING position 2 Thermostat or interlock calls for heat 3 Optional motorized inlet or discharge damper opens 4 Blower motor starts 5 Low airflow switch closes 6 Entering air thermostat closes when inlet tempera ture is below setpoint after the prepurge delay 7 Igniter warm up timing 8 Gas valve opens 9 Burner lights 10 Igniter is de energiz...

Page 38: ...output relay Separate settings for HEAT ON and HEAT OFF settings Temperature Calibration for accurate temperature control EEPROM storage maintains temperature settings indefinitely in case of power loss The thermistor enclosure SH 1 is packed inside the Remote Control Station for shipment It can be mounted on the exterior sides or bottom of the Remote Control Station or a remote location within 50...

Page 39: ... desired tempera ture for the heater to turn ON is displayed 2 Press and hold the HEAT OFF button while pressing the UP or the DOWN button until the desired tempera ture for the heater to turn OFF is displayed TEMPERATURE CALIBRATION To compensate for lead wire resistance it may be neces sary to make an adjustment to the displayed temperature to correct it to the temperature measured at the thermi...

Page 40: ...ic adjustment for Daylight Saving Time Nine Holiday Setback Periods for temporary setback operation Temperature Calibration for accurate temperature control Capacitor backup maintains current time and day of week for power loss of up to 96 hours EEPROM storage maintains schedules and temperature settings indefinitely The thermistor enclosure SH 1 is packed inside the Remote Control Station for shi...

Page 41: ...the DAY OF WEEK button while pressing the UP or the DOWN button until the light for the current day is illuminated 2 Press and hold the TIME button while pressing the UP or the DOWN button until the current time is dis played 3 Press and hold the MONTH DAY button while press ing the UP or the DOWN button until the current date is displayed 4 Press and hold the YEAR button while pressing the UP or ...

Page 42: ...e OFF time schedule is in effect See SETTING SCHEDULES for instructions on setting the ON and OFF schedules With the keyswitch in the SUMMER VENTILATION posi tion the heater fan will run based on the time schedule with no temperature control HEATING MODE ON Time Schedule The HEATING mode requires two temperature settings When the temperature drops below the HEAT ON set ting the heater will turn on...

Page 43: ... by the VENT MODE light on the TSS Controller being illuminated Before attempting to program the schedule determine the planned time periods for HEAT ON and SETBACK OFF for the HEATING mode and the planned ON and OFF time periods for the Ventilation mode The time that it takes to recover from the SETBACK temperature to the HEAT temperature must also be taken into consideration for the ON time in t...

Page 44: ... 4 On 5 Off 5 On 6 Off 6 On 7 Off 7 On 8 Off 8 On 9 Off 9 On 10 Off 10 On 11 Off 11 On 12 Off 12 On 13 Off 13 On 14 Off 14 SUMMER VENTILATION SCHEDULE Cycle Time AM PM Day On M F Off M F On 1 Off 1 On 2 Off 2 On 3 Off 3 On 4 Off 4 On 5 Off 5 On 6 Off 6 On 7 Off 7 On 8 Off 8 On 9 Off 9 On 10 Off 10 On 11 Off 11 On 12 Off 12 On 13 Off 13 On 14 Off 14 ...

Page 45: ...s and bold the TIME button while pressing the UP or the DOWN button to scroll to the desired OFF time for Monday through Friday 6 If Monday through Friday is the only schedule required proceed to Step 14 If any additional pro gramming is required proceed with the following steps Remember that subsequent program cycles must not overlap with the ON and OFF times set above 7 Press the UP button once ...

Page 46: ...red program cycles have been entered 14 Press the SETBACK SCHEDULE EXIT button to exit the scheduling program 15 Verify that the correct current time and light for day of the week are still displayed HOLIDAY SETBACK SCHEDULE The Holiday Setback Schedule overrides the normal schedule and holds the space at the SETBACK tempera ture The TSS Controller allows up to nine holiday peri ods Holiday Start ...

Page 47: ...g the UP or the DOWN button to scroll to the desired holiday start date 4 Press the UP button once to step to the first holiday end date cycle HEd1 5 Press and hold the MONTH DAY button while pressing the UP or the DOWN button to scroll to the desired holiday end date NOTE Holiday end date must be at least one day after holiday start date 6 Repeat steps 2 5 until all required holiday cycles have b...

Page 48: ...llows the displayed temperature to be offset either above or below the actual sensed temperature Be sure to use an accurate tempera ture meter for making this correction 1 Press and hold the HEAT ON and HEAT OFF buttons while pressing the UP or the DOWN button until the correct temperature is displayed A period after the F will indicate the Calibration Mode 2 Pressing the UP or the DOWN button wil...

Page 49: ... year Seasonal Service Motor is idle for 6 months or more 1 year 1 year Continuous Operation Severe Service High ambient dirty or moist location high vibration 6 months 6 months BELT TENSIONING Using a Browning Belt Tension Checker and a straight edge verify proper belt tension exists according to the following table Periodic belt adjustments may be required Indications of loose belts include bark...

Page 50: ...ge Opening Discharge Duct Size Model W L W L M110 12 7 13 6 16 25 16 25 M112 12 9 15 9 17 75 17 75 M115 18 6 15 9 20 75 20 75 M118 21 9 18 7 23 5 23 5 M120 24 5 24 7 27 5 27 5 M125 31 2 31 2 33 33 M130 36 6 36 6 39 39 M136 42 5 42 8 45 45 M140 50 50 52 52 Applies to both horizontal and vertical mount HEATER DISCHARGE DIMENSIONS Wall Opening1 Discharge Inlet Model W H W H M118 25 5 25 5 69 57 5 M12...

Page 51: ...hnical Manual 49 Cambridge Engineering Inc REFERENCE GAS TRAIN DRAWINGS Horizontal Mount 400 MBH CSA Certified Vertical Mount 400 MBH Low Pressure CSA Certified Horizontal Mount 400 MBH High Pressure CSA Certified ...

Page 52: ...dation 5 Remove the fasteners that secure the burner to the housing The burner will then be free to slide out mCAUTION Be sure to take necessary safety precautions such as wearing eye protection etc before attempting this step 6 Clean the burner by back flushing using high pressure air 40 80 PSI Continue back flushing until dust par ticles are completely expelled from the burner 7 Re install the b...

Page 53: ...ore assembly and the diaphragm assembly when lubricating the pilot disc 6 Replace the body gasket and the core diaphragm sub assembly with the closing spring attached Locate the bleed hole in the core diaphragm sub assembly approximately 30 CCW from the valve inlet 7 Replace the valve bonnet and the bonnet screws 6 Torque the screws in a crisscross manner to 100 10 in lbs Replace the solenoid and ...

Page 54: ...T GASKET VALVE BONNET VALVE BODY CORE DIAPHRAGM SUBASSEMBLY BONNET SCREW BODY GASKET Indicates parts supplied in ASCO Rebuild Kit CAUTION Do not damage valve seat Locate bleed hole in core diaphragm sub assembly approximately 30 from valve inlet BLEED HOLE Disassembled View of ASCO Valve ...

Page 55: ...gainst the filter tracks These filters are unaffected by moisture and may be installed in the rainhoods or in the V bank filter section CLEANING AND REPLACEMENT Shut down the heater and turn off the blower before ser vicing the filters Remove the filters from the rainhood or filter section Handle carefully to prevent debris from being dislodged from the filter into the heater Permanent filters can...

Page 56: ...6 2x3 3 1x3 Lower 4 2 4 2x2 2 1x2 M125 Upper 12 12 4x3 Lower 8 8 4x2 M130 Upper 12 4 12 3x4 4 1x4 Lower 9 3 9 3x3 3 1x3 M136 Upper 15 5 15 3x5 5 1x5 Lower 12 4 12 3x4 4 1x4 M140 Upper 5 25 5 1x5 25 5x5 Lower 4 20 4 1x4 20 5x4 Filter Section M110 3 3 3x1 M112 3 3 3x1 M115 6 6 3x2 M118 8 8 4x2 M120 10 10 5x2 M125 20 20 5x4 M130 24 24 6x4 M136 28 28 7x4 M140 56 56 8x7 Filter Type Permanent or Disposa...

Page 57: ...M Series Technical Manual 55 Cambridge Engineering Inc REFERENCE ELECTRICAL CONTROL ENCLOSURE ISOMETRIC DRAWING M110 M115 ...

Page 58: ...Cambridge Engineering Inc 56 M Series Technical Manual REFERENCE ELECTRICAL CONTROL ENCLOSURE ISOMETRIC DRAWING M118 M136 ...

Page 59: ...M Series Technical Manual 57 Cambridge Engineering Inc ELECTRICAL CONTROL ENCLOSURE ISOMETRIC DRAWING M140 ...

Page 60: ...e Safeguard Relay HSI SYMBOL DESCRIPTION FU1 Fuse 24 Volt Control FU2 Fuse 120 Volt Control HGP High Gas Pressure Switch HL High Limit IG Ignitor L1 Light Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LTC Low Temperature Cutout M Motor MS Motor Starter MV Modulating Valve SYMBOL DESCRIPTION OL Overload Relay PT Purge Timer RA Remote Adjust R1A R1B Relay Gas Valve SOV Shut Off Valve Gas SSV S...

Page 61: ...N FU1 Fuse 24 Volt Control FU2 Fuse 120 Volt Control HL High Limit IG Ignitor L1 Light Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LTC Low Temperature Cutout M Motor Supply Fan MS1 Motor Starter Supply Fan MS2 Motor Starter Exhaust Fan MV Modulating Valve SYMBOL DESCRIPTION OL1 Overload Relay Supply Fan OL2 Overload Relay Exhaust Fan PT Purge Timer RA Remote Heat Adjust R1A R1B Relay Gas V...

Page 62: ... Control SYMBOL DESCRIPTION FU2 Fuse 120 Volt Control HGP High Gas Pressure Switch HL High Limit IG Ignitor L1 Light Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LTC Low Temperature Cutout M Motor MS Motor Starter MV Modulating Valve OL Overload Relay SYMBOL DESCRIPTION PT Purge Timer R1A R1B Relay Gas Valve RC Resistor Calibration SOV Shut Off Valve Gas SSV Safety Shut Off Valve Gas STS Sp...

Page 63: ...20 Volt Control SYMBOL DESCRIPTION HL High Limit IG Ignitor L1 Light Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LTC Low Temperature Cutout M Motor MS Motor Starter MV Modulating Valve OET Operating Electronic Thermostat OL Overload Relay PT Purge Timer R1A R1B Relay Gas Valve R2 Relay Intermittent Continuous SYMBOL DESCRIPTION RC Resistor Calibration RTS Remote Temperature Sensor SOV Shut...

Page 64: ...t Control SYMBOL DESCRIPTION HL High Limit IG Ignitor L1 Light Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LTC Low Temperature Cutout M Motor MS Motor Starter MV Modulating Valve OTS Override Timer Switch OL Overload Relay PT Purge Timer R1A R1B Relay Gas Valve SYMBOL DESCRIPTION R2 Relay Intermittent Continuous RC Resistor Calibration RTS Remote Temperature Sensor SOV Shut Off Valve Gas S...

Page 65: ...ight Alarm L2 Light Fan L3 Light Heat LFS Low Fire Start LPR Relay Low Pressure LSK Low Speed Kit LSR Relay Low Speed LTC Low Temperature Cutout M Motor MV Modulating Valve PDA Profile Damper Adjustment PDM Profile Damper Motor PT Purge Timer SYMBOL DESCRIPTION PXR Pressure Transducer R1A R1B Relay Gas Valve SOV Shut Off Valve Gas SSV Safety Shut Off Valve Gas STS Space Temperature Selector SW1 Se...

Page 66: ...N MAXITROL SERIES 44 SYSTEMS AND SERIES 14 SYSTEMS WITH OPTIONAL RHA CONTROL FOR MAXITROL SERIES 44 SYSTEMS AND SERIES 14 SYSTEMS WITH RHA CONTROL USE 2 WIRE SHIELDED TWISTED PAIR 18 AWG MINIMUM RUN SEPARATE FROM ALL OTHER AC WIRING GROUND SHIELD AT REMOTE CONTROL STATION ONLY Typical ...

Page 67: ... modes Exhaust Fan Interlock Temperature Setback System Manual Make Up Air Switch etc REMOTE CONTROL STATION COM PONENTS Remote Control Station The Remote Control Station is a lockable NEMA 1 enclosure 9 wide x 14 high x 5 deep equipped with a three position key lock selector switch Summer Ventilation Off Heating and indicat ing lights for blower operation green burner operation red and reset ambe...

Page 68: ...cate a clogged filter con dition Includes an adjustable pressure switch mounted in the make up air heater control enclosure to monitor the pressure drop across the filters Manual Make Up Air Switch A manual make up air toggle switch is used to manu ally turn the heater on and off It is either mounted on the exterior of the door of the Remote Control Station or mounted inside the Remote Control Sta...

Page 69: ...and is provided with terminals located in heater s electrical enclosure The dry contact is typically wired into an exhaust fan control circuit to activate the exhaust fan as a slave to the make up air heater FLAME SAFEGUARD RELAY The flame safeguard relay supplies 24 Volts AC to the igniter for 4 seconds prior to the gas valve being energized If the burner does not light flame is not estab lished ...

Page 70: ...e INTERIOR LIGHT S Available for the heater cabinet electrical control enclosure and or gas train enclo sure Light switches are located inside the heater s electrical enclosure Furnished with safety guards 100 watts maximum each A separate electrical supply source is required LEAK TEST FACILITY The leak test facility is provided on all heaters over 400 000 Btu hr and consists of a momentary switch...

Page 71: ... F 68 F or 70 F 4 The PT Purge Timer circuit function is preset at the factory to provide four air changes within the heater cabinet prior to an ignition attempt normally set at 4 or 8 seconds If inlet ducting is attached to the heater the delay time can be increased to 8 16 or 32 seconds as applicable 5 The patented LFS Low Fire Start circuit func tion limits the initial heater firing for the fir...

Page 72: ...ge to the drive tube of the damper assembly CAUTION If the drive tube bottoms out against the damper motor housing damage to the PC board or trip ping of the onboard fuse may result If the fuse trips place the blower service switch in the OFF position for 15 seconds to allow the fuse to reset Proceed with steps 4 through 10 BEFORE connect ing the damper motor to the linkage arm 4 Verify the cam lo...

Page 73: ... the 3 8 diameter bolt can seat into the nut on the damper linkage Maintain the damper blades in the tightly held fully closed position dur ing this adjustment 13 Turn the heater disconnect switch on and place the blower service switch to the LOCAL position Damper will open to the point the upper cam engag es the upper limit switch 14 Using the deep well 1 2 hex socket or nut driver turn the upper...

Page 74: ...ngineering Inc 72 M Series Technical Manual GAS TRAIN DRAWINGS FM IRI Vertical Mount 2500 MBH Factory Mutual FM Compliant CSA Certified Horizontal Mount 400 MBH Industrial Risk Insurers IRI Compliant CSA Certified ...

Page 75: ...ontrol fuse C Defective transformer a Check disconnect and supply fusing b Replace control fuse c Replace transformer 7 Class II Transformer a No output voltage b Defective transformer a Check supply voltage b Replace transformer 8 Multi Functional PC Board a No input voltage on Terminal G RCS b Improper wiring c Defective board a Check voltage in RCS b Check wiring c Replace multi functional PC b...

Page 76: ... EAT setting III BLOWER RUNS NO HEAT FLAME SAFETY RELAY LOCKS OUT 1 Igniter a No current open igniter b No voltage During trial for ignition a Check igniter current b Check FSR output to igniter 2 High Limit a High limit tripped a See Problem Number VI 3 High or Low Gas Pressure Switches a Low gas pressure switch tripped b High gas pressure switch tripped c Defective gas pressure switch a Check ga...

Page 77: ...R grounded a3 Tighten loose ground screws b Clean terminal and reinsert 4 Fluctuating Flame Current a Unit overfiring b Minimum fire set too low c Intermittent ground connection d Defective burner a Check manifold pressure b Adjust minimum fire on modulating valve c Tighten all ground points d e Replace burner 5 Flame Safeguard Relay a Defective FSR a Replace FSR 6 High Limit a High limit contact ...

Page 78: ...c Reduce differential setting d Replace thermostat 2 Burner Service Switch a Switch in LOCAL position a Place switch in REMOTE position 3 Auxiliary Control a Auxiliary contacts closed a Check auxiliary circuit wiring and contacts 4 Misunderstood Control System Operation a Control system doesn t function as expected a Review control system operational charac teristics VIII MODULATING VALVE DOES NOT...

Page 79: ...sembled a Disassemble valve and remove foreign material b Disassemble valve and assemble correctly IX MODULATING VALVE DOES NOT MODULATE CONTINUOUS LOW FIRE 1 Class II Transformer a No voltage output to amplifier a1 Check for short in modulating valve coil a2 Replace transformer 2 Modulating Valve a Valve coil is open or shorted b Plunger jammed c Ruptured main or balancing diaphragm a Replace val...

Page 80: ...flow Switch a Measure pressure drop and adjust profile damper b Replace Airflow Switch 8 Multi Functional PC Board a Temp sensor wires not seated properly in terminal block b Defective board a Reinstall sensor wires b Replace board X ERRATIC OR PULSATING FLAME 1 High Pressure Regulator a Vent undersized b Defective regulator a Enlarge vent piping size or reduce vent piping length b Replace regulat...

Page 81: ...s less than 10 000 cfm The Cambridge Engineering Temperature Setback System TSS will meet the standard A properly configured building DDC system with the necessary programming for zone control automatic shutdown and setback can also meet the standard Total airflow of all heaters exceeds 10 000 cfm The Cambridge Engineering Temperature Setback System TSS with optimum start con trol will meet the st...

Page 82: ...Cambridge Engineering Inc 80 M Series Technical Manual MODEL NO SERIAL NO Date Activity Technician MAINTENANCE LOG ...

Page 83: ...ves the right to change specifications modify the design and or substitute equivalent materials without notice as the result of code requirements product enhancements ongoing research development and vendor changes beyond our control ...

Page 84: ...760 Long Road Crossing Dr Chesterfield MO 63006 Phone 800 899 1989 Fax 636 530 6133 www cambridge eng com ...

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