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EngA ENGINEERED AIR DJM2.4 Installation, Operation And Maintenance Manual

Indirect fired heating controller
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INSTALLATION, OPERATION
AND MAINTENANCE MANUAL
INDIRECT FIRED HEATING CONTROLLER
CANADIAN
HEAD OFFICE
AND FACTORY
1401 HASTINGS CRES. SE
CALGARY, ALBERTA
T2G 4C8
Ph: (403) 287-4774
Fx: 888-364-2727
SALES OFFICES ACROSS CANADA AND USA
Retain instructions with unit and maintain in a legible condition.
Please give model number and serial number when contacting
IOM-16
A
DJM2.4
UNIT MODEL NO. _________________
UNIT SERIAL NO. _________________
SERVICED BY: ___________________
TEL. NO: ________________________
HEAD OFFICE
AND FACTORY
32050 W. 83
DESOTO, KANSAS
Ph: (913) 583-3181
Fx: (913) 583-1406
Engineered Air for information and/or parts.
www.engineeredair.com
FOR
USA
rd
STREET
66018
CANADIAN
EASTERN FACTORY
1175 TWINNEY DRIVE
NEWMARKET, ONTARIO
L3Y 5V7
Ph: (905) 898-1114
Fx: (905) 898-7244
Oct 00 R2

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Summary of Contents for EngA ENGINEERED AIR DJM2.4

  • Page 1 INSTALLATION, OPERATION AND MAINTENANCE MANUAL DJM2.4 INDIRECT FIRED HEATING CONTROLLER UNIT MODEL NO. _________________ UNIT SERIAL NO. _________________ SERVICED BY: ___________________ TEL. NO: ________________________ CANADIAN CANADIAN HEAD OFFICE HEAD OFFICE EASTERN FACTORY AND FACTORY AND FACTORY 1401 HASTINGS CRES. SE 32050 W.
  • Page 2 DJM2.4 If any errors or omissions are noted in this manual please contact Engineered Air – Calgary Service at (403) 287-2590 or Fax (403) 287-4799 or email service@engineeredair.com. To ensure warranty is honored, only a qualified HVAC service person, who has received training on the DJM2.4, should be employed for service and troubleshooting.
  • Page 3 DJM2.4 MANUAL Oct 00 R2...

  • Page 4: Table Of Contents

    DJM2.4 MANUAL TABLE OF CONTENTS TEMPERATURE CONVERSIONS ............................5 APPLICATION ................................5 SERVICE ..................................5 III. GENERAL................................... 6 WIRING ..................................7 SYSTEM TIMINGS ..............................7 POTS ..................................7 HIGH FIRE OVERRIDE ............................8 VII. VIII. STATUS LIGHTS ..............................8 BASIC BURNER OPERATION ..........................10 TEMPERATURE CONTROL –...

  • Page 5: Temperature Conversions

    DJM2.4 MANUAL MODEL DJM2.4 NOTE: In this manual references to DJM, DJM2 or DJM2.x refer to the model DJM2 in this manual. The DJM2 differs from the original DJM with the addition of status lights and the ability to control the “high turndown burner”. The DJM2 also has an optically isolated 0-10 VDC input to accept a modulating heat signal from such devices such as the Engineered Air C-TRAC.

  • Page 6: General

    DJM2.4 MANUAL III. GENERAL The DJM2.4 is a programmed logic controller designed for use with the Engineered Air DJ series of heaters. The DJM2.4 is designed to be backward compatible with the original DJM and DJM2 controllers. Like the original controllers, the DJM2.4 uses a variable speed combustion blower and an electro-mechanical modulating gas valve (usually Maxitrol).

  • Page 7: Wiring

    DJM2.4 MANUAL IV. WIRING Power supply to H and N is 24 VAC and the current draw of the DJM2.4 control itself is 20 VA. (This does not include current draw of components attached to it such as burner motors, ignition controls, gas valves, etc.) Normally, the DJM2.4 is to be powered from the main control transformer.

  • Page 8: High Fire Override

    DJM2.4 MANUAL CURVE (Pot 7) Curve matching. (CW = Increase O2 reading) MINSP (Pot 8) Combustion blower minimum speed. (CW = slower) Pot 9 (not Tachometer calibration (Factory Set for optimal light off speed visible) (CW=faster) Pot 10 (not Tachometer calibration (Factory Set) visible) Proportional/Integral Setting (CONT Pot 3) The DJM2.4 is a Proportional and Integral (PI) controller.
  • Page 9 DJM2.4 MANUAL  IRREGULAR (2 short ON flashes followed by a long off) LED 1 (Pre-Purge) The 50 second pre-purge timer is active. The heat exchanger ignition pre-purge is completed or there is no call for heat. SLOW FLASH There is trouble with the combustion air blower tachometer. The DJM2.4 is receiving a tachometer signal that is not consistent with the combustion blower status.

  • Page 10: Basic Burner Operation

    DJM2.4 MANUAL SLOW FLASH There is a heat call but the heat switch is open. (HS terminal). IRREGULAR FLASH Terminals SV and SR are jumpered. The unit is in service mode. LED 3 (Flame Relay or Ignition Enabled) The flame relay or ignition control device is not energized. The flame relay or ignition control device is energized.

  • Page 11: Temperature Control - General Overview

    DJM2.4 MANUAL 7. After the main flame has been established, the combustion blower speed may slow down to the low fire speed (standard round burner 1850 RPM, high turndown rectangular burner is 1250 RPM at 10:1 turndown and 1150 RPM at 15:1 turndown). After about 10 seconds, the pilot solenoid contacts between DJM2 terminals "PV1"...
  • Page 12 DJM2.4 MANUAL  Johnson TE 6000 sensor and built in internal set point. (The DJM2.4 isn’t compatible with Johnson’s TE 6100 room thermostat/set point.)  135-ohm slide wire electro-mechanical device.  Direct voltage or current input from BMS, MEGATRAC, or C-TRAC. If more than one signal source is connected, the DJM2.2 will only respond to the temperature control which is demanding the most heat.

  • Page 13: Bms Control

    DJM2.4 MANUAL BMS CONTROL See Section XII for information on BMS control wiring connections. Note the comments under the following headings if a BMS or other DCV control device is connected to the DJM2.  "W " (See section IV) IRING ...

  • Page 14: Discharge Sensor Readouts, Calibration, Etc

    DJM2.4 MANUAL management system the DJM2.4 has the ability to accept that as a control signal if wired into + and - terminals. This is similar to the above set up except the control source is different. (If controlled by a BMS, there should be a discharge control device to stop discharge air temperatures exceeding 120°F to avoid high limit tripping.
  • Page 15 DJM2.4 MANUAL BMS signal at zero. The BMS signal should be calibrated as noted in section X. If the DJM2.4 is being slaved to a C-TRAC, METASYS, or some other device, then there will not be a set point connected to the DJM2.4. The setpoint is at the master control; therefore no discharge sensor calibration is necessary.

  • Page 16: Burner Set Up

    DJM2.4 MANUAL NOTE: Our design discharge temperature range is 30 to 140ºF, with about 55-75 being the usual set point. Maxitrol Discharge Sensor/Selector If the system uses a Maxitrol set point, the set point is that indicated on the TD114 dial. There is also a calibration pot on the back of the Maxitrol dial.
  • Page 17 DJM2.4 MANUAL  No jumper to be cut on DJM2.  Light off speed about 2700 RPM.  Modulation between 1850 and 3400 RPM. THE HIGH TURNDOWN (Rectangular) BURNER  Capable of 15:1 turndown.  You must cut the jumper on the back of the DJM2 board. It is located next to terminal “P” on the bottom of the board.
  • Page 18 DJM2.4 MANUAL Refer also to “Water and Ice from Combustion” on page 32 regarding another problem with improper combustion set up. High Turndown (Rectangular) Burner HIGH FIRE SET UP 1. Place a jumper across the DJM2.4 terminals “SV and SR” to force the control into a manual firing mode.
  • Page 19 DJM2.4 MANUAL 1. Once the high fire pressure and combustion have been set up at point “B” above, turn the manual firing pot (fully CCW) to achieve low fire 2. Adjust the low fire RPM pot 8 (MINSP) until the low fire speed on the combustion fan motor is 1250 RPM ±10 RPM (20.8Hz) for 10:1 set up.
  • Page 20 DJM2.4 MANUAL create sooting of burner parts and the heat exchanger. If the locking ring is missing, drop one drop of Loctite thread locker 222 onto the brass screw threads. Series 50/M550, M650 AND ES350 (High Turndown) These valves have only 1 low fire adjustment (spring activated low fire). NOTE: These valves are not used on 15:1 turndown.
  • Page 21 DJM2.4 MANUAL Standard (Round) Burner Most standard turndown DJ units will employ one of the following Maxitrol modulating DC volt gas valves. Note that there is an orifice where the pilot gas line is connected to the pilot air tube. This orifice is sized to the BTU and altitude requirements of the burner.
  • Page 22 DJM2.4 MANUAL After setting up the low fire, adjust the curve matching pot as described in points 8 and 9 above. Need of a resistor on the valve as described in the text above for the high turndown burner is greatly reduced on the standard burner. Pilot Set Up for DJ Series Standard Burners Do not set up pilot until you are confident the burner is operating with correct air/fuel mixture.
  • Page 23 DJM2.4 MANUAL This reading is used to determine the adjustment that will usually give the best pilot lighting and proving strength. However, care must be taken to not adjust the reading for pilot gas pressure below 2.5 inches water column pressure or you will break the pilot ceramics. Next, visually observe the pilot flame.

  • Page 24: Special Service Notes

    DJM2.4 MANUAL NOTE: After set up is complete remove jumpers. XV. SPECIAL SERVICE NOTES On Board Fuse The DJM2.4 is equipped with a 2-amp fuse. This fuse is located on the bottom of the main board. If there is 24 VAC to terminals H and N and the DC voltage from terminals OS to GS is 0 VDC, check the fuse.
  • Page 25 DJM2.4 MANUAL at any place in the programmed burner control process is by setting the Fluke multi-meter to AC volts. Attach the meter to the DJM2 terminals “YS” and “GS”. Press the Hz button once. The number should read between 15 and 59 Hz depending on the speed of the fan (which would be 3450 RPM or 59Hz if the unit were in pre-purge mode).
  • Page 26 DJM2.4 MANUAL Constant Heat Call Light, No Combustion Fan If the heat call light is on and the pre-purge light off and there is no attempt to start or slow the combustion fan down to ignition speed, check if DJM2.4 terminal VFB24 or VFB120 depending on the gas valve has constant power on it.
  • Page 27 DJM2.4 MANUAL above, the temperature rise would only be about 80 degrees to give a final discharge temperature of about 50° at about 11,800 CFM at high fire.) Improper Burning  Plugged 12 AO6 vent orifice (on units equipped with one on regulator). ...
  • Page 28 DJM2.4 MANUAL  Combustion blower runs at light off speed unless power is turned off.  If an external low limit is on the unit and it trips it will shut off the fan and the dampers, and usually leave power to the DJM although some units are designed to lock the DJM off also.
  • Page 29 DJM2.4 MANUAL casing to the mounting screw near the spark connection, or through the back of the case. Mount the ignition control off the wall on insulated spacers and do not install a mounting screw next to the spark wire location. 4.
  • Page 30 DJM2.4 MANUAL Regulator Gas Pressure Responses On some indoor units the vent orifice fitting on the RV appliance regulator is to be vented to atmosphere. The field installed vent line should be sized adequately, especially on longer runs. If there is more than one regulator connected to a common run, which includes the main regulator and the line, is not adequately sized, changes in pressure on the RV diaphragms are applied to all regulators.
  • Page 31 DJM2.4 MANUAL is suddenly lowered the burner may delay before cycling off. If this effect is undesirable, decrease the Integral effect as set on pot 3. This is done by rotating the pot CCW to full proportional. NOTE: If the unit is controlled by a zero to ten VDC signal such as from a C-TRAC or METASYS it is important to set the BMSS and BMSZ pots correctly also.
  • Page 32 DJM2.4 MANUAL On heat/cool units the combustion air is normally drawn by the combustion fan from the intake screen located on the compressor floor area. As this floor area is cantilevered it can plug up with blowing snow, especially if the unit is mounted on a low level roof curb. This can cause combustion air to starve and result into sooting or the heat exchanger.

  • Page 33: Set Up When Installing A Djm2.4 In Field

    DJM2.4 MANUAL Power Vented Flues Engineered Air offers Tjurland vent devices for side venting some units. If technical information is required on the operation of the control system for these devices, contact a Tjurland representative or Engineered Air. In many cases there are power ventors that operate only when the combustion blower is in operation.

  • Page 34: Miscellaneous Notes

    DJM2.4 MANUAL 2. There are two possible burners that the DJM2.4 can be applied to. Check the burner in your unit and if necessary cut the jumper next to terminal “PV1” on the back of the control before mounting the control. ...
  • Page 35 DJM2.4 MANUAL  Low fire combustion blower speed  10:1 turndown is about 1250 RPM ±10 RPM (20.8 Hz)  15:1 turndown is about 1195 RPM ±5 RPM (19.91Hz) [1150 to 1400 RPM]  High fire combustion blower speed is about 3400 RPM ...
  • Page 36 DJM2.4 MANUAL condensate pump must be used. The condensate return line connection on the humidifier must be sealed off if not in use. The SH unit must be drained daily to reduce scaling from the minerals etc that are left behind when the water is boiled off into steam. If this is not done the unit will fail prematurely.

  • Page 37: Maxitrol Gas Valve Drawings

    DJM2.4 MANUAL XIX. MAXITROL GAS VALVE DRAWINGS M450, M550 AND M650 GAS FLOW WHITE PLASTIC BEING REPLACED BY N.C. VALVE DISK COVERING M_____20 ETC LOW FIRE DJ 20, 40, 60 100, 140 PLUNGER BLACK ADJUSTMENT NO COVER NO SPRING ON TOP OF SIDE UP PLUNGER VENT HOLE (MUST BE PLUGGED...

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