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Warning FIRE OR EXPLOSION HAZARD • Failure to follow safety warnings exactly, could result in serious injury, death or property damage. • Be sure to read and understand the installation, operation and service instruction in this manual. • Improper installation, adjustment, alteration, service or maintenance can cause serious injury, death or property damages.
Table of contents Code and regulation ....................3 Specifications ......................4 Gas supply ........................4 Gas pressure adjustments ..................5 Unit Dimensions ......................6,7,8 Installation guidelines ....................9,10 Electrical control ......................11 Components ......................11,12,13 Flue vent and combustion air ..................14,15,16,17 Start-up instruction ....................
Code and regulation Important This product is intended for installation on positive pressure side of the circulating air blower. This heating unit is designed for industrial or commercial use only. The installation must comply with the latest laws and regulation for heating units; CSA B149.1, ANSI Z223.1 / NFPA 54, to the electrical code C22.1/ NFPA 70 and to local regulations.
Unit dimensions WARNING Improper installation, adjustment, alteration can cause serious injury, death or property damages. DTH - Horizontal discharge • Left hand control (when facing air stream). Note: The controls shown are on the left-hand side of the unit (for a right-hand unit, the drawing is mirrored and dimensions are identical).
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DTH – Vertical discharge • Left hand control (when facing air stream). Note: The controls shown are on the left-hand side of the unit (for a right-hand unit, the drawing is mirrored and dimensions are identical). Installation and operation manual–DTH-V9-2020...
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UNIT DIMENSIONS Imperial [in] 64 ½ 64 ½ 64 ½ 64 ½ 70 ½ 70 ½ 95 ½ Metric [mm] 1194 1194 1194 1334 1334 1422 1473 1549 1721 1721 1092 1092 1092 1226 1226 1226 1226 1226 1397 1397 1638 1638 1638...
Refer to the exhaust system sections of this manual. • If no control cabinet is supplied by Nagas with the unit, the installer must be made one for component protection and must include aeration openings at least equal of two 2 inches holes.
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Positioning of the sensor controlling the supply temperature WARNING The positioning of the supply temperature sensor is essential for the proper operation of the unit. Improper positioning of the supply temperature sensor could result in high temperatures in the supply ducts, a thermal protection shutdown, the closing of the fire damper and may result in damage to the unit and void the warranty.
Every component requires a minimum ambient temperature during operation. If you don’t order the Nagas heating and control cabinet solution you must build your own. Also, every component must be protected from environmental elements and covered because of high voltage hazard.
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• Component identification Electrical box HMI touch screen interface Programmable logic controller (PLC) Heating element Input/output expansion module (I/O) Ignition transformer High limit protection (set at 160 Flame safeguard module Thermostat for heating element Power supply transformer Control relays Safety pressure switches Installation and operation manual–DTH-V9-2020...
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Gas train Pilot solenoid valve and gas regulator Pilot manual gas valve Main manual valve (by other outside the unit) Test port inlet pressure Main gas regulator Main gas safety shutoff valve 1 Valve proving system (with IRI option) Main gas safety shutoff valve 2 Modulating gas valve actuator Modulating gas valve Low fire orifice bypass...
Flue vent and combustion air Depending on the model, the flue vent connector diameter ranges from 6 to 10 inches. The DTH model series is designed to operate effectively and safely (against a positive pressure of 0.25 in.w.c) with a positive stack (category III) type sealed single wall or double wall flue vent listed for this application, whether vertical arrangement or horizontal or a combination of both.
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The flue vent joints must be sealed in a manner that will not allow leakage of the combustion product into the room. See flue vent manufacturer instructions for more details. The horizontal conduit sections should be supported every six feet with non-combustible products such as, chains or steel belts.
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• Recommended roof top Flue Vent Exhaust and/or Combustion Air Duct • Recommended wall horizontal Flue Vent Exhaust and Combustion Air Duct – Concentric kit Installation and operation manual–DTH-V9-2020...
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• Recommended wall vertical Flue Vent Exhaust Ducting Flue vent Combustion Air Unit Flue vent diameter intake diameter diameter (minimum) (minimum) Model Inches Inches Inches 152.4 152.4 203.2 203.2 203.2 304.8 Important The flue vent and combustion air duct can have a maximum equivalent length of 100 feet calculated.
Start-up instruction Important Start-up can only be performed by a qualified technician qualified to install gas heating star system (with accreditation) with knowledge in electricity and ventilation. Warning • Do not smoke during start-up. • Do not try to light the burner if the gas has accumulated in combustion chamber or in the area, if the combustion chamber is filled with vapors or if it is very hot.
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3.0 Burner adjustment Install a pressure gauge (0-10 in. w. c.) on the manifold pressure test port located downstream of the modulation gas valve. See component identification section for location. For the combustion test, it is recommended to use a (2-10VDC) manual potentiometer to simulate the modulation signal to the burner.
Control sequence A PLC controls the burner duties by controlling the modulating gas valve, the fan speed and their relative position to each other depending on the input signal (2-10 VDC) from the temperature controller. The control sequence is defined and executed following these eight steps: 1.
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Step 3 - Pre-Purge (S40) The blower starts and set to 100% of its capacity for about 60 seconds then a 10 seconds timer to let the fan speed slow down before the burner ignition. When complete the burner ignition step is enabled.
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Step 8 - Post-purge (S100) This step is allowed when the burner modulation request is lower than 2.3V DC for more than the low fire delay, if the heating demand is turn OFF or if an alarm has been detected with the burner operation.
Programmable logic controller features & I/O Item Option Description Run/Stop Run/Stop manual switch switch SD card SD card programming slot slot Battery holder Real Time Clock battery (RTC) **Replace every 2 years (BR2032)** Cartridge slot Not used LEDs Digital inputs, relay outputs and fast output LEDs I/O states For terminal connection to a computer for programming (need USB mini-B port...
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Serial line port 1 Type RJ45 (RS-232 or RS-485) - Used for HMI communication Serial line port 2 Screw terminal block type (RS-485) Input terminals Digital inputs TM3/TM2 bus For TM3 expansion modules connector Protective cover Cover for SD card, Run/Stop switch and USB mini-B programming port. Locking hook Hook not included PLC status LEDs description:...
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On: Battery needs to be replaced Battery Flashing: Battery charge is low Serial line 1 Green Flashing: Activity on serial line 1 to HMI touch screen panel Not used Not used #3 Used PLC I/Os Input Description Blower Speed (RPM) Start/Stop Burner request (by others) Burner air proving switch (Alarm) Flue vent back pressure (Alarm)
Display (HMI) features The following diagram describes the structure of different levels in the HMI Home page window Level 1 menu Level 2 menu Level 3 menu Password protected Level 4 menu Password protected Installation and operation manual–DTH-V9-2020...
Run window Run window features: Item Description This section allows the user to see what the heating demand is, which control sequence is active and how the burner reacts to the demand. The gas valve General will react with the heating demand following a linearization curve and the air blower will follow the gas valve feedback position with the correspondent value determined in the fan modulation table.
Level 1: Air/Gas relation Air/Gas relation window: Item Description This section allows a qualified technician to adjust the 20 points air General adjustment curve (air/gas relation) for each gas valve position range. Use ‘’+ ‘’ or ‘’-‘’ to select the gas position where you want to modify Gas feedback the air ratio.
Level 1: Alarm history Alarm history window: Item Description This section keeps a history of the last 8 alarm codes. The number 1 being the General most recent code. The alarm code number is related to an alarm type (first digit) and in which Code steps it’s happened (second digit).
Level 2: Fan RPM auto tuning Fan auto tune Fan RPM auto tuning window: Item Description This section is to perform an automatic fan auto tuning. This is necessary (first start-up and fan replacement) to record the RPM feedback of each General command level.
Level 2: Signal supervision Signal Supervision window: Item Description This section shows how the Air/Gas relation command (Cmd) and feedback General (Fbk) reacts with the demand signal. Heat Direct heating demand signal in Volt. Gas valve modulation signal demand (first row) and actual position feedback signal (second row).
Level 2: Step timer Step timer window: Item Description This section shows the active timer in the actual step (see #3) of the burner General sequence. Numbers can appear or disappear depending if a timer is active. In this example the prepurge step is now at 6 seconds on a 40 seconds timer. Actual Timer count in real time (sec).
PLC alarms An error message is displayed in a red window when an alarm is active. The following table shows the different alarms configured in the PLC. Each alarm will be displayed on a red window with the description and an alarm number on the left corner. ALARM DESCRIPTION POSSIBLE CAUSES...
Flame safeguard alarms Flame safeguards warning lights status: The table below lists the most common and important operational fault codes in the flame safeguard relay. (Refer to flame safeguard instructions manual for other codes not listed in this table) Red Lights Trouble Trouble description code...
Flame safeguard troubleshooting Refer to the flame safeguard alarms section to get the right trouble description. Troubleshooting table Trouble description Corrective action • Verify gas supply as well as the pressure • Verify ignition transformer • Verify flame signal strength •...
Start / stop recommendations In emergency situation When it is necessary to stop the heater in case of emergency, turn the main switch to the OFF position and close the gas supply by closing the manual supply valve on the outside of the heater. Extended shutdown When the duct furnace is not to be used for a long period of time, it is recommended to cut and plug the gas supply.
Unit maintenance Perform the following verifications to the necessary prescribed frequency to keep the unit in good working condition. Do not limit the inspection to this list as some environmental conditions may require other or more frequent inspections. Recommended audit frequency Verification list Weekly Monthly...
Only dealers or contractors who are registered with us are authorized to perform this warranty. Should the dealer or the contractor need assistance, the authorized agent for Nagas is available for support, and we, at Nagas, in turn, support our agent's efforts.
Start-up report Unit tag: ____________________________________ Project: ______________________________________ Technician: ____________________________________ Address: ______________________________________ Contractor: _____________________________________ email: ______________________________________ Phone #: _____________________________________ Manufacturer information Model number: _________________________________________ Serial number: __________________________ Inspection Unit casing: Combustion air proving switch: Airflow switch: Gas leak: Control panel installed (by other): Gas vents if applicable: Combustion air openings: High limit adjustment:...
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Combustion Ambient temperature: _______________°F Oxygen Gas flue Room Efficiency Excess air PPM CO* Signal Temp. °F Temp. °F (Air free) 2.5V 4.0V 6.0V 8.0V 9.0V 10.0V *This value must be as low as possible and must never exceed 400 ppm. Note: ___________________________________________________________________________________________________ ___________________________________________________________________________________________________...