COMBAT CUHA Installation, Commissioning, Service & User Instructions
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COMBAT CUHA Installation, Commissioning, Service & User Instructions

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  • Page 3 hese appliances have been tested and certified as complying with the essential requirements of the Gas Appliance Directive, The Low Voltage Directive, The Electromagnetic Compatibility Directive and the Machinery Directive for use on natural gas and L.P.G. gas when installed, commissioned and maintained in accordance with these instructions.

  • Page 4: Table Of Contents

    Combat Engineering Ltd. reserves the right to alter specifications without prior notice. Combat shall not be liable to rectify any defects or damage caused by any modifications made or attempted to be made to the heating units by the customer, his servants, agents or employees.

  • Page 5: General Specification

    A permanent electrical supply of 230 volts 50 Hz, single phase is required for all models and all models must be earthed. ON/OFF, temperature and time control may be obtained by use of the Combat range of control consoles, or by the use of individual controls as per the circuit diagrams in Section 5.

  • Page 6: Heater Operation

    1.2.1 Automatic Ignition Burner Combat CUH.../A range warm air heaters are fitted with an automatic ignition control which ignites the gas and monitors for the safe operation of the burner each time the external controls call for the heater to operate.
  • Page 7 Fig 2.1 Dimensions etc. CUHA... 60 to 300...
  • Page 8 Fig 2.2 Dimensions etc. CUHA... 340 to 380...
  • Page 9 Fig 2.3 Dimensions etc. CUHB... 60 to 300...
  • Page 10 Fig 2.4 Dimensions etc. CUHB... 340 to 380...
  • Page 11 Fig 2.5 Dimensions etc. CUHC... 60 to 300...
  • Page 12 Fig 2.6 Dimensions etc. CUHC... Models 340 to 380 Range...
  • Page 13 Fig 2.7 Dimensions etc. CUHD 60 to 300...
  • Page 14 Fig 2.7 Dimensions etc. CUHD 340 to 380...

  • Page 15: Technical Data

    Table 2.1 General Technical Data - All Models...
  • Page 16 Table 2.2 Technical Data CUHA, CUHB, CUHC and CUHD Manual Ignition Range Appliance Category II Propane Gas Inlet pressure 37 mbar (25 - 45) 2H3+ Natural gas inlet pressure 20 mbar (17 - 25) Butane gas Inlet pressure 29 mbar (20 - 35)
  • Page 17 Table 2.3 Technical Data CUHA/A, CUHB/A, CUHC/A and CUHD/A Automatic Ignition Range Appliance Category II Propane Gas Inlet pressure 37 mbar (25 - 45) 2H3+ Natural gas inlet pressure 20 mbar (17 - 25) Butane gas Inlet pressure 29 mbar (20 - 35)
  • Page 18 Gas Controls - Automatic Ignition The heaters may be fitted with one of two types of gas control valves dependent upon the model, each giving the same control elements as follows (see Section 4). 2.1.1 Main Gas Burner The multifunctional main gas valve contains a gas regulator and two automatic shut off valves. When set up as defined in Section 4 the valves will have a step opening operation on the main gas to give smooth lighting.
  • Page 19 Fan Thermostat The fan thermostat controls the operation of the main fan during the heater operating cycle. This control also ensures that the main fan continues to run after the burner turns off to dissipate the residual heat from the heat exchanger. The white button on the fan thermostat should be pulled to its “out”...
  • Page 20 DESCRIPTION OF SATRONIC TFI 812 2B Mod 10 CONTROL BOX The fully automatic gas burner fitted to all CUHA/A, CUHB/A, CUHC/A and CUHD/A models is controlled by a Satronic TFI 812 2B Mod 10 plug-in control box. This control ensures the safe start and stop sequence and also monitors the safe presence of a flame.

  • Page 21: External Controls

    Typical flame probe current 3-5 µA DC External Controls CUH... range heaters may be operated from external controls or consoles supplied by Combat Engineering Ltd. which are described in their own instructions book. The wiring diagrams for the external controls are shown in Section 5.

  • Page 22: Heater Installation

    Section 3. HEATER INSTALLATION Required Standards It is important that all gas appliances are installed by competent persons, in accordance with the relevant requirements of the local laws and regulations. Failure to install gas appliances correctly could lead to prosecution. THE RELEVANT REGULATIONS ARE: Gas Safety (Installations and Use) Regulations 1984;...
  • Page 23 General All models must be installed with the base level and may be suspended from above or from specially prepared wall brackets of sufficient strength to adequately support the weight of the heater as listed in Section 2. Data Tables. Drop rods should be a minimum of 10 mm diameter mild steel. The four hanging brackets are located on top of the heater, for all models.
  • Page 24 B.S. 6230 or B.S.5440 Part 1 as appropriate. Suitable flue may be supplied by Combat Engineering Ltd. A separate draught diverter is not required as the heaters have one built in. No other appliance may be...
  • Page 25 Models 340 and 380 only The models 340 and 380 heaters are provided with two outlet spigots on top of the heater and a flue assembly as shown in Fig 3.2 to combine these two flue outlets into a single vertical flue for the appliance.

  • Page 26: Air Supply

    If the flue passes through a wall or ceiling of combustible material it must be enclosed by a sleeve of noncombustible material and be separated from the sleeve by at least a 25 mm air gap. The temperature of any combustible material near the flue or heater must not exceed 65°C when the heater is in operation. The flue must be at least 50 mm from any other combustible material.

  • Page 27: Building Ventilation

    For buildings with a design air change rate 0.5/h or greater and where the volume of the heated space is greater than 4.7 m per kilowatt of total rated heat input, as appropriate, additional high and low level ventilation will not be required. Where natural ventilation is used for compartment/plant rooms, suitable permanent openings at low and high level, communicating directly with the outside air, must be provided.

  • Page 28: Electrical Supply

    Any such device must be in parallel with the fan thermostat so that the fan run-on operation will still take place. CUHD heaters are fitted with two combination thermostats, at the front and in the rear inlet spigot to cater for this effect. Contact Combat Engineering Limited Design Department for advice regarding duct resistance and design. 3.7.1...

  • Page 29: Remote Controls

    1 sq. mm cable on all models. A fuse size of 5 Amp must be used for all models CUHA and CUHA/A up to and including model 240, and 10 Amp for all remaining CUHA , CUHA/A ,CUHB, CUHC,CUHB/A and CUHC/A models except for models CUHB…...
  • Page 30 3.9.2 Remote Room Thermostat A remote room thermostat may be connected to terminals 2 & 3 in the main terminal block on the side of the heater (see Section 5). 3.9.3 Remote Frost Thermosatat Where a remote frost thermostat is required to override the operation of a time switch during its "off" periods, this may be connected to terminals 2 and 3 in the main terminal block on the side of the heater.

  • Page 31: Wiring Diagram

    Check that all site wiring is connected in accordance with the appropriate wiring diagram of Section 5. Check the correct fuse size is fitted; 5 Amp must be used for all models CUHA and CUHA/A, and 10 Amp for CUHB, CUHC, CUHB/A and CUHC/A models, except for models 340 and 380 where the fuse size should be 20 Amp.

  • Page 32: Mechanical Checks

    Gas Supply The whole of the gas installation including the meter should be inspected, tested for soundness and purged in accordance with local regulations. It will be necessary to ensure that the air is fully purged from the heater inlet pipe up to the main gas valve inlet test nipple before the start gas burner will ignite.
  • Page 33 Note: At the first firing of the heater it may be necessary to repeat several times whilst purging the remaining air from the gas train. There is no adjustment for the start gas burner. Once the start gas flame has ignited it will be monitored by the flame probe and should remain on until the controls turn it off.
  • Page 34 Regulator (under cover) Inlet Pressure Pilot gas outlet of valve Blanked off Burner pressure Fig. 4.2 S.I.T. Nova 0.822.177 Automatic Ignition Gas Valve Burner Pressure "A" Thermocouple interrupter Manual control knob Thermocouple relay connections Inlet Pressure "E" connection Regulator adjusting screw Pilot Gas pipe connection Electrical connection...
  • Page 35 The main gas control valve used on all versions of the models CUHA/A, CUHB/A, CUHC/A and CUHD/A 340 and 380 is the Johnson GM 240 9001 combination gas valve or alternative Dungs MBDLE 405 BO1 (see Fig 4.4). These controls contain two main safety shut off valves and burner pressure regulator.
  • Page 36 4.4.2 Commissioning the Gas Valves - Natural Gas Depending on the model of the heater there will be an S.I.T Tandem valve, an S.I.T Nova valve or a Johnson controls gas valve (see Data Table in Section 2 and Figs 4.1 to 4.4). Connect a manometer to the outlet (burner) pressure test point of the gas valve after first removing its screw cover.
  • Page 37 Manual Ignition Unit Heaters All CUH manual ignition unit heaters are controlled by an S.I.T Nova 0.820.054 multifunctional gas valve (see Fig 4.3). First remove the electrical plug from the multifunctional gas valve to ensure that main gas cannot be released.
  • Page 38 Wherever possible a reading of the gas rate timed through the gas meter should be taken and compared with the nominal rating in the Data Table, Section 2. The burner pressure should be adjusted to give this nominal gas rate. 4.5.2 Commissioning the Gas Valves - L.P.G.
  • Page 39 4.10 External Controls Operate the External Controls as installed which may include time switch, room thermostat and manual switch to ensure that they function correctly. Set the time switch (if fitted) and room thermostat to the users requirements. See Sections 2 and 9. 4.11 Handing Over Ensure that all covers are fitted correctly and all test points are properly sealed before leaving the...
  • Page 40 Section 5. WIRING DIAGRAMS MANUAL IGNITION Fig. 5.1 Wiring for CUHA Manual Ignition Range...
  • Page 41 MANUAL IGNITION Fig 5.2 Wiring for CUHB & CUHC models 60 to 160...
  • Page 42 MANUAL IGNITION Fig 5.3 Wiring for CUHB & CUHC models 180 to 300...
  • Page 43 MANUAL IGNITION Fig 5.5 Wiring to CUHD Manual Ignition Range (All models)
  • Page 44 AUTOMATIC IGNITION Fig. 5.6 Wiring Diagram for CUHA/A Range of Heaters Models 60 to 240...
  • Page 45 AUTOMATIC IGNITION Fig. 5.7 Wiring Diagram for CUHA/A Range of Heaters Models 280 to 380...
  • Page 46 AUTOMATIC IGNITION Fig 5.8 Wiring For CUHB/A & CUHC/A Models 60 to 160...
  • Page 47 AUTOMATIC IGNITION Fig 5.9 Wiring For CUHB/A & CUHC/A Models 180 to 300...
  • Page 48 AUTOMATIC IGNITION Fig 5.10 Wiring For CUHB/A & CUHC/A Models 340 to 380...
  • Page 49 AUTOMATIC IGNITION Fig 5.11 Wiring of CUHD/A Range - Automatic Ignition - All Models Fig 5.12 Alternative wiring of external motor for CUHD Range - All Models...
  • Page 50 Fig 5.13 Individual controls for all CUH Range heaters...

  • Page 51: Servicing Instructions

    Section 6. SERVICING INSTRUCTIONS After commissioning, the heater will require maintenance to be carried out at least once per year to ensure that peak performance and safety are maintained. If the heater is used in a dirty or dusty area, then more frequent maintenance may be necessary.

  • Page 52: Heat Exchanger

    It is essential that the fans are not operated at higher speeds than the original setting on the heater without prior consultation with Combat Engineering Ltd. Such action may cause the fan motors to be overloaded.
  • Page 53 Gas Control Valves Automatic Ignition There is no regular maintenance required on these devices. To change gas control valves, see Section 7.4. Manual Ignition There is no regular maintenance required on these devices. To change gas control valves, see Section 7.4. Pilot Drop Out Test - Manual Ignition Models During the routine service a check must be made that the flame failure device operates correctly To do this:-...

  • Page 54: Removal And Replacement Of Parts

    Section 7. REMOVAL AND REPLACEMENT OF PARTS See warnings and notes at the start of Section 6 before removing or replacing parts. Burner Tray The burner tray may be removed from the heater only from the front. It may be removed complete with the gas valve train assembly or on its own leaving the gas valves in the heater.
  • Page 55 Main Burner Bars/injectors 7.2.1 Remove the burner tray as in 7.1. 7.2.2 To remove the burner bars first remove the screws securing the retaining bar at the front end of the burner and pull off the retaining bar (see Fig. 7.1). Remove the screws securing the burner rear baffle and pull it upwards to remove.
  • Page 56 Ignition Burner Assembly CAUTION: Do not kink or tightly bend the pilot gas pipe or thermocouple (where fitted). There are two options to the pilot burners used for the complete range of heaters. These are shown below in Fig 7.2. However a different pilot injector is used for natural gas and L.P.G. The pilot burner for use on natural gas is fitted with an injector marked 34.
  • Page 57 7.3.1 Removal of pilot burner Remove the rear lower panel of the heater. Unscrew the pilot gas pipe at its compression fitting with the pilot gas valve or main gas valve as appropriate. iii) Unplug the H.T cable from the Piezo electric igniter or spark generator, as appropriate. Either unplug the flame probe from its jack socket or unscrew the thermocouple from the gas valve.
  • Page 58 7.4.2 Removal of Gas Valves - Automatic Ignition There are two mounting systems used for the automatic ignition gas valves. S.I.T Tandem valves These are connected to the main gas manifold using a navy union. Electrical connection is by a plug on the end of a flying lead. S.I.T Nova automatic gas valves These are connected to the main gas manifold using the valve manufacturers angled outlet flange.
  • Page 59 NO ATTEMPT SHOULD BE MADE TO OPERATE THE HEATER WITHOUT THIS RELAY. FAILURE TO COMPLY WILL CAUSE A SEVERE FIRE HAZARD CUHA Axial Fan/Guard/Motor Assembly The Axial fan unit for the CUHA range of heaters is supplied completely assembled and balanced. These components are not replaceable separately 7.5.1...
  • Page 60 CUHB & CUHC Centrifugal Fan/Guard/Motor Assembly The direct drive fan/s for the CUHB & CUHC range is supplied as a complete assembly and therefore does not need to be disassembled. Each fan is fitted to the rear of the cabinet secured with four fixing screws and washers.
  • Page 61 7.7.3 Unscrew two fixing screws and withdraw the unit from the cabinet feeding the cables through the plastic conduit connection. 7.7.4 To refit, reverse the above procedure reusing the plastic conduit connection and reset as in the commissioning instructions, Section 4. Note: the new thermostat should have the limit setting sealed by a suitable method to prevent unauthorised adjustment.
  • Page 62 7.8.5 To refit a thermostat, first carefully straighten the capillary tube, it is important not to kink or crack it. Proceed to replace by reversing the above procedure ensuring that the sensing bulb at the end of the capillary tube is positioned against the base of the heat exchanger towards the centre of the fan outlet. (Where there are two fans the position of the sensing bulb should be towards the centre of the fan on the opposite side of the heater from the controls).
  • Page 63 Us e 8.2 to te st burne r He ate r ope ra ting Following the replacement of parts carry out the Commissioning procedure as in Section 4. Should these procedures not resolve any problem, please contact Combat Engineering Ltd.
  • Page 64 8.1.1 General - Manual Ignition Warning Fault finding should only be carried out by experienced engineers who fully understand the operation of the burners. There is a risk, including that of explosion, when burners are faulty and not repaired correctly. STA RT A ssum ing ga s &...
  • Page 65 8.2 Fault Finding For Automatic Ignition Burner Systems STA RT WARNING Ignition output from the A ll con trols ON spark generator is 160 kv to earth. Extreme care must be taken I s Gree n lig ht ON ? Ch eck for e lec tric al supply opera tion o f e xte rna l c on trols &...
  • Page 66 Flame Supervision System 8.3.1 Automatic Ignition Systems M axim um flam e current M inim um flam e current with no fla m e with pilot only 0 to 0.5 µA D.C. 1.0 µA D.C. Typical fla m e current 3.0 to 5.0 µA with m ain Burne r ON Conne ct a D.C.
  • Page 67 8.3.2 Flame Supervision Systems - Manual Ignition Doe s pilot flame light ? Chec k gas supply a nd pilot Chec k if pilot flame will light gas pipe for bloc ka ge using a taper Chec k piezo ignite r, le ad a nd ignition e lec trode for dama ge .
  • Page 68 Fault Finding for Main Fan Fa n doe s not run automa tic ally? Check for elec tric al supply Fa ult elsewhere 230v L to N Press in m anual switch of Te st for 230v be tween term inals Fa ult elsewhere com bination the rm ostat 1 a nd N in te rm ina l block...

  • Page 69: User Instructions

    (there are two of these on the models 340 & 380) The CUHA, CUHB, CUHC & CUHD ranges of heaters are manual ignition of the pilot, but operate automatically from the remote controls fitted on site providing that the pilot flame remains alight.
  • Page 70 Note: On some fully ducted heaters the fan will come on during the burner firing cycle and not wait for the temperature rise. This is to ensure that there is always a proper operation of the heater under all possible duct conditions. When the remote controls turn off the heater, the burner turns off immediately leaving the fan(s) to run on to cool the heat exchanger.
  • Page 71 The fault must be traced and repaired by a competent person. Lighting Instructions for Automatic Ignition Heaters Types CUHA/A, CUHB/A, CUHC/A and CUHC/A (See 9.6. for lighting manual ignition heaters) 9.4.1 Ensure that the electrical and gas supplies to the heater are on. Check that the time switch is in an “ON”...
  • Page 72 WARNING The electrical isolator must not be used for turning the heater off other than in an emergency. This will prematurely turn off the distribution fan and will seriously shorten the life of the heat exchanger, invalidating the warranty. Such action may also cause a fire hazard. User Controls for Manual Ignition Versions 9.5.1 Multifunctional Gas Valve...
  • Page 73 Lighting Instructions for Manual Ignition Heaters Types CUHA, CUHB,CUHC and CUHD (See 9.4. for lighting automatic ignition heaters) 9.6.1 Ensure that the electrical and gas supplies to the heater are on. Check that the remote controls are set to “OFF”.
  • Page 74 9.6.2 To Turn the Heater Off (Short Periods): Operate the remote controls to the “OFF” position. The burner will turn off immediately, but the distribution fan will continue to run for a few minutes to cool the heat exchanger before turning off automatically. The heater will then be at rest until the controls are turned on again.
  • Page 75 9.7.1 Simple Fault Finding - Automatic Ignition Heaters If under fault conditions the burner fails to ignite for any reason then it will go to the lockout condition this will be indicated by the red lockout warning light on the heater or remote control To reset press in and release the lockout reset button after waiting for one minute (see Figs 2.1 &...

  • Page 76: Burner Conversion

    Section 10. Conversion Between Gasses 10.1 General Note all versions of models CUH...60 may not be operated on L.P.G All versions of the heaters use the same main burner bars and pilot burners. Natural gas All natural gas versions use the same main burner injectors, marked 840, and pilot injectors marked The gas valves vary according to the models size and method of control i.e.
  • Page 77 10.3 Gas Valves - Automatic Ignition There are three type of valve used for this range of heaters (see Data Tables in Section 2 for part numbers and specification numbers). CUH.../A 60 to 140 use the S.I.T. Tandem gas valve. Note: Model CUH.../A 60 heaters only cannot be operated on L.P.G.
  • Page 78 10.3.3 Conversion of Johnson Valve to L.P.G. For the Models 340 and 380 the valve for use on L.P.G. Propane or Butane is exactly the same Johnson valve as for natural gas however the pressure regulator must be put out of service. To do this for the Johnson gas valves an adaptor pipe is fitted to connect the pressure regulator breather port to one of the valve centre test points (see Fig 10.3).
  • Page 79 10.4 Conversion of Manual Ignition Valves All CUH... range manual ignition unit heaters use an S.I.T Nova multifunctional gas valve. The Models CUH... 60 only cannot be operated on L.P.G. Nova Range valves Nova range main valves may be converted to operate with or without a burner gas pressure regulator. Follow the instructions in Section 7 of this manual for removal of gas valves.

  • Page 80: Parts List

    Honeywell combination fan/limit thermostat. K 017 Second limit thermostat K 120 Note: Always quote the model and serial number of the heater when ordering spare parts. Parts available from: Combat Engineering Ltd. Oxford Street, Bilston, West Midlands WV14 7EG SWITCHBOARD SPARES SERVICE...

  • Page 81: Commissioning Data Sheet

    Section 12. COMMISSIONING DATA SHEET CUSTOMER SITE ADDRESS HEATER LOCATOIN MODEL SERIAL NUMBER GAS TYPE NATURAL/L.P.G. INLET GAS PRESSURE mbar BURNER GAS PRESSURE mbar GAS RATE MEASURED AT METER /hr (ft /hr) AMBIANT TEMPERATURE °C GROSS STACK TEMPERATURE °C NET STACK TEMPERATURE °C CARBON DIOXIDE IN FLUE CO CARBON MONOXIDE IN FLUE CO..

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