Nortek Reznor VRA20-4E Installation, Commissioning, Servicing

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Nortek Reznor VRA20-4E Installation, Commissioning, Servicing Manual pdf 14 page image

1712VRA‐4EGBEN, pag.. 14/25SERVICING INSTRUCTIONSIMPORTANT: Only appropriately qualified personsmay carry out servicing and fault finding on this gasfired equipment. Before commencing service ensurethat both the gas and the electricity are turned andswitched "OFF" and that the air heater has cooleddown. Inadvertent substitution or replacement ofcomponents similar to those specified or replacementin a manner contrary to the method herein describedcould constitute a hazard and lead to prosecution.VRA-4E air heaters will operate with a minimumof maintenance. To ensure long life andsatisfactory and safe performance, an air heaterthat is operated under normal conditions shouldbe inspected and cleaned at the start of eachheating season. If the air heater is operated in anarea where unusual amounts of dust, etc arepresent in the air, more frequent servicing isrecommended.When any service is completed, be sure thatcomponents are reassembled correctly to ensurethat no unsafe condition exists.Upon completion of the service carry out thecommissioning instructions outlined in section 6of this document.WARNING: Excessive dirt build-up on the inside ofthe burner ports could cause unburnt gas to spill outof the back of the burner tube causing a fire orexplosion. To prevent this occurring, clean all of theburner ports at least annually.CAUTION : When cleaning air heaters, wearing of eyeprotection and a dust face mask is recommended.Service procedureThe following procedures should be carried out atleast annually:1. Remove the burner assembly as in section8.1. Clean thoroughly, (cleaning the burnersrequires an emery cloth, wire brush and acleaning cloth -stubborn deposits on burnersare best cleaned using "acetone" as asolvent).* Check the condition of the ignitor and cleanto remove all deposits. Check the spark gap(3,0 mm).* Check the sensor - clean as necessary.* Remove any soot deposits from the burnerwith a wire brush. Clean the ports with adegreaser or acetone. A vacuum cleaner orcompressed air may assist in this cleaningoperation. Wipe the inside of the burner tubeclean (cleaning thoroughly with a degreaseras recommended will retard future build-up ofdirt). Inspect the burner for any damage ordeterioration. If the burner is damaged orcorroded, replace it.2. The heat exchanger should remain cleanunless a problem has developed due to poorcombustion. Examine the heat exchangertubes internally and externally for any sign ofdeterioration. The outside of the tubular heatexchanger can be cleaned from the front ofthe heater with an air jet and/or a flexiblebrush. Remove any dust and grease deposits.The inner surfaces of the heat exchanger canbe reached for cleaning with the burner andcombustion air fan (venter) assembliesremoved. Clean with a flue brush or a heavywire to which wire wool has been attached.Brush inside each heat exchanger tube untilall foreign material has been removed. Theuse of a flashlight is necessary to carry outthis operation.3. Clean the axial fan blades, fan guard, and fanmotor to remove all external dirt. Check thesecurity of the fan on the motor.Note: Fan motors are lubricated for life and donot require lubricating.4. Remove any dirt and/or grease that may haveaccumulated on the venter fan motor and itshousing. Note: The combustion air fan motorsare lubricated for life and do not require oilingor greasing.5. The gas multi-functional control valve requiresno field maintenance except cleaning of itsexterior and checking the condition of the wireconnections. Instructions for testing pressureare given in section 6.6.6. Check the flue/combustion air system forsoundness. Reseal/replace any parts that arenot sound.7. Check all wiring connections. Check wiring forany signs of damage. Replace any suspectwiring with an equivalent specification.8. Check operation of thermal fan control andcontrol relay.9. When service is complete carry out fullcommissioning procedure as per section 6 ofthis document.7