Nortek Reznor VRA20-4E Installation, Commissioning, Servicing

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Nortek Reznor VRA20-4E Installation, Commissioning, Servicing Manual pdf 21 page image

1712VRA‐4EGBEN, pag.. 21/25USER INSTRUCTIONSOperatingHow the air heater works Gas is burned by anatmospheric burner which fires into a heat exchanger.The gas burner is controlled by a double gas valve viaan electronic burner control, which is actuatedautomatically via external controls i.e. a roomthermostat and/or a time switch. The burner is ignitedby a spark igniter. When the burner fires and warmsthe heat exchanger, the heat is sensed by a thermallyactuated fan control which switches on the fan whenthe air temperature has reached its preset operatinglevel. At the end of a heating cycle the burner isswitched off, the air circulation fan will continue to rununtil the air heater has cooled to a safe condition.Thereafter the fan will remain off until the next cycle isinitiated.Safety1. Flame failure is detected by the ionization probewhich is the sensor and will immediately result ingas valve shut down.2. Safety against overheating is assured by twooverheat controls. The first is an automatic recyclecontrol which protects against low air flow i.e.clogged air ways, fan failure etc. The second,which is set to a higher level than the first one, is acontrol which locks out and switches off the burnerin the event of gross overheating for any reason.Manual intervention is necessary to reset thiscontrol device. Resetting of the automatic burnercontrol may also be required.3. The location of the air heater should be maintainedat normal atmospheric pressure. Changes to thebuilding after air heater installation, should haveregard to the heating installation, i.e. structuralchanges causing excessive draughts from doors,windows etc. Other air handlers and installation ofair extraction equipment which may cause anegative pressure environment, can seriouslyaffect the operation of this type of air heater,especially if combustion air supply is not ducted.To light the heater1. Turn on the gas supply to the air heater.2. Switch on the electricity supply to the air heater.3. Ensure time switch (if fitted) is set to an 'ON' cycle.4. Adjust control/room thermostat to desiredtemperature.5. Air heater will light automatically when the roomthermostat calls for heat after about 30 sec.6. If the appliance does not light:a) check that the burner control does not requireresetting. An indicator light glows at the insidepanel of the appliance and on a remote control iffitted. Reset by pushing reset/button inside theappliance or the remote control.b) check if thermal overheat control requiresresetting7 If the thermal overheat control requires resettingand doing so restarts the air heater, wait until theappliance warms to thermal equilibrium, to ensurethe overheat control does not lock out again. If itdoes and the temperature near the heater is lessthan 30°C, then switch off the appliance and callfor service. If the temperature is over 30°C, takeappropriate action to reduce the ambienttemperature near the air heater.Air circulation1. The space heating process is for air to becirculated through the appliance whereby it gainsheat from a heat exchanger. The air is directlydischarged into the space to be heated. The air iseventually re-circulated. Therefore it is veryimportant that an unobstructed path for thecirculation of the air will be maintained. This isparticularly important if the air heater has beeninstalled to blow through the wall between tworooms.2. Sometimes the air circulation fan of the applianceis connected to a remote over-ride switch. Thisenables air to be used for circulation purposeswhen the air heater is not used for heatingpurposes e.g. in summer.To use this feature:a) switch ON electricityb) switch ON manual override switch, this may befitted as a feature on a remote composite control.Maintenance1. Maintenance and service must only be carried outby appropriately qualified persons e.g. "Corgi"registered undertakings.2. It is in your interest to ensure proper service andmaintenance is carried out at a regular basis.Periods between services are dependent upon thelocal environment where the heater is installed. Allgas appliances should be serviced at least once ayear.3. In case of any damage to the appliance, it must beshut down completely and checked by anappropriately qualified person.4. In the event of difficulties in resolving any of thesematters, please do not hesitate to contact yourdistributor.NEVER SWITCH OFF ELECTRICTY SUPPLY TO THE AIRHEATER WITHOUT FIRST CLOSING THE GAS ISOLATINGTAP.12