Zehnder Rittling FF-200 Installation, Operation And Maintenance Manual

Zehnder Rittling FF-200 Installation, Operation And Maintenance Manual Manual pdf 42 page image

40Electric heating elementElectric resistance type heatersgenerally require no normalperiodic maintenance whenunit air filters are changedproperly. The operation andservice life may be affected byother conditions and equipmentin the system. The two mostimportant operating conditionsfor an electric heater are properairflow and proper supplyvoltage. High supply voltageand/or poorly distributed orinsufficient airflow over theheater will result in the elementoverheating. This conditionmay result in the heater cyclingon the primary automatichigh limit thermal cutout. Ifthe temperature becomes toohigh, the secondary high limitthermal cutout may be activated,breaking the circuit and leavingthe unit non-operational.The primary automatic thermalcutout will reset automaticallyafter the heater has cooleddown, allowing the unit to runagain without intervening.The secondary thermal cutoutis a safety device only, isnot intended for continuousoperation and will need to bereplaced before the unit willoperate again. With proper unitapplication and operation, theprimary high limit thermal cutoutwill not operate. This deviceonly operates when there is aproblem and ANY condition thatcauses the high limit cutout tooperate MUST be correctedimmediately. High supply voltagealso causes excessive amperagedraw and may trip the circuitbreaker or blow the fuses on theincoming power supply.After proper airflow and supplypower are verified, regular filtermaintenance is important toprovide clean air over the heater.A dirty filter will inhibit the properairflow, leading to high temperaturesituations. Improper filtration will alsolead to dirt being deposited on theheating element, causing hot spotsand eventual element burn through.These hot spots will generally notbe enough to cause the high limitswitches to trip and may not beevident until the element actuallyfails. Dirt deposited on the elementmay also cause unwanted odors inthe air-conditioned space as theforeign material is burned off.Electrical wiring & controlsElectrical operation of each unit isdetermined by the components andwiring of the unit. This may varyfrom unit to unit. Refer to the wiringdiagram located in a zip-lock plasticbag in the electrical control box ofeach unit for the actual type andnumber of controls provided on eachunit.The integrity of all electricalconnections should be verified atleast twice during the first year ofoperation. Afterwards, all controlsshould be inspected regularly forproper operation. Some componentsmay experience erratic operation orfailure due to age. Thermostats maybecome clogged with dust/lint, andshould be periodically inspected andcleaned to provide reliable operation.When replacing any electricalcomponents such as fuses,contactors, relays or transformers,use only the exact type, size andvoltage component as furnishedfrom the factory. Any deviation fromthis could result in personnel injuryor damage to the unit and will voidthe manufacturer’s warranty. Allrepair work should be done in sucha way as to maintain the equipmentin compliance with governing localand national codes, ordinances andsafety testing agency listings.Valves and pipingNo formal maintenance isrequired on the valve packagecomponents other than a visualinspection for possible leaksduring normal periodic unitmaintenance. Strainers, whenincluded, should be checkedregularly for build-up and rinsedas needed. In the event that avalve should need replacement,the same precautions takenduring the initial installationto protect the valve packagefrom excessive heat shouldbe implemented duringreplacement.Throwaway filtersThese types of filters shouldbe replaced on a regular basis.The time interval betweenreplacement is dependent uponthe environment in which theunit is operating and shouldbe established based onregular inspection of the filter.Record the time interval in themaintenance log for futurereference. Refer to the productcatalog for the recommendedfilter size. If the replacementfilters are not purchased fromthe factory, the same type andsize filters should be obtained.Pleated media or extendedsurface filters should not beused without consent fromthe factory due to the high airpressure drops associated withthese types of filters, negativelyaffecting unit performance.Normal operation/maintenance