Aprilaire 1953 & 1972 - Manual (Page 10)

10
IV. ANNUAL LAMP REPLACEMENT
The Aprilaire Ultraviolet Germicidal Lamp is designed for the lamp to be on at all times. After 9,000 hours of operation – 1 year of
constant use – the effectiveness of the lamp inside the unit diminishes and needs to be replaced. Rarely will a lamp burn out in one
year of continuous use; replacement is necessary because the lamp’s intensity decreases. Installation of the replacement lamp is best
handled by a qualified HVAC Service Contractor.
a. Shut off power to the rooftop unit. Wait several minutes for
lamp to cool before proceeding. Remove access panel(s) to
the rooftop unit.
b. Remove Lamp from Unit. For External Mount Units, open the
cover of the Unit Base, disconnect Lamp Retaining Bracket,
and slide the Lamp to the large side of the keyhole slot and
then pull straight out. For the Internal Mount Unit, simply
disconnect Lamp Socket and remove Lamp.
c. Use alcohol to remove any dirt and/or fingerprints from the
new Lamp. Insert Lamp into the unit and attach Lamp Socket
to the Lamp.
d. For External Mount Units, close and secure the cover of
Unit Base.
e. Put access panels of the rooftop unit back in place.
f. Turn power to rooftop unit back on.
g. Refer to ‘Check Lamp Operation’ of the previous section to
verify operation.
h. Record the date the lamp was replaced in this manual so
that the date for next replacement is clear.
Refer to ‘Troubleshooting’ section if the Lamp does not operate.
Under normal conditions, the Aprilaire Ultraviolet Germicidal Lamp should not require any maintenance other than annual lamp replacement.
LAMP REPLACEMENT INSTRUCTIONS (EXTERNAL & INTERNAL MOUNT UNITS):
CHECK LAMP OPERATION
The preferred method for checking lamp operation is to measure the current draw of the lamp using a clamp-on ammeter. To detect
the low current of the UV lamp, the ammeter must be capable of measuring 100 mA and above. To prevent accidental exposure to
harmful UV germicidal light during this procedure, the location where the amperage measurement is taken must be in a
separate compartment from where the UV lamp is installed. To measure the current draw of the lamp:
a. First, shut off power to the HVAC equipment.
b. Next, in the control panel for the HVAC equipment, locate the hot and neutral wires that were installed to provide power to the lamp.
c. Place the clamp-on ammeter around either the hot or neutral wire. Make sure the ammeter is set to read amps in the mA range.
Again, make sure that the UV lamp – or light from it, if it were on – is not visible from where the ammeter is placed.
d. Next, turn the power to the HVAC equipment back on.
e. If the lamp has been installed correctly and is drawing power, the amp reading will be a minimum of 150 mA. For multiple lamps,
the reading would be a multiple of this value, i.e., with two lamps installed, the amp reading will be at least 300 mA.
f. If the lamp is operating correctly, remove the ammeter from the wiring and put back any access panels that were removed during
this procedure. If the lamp is not operating correctly, refer to the ‘Troubleshooting’ section of this manual.
Note: If other electrical components or accessories share the same circuit as the UV lamp(s), the current draw will be higher and the
above method may not be an accurate indication of lamp operation.