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MUA-SVX005B-EN
IImmppoorrttaanntt:: It is important that the final temperature leaving the unit does not exceed 160° F (71°
C). When final air throughput adjustments are being made, a check of the discharge
air temperature should be made after unit has operated for 15 to 20 minutes.
WWAARRNNIINNGG
FFiirree HHaazzaarrdd!!
FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy,, aanndd pprrooppeerrttyy
ddaammaaggee..
AA uunniitt sshhoouulldd nneevveerr bbee aalllloowweedd ttoo ccyyccllee oonn tthhee pprriimmaarryy lliimmiitt ffoorr aa pprroolloonnggeedd ppeerriioodd ooff
ttiimmee.. IItt iiss aa ssaaffeettyy ccoonnttrrooll ttoo pprreevveenntt aa ffiirree.. IIff ccyycclliinngg oonn tthhee pprriimmaarryy lliimmiitt iiss nnootteedd,,
ccoorrrreeccttiivvee mmeeaassuurreess sshhoouulldd bbee ttaakkeenn iimmmmeeddiiaatteellyy..
IImmppoorrttaanntt:: At initial unit installation, unit should be started momentarily to confirm proper
blower wheel rotation as the unit will deliver some air with the blower wheel running
backwards.
Two basic air control systems can be used to deliver conditioned air to the occupied space:
intermittent or constant fan operation.
• IInntteerrmmiitttteenntt FFaann OOppeerraattiioonn: The unit employs an air control system which utilizes a fan time
delay relay to operate the fan while heating and the thermostat while cooling. Refer to unit
wiring diagram.
• CCoonnssttaanntt FFaann OOppeerraattiioonn: The unit can be wired to give an air control system which
constantly circulates air through the unit and occupied space with constant fan operation.
Refer to unit wiring diagram.
IImmppoorrttaanntt:: Check blower belt tension. Proper belt tension is important to the long life of the belt
and motor. Proper belt tension will allow the belt to be depressed 1/2" to 3/4".
• It is important that the blower motor and the blower wheel pulleys be in good alignment, with
the motor and blower shafts parallel.
• Belt tension must be adjusted to give approximately 3/4" deflection of the belt when finger
pressure is applied to the middle of the belt (See Figure 10, p. 25). Small changes in this
tension may be necessary for optimum operation. Belts will stretch over a period of time,
requiring an adjustment to this tension. See “Maintenance,” p. 30 section for belt and pulley
adjustments.
• These units are set at the factory for the RPM required to meet the air volume (CFM) and
external static pressure ordered. If the estimated external static is incorrect, or changes were
made to the duct system, the blower RPM may need to be changed.
• Both the Standard and High CFM Blowers use motors which are equipped with adjustable
pitch pulleys. After removing belt(s), loosen the pulley set screw and remove the key, turn
adjustable half of a pulley clockwise to increase RPM, or counter-clockwise to decrease RPM.
Insert key, tighten set screw and replace belt(s). Adjust belt tension to give 1/2" to 3/4" belt
play when depressed.
NNOOTTIICCEE
BBlloowweerr MMoottoorr FFaaiilluurree!!
FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinn iimmpprrooppeerr uunniitt ooppeerraattiioonn aanndd mmoottoorr
ffaaiilluurree..
BBlloowweerr mmoottoorr ffuullll llooaadd aammppss sshhoouulldd nneevveerr bbee eexxcceeeeddeedd.. RReeffeerr ttoo mmoottoorr ddaattaa ppllaattee ffoorr
mmaaxxiimmuumm ffuullll llooaadd aammppss..
• After changing blower RPM, confirm blower motor full load amps have not been exceeded.
See motor data plate for maximum full load amps.
OOppeerraattiioonn
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