D4OPTRS 6 2019
M01309
PRECAUTIONS
The TYMCO DST feature is intrinsically simple and safe to operate. However, a few operational
and service precautions should be followed when working around the fi lter box area.
SAFETY
Do Not open the fi lter box large access door without fi rst turning off the sweeper ignition key
on the sweeper control console in the cab. This prevents the high velocity purge back pulse
from discharging when in this area. A proximity sensor at the top of the service door also
prevents the purge system from engaging when the door is open.
Always bleed down the air tank pressure before working inside the DST box. Use the ball
valve at the shop fi ll port to drain the air tank.
Once the access door is open, turn off the service switch located on the bottom of the VMM
enclosure. (Illustration M01309). This turns off the power to the VMM control module and all
components of the DST system. If the door is open, with the sweeper ignition and the service
switch is in the on position, the DST Power Indicator Light will fl ash to indicate the system is
still active. If the Power Indicator Light is on solid, the purge system is active and could fi re at
any time! This condition cannot occur with the door open, unless the service door proximity
switch is bypassed.
Use a dust mask when servicing the fi lters or precleaner or when cleaning out the fi lter box
hopper.
DOOR
PROXIMITY
SWITCH
AIR TANK
PRESSURE
TRANSMITTER
(BEHIND PULSE
VALVE “A”)
PULSE
VALVE “A”
PULSE
VALVE “B”
SCAVENGE
LINE
VALVE
DRAIN
VALVE
VMM
ENCLOSURE
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