Xylem IM 16 Seal-less Centrifugal Canned Motor Pumps For Instant Hot Water Recirculating System (obsolete) - Manual (Page 5)

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13. If you have an SMT or UCT timer pump, set your timer in accordance with the instructions below.
Timer Controlled Operation
If timer controlled operation is desired, the timer may be programmed to allow the system to operate
during the hours desired (i.e. “ON” from 7:00 a.m. to 9:00 p.m. and “OFF” from 9:00 p.m. to 7:00
a.m.) as follows:
• Open the timer cover and rotate the dial clockwise
until the correct time is aligned with the pointer (P)
on the dial face. If the indicator cannot be located
on the face of the timer, there is an additional arrow
indicator (P) on the side of the timer. Be certain to
choose the correct “AM” or “PM” time.
• Pull all the tabs upward or outward during the time
you want the system to operate automatically. (Pull
the tabs “upward” on Timer Version A or push the
tabs outward on Timer Version B).
• On Timer Version A, each tab is a 30-minute increment. On Timer Version B, each tab is a
15-minute increment. As an example, if the desired time of operation is between 7:00 a.m. and
9:00 p.m., all of the tabs between 7:00 a.m. and 9:00 p.m. should be pulled upward or pushed
outward.
• Slide the switch bar to “timer”.
The timer mode will provide the most cost effective method of operation and can be programmed to
run only during the time periods when hot water is most frequently required.
Does and Do Not’s
Do
• install an air vent mounted in a vertical position (if provided).
• use 1/2”(5/8”) recirculation line tubing.
• check to be sure there are no crimps or sharp bends in the recirculation line that would restrict the flow.
• be sure the check valve is installed in the proper direction of the flow.
• be sure all air is purged from the system prior to starting the pump.
• use a water conditioner if you have hard water.
• be sure the gate valves are open before turning on the pump.
• install the pump pumping in upward direction only.
Do Not
• use grease or oil to lubricate the pump - it is self-lubricating.
• over tighten the screw ring (SM/UC-303/353 models).
• install the pump with the motor above the pump housing.
• install the pump pumping away from the water heater nor pumping downward.
• start the pump before the system is full of water and purged of air.
• allow the water heater temperature above 140ºF (60ºC). (only in the US)
• install the pump in the supply line to faucet/taps.
• use any pipe size other than 1/2”(5/8”) for SM-303/353 (only in the US) or UC-303/353 models.
• position the pump at the top of the water heater.
Version A Version B
Wiring Diagrams for Units Not Supplied with a Cord .
SM-303 SMT-303
red
red
black
yellow
brown
black
white
green
red
red
black
yellow
brown
brown
red
black
white
green