Xylem IM 16 Seal-less Centrifugal Canned Motor Pumps For Instant Hot Water Recirculating System (obsolete) User Manual
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Oversized Pumps: Pumps should not be so large as to produce flow rates that may eventually erode
holes in the pipes. According to the Copper Development Association, excessive erosion occurs at a
velocity of about 5 ft. (1.5m) per second and higher; or about 4 GPM (15 LPM) in 1/2” (5/8”) Type M
copper pipe; and 8 GPM (30 LPM) in 3/4” pipe. Use the recommended recirculation line size shown in
the Pump Selection Guide. Laing pumps are sized so that flow velocities are well below these limits.
Pump Selection Guide: The Laing SM and UC 303/353 models are designed to handle the
recirculation requirements of residences with a pipe loop (the total length of hot water supply line
plus the recirculation line) up to 250 feet (76 M) while the SM-909/959 model pump is designed to
handle the circulation requirements of residences and small apartment complexes with pipe loop runs
to 700 or 1000 feet (213 - 304 M). The chart below provides a simple rule of thumb to help you match
the pump to your system.
UC Prefix denotes UltraCirc Housing
The 3rd digit T denotes with timer
Maximum Pressure 150 psi (10 BAR)
Maximum Temperature 230ºF (110ºC)
Installation and Start-Up
1. Select the sink under which to connect the recirculation line (the sink where the hot water takes
longest to arrive which is usually the sink farthest from the water heater).
2. Plan your installation. Decide on the course of the recirculation pipe (also determining the length
of the pipe required) and whether the return line should be connected to the water heater cold water
inlet line (tee fitting required) or to the bottom water heater drain valve (“Y” type fitting required to
fit to existing drain valve outlet). See figure 1 and 2 for the installation schematic.
Australia
This pump must be installed in accordance with AS3500.
U.L. Caution
This pump has been tested using water only. Its suitability for use with liquids other than
water is the end user’s responsibility.
Model
Volts
Cycle
Watts
Amps
SM-303-B
115
60
33
.03
SM-303-B
230
60
33
.15
SM-353-B
230
50
28
.13
SM-909-B-14
115
60
65
.58
SM-909-B-14
230
60
65
.29
SM-959-B-14
230
50
55
.25
SM-909-B-18(21, 26)
115
60
98
.95
SM-909-B-18(21, 26)
230
60
98
.47
SM-959-B-18(21, 26)
230
50
82
.40
SM-1212-B-26
115
60
140
1.22
SM-1212-B26
230
60
140
.61
SM-1252-B-26
230
50
115
.61
Housing Codes
Material/Connection
Available On
BS 1/2
Brass 1/2” (5/8”) Sweat
All
BT 1/2
Brass 1/2” (5/8”) Threaded Female NPT
303
BS 3/4
Brass 3/4” Sweat
909/1212
ST 3/4
Stainless 3/4” Threaded Female NPT
909/1212
BF
Bronze 3/4” Flanged
909/1212
HF
Cast Iron 3/4” Flanged
909/1212
Note: Sizes in parentheses are Australian pipe sizes