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Hose Bib

Recirc 

Pump

Hot

Water

Heater

Air

Vent

Return Line

Hose Bib

Recirc 

Pump

Air Vent

Hot

Water

Heater

BU Models

A.  Return into Cold Water Line at Top of Water  

     Heater fig. 1

B.  Return to Drain Valve at Bottom of Water  

     Heater fig. 2

Pump Selection Guide

The Laing e

3

- 4 Series 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 ft (76 M). The e

3

- 6 Series model pump is 

designed to handle the circulation requirements of residences and small apartment complexes with pipe loop runs to 

700 or 1000 ft. (213-304 M). The figures below provide a simple rule of thumb to help you match the pump to your 

system.

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).

Adjustable Thermostat Option

For models with the adjustable thermostat, there is an adjustable 

Set Point range from 68

º

F to 158

º

F (20

º

C to 70

º

C). This built-in 

temperature sensor will turn the circulator off when it reaches the 

set point and turn the circulator on when the temperature is more 

than 10

º

F (6

º

C) below the Set Point. The adjustable thermostat is 

only available on fixed-speed motors.

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.

CAUTION: 

The use of Teflon

®

 impregnated pipe compound and Teflon

® 

tape on pipe threads provides lubricity 

which can lead to overtightening and breakage. Do not overtighten. Failure to follow this instruction can result 

in moderate personal injury from hot water and/or property damage.

CAUTION: 

Make sure the power is turned off before placing anything inside the discharge opening to move 

the impeller. Failure to follow these instructions could result in serious personal injury, death and/or property 

damage.

WARNING: - Electrical Shock Hazard - 

Disconnect and lock out the power before making electrical 

connections. Failure to follow these instructions could result in serious personal injury or death.

WARNING: - Hot Water Leakage Hazard - 

Pressurize the body slowly while checking for leaks at all joints with 

gaskets or solder connections. Failure to follow these instructions could result in serious personal injury and/or 

property damage.

Summary of Contents for Laing Thermotech E1 Series

Page 1: ...ump The pump only has to produce continuous flow at a pressure sufficient to overcome the friction losses created by the piping in the house water supply line and the return line 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 5ft 1 5m p...

Page 2: ...han 10º F 6º C below the Set Point The adjustable thermostat is only available on fixed speed motors 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 t...

Page 3: ...ble for at least 221ºF 105ºC F Laing circulators are thermally protected and do not require external overload protection G If a remote device such as a thermostat aquastat is connected to the pump it must be wired in series with the power conductor 4 Purchase materials required Laing e3 ReCirc 1 1 2 5 8 or 3 4 swing check valve Copper pipe or tubing not required on BU models Tee for under sink con...

Page 4: ...mp 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 all models Position the pump at the top of the water heater Correct Installation Improper Installation Do NOT moun...

Page 5: ...ng causing the rotor to wobble during operation If the return line connects to the cold water supply at the top of water heater the warm water may be creating back pressure in the cold supply line If so add a check valve non return valve on the cold supply line above the return line tee connector Pump Operating Intermittently or Not at All No power to the pump There is debris or foreign matter in ...

Page 6: ...the motor leads before continuing Failure to follow these instructions could result in serious personal injury death and or property damage WARNING High Pressure Hazard Pressure may be present in the pump body This pressure can be relieved by loosening the flange bolts and shifting the pump assembly slightly to allow the pressurized water to escape Failure to follow these instructions could result...

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