Recirculation Tools

These tools are designed to help service providers calibrate recirculation based on actual flows of a particular system. They can (1) calculate average daily flow using two readings from a flow meter, (2) calculate ON/OFF settings based on parameters providers select, (3) suggest settings for dial-type timers and (4) reverse calculate flows based on timer settings. The fields with green text are input fields, while blue text indicates calculated outputs.

Average Daily Flow

Enter two dated meter readings to calculate the average daily flow before using the recirculation settings below. Use the calendar button to jump quickly by month and year.

Previous date Previous reading Current date Current reading

Average Daily Flow0 GPD

Enter both readings.

Recirculation Calculator

Enter the system values and desired recirculation interval.

Length of cycle

Example: four times per hour would mean a 15-min cycle. If there's minimal use throughout the day (e.g., everyone works outside the home), less frequent cycles will help performance.

Recirc multiplier

For optimal denitrification, recirculate two-to-four times daily flow.

System flow

Recirc pump rate

Use 2.5 GPM for airlift recirculation.

Maximum cycle0 min

0 sec

Target recirc0 GPD

Pump runtime 0 min/day

Runtime per hour0 min

sec/hr

Recommended ON Time0 min

0 seconds

Recommended OFF Time0 min

0 seconds

Suggested Timer Positions

Blue wheel relay suggestions use range-segment positions, including the longer hour ranges. Orange wheel relay suggestions use the selected maximum range and wheel percentage.

Blue wheel Crouzet relay timer with numbered position markers — **Blue wheel relay**

#1 ON Timer Range-

#2 ON Timer Position-

#3 OFF Timer Range-

#4 OFF Timer Position-

Orange wheel Crouzet relay timer with numbered position markers — **Orange wheel relay**
Note: the top ON-marked section controls the OFF timer. The bottom OFF-marked section controls the ON timer.

#3 OFF Timer Max-

#4 OFF Timer Percent-

#1 ON Timer Max-

#2 ON Timer Percent-

Relay type	Calculated ON/OFF	Suggested ON	Suggested OFF	Position guidance	Equivalent system flow	Notes