Troubleshooting Tips
No - Flow
What is No Flow ?
NO FLOW is a feature found on Clock Demand systems. When the pump is operating water must flow continuously through the discharge pipe as detected by the flow switch in the pump discharge manifold. With the HOA switch in the AUTO position, if the pump is operating and no water is flowing continuously for 1 minute, a NO FLOW alarm is declared: the pump is turned off and a door mounted red pilot light labeled NO FLOW turns on. If the station is equipped with the AUTO-RESTART feature then read the next paragraph. If the station is not equipped with the AUTO-RESTART feature then the pump station will not work again until the RESET button is depressed. All Irrigation Craft clock demand stations built since late 1997 have Auto-Restart as a standard feature.
If the station is equipped with AUTO-RESTART the following will occur. After the NO FLOW alarm is declared the pump will remain off for 15 minutes during which time the NO FLOW alarm light will flash on and off. After 15 minutes the pump will restart. The AUTO-RESTART feature will automatically restart the station 5 times at 15 minute intervals. If the system shuts down on NO FLOW 5 times in a row, the system will turn off and the "NO FLOW" light will turn on steady (not flashing). The pump will remain off until the RESET button is pressed.
NO - FLOW Can Be Caused by 4 Problems
(Listed in the order of most common first)
1. Zone valve not opening.
a) Irrigation controller programmed incorrectly (non-existing zone programmed).
b) Valve problem such as failed solenoid coil, diaphragm ripped, clogged port, etc.
c) Valve turned off manually.
d) Irrigation control wire cut, bad wire splice, valve solenoid not connected to wire.
e) Irrigation controller not working properly.
2. Pump lost prime.
a) Air must enter the system to lose prime - find the source of the air. Water leaking back through a check valve will normally cause a loss of prime because no air can enter the system in this way unless the pump is off for long periods.
b) Check for air leaks first at fittings, then pipe joints.
c) Intake screen missing - debris interfering with check valve. Prime pump, turn pump off, open hose bib and air will rush into the hose bib.
d) Leaking pump seal. If you see no visible leak when running under pressure then the pump seal is not causing the loss of prime.
3. Pump or Motor problem – Impeller has come off motor shaft, usually involves broken or unscrewed center bolt, or a broken motor shaft.
4. Flow switch or flow switch circuit malfunction giving false indication of NO FLOW.
