Transcript Irrigation system troubleshooting - Metropolitan Water District of

California Friendly
Landscape Training
®
Irrigation System
Troubleshooting
The Metropolitan Water District
of Southern California
and the
Family of Southern California Water Agencies
California Friendly®
Landscape Training
Workshop 1: Irrigation Principles & System
Adjustment and Repair
Workshop 2: Irrigation System Troubleshooting
Workshop 3: Controller Programming
Workshop 4: Irrigation Scheduling
Today’s Workshop
Irrigation System Troubleshooting
• Electrical Concepts
• Field Skills
• Electrical System
• Mechanical Operation
• Troubleshooting Steps
Water Efficient Devices
• Rotating Nozzles
• Smart Sprinkler Controllers
• Synthetic Turf
Goal of Today’s Workshop
To open and close the valve with the
irrigation controller!
Controller
Valves
Electrical Concepts
• Current
• Voltage
• Resistance
All these are related, but they’re not the same thing!
Current
• Current is the movement or flow of
electrons
• Amps
• Current activates the valve solenoid
Wire
Current: rate of speed of electrons
Voltage
• Voltage is the force that pushes
electrons through the wire
• Volts (VAC or VDC)
Wire
Voltage: Force that pushes electrons
Types of Voltage
• Direct Current (VDC)
• Flow is in one direction from batteries
• Alternating Current (VAC)
• Flow alternates direction – typical
electrical systems
Resistance
• Resistance to flow of electrons
• Affected by wire size and length
• Measured in Ohms (symbol Ω)
Wire
Smaller Wire
Higher Resistance lowers amount of Current to Solenoid!
For Troubleshooting...
• Need to measure Voltage (Volts) to
check the Controller
• Need to measure Resistance (Ohms Ω)
to check the wiring, solenoid, and
connections
Controller
Valves
Typical Electrical System
Irrigation
Controller
Common Wire
24-28 VAC
110 VAC
24-28 VAC
With Step-Down
Transformer
Valve
Solenoid(s)
Controller
• 110 VAC supply voltage – very dangerous!
• Flows through step-down transformer
• 24 VAC Volts output to control valves
• Controller switches open and close valve
circuits
Typical Voltage
110 VAC
• Supply to Controller
24 VAC
• From Controller to Valves
Measurements
• Volt-Ohm Meter
• Multi-Meter
• “Check Mate”
Voltage Measurements
• Meter Setting
• Probe Placement
• Safety
Safety
120 Volts – very dangerous!
• Experienced personnel only
24 Volts – not dangerous
• But be careful – work with caution
Measuring Voltage - VAC
Tip: disconnect the common wire from the terminal
Input and Output Voltage
Valves
Output
24-28 VAC
Input
110 VAC
Controller
Output
24-28 VAC
Voltage Output Problems
If less than 24 Volts:
• The controller station switch may be
faulty
If more than 28 Volts:
• The transformer may be faulty – may
need to replaced
If voltage output is OK, check field circuitry next...
Control Circuit
Two Wires
• Control Wire
• Switched, Open or Closed
• Common Wire
Common Wire
Control Wires
Measure Resistance
to Check Circuits
• Resistance in Wire (Conductors)
• Resistance to electrical movement
• Wire size and length
• Units – OHM ()
Resistance Readings
Wire - 1,000 feet of 14 gauge wire
• 3 Ohms (approx.)
Solenoids – different manufacturers
• 20 to 60 Ohms for most solenoids
• Some have very high readings (Griswold)
Resistance of Solenoid
Wiring Problems
Wiring problems that resist the
amount of current to the solenoid
• Broken Wires
• Inside the Solenoid
• Control Wire
• Common Wire
• Bad Connections
• Solenoids
• Junction Boxes
• At the Controller
• Damaged Wires
• During Installation
• Other construction
done after
installation of wires
(fences, trenches,
etc.)
• Tree Roots
• Animals
Steps and Safety
• Power OFF!
• Damage the multi-meter
• Tip: disconnect common
• Set meter scale high
• One probe at common wire
• Other probe at control wire
• Begin test
Resistance Reading
Circuit Condition
1. Closed – Complete/Good Circuit
2. Open Circuit – Fault
3. Partial Open Circuit – Fault
4. Short Circuit – Fault
1. Complete (Closed) Circuit
• Functioning properly
• Proper flow of electricity between
Controller and Control Valves
• There are no wire breaks, shorts, or
bad connections
Typical Response
Complete Circuit
Closed/Complete Circuit:
• Resistance Reading: 20-60 Ohms – Normal
2. Open Circuit Fault
• There’s a break in the circuit
• Break in the wiring
• Break inside the solenoid
• A connection came apart
Typical Response
Open Circuit
Open Circuit Fault:
• Maximum Resistance, infinite Ohms
• 1 on left side of display (digital meters)
• This circuit will not operate
3. Partial Connection
• Circuit wires make partial connection at:
• Controller
• Control Valve
• No waterproof connectors
• Nicked or damaged wires (not completely broken)
Typical Response
Partial Connection
Partial Connections Fault:
• Resistance: higher than normal Ohms
• Erratic system performance
4. Short Circuit Fault
• Common wire and Station (Control)
wire make contact
• Solenoid interior coil wires make contact
Typical Response
Short Circuit
Short Circuit Fault:
• Fuse will burn or breaker will trip
• Resistance Reading: 0 to 10 Ohms
• This circuit may come on with other valves
Summary of Circuit Conditions
Circuit Condition
1. Closed Circuit
2. Open Circuit
3. Partial Connection
4. Short Circuit
Resistance - Ohms
20-60 Ω
Maximum Ω
Higher than normal
0-10 Ω
Waterproof Connectors
Black Box Exercise
Notes:
• Simulation of circuit conditions
• Closed Circuits
• Open Circuits
• Partial Connections
• Short Circuits
Questions?
Electrical Troubleshooting
Mechanical Troubleshooting
• Water Supply
• Valve Operation
Valve – Closed
Valve – Opening
Valve – Open
Flow Control
Outlet Port
Bleeder Screw
Valve Spring
Diaphragm
Stopper
Valve Body
Inlet Port
Valve
Seat
Common Valve Problems
• Cracked diaphragm
• Broken spring
• Plugged inlet port
• Calcium deposits inside solenoid
• Rocks or debris on stopper seat
Valve will not Open
• Insufficient Voltage
• Hole on the diaphragm (Reverse Flow Valves)
• Flow stem is closed
• Plunger is stuck or missing
• Outlet port is plugged
• Bad Solenoid
Valve will not Close
• Hole on the diaphragm (forward flow valve)
• Debris on the valve seat
• Flow stem turned up too high
• Inlet port gets plugged during operation
Valve Assembly
• Class Exercises
• Disassemble Valve
• Reassemble Valve
Wiring from Top of Valve Removed
Screwing off Top of the Valve
Spring Removed from Valve
Diaphragm
Empty Valve Housing
Reassembled Valve
Look for the obvious first
• Is the water turned on?
• Is the controller plugged in?
• Is the timer programmed correctly?
• Is there an isolation valve?
Questions?
California Friendly®
Landscape Training
Your hosting water agency would
like to thank you for being water conscious and
attending this Workshop