Lawn Sprinkler Garden Automatic Water Timers
Best of Mechanical, Electronic, Programmable and Countdown Timers
Mar 28, 2009
Water timers are connected between the faucet and the sprinklers, opening and closing valves to control the water flow. Gradual-opening and closing valves are best, avoiding a "water hammer" bang that can damage pipes.
Popular brands include Gilmour, Gardena, Melnor and Nelson.
Countdown Timers and Flow Counters
These function like kitchen egg timers, counting down minutes (countdown timers) or gallons (flow counters). They can guard against forgetting to turn off the water: saving money and protecting against over-watering. Most are mechanical, driven by the water flow or a mechanical spring.
Advantages
- Simple, easy to use. Just turn the dial to the required number of minutes or gallons (or liters).
- No batteries required.
Disadvantage
- Needs to be set by hand before every use. There is no automatic repeat feature, or delayed start (for example, to start at 5am)
Water timers are easy to use. It is intuitive to think in terms of how many minutes of watering are required for a lawn. Few people know how many gallons their lawn requires.
Flow counters are useful in areas with variable water pressure, delivering the same amount of water even if the pressure changes. They are also suitable for filling pools and aquariums. However they do require a minimum amount of water pressure to work. If the pressure is too low, a water timer is a better choice.
Programmable Lawn Sprinkler Water Timers
Programmable timers allow hands-off automatic watering.
Most are electronic, running on AA or 9 volt batteries. Even if designed for outdoor use, covering the timer with a pail or old tin will help protect it from the sun and rain, improving reliability.
There are many different types of programs. Details of the programs should be checked before purchase:
- Number of on/off cycles per day.
- Range of on-time duration (minutes).
- Daily, alternate day, weekly or other repeat mode.
Additional features that may be useful
- Misting feature, useful for keeping animals cool (short on/off cycles every few minutes).
- Rain sensor (normally an optional add-on) to stop watering if there is rain.
- Manual hold to temporarily stop the program for a few days (used if there is no rain sensor).
- Manual override to force watering on extra dry days, without changing the program.
Advantages
- Flexible. Complex on/off timings can be programmed.
- Automatic. Can be used for long periods of unattended operation: especially useful during vacations.
Disadvantages
- Can be difficult to program.
- Batteries need to be replaced every few months, a year or two at most.
- Valves can lock in the open position if the batteries run out at the wrong time.
Water Timer Problems and Tips
The constant high pressure on the timer can result in leaks or complete rupture of the timer, wasting water until the tap is manually turned off.
Household water supplies are designed to work at a pressure of about 50 psi (pounds per square inch). However actual pressures can be half or double this. Some timers are rated to over 100 psi. Even with such timers, a cheap (a few dollars) water pressure regulator can be connected before the timer to protect it. The regulator will reduce the pressure to 50 psi.
A water pressure gauge can be plugged into the faucet to check the pressure.
The Best Water Timer
The consequences of a timer failure can be serious.
- A leaky or burst timer can mean a huge water bill.
- A timer that doesn't turn on as scheduled can mean dead plants or a brown lawn.
Because of this, reliability is important. The Internet should be searched for user reviews and complaints. When on vacation, a friendly neighbor or family member should be asked to check every few days to ensure that everything is working.
 |
