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Issue #227 June 2009
Lawns and Ponds
by Steve Ciarcia
During college I stayed with out-of-state relatives. One of my jobs in “being part of the family” was that I got to mow the lawn every week during the summer. This wasn’t just any lawn, mind you. It was a bloody golf course! No, seriously, it was about an acre of rocks, outcroppings, tree stumps, and hills. OK, I didn’t have to cut it with a manual push mower, but 5 hours behind a non-self-propelled gas mower wasn’t much better. Their attitude was that all that sweat-equity would “build character,” and the hotter and more humid the weather, the better the experience. My perception was that I was “cheap labor.”
I never wanted to deal with this short green stuff ever again, and as absurd as it sounds, I’ve been true to this directive for the last 30-plus years of home ownership. If you look back at the photos in my solar system article series, you’ll see that I don’t have a lawn. My house is completely surrounded by hemlock mulch (spreading 60 yards of mulch may seem equally absurd to some people). ;-)
A couple years ago, we bought a “cottage” for vacation getaways. It’s in a very nice “gated community,” where part of the ownership understanding is that people are to maintain their property to specific “community standards” (kinda like a condo agreement). The major concession for me was that these standards dictated that I keep a well-manicured lawn instead of a brown blighted-looking quarter-acre mulch smudge among the rows of green encircled houses. At least that’s how the community’s “little old lady patrol” would have viewed my territorial preferences.
Of course, I completely miss the rationale where people try to grow lawns where none should normally exist—like deserts, swamps, and arid areas. At the cottage, I have a service that cuts the grass weekly, but unless I pour a thousand gallons of water on this lawn two or three times a week, it will be like the Mohave desert. As you might have guessed, along with all my neighbors, the cottage needs an automatic lawn irrigation system.
For those of you readers living in temperate climates, let me just say that a lawn irrigation system is simply a bunch of buried pipes separated into various areas called zones. Each zone is connected to the water supply through a solenoid “zone” valve. The irrigation controller is typically nothing more than an electromechanical timer that turns on a water pump and sequences through the zones on a preset schedule.
Since I’m basically an absentee owner, I have to trust that things still function properly when I’m not there. Certainly I can always count on a call from the management if the lawn starts looking like a dried up oasis or a small pond, but emergency repairs from a distance are both aggravating and expensive. The preventive course was to add supervisory monitoring and remote activated controls like I have in the Connecticut house. When I am at the cottage, I can check oil tank levels, room temperatures, web cams, and more in Connecticut. It made perfect sense to install a similar system in the cottage.
The irrigation controller, albeit electromechanical, seemed straightforward. I monitor the control lines that tell me the power is on, the rain sensor is on or off, and that the zone valves are on or not. Since I know which days it is supposed to run, I can look at the monitoring log and see that all the irrigation control outputs trip in the right sequence. Or, if I really need more assurance, I can turn on a web cam and see the sprayers running in real time (at 5 AM) and that the lawn is still green. The irrigation system and my electronic oversight has worked fine for 2 years.
I always start the system before packing up to check that all the spray heads are clear. Then I put it back on automatic. This time was no different. As expected, the controller turned the water pump on, sequenced through the four zones, and shut off. But wait, the pump and zone 4 were still on. My voltage sensors said the controller and zone valves were powered off, but the water was still pouring out. “Help!” I thought. The irrigation company was there in less than a half hour. By then I had pulled the breaker on the water pump, but I couldn’t help but wonder about the consequences of this happening a couple days later when I was back in Connecticut.
Well, welcome to the world of plumbing control versus electronic control. You’d think that the irrigation controller would actually control the water pump. Closed loop control? Yeah, right. Guess again. Apparently, the water pump is only controlled by a pressure switch. When the irrigation controller turns on a solenoid valve, the pressure switch turns the pump on to maintain pressure in that zone. Turn the valve off and the pressure goes up to where the pump shuts off again. So, what happens when a little tree root grows into the underground zone valve that causes it to stick open? How about Niagara Falls! Who the heck designed this thing?
Cleaning the area around all the zone valves restored some confidence, but I know I have to close the control loop. I have to keep the present electromechanical controller because workmen access the system in my absence, but I can’t deal with such “open loop” uncertainties. You can bet your life that very soon the water pump will have an HCS-controlled power relay that coordinates the zone actuation and pump runtime. Lawns are bad enough. I don’t need a pond to go with it.
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