Replace existing sprinkler system?

[dan]

Info:

4 zones 1.5 HP pump on well Lot size: 125 X 80 House Size: 55 X 55 (Guesstimate) Shed: 16 X 12 Age: approx 15 years (That's a guess, the house is that old)

All zones appear to have low pressure. I measured one zone it was at about 21 psi and another around the same (so low the pop-up sprinklers won't rotate). I believe the system was designed at bare minimums and does not fully cover the lawn. It also has a mosh-posh of zoning (one zone hits half of back yard and 2 heads in the front yard.

I believe my main issue is pressure. I thought about going to a 2hp pump. But then the zones really don't fully cover the lawn anyway so I'm thinking about just replacing the whole system and going with 5 zones.

I hate leaving the old piping in, but it would be a pain to take out. I thought about using different colored pipe so in the future, I'd know what the new system was on. The current system uses white pipe from what I have seen, but who knows what it uses where I haven't seen it.

Thoughts?

[ransley]

It would be thousands cheaper to add pipe and heads and maybe a new pump. I would fix and upgrade it.

[Norminn]

You say it doesn't cover well......did you formerly have higher pressure and it still didn't cover? Seems such low pressure would be the problem, and boosting the pressure the solution.

15 years isn't very old for pvc pipe - ours is 40 and in fine shape. We have had pipe damage when mowers run over s.h.'s, but that is carelessness. Flex pipe can also help. We get strips that get too dry because trees planted since the s.s. instlalation block water to a strip.

Sprinkler head companies provide design service if you sent drawings; that would be one solution to get adequate coverage. Any time you put in heads with different flow, you change the coverage to the other heads on the zone. Might just need adjusting or changing the heads if you get the pressure up to a decent level. What is the water supply? Meter on full?

[dan]

We bought the house with it installed. It never had adequate cover from the time we bought it.

I plan to have a design done just to see if the original was ill-planned. Something else I didn't mention. We had a sprinkler company come in to "fix" low pressure on one of the lines. They said there was a leak somewhere. Instead of fixing, they just put in a new line with sprinkler heads - idiots! Now I have one dead set of lines and another that still doesn't work properly.

[Norminn]

clipped

What I asked was whether the pressure was any different when you bought the house? Are you on municipal water supply? If so, you should be able to find out what the pressure is at the meter.

[dan]

It's on a well (at the top of my original post). I have no idea if the pressure changed since I bought the home - it has always been low in at least one zone. Some others seem fine.

[trader4]

Certainly figuring out what the pressure and flow rate are at the beginning of the system is the key. It could be that is the problem or it could be a problem in the irrigation system itself, or a combo of the two.

[dan]

I installed a pressure gage just after the pump and just before the valves to the zones. The pressure ranged from 20-28 psi. That seems low to me. Also, the pressure gage "bounced" like it was being vibrated. The pressure was not steady. I'm not sure if this is normal on a sprinkler system.

[ransley]

28 is too low, 50-80 is more normal, probably its the pump. With correct volume and pressure adding a run and heads might do it.

[dan]

It seems obvious that the pump is bad (low pressure) but are there any ways to really tell? I'd hate to replace the pump to find the well couldn't keep up and that's the real issue or something like that.

[Jerry]

Toro's design guide recommends a minimum of 45 PSI at 10 GPM flow for use with pumps.

Jerry