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Starting Member


Saturday, April 7th 2007, 8:50am

Design and layout questions

I'm getting ready to install my sprinkler system and was wanting to run this past everyone to get their opinion.

I have a 1.5hp P series Mcdonald pump (performance chart : that is down around 125ft. According to the perf curve, it looks like it can deliver ~20gpm. My testing shows that the well and pump delivers very close to this out of a 1.25" line. My pump switch is set to 50/70psi cutoff and I have a 50 gal pressure tank. Small note is that the water is very hard (~125 grain). To me, this sways my thoughts on types of head (and perhaps valves) to use.

I was planning on running 1.25" 160psi poly as the trunk and tapping off of that to the valve and going 1" 100psi poly to each head with a blazing saddle and funny pipe into the side of the head. I chose a Rainbird maxipaw head due to the hardness of the water. I've heard that gear heads eventually stop functioning with very hard water due to build up in the gears. Since I want this set up to last a very long time, maxipaws appeared to be the only 'dirty water' head in my price range (~$12/head).

Head Distance: I was planning on using 4-5 heads per zone and limit/eliminate pump cycling by using different tips. Since the maxipaw has 3gpm - 8gpm tips, I figured that this would work. Thoughts? I have about 1.5 - 2 acres of fescue. As I laid it out, I went 25-30ft between heads. I came up with ~90 heads!! Does this sound correct?? That doesn't even include 1-2spray head zones around the house and 1 to 2 drip zones.

Controller: With ~90 heads with 4-5 heads/zone, That works out to 23-28 zones!!!! This concerns me but this may just be the nature of the beast. Is there something to do here? Price wise, I was thinking of buying 2 controllers rather than 1 very large controller. 2 Hunters with zone modules maxed out to 24 zones was ~$280 vs 1 24 zone Nelson controller for $400. Plus, if it turns out that I could run more water,I could have 2 controllers watering at once. Thoughts?

Valves : Any suggestions on valves? I was considering the Hunter PGV100MB valves and making a manifold out of PVC, then go back to poly. Ideas or best practices?

Drains : Any suggestions on a most effective drain type, locations and amounts? I was considering using gravel or rock rather than sand so as to not clog up the valve. Also, i was planning on putting main line and zone drains at the lowest point. i was also planning on putting a drain near the valves just in case, so any standing water wont damage the valves. This needs to work properly because here in Kansas, we get all kinds of wierd weather. Shoot, it's the first week of April and we usually are pretty warm here. Today, it's 32 degrees.

Am I way off here?

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