Rotor Head Hookup question

Discussion in 'Irrigation' started by turbosl2, Jul 6, 2012.

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  1. turbosl2

    turbosl2 LawnSite Member
    Posts: 56

    I have a very basic question that i am having a hard time getting answered.

    I have Rainbird 5004 heads and the inlet is 3/4" and my main line is 1" poly, fed by 3/4" copper from the meter. Each head is hooked up using 1/2" funny pipe off each zone, did i make a mistake and should have used 3/4" to hookup each head. Basically i used a saddle Tee off the 1" poly with a reducer to 1/2" funny pipe, same reducer elbow is on the bottom of the head (3/4" -1/2" funny push lock).

    I am not happy with the coverage, the distance is way low from what rainbird claims, and close in watering is terrible, it seems to have large drops at the end of the stream.

    For example, i have roughly 2-3 heads per zone, with the nozzles not adding up to more than 12GPM. So if i have 2 heads i will have 6GPM for each nozzle, which is suppose to be like 47', i get like 25'

    I have a 1.5Acre lot, and the system is designed for 12GPM at 50Psi. This was mostly to still provide water in the house while the system is on.

    What do you think
     
  2. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,786

    I don't know what to think, other than a screw-up. Depending on the psi/gpm, a 5000 series will chuck to 50'. However, you need at LEAST 45 psi at the head and each head will gulp 6 to 8 gpm. If I was using the 5000 to chuck that far, (which I never would do unless I knew I had enough psi/gpm),swing pipe would not be my choice, as friction loss will kill the system. How did you take the original measurements?
     
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 46,979

    bad system design by someone who never bothered to find out what the water supply was
     
  4. AI Inc

    AI Inc LawnSite Fanatic
    Posts: 25,233

    where did you get the 12 gpm # from?
     
  5. turbosl2

    turbosl2 LawnSite Member
    Posts: 56

    I measured it myself. I measured 12GPM at a 1/2" spigot right off my 3/4" meter. I also measured between 50-55PSI pressure, so i did start the design with the pressure and flow measurements , no way to design a system without it.

    This is not relevant but:
    I also measured alot more GPM right off my 3/4" line before it goes into the double check valve. I decided to use the 12GPM that i got with the 1/2" valve in the basement as a max number that i want the sprinkler system to use, this leaves me with reserve in the house(i.e. i didnt care that it could flow more since it was going to be on 3/4). The 1/2" spigot was there before the system was installed so thats another reason the 12GPM reading was chosen for the design value.

    Moving on do you guys think i made a mistake listening to the advice to use the funny pipe to go to each head. Basically here is how it works, i will try to simplify things, i am not the best at explaining.

    -Residential Lot (1" line coming to the home, 550' from road/main)
    -1.5Acres irrigated
    -16 Zones (2-3 heads per zone, all nozzles added together not to exceed 12GPM)
    -Rainbird 5004 Heads, nozzle sizes vary depend on location, if its a full circle in the center of the property i have 6GPM in each nozzle and 2 heads per zone. If its a 180deg (edge of property) i have 3 heads with 4GPM nozzles installed.
    -3/4" meter in the house, 3/4" copper goes outside and then transitions to 1" poly.
    -1" poly runs into 5 boxes with 3 valves in all but one, the other has 4. ( run length varies depending on box location, but some are 100', others can be 250-300'
    -1" rainbird valves
    - Out of each box is 1" poly where i used the saddle Tees in the middle and an end fitting on the line with a 1" - .5" funny pipe fitting (no clamps needed). This is not swing pipe, there are no elbows, it just comes as 100' spool of flexible pipe with a green strip.
    - Each saddle Tee has a 3/4" thead where i was supplied a 3/4"NPT - .5" funny pipe fitting (again you just push the pipe on)
    -Each head has this same 90 deg fitting that is 3/4" - .5"

    I asked why is the systems designed with 1" pipe in the ground, and then there are 3/4" fittings on all the heads but from the poly to the head (which is only a few feet) i go to .5", doesnt this limit the head by alot. The advice i recieved was this is how we do them all, it keeps the pressure up.

    So my question is, does anyone see anything wrong with this, it seems dumb to reduce the pipe size for that few feet to .5", it seems that if it was suppose to take a 3/4" threaded fitting you would use 3/4".

    I am unsure because this is residential but the distance and heads are more small commercial.
     
  6. turbosl2

    turbosl2 LawnSite Member
    Posts: 56

    Here is the plot layout

    Sprinkler Layout.jpg
     
  7. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    I have never heard of 3/4" Funny/swing pipe. It's not even 1/2", it's actually designated as 3/8".

    I have never seen a 5000 head on a resi system shoot 40+ feet. I keep them around 24'-28' if possible. Start by reducing the nozzle size in the rotors. Unless you have higher pressure and less-restricted flow leading to the head (no swing pipe and all 3/4" fittings leading in to it), I don't see you pushing 6 GPM through those nozzles.

    Easiest thing to start with, change out the nozzles.

    .5" funny pipe fitting (no clamps needed). This is not swing pipe, there are no elbows, it just comes as 100' spool of flexible pipe with a green strip.

    Not sure what you mean here. To me, swing pipe is funny pipe, same thing. Someone correct me if I'm wrong. If it's the Rainbird swing pipe with a green stripe, call it what you want, it's swing pipe.
     
  8. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,503

    Just to make sure we are on the same page, the green striped pipe is commonly referred to as "funny" pipe.

    funny pipe.jpg
     
  9. turbosl2

    turbosl2 LawnSite Member
    Posts: 56

    This is exactly my setup. The same fittings, just instead of PVC i have poly with a Blazin saddle Tee. The head shown above is what i have in my mulch garden, and i am famialr with the fittings because the black are 1/2"NPT - 1/2" funny pipe, and the grey 90deg elbows are 3/4"NPT to 1/2" funny (not shown).

    The issue i am having is not just with the distance, i need the GPM too. I have pure sand for soil. Its like a beach when dry. I water 40mins per zone and its still dry by the end of the day. The reason i have to water so much is because i dont get good close in watering (my opinion) and with a large circle it seems to take a while to put the In/Hr down in the soil. The grass is still on the edge of drying out, but with this soil we have here its hard to retain moisture.
     
  10. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    Yeah, that's what we call swing pipe here. I rarely hear anyone call it funny pipe. Even the supply house guys call it swing pipe.
     
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