A sprinkler will not pop up, or will not retract

What has gone wrong

Three versions of the same tired part.

• It stays down when the station runs. Sand has packed around the stem, or the head is broken internally.
• It stays up when the station stops. The retract spring has weakened, or sand is holding the stem out.
• It rises but water sprays around the stem. The wiper seal has worn through. That leak also robs pressure from the nozzle, so the head throws short as well.

None of this involves electricity. A pop-up is a spring, a seal and a nozzle in a plastic tube, and it is the most approachable repair on the whole system.

One thing to rule out first: if every head on that station is sluggish rather than just one, it is not the heads. That is a pressure problem — see low pressure everywhere.

Why this happens in Perth

Perth sand is the entire story here. It is fine, it is everywhere, and it gets past a wiper seal that has any wear in it at all. Once it is inside, it works like grinding paste every time the head cycles, so a seal that was slightly worn in March is badly worn by November.

The three-month ban makes it worse rather than better. A head left retracted from 1 June to 31 August has sand and soil settle in around the stem and pack down with the winter rain. On 1 September it either does not rise or does not come back.

The other Perth classic is the mower. Risers sit at turf height, turf grows over summer, and sooner or later a head gets clipped. A mown head is not repairable — the body is cracked below the seal and it will keep leaking whatever you fit to it.

Is this a DIY job?

Yes. Everything below is 24V AC or purely mechanical, which is the part of a reticulation system a homeowner can safely work on.

Free first, as always

Flush it. Run the station. Unscrew the nozzle from the top of the raised head — it comes off by hand, or with the plastic key that came with it — and let the station run for fifteen or twenty seconds with the nozzle off. Grit and sand come straight out. Put the nozzle back and see whether it behaves.

That clears a surprising number of stuck heads, and it costs nothing but the water.

Clean around the stem. With the station off, scrape the soil and turf back from the top of the head so the stem has a clear ring around it. If turf has grown over the top of the body, the head is fighting the lawn every time it rises.

Pull it up by hand. With the station off, grip the stem and pull it up gently, then let it go. It should return under its own spring. If it comes up gritty, or does not return, the seal and spring are done. If it is smooth and returns cleanly, look at the nozzle instead — see dry patches and uneven coverage.

Replacing the head

No water shut-off is strictly needed for one head if you are quick, but turn the station off at the controller and do it properly the first time.

1. Cut the turf around the head with a spade in a square, and fold it back rather than removing it. It goes back down afterwards and nobody can tell.
2. Dig down until you can see where the head screws onto the fitting below it. That fitting is usually a threaded elbow on a short flexible riser.
3. Hold the fitting still and unscrew the head anti-clockwise. Hold the fitting — if you twist the riser you will crack the joint below and turn a ten-minute job into a proper dig.
4. Wrap the new head's thread with a few turns of thread tape and screw it on hand-tight. These are plastic threads; a spanner will split them.
5. Set the head so the top sits flush with the turf, not proud of it. Proud is what gets mown.
6. Run the station before you backfill. It is much easier to adjust the arc now than after the turf goes back.
7. Backfill, firm it down, fold the turf back over.

Do the whole station while you are there. Heads on one station were installed on the same day and have done the same hours, so they fail within months of each other. Replacing four while the spade is already out is one afternoon. Replacing them one at a time is four afternoons spread over a summer.

What it costs

Pop-up bodies and nozzles are the cheapest parts on the system — this is a low-cost repair whichever way you do it. We have not verified current Perth prices on individual heads, so treat any figure you see quoted elsewhere as an estimate until you ring a supplier. Buy the same brand and the same body height as what is already in the ground and the fitting will match.

Thread tape is a couple of dollars and you will use it on everything else here too.

If you pay somebody. Unverified, and worth asking two repairers. Be aware that a callout to replace one $10 head is mostly callout — if you are paying for the visit anyway, have them do the whole station.

Common questions

Why will my pop-up sprinkler not rise when the station runs?

Usually sand packed around the stem or a broken head. Flush it first: run the station with the nozzle unscrewed for fifteen seconds and let the grit out.

Why does my sprinkler head stay up after the station stops?

The retract spring has weakened or sand is holding the stem out. Both mean the head has reached the end of its life and is worth replacing.

Should I replace one sprinkler head or all of them?

Do the whole station. Heads on one station were installed on the same day and have run the same hours, so they fail within months of each other.