Why your AutoPot tray isn't cycling, and how to fix it

AQUAvalveHappy Hydro
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This is for AutoPot owners whose trays won't fill, won't stop filling, or won't dry out. The AQUAvalve5 has no motor, timer, or electronics, so every cycling fault is physical: height, level, a seal, a blockage, or air. Run the five checks first, then find your symptom below and work its causes in order.

The short answer

  • An empty tray can wait up to an hour before it refills. Give it that hour before touching anything.
  • Measure from the tank's tap to the top of the highest valve. Under 6 inches, raise the tank.
  • Level every tray and check the top-float silicone at eye level. Both are common flood causes.
  • Running AirDomes? Bubbles in the tray break the cycle. Turn the pump down.
  • Clear a blocked nozzle with a paperclip or pipe cleaner. Never a drill.

What a normal cycle looks like

  1. Fill. Solution enters the tray through the valve nozzle while the top float sits down, sealing a hole on the main body.
  2. Shut off. At about 1 inch, halfway up the valve collar, the top float lifts, trapped air escapes, and the inner float rises to close the inlet.
  3. Hold. The top float drops back and reseals the body, and the vacuum that creates keeps the valve closed while the plant drinks.
  4. Reopen. Once the level falls below the main body, surface tension around the valve has to break, which can take up to an hour. Then the inlet opens and the cycle repeats.

The dry stretch between step 4 and the next fill is the point of the system: it's what gives roots a true wet and dry cycle. A dry tray is only a fault if it stays dry past that hour.

Five checks that come before any diagnosis

Close the inline tap before lifting pots or pulling valves. Moving pots and trays is one of the common ways valves and fittings get knocked loose in the first place.

  1. Height. Run a tape measure from the tap at the base of the tank to the top of the highest AQUAvalve5 in the system. AutoPot's minimum is 6 inches (150 mm), and the water line inside the tank doesn't count.
  2. Level. Set a level across each tray in both directions. AutoPot is specific that an uneven tray interferes with the valve.
  3. Silicone. Lift the valve out and hold it at eye level. The silicone on the top float must sit parallel on the hole below it; if it doesn't, lift the float, press one side of the silicone, drop the float, and look again.
  4. Seating. Put the valve back with the half-moon on its rear over the T-section in the tray floor, and push down on the main body only, never the floats.
  5. Clean tray. Wipe the sides and bottom of each pot before it goes back in. Perlite and media that reach the valve jam the floats.

Find your symptom

The tray never fillsTank has solution, tray stays bone dry past the one-hour mark.

  1. A tap is closed. On AutoPot's Pro inline tap, the handle in line with the pipe is open and across it is closed. Check the tap at the tank, any taps at the ends of the line, and any shutoff before an individual tray.
  2. The tank is low, empty, or below the valves. Recheck the height. After a refill, turn the tap off, refill, and let it settle 30 to 60 minutes before reopening so sediment stays out of the line.
  3. The filter is clogged. Pull it and rinse it. AutoPot says to check it weekly, and more often with organics or poor water.
  4. The pipe came off the nozzle or is kinked. Push the pipe through the collar onto the nozzle and screw the collar down until you feel it grip, then stop. Draw any slack pipe back out of the tray so it can't fold.
  5. Lime scale is blocking the nozzle. Push a paperclip or pipe cleaner through it, or blow through it.

Never drill the nozzle. AutoPot warns that a drill or drill bit can damage the AQUAvalve5 beyond repair, even if the blockage looks stubborn.

The tray fills, but slowlyA trickle that takes far longer than the other trays.

  1. A partial blockage. A filter or nozzle slows down before it stops, so run the filter and nozzle fixes from the card above.
  2. Too many pots on 3/8" pipe. AutoPot sizes 3/8" pipe for up to 6 pots. Above 6, the main line should be 1/2", reducing to 3/8" at each tray.
  3. Hard water sediment in the lines. Hard water reacts with nutrients and drops sediment, so AutoPot says to flush pipework more than once a week in hard water areas. Open the tap at the end of each run into a bucket for 30 to 60 seconds; the full routine is in keeping your AutoPot clean between runs.
  4. Height right at the minimum. Six inches is AutoPot's floor, not a target. Measure to the highest valve in the system, not the nearest one.

The tray overfills or floodsWater past the 1-inch mark, over the lip, or on the floor.

  1. A silicone is crooked, worn, or missing. Redo the eye-level check. Each valve carries two silicones, a smaller one on the top float and a larger one on the bottom float; replace any that are missing, torn, or won't sit flat.
  2. The tray isn't level. Shim under the low side until the level reads true in both directions.
  3. The valve isn't seated on the T-section. A bumped pot or tray can lift it. Reseat it half-moon over the T and press on the main body only.
  4. Media or roots in the valve compartment. Lift the pot, rinse the tray, and check the root control under or in the pot is still intact.
  5. Water leaking out the front of an XXL or Tray2Grow tray. The 1/4" blanking grommet is missing or loose. AutoPot says to keep it in place indoors and remove it only outdoors.
  6. Leak at the nozzle. An overtightened collar cracks. AutoPot sells the collar on its own as a replacement.

The tray refills before it's emptyIt never gets a dry period, or tops up while solution is still in it.

  1. An air pump is pushing air back into the tray. Bubbles or moving water in the tray disrupt the valve. The usual culprits are an oversized pump or a compressed 100% coco or soil mix; turn the pump down. Each AirDome needs 15 gph, so 4 domes need a 60 gph pump.
  2. AirDomes were switched on too soon. AutoPot says to wait 2 to 3 weeks after the system goes on. Run the pump on the light timer, keep it off cold floors, and blow air at 64 to 70°F.
  3. The top float isn't resealing. Without that seal there's no vacuum to hold the valve shut, so it reopens early. Redo the eye-level silicone check.

The tray stays full for hours or daysThe valve works, but the plant isn't drawing the solution down.

  1. The plant isn't established yet. Small root systems drink slowly. AutoPot USA's rule of thumb is to top feed until the leaves extend past the pot rim, and if growth doesn't take off after switching on, to turn the system off and top feed about another week. Timing by pot size is in the first run guide.
  2. The tray is on cold concrete. Concrete chills tray water from below. Put polystyrene or cardboard under each tray.
  3. The mix is too dense. AutoPot's target is about 50% perlite or clay pebbles with soil or coco, and warns that 100% coco, soil, or peat-heavy mixes compress. A drainage layer or AirBase keeps the substrate above the tray's fill line; fix both at the next potting up.

Parts that fix this

Questions

Probably not. AutoPot's own documents give the fill depth as anything from about 3/4 inch to 1 inch, so a level anywhere in that range is a working valve. A tray that shuts off well short of 3/4 inch, or at different depths from one cycle to the next, points back to the silicone check.

Swap the two valves. If the problem moves with the valve, it's the valve: silicones, nozzle, or collar. If it stays with the tray, it's the tray's level, its seating, or the pipe feeding it.

Start with the silicones, since they're the wear part and the valve body rarely fails. If you can't tell which one is bad, replace both. Replace the whole valve only if the body or floats are cracked; a cracked collar is sold separately.

Not once the plant is established on bottom feeding; AutoPot recommends against switching back. Pouring solution onto the valve itself can also disrupt cycling and leave you resetting the tray. Fix the cause from the cards above instead.

The valve and every card above apply the same way. The tray is nearly 44 inches long, so level matters more over that distance; use its three spirit levels and recheck once it's loaded. Mat and wicking problems are covered in the Tray2Grow setup guide.

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Happy Hydro has been serving growers since 2006. Email us before you order, after you order, or any time something comes up with your AutoPot. When you're happy, we're happy.

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