What's Inside a Garden Hose Water Timer Unit

Full teardown and analysis of the electronics, mechanics and hydraulics of a garden hose water timer device.

[@tdcattech]

I love how the simplest everyday objects actually have some truly ingenious engineering within them. I take way too much for granted!

[@Theworldwelivefake]

How can 20 people give thumbs down when he kindly educates in-depth electronic and mechanical information. Great info as I’ve just bought this exact type of timer for my allotment.

[@Alan-jq3ig]

WATER BUTT USERS NOTE> Thank you Julian for the time taken in this fantastic video. I'd like to add the most recent version of this product is not really suitable for use on a water butt as they designed a new more powerful spring and there is too little water pressure to make it work. HOWEVER, if you have the newer larger diameter thicker spring swap it out. I ordered a replacement spring from China, Wire Dia 0.3mm x Outer Dia 6mm x Length 20mm. It now works very well on my water butt, not quite as good as the motorised timers but acceptable.

[@elavips982]

Thank you so much. Before buying this I was curious to see how inexpensive device like this do this. In your clear explanation I've not only learned it's operation, but also leaned the how solenoid work. Now I know how my toilet cistern diaphragm works. Thanks a lot!

[@mtslyh]

Excellent tear down and explanation. The human mind never ceases to amaze me. I would not have been able to come up with this design if I had taken a million years to think about it.

[@DogsBAwesome]

I shouted 'spring" at the computer when you did not put it back. It's a very clever solution that uses the water pressure to do the heavy lifting

[@jcw74801]

Wonderful! Thank you! Saw it at a lower price than other timers and was hesitant to buy. Now that I see the design I will buy one.

[@Jackinthewoodz]

Entirely wizard grade piece of engineering that. I love how it makes the water pressure to all the heavy lifting! Thanks for the post.

[@sunshine5798]

Thoroughly enjoyed the way you visibly loved to explore it all and discover what lies beneath the cover and how it all works with a curiosity of a little child and understanding of an informed adult. Kudos!

[@codebeard]

The valve is really cool, reminds me of a transistor

[@shadowwalker23901]

I wonder if you could make a full-adder using water valves.

[@wolfgangmcq]

+Cory Marshall The term you're looking for is "fluidics": en.wikipedia.org/wiki/Fluidics

[@jamesmitchell65]

An old video but it gave me confidence to pull apart a Holman timer which enabled me to get it working again (jammed cogs). Thanks Julian.

[@p1nesap]

Excellent valve system vlog, delivered with panache. Nice to hear timeless enthusiasm of discovery. I must do H-bridge breadboard project now!

[@azyfloof]

Fascinating valve mechanism! Never seen that before :D Looks like something you could so easily control with home automation, being only a small DC motor

[@JulianIlett]

Yes, a wireless module would fit easily inside the case of this thing :)

[@iceberg789]

yes, please hack and mod this with your NRF thing, to control the timing & on/off from room. and you wont have to screw out that plastic cap every time anymore.

[@ronen124]

a very lucid explanation and reverse engineering of the electronic faucet, thank you

[@realflow100]

OMG I use your method of preventing cross threading screws all the time! its really useful!!

[@jayfehr]

That trick to prevent cross threading is awesome! I've never heard of that one before.

[@timonix2]

that valve was awfully clever. I am in awe

[@jmanisgreatlastname2058]

Yes really. I made my guess before he took it apart and I was more or less close, but I didn't think of doing a passive diaphragm. This is way simpler than what I had.

[@Graham_Langley]

I think you may have missed out the fundamental point about how this kind of valve works. The back chamber has a larger area acting on the diaphragm than the valve inlet, so in equilibrium the force pushing the diaphragm onto the valve seat will always be greater than the force trying to open it. They're used all over the place, in toilet cistern fill valves, washing machines inlets and so on.

[@nikolazdunic2201]

Your the man, this helped me a lot, my timer does not go to pipe, it goes on barel, so I had to find a way to make it opens on weaker pressure, thanks

[@TimSmith-db1iu]

I hard wired one of these into a mister systems. Amazon sells a AAA battery adapter kit that includes a power supply. I ran the power cable of the back side/bottom of the plastic housing and sealed the cable hole with waterproof epoxy. Works perfectly!! And out of the sun.

[@mohammadaminurrahman1168]

Enjoyable tear down videos. Thanks for the efforts.

[@maestrovso]

Learn something every day. Nice mechanical amplifier. Fascinating indeed. Seems a copy of Gardina. Thanks for keeping us entertained.

[@maskara0147]

Great video! I was able to open and fix mine thanks to your detailed explanation of the system.

[@fhedy1]

what was the problem?

[@juliushildmann2364]

That, good Sir, was absolutely fascinating! Big thank you for your videos from Bavaria!

[@RobertSzasz]

interesting, a gear and cam operated pilot valve. It has the possibility of a stuck on failure mode when power dies though, which isnt exactly optimal.

[@michaelfav137]

Very well explained and without superfluous details

[@rameshjitkar]

Nice informative video. I was wondering how a water timer works and this resolves my questions exactly.

[@turanibrahimov1349]

Great video. Thanks for this!

[@lotlikarvarun]

Very good educational video.. I liked the narration a lot. Nice explanation too

[@JohnSnow-vf8jo]

Mine ( new ) does everything yours did on the tap, but the timer doesn't seem to do anything unfortunately, Thanks for the vid.

[@Shoetiefly]

Many flow control valves in various industries - including refrigeration and petroleum - employ this design of leveraging a small pilot force to control larger fluid forces and flows. Imagine many of these 'garden' controls are sold to cannabis growers. I enjoyed the vid.

[@ElGatoLoco698]

I gotta get me a few of those for my garden. Good deal. Good review. Thanks Julian.

[@marhar2]

Another great teardown. Learned a lot, that is a fascinating device.

[@GadgetUK164]

Awesome!!! Really interesting seeing how that works!

[@testem4m446]

Very good explanation. Thanks a lot!

[@harryjnr2335]

great teardown Julian, that valve is awesome, nice one.

[@websitesthatneedanem]

Two great videos this week Julian! Thanks for the laughs!

[@SilverGreen93]

One of your best videos! Never thought about how these valves work. Great info! :)

[@Moostery]

Soooo. It's a piston valve that has the pressure release runoff directed in to the output. Very nice. This one gets a bookmark for sure.

[@letsbuildstuffandthings]

good video Julian, glad you took it apart after you showed it a few weeks ago on your channel. I want to make something like this controlled by an arduino some day :)

[@NivagSwerdna]

Nice mechanism. I did a bit of googling and only found solenoids that open when power is applied; this design only used power to change from open to close or v.v. very clever

[@dumle29]

+Julian Ilett: The important thing to remember with valves like this, and the reason the water pressure closes, and doesn't open the valve, is that the surface area of the diaphragm is larger in the pressure area place stuff.

[@felixcat4346]

This is also the way a gas pressure valve works only its all mechanical. The gas tank on my roof reads the psi in the storage tank which is periodically filled when I pay for more. From that is a pressure regulator with this device. It has an adjustment screw which varies the amount of tension on the diaphragm thus providing a very small movement regulating a much higher tank pressure. No matter how low (or high )the pressure is in the tank, within reason, the gas pressure to my stove remain adjustable from the diaphragm. Of course, the whole thing is sealed shut and made repairable by the manufacturer to protect us from ourselves.

[@douro20]

Protect us from ourselves...much like what the government is trying to do to us...

[@ParedCheese]

When removing plastic labels, a hot air gun is your friend. 😉 A quick blast at 100C or so softens the glue nicely, enabling easy-peel action. 👍

[@universal7564]

fascinating. Just bought one. Nice to know what going on in there.

[@teravolt1195]

14:01 Wow, so the water analogy works again for electronics. This is basically a transistor! You input a small current from the high impedance base and it causes the collector to 'open' and both flow out the emitter.

[@nrdesign1991]

Pneumatic valves are very similar, with a little valve controlling a beefy valve.

[@virmontisfbg]

Very good, I really enjoyed this teardown.

[@scottvickrey2743]

Thank you. You saved me 30 bucks!

[@WaltonPete]

You should be able to stop the leak from the brass adaptor by using PTFE tape. You could also remove the gland nut from its seat and wrap some around the tap spindle then, using the gland nut to push the tape down the spindle, re-tighten the gland nut to stop the leak from the tap without making the tap impossible to operate.

[@0neye1]

Thanks for the video, I have one and it was leaking had now idea how to open it up. My one had one screw at the top under the sticker.

[@proyectosledar]

Yeees, you know what we want!!!

[@JulianIlett]

First comment Amigo! Usted gana gran premio de hoy!

[@proyectosledar]

ya sabes lo que quiero. abrazo

[@sebastianparis8533]

No esperaba encontrarte acá. Tienes uno de estos? busco opiniones de este modelo

[@calinracasan7902]

Hi Julian, nice educative video. Do you know what is the lowest pressure this would work on. I want to use it from a rainwater barrel, maybe 1 meter from the ground. Thanks in advance.

[@wesamswailem]

Hi Calin,gravity flow pressure won’t close it unfortunately

[@tiennguyendanh4549]

Nó đây: Zero Pressure Ball Valve Watering Timer Garden Irrigation

[@biffoswilly]

You need ptfe tape to solve the leaks

[@PhattyMo]

A lot of valves for in-ground yard/garden sprinkler systems work on the same principal,but use a solenoid instead of a motor/cam/plunger. Also of note,they're commonly rated 24Vac,but I've found that they will often function from a 9V battery,or similar.

[@teravolt1195]

This is a no power needed on version then. those solenoids would have an armature electromagnetically held back from a spring. i thought a solenoid generally referred to a springed electromagnetic operated armature (used in other things like door locks and relays)

[@luisacalderon717]

I purchased two Melnor aqua timers and both malfunctioned on the second year. The problem is that apparently the valve is not opening. What could be the problem? Could there be hard water deposits? Could the spring have broken? Could the solenoid have a loose contact? I really want to fix these timers, but I’ve yet to take them appart. Your video has been hugely useful, thanks a lot from Mexico.

[@martinverbaas]

After seeing your video I bought the same one with the Idea to fit a microcontroller into it...

[@xanataph]

On a more serious note. Yeah it's clever how they use the motor driven plunger in place of an actual solenoid in this arrangement. Has a huge advantage when running off a couple of batteries in that it does not need be constantly energised to keep the valve open. I reckon those extra transistors are to do some kind of voltage level shifting and/or inversion to make the H bridge work.

[@JulianIlett]

Yeah, the other 2 NPNs will pull the PNP bases down to 0V.

[@stefflus08]

I have to say, as I only started fiddling with electronics a few months ago, mechanics are vastly more evolved than electronics. In analogs it is almost without limits, whereas electronics is like building with blocks. Quite strange really, as electronics aren't exactly a new thing. I wonder if the quest for speed and going the digital route is holding us back. It seems easier (cheaper?) to convert to digital going through a microcontroller and then back to analog than it is to make a discrete analog device, even for the simplest task. Also it's rather amusing to watch Mr. Ilett and Mr. Carlson go on about the mechanics in length, while the electronics is so obvious to them it's barely mentioned. Mr. Jones and especially Mr. BigClive doesn't seem to dwell so much on the position of screws.

[@viermidebutura]

one small correction in the closed position the spring is what holds the diaphragm closed because the water on both sides of the diaphragm has the same pressure

[@m8e]

Well. There's also the difference in area on the diaphragm. The incoming water can only push on the center of the diaphragm. The water in the chamber pushes on the whole diaphragm. The pressure is the same on both sides, but not the total force on the diaphragm is not.

[@gastongroisman8817]

Julian: Twice you talked about "accumulated pressure in the back chamber". I think that when the needle closes the channel the pressure on both sides of the diaphragm is the same. What closes the valve is the spring. When the water is let through the small channel the pressure in front of the diaphragm is larger than behind and now the front pressure of the water opens it.

[@GrahamDIY]

Gaston Groisman yes! Even though this is an old video I was going to make the same comment but checked to see if someone had already made the same comment. And you have :) It really doesn’t matter how weak the spring is, it just has to apply *some* force (even tiny tiny) to mean the closing of the valve. For me, it’s that which is the genius of this invention from 1910 or whatever. Interesting video, Julian

[@BenjaminGatti]

One more detail, the surface area on the back of the valve is larger than the front, and thus even at the same psi there is more force holding it closed, venting the back pressure permits it to open of course.

[@KF5GXZ]

I wonder how this would operate at low pressure? Like a gravity fed rain barrel system.

[@tiennguyendanh4549]

Bạn hãy dùng loại van này nhé: Zero Pressure Ball Valve Watering Timer Garden Irrigation

[@AlanLifeson]

Very interesting. I bought a very similar item from Amazon for £12, but it doesnt work in the same way. Mine uses a ball valve in which a motor turns the ball 90 degrees each time you activate the switch or timer. It seems its a lot simpler method but not sure which is best.

[@anonymouseniller6688]

The ball valve is better imo, the control electrinics are simpler, it's mechanically simpler, it doesn't require a minimum inlet pressure and it doesn't clog as easily. The other one is more clever though

[@jp040759]

Kind of like a mechanical transistor. A small flow of water controls a larger flow of water. My lawn sprinkler system vales work this way. I was very impressed with the design once I figured it out. I believe it uses mechanical hydraulic advantage to move the diaphragm. The chamber on the back of the diaphragm has a larger surface area so the tap water pressure pushes harder on the diaphragm (more pounds per square inch) to close it against the incoming tap water pressure. Very ingenious.

[@TelmoMonteiro]

I'm amazed. Nice video! Very good indeed!

[@GrahamCaulton]

I share your enthusiasm for this water timer. It’s a pity it won’t work on gravity fed systems. Do you think increasing the spring strength and/or coating the diaphragm in vaseline would work? Graham .

[@John_Ridley]

This is the standard way that water pressure valves have worked for decades. They use the water pressure itself to operate the valve that controls the water pressure.

[@KF5GXZ]

I have the solar powered model. Very nice video

[@markg735]

A great explanation of how these kinds of valves work is available on the washing machine episode of the Brittish TV series "The Secret Life of Machines." It's a fantastic series.

[@TimSmith-db1iu]

What are your thoughts about wiring a panel mount on/off switch to this? I'd like to be able to turn it on and off without having to screw off the front plate. They sell water proof panel mount switches. It's going to be used for a mister system so the auto settings will only be used for when we want to run the misters on a hot day. It would be nice if I could just turn the dials to a setting, screw on the front plate, and only have to hit the button when using.

[@willofirony]

A very entertaining presentation. One wonders if there is an electrical/electronic analog for how the solenoid valve works. Though the problem of mains electric (the equivalent of mains pressure water) with delicate electronics (the equivalent of those tiny vents) would be problematic.

[@JulianIlett]

I wondered the same thing

[@andrejfusek458]

Very nice! Thank you for explanation of this wonderful principle. I like water physics as well as electronics :)

[@ArduinoKing]

That's really cool. I'm wanting to do a 6 channel irrigation arduino project. These valves seem that they would be awesome. I was surprised I couldn't find any ebay versions. Just wanting the guts so I can build my own controller.

[@jmair.r.3187]

Nice video full of information, thus this device applicable on low pressured running water?

[@fredbloggs5822]

My toilet cistern has that kind of valve in it. Took me a while to get my head round it first time it needed fixing.

[@Neffers_UK]

Mine too. The supplied diaphragm was shit and was split within 6 months, leaving the cistern empty as it wouldn't hold back-pressure. Suffice to say when the guy from the housing came to repair it I blagged a few of them for spares.

[@RS2Racer91]

the H-bridge is built out of 2x pnp and 2x npn (ss8050). The remaining 2 npn's will be to pull the pnp's to gnd (to activate them)

[@DavidHoshor]

I enjoyed this video. Thanks.

[@chazM6116]

valve works like the ones in washing machines kept closed by the water pressure

[@WeissBlau42]

excellent examination!

[@ZillionPrey]

Nice, keep up the good teardowns

[@alexisautube]

you should insert a second rubber washer inside the brass fitting which attaches to the faucet in order to stop the leaking

[@gedm2]

Hi Julian, I have one of these units and I'm interested in using NiHM batteries and a small solar cell to trickle charge them. Could you please consider a video on the best way to set this up? I don't have any experience with solar but I am into RC hobbies so I'm OK with soldering, etc. Thanks for your very informative videos.

[@umpsfar]

Hi Julian I have a 6 of these and they all have the same kind of issue (they require mains water pressure to work) i have two water barrels connected together and am only getting a dribble at the output.there is a fair amount of pressure from the 400 liters . Ive tried to remove the spring, cut the spring in half, drill a larger hole in the solenoid end. (am now about to drill a larger hole in the diaphragm end as well. ) (and also going to replace the tap on the barrel with a larger diameter tap .) in your wisdom which of these or an other idea would allow full flow with little pressure.

[@tiennguyendanh4549]

Bạn hãy mua loại van bi nhé: Zero Pressure Ball Valve Watering Timer Garden Irrigation

[@hassanburrows8535]

Hi Julian, I was thinking along the lines of an equilibrium valve as per we can find in a float operated cistern valve, but are there not similarities to the gas valves operated by, for example, a thermocouple? Very neat anyway.please include a subset of plumbing investigations, but I will sub anyway. I am captured. Muchas gracias desde el chico electricista en el distrito de lagos, inglaterra.

[@DoRC]

I had to figure how these worked out by myself when I took one of these apart when I was a kid. It took a while.

[@AlanDavidoff]

It's a nice device, but if the batteries run out in the "ON" position, the plants won't be very happy :) I wonder if it monitors the voltage to prevent this from happening. A low voltage test would be interesting.

[@holtzda]

These are definitely nifty valves that take advantage of the fluid version of mechanical advantage - using a small force to switch a high pressure. It's my experience that they don't work very well for switching low-pressure water, like that from a gravity fed water collection system (i.e. rain barrel). Another advantage of them, though, is that they don't require constant power to be on or off - they latch their state.

[@jp040759]

The trade off with this latching techniques is it is not failsafe if power is lost. It saves electric energy but might die before it shuts the water off. The other solution with a constantly powered solenoid version for example is you use electric the entire time the vale is open.

[@holtzda]

True. I hadn't considered failure modes.

[@Neffers_UK]

I would like to see at which point the valve fails to operate at low voltage. Most of the devices like this I have seen used have died with the valve open allowing water to flow all day and night while the tenants are away on holiday, which can be problematic at the very least.

[@jp040759]

Good point. The valves on my sprinkler system are similar in design but use a solenoid instead of the motorized thingy. That way it is failsafe. When power is applied or the solenoid coil fails the solenoid de-energizes and closes the water path thus shutting off the main water supply. This motorized version will not do that.

[@therealchayd]

You may be interested to know that this is also how some common-rail diesel injectors work (I think they're called servo-hydraulic injectors or something like that)

[@AgentOffice]

ChayD piezo electric, my jetta has then and pressure is like 10,000 bar

[@MrBstefan]

Hello Julian, If I got it right you said there is no endpoint sensors on the motor, what happens if power is removed during the travel of the piston? will the water pressure push the rest? Regards Stefan

[@jamesburty6696]

Hi @Julian ilett .. do you have an idea what will happen if you are on holiday and using this timer at home for irrigation and the battery is low?

[@ArcanePath360]

Very clever

[@ArcanePath360]

Is this a 1/2 inch or 3/4 inch tap connector? I've looked at hundreds now on ebay and Amazon and nothing tells you. I need to know because I need to convert it to run on the end of a hose.

[@daniel19831123]

I have one of these unit and I actually came online to find a solution to a water leaking problem. It was leaking from the battery slots so I'm guessing one of the rubber gasket on the inside is not sealing the electronic properly. Any suggestion how to correct this?

[@DaveCurran]

In that unit the motor is required to turn it on and again to turn it off, so if the batteries fail at the wrong point it could leave the water running? I suppose the advantage of a solenoid over the motor would be if the power failed, it would stop the flow of water. But it would use more power when operating.

[@JulianIlett]

Battery voltage could be monitored by the microcontroller. If the controller detects brownouts, it could turn off the water flow.

[@DaveCurran]

....assuming there was enough power left to drive the motor to cut the water off.

[@bridgendesar]

look up surestop water switch,same principal, but manually operated by you!

[@charlesyue3891]

have you got a chance to check out roughly how long can the batteries last?

[@brucewoods9377]

Use some Teflon Tape on the tap threads, and yes, replace your tap washers

[@augustus4711]

Wonder how long this thing works if you have very hard water...

[@PartTimeRonin]

Is there a way to modify this timer to change frequency from hours to minutes and water time to seconds instead of minutes? Or just make a new circuit instead?

[@robertheal5137]

a plain solenoid valve is not much use if it needs to be energised for more than a few minutes, they overheat. also uses too much current from batteries for the magnet coil. You need a design which is only consuming power when it is actually switching from one state to the other.