4 ms·

As always, anyone trying to work with gravity fed systems that sit in the range between ~2 metres head (the usual maximum of very low-head valves) and standard

by Jedd 9y ago

As always, anyone trying to work with gravity fed systems that sit in the range between ~2 metres head (the usual maximum of very low-head valves) and standard / city pressure, are somewhat stuffed. I'm working with about 10 metres of head - a decent standing pressure, despite coming through 400 metres of 50mm polypipe - but it's too much for the specialised 'water barrel' type valves mentioned here. Combined with no power (if i had power I'd have a pump :) means it's also not feasible to use always-closed solenoids, or have sufficient pressure to reliably get residential grade water computer valves to open / close.

maxerickson 9y ago
Have you evaluated how much it would cost to use solar power? Or would the possibility of the system not running be a disqualifier?
- Jedd 9y ago
  Yeah, solar for charging batteries to then run solenoids, absolutely feasible - but most solenoids are either Normally Open or Normally Closed, and need constant power when holding them in the other position. For relatively low-flow situations these are non-starters, as you usually want to have a circuit open for an hour or more. There are switching solenoids that only draw power as you change state. Downside, they don't fail safe. They're also more expensive, and AFAICT you can't use standard (NC / NO) controllers with them. To complicate matters, switching solenoids usually want a certain amount of pressure (about twice what I'm working with). It's an area that's slowly getting better served by cheap fab places out of China. You can already get A$20 'residential' grade 13mm single line water controllers that are mostly reliable, but their valve comes down to about a 1mm hole, so big impact on flow rate, and highly susceptible to debris.
  - maxerickson 9y ago
    What about stuff like holding open a larger solenoid to charge a gravity tank?
pedrocr 9y ago
Have you tried something like this: https://www.aliexpress.com/item/Irrigation-water-timer/1510781067.html https://www.aliexpress.com/item/Irrigation-water-timer/15107... Since it's a ball valve operated by a motor it works with zero pressure. It's a relatively small ball valve but should be enough for almost all applications. I have one of those controlling about 100 meters of drip tubing from a source that's not more than 2 meters high (less if the tank is empty) and it works fine. For better flow I'll be trying one of these ball valves: https://www.aliexpress.com/item/Stainless-Steel-BSP-1-Actuator-Valve-2-Way-DN20-Electric-Motorized-Ball-Valve-DC12V-3-Wires/32802819942.html https://www.aliexpress.com/item/Stainless-Steel-BSP-1-Actuat... It's much less convenient as they don't have an integrated controller. I'll be trying it with this controller: https://www.aliexpress.com/item/NO-NC-220-240V-timer-switch-multipurpose-programmable-digital-timer-module/32692258610.html https://www.aliexpress.com/item/NO-NC-220-240V-timer-switch-... and a 12V battery together in a waterproof casing of some sort. I've been looking for a plastic case similar to the water timer one that's a screw on with an o-ring but haven't found one yet.
- catmanjan 9y ago
  I used to have the first one, it was garbage - didn't even last an Australian summer, I think it overheated.
  - pedrocr 9y ago
    That sucks. I've had good luck with the solenoid version of those. But I can see how the fully enclosed design can cause overheating if it's left in the australian summer sun.
- Jedd 9y ago
  I actually picked up a few of the first ones there via ebay a while ago, to trial off a smaller tank with around 2 metre head, but haven't plugged them in yet. Winter means frosts, and no great need for automatic watering. I note someone else has had bad experience with them - I've used the normal pressure versions of those with some success - a couple of years, with 9-monthly battery changes, seems reasonable for the price - just frustrating when they go wrong (usually just before a fortnight of 40+ Celsius days). The actuator though, that looks very relevant to my interests. I've just done a google spiral on CR02 (and similar) wiring, to control via an arduino, say. With 3s to close / open, and only 12V required, this seems quite feasible to have a cheap solar charged battery sitting and running a half dozen of these of a manifold. The benefits of a switching solenoid in terms of power consumption, with a simpler control mechanism? The last link you posted seems to imply it will talk to a solenoid (NC or NO) only - would be very curious how that goes. I have several dozen old water timers with the o-ring seal ... where the o-ring seal has failed, and the insides rusted out. I now cover them all in thick plastic bags, and keep them under pit covers / galv steel lean-tos. Probably explains why they tend to last more than one Australian summer, too.
posterboy 9y ago
> but it's too much for the specialised 'water barrel' type valves mentioned here what are you using instead?

by Jedd 9y ago

maxerickson 9y ago

Have you evaluated how much it would cost to use solar power? Or would the possibility of the system not running be a disqualifier?

Jedd 9y ago
Yeah, solar for charging batteries to then run solenoids, absolutely feasible - but most solenoids are either Normally Open or Normally Closed, and need constant power when holding them in the other position. For relatively low-flow situations these are non-starters, as you usually want to have a circuit open for an hour or more. There are switching solenoids that only draw power as you change state. Downside, they don't fail safe. They're also more expensive, and AFAICT you can't use standard (NC / NO) controllers with them. To complicate matters, switching solenoids usually want a certain amount of pressure (about twice what I'm working with). It's an area that's slowly getting better served by cheap fab places out of China. You can already get A$20 'residential' grade 13mm single line water controllers that are mostly reliable, but their valve comes down to about a 1mm hole, so big impact on flow rate, and highly susceptible to debris.
- maxerickson 9y ago
  What about stuff like holding open a larger solenoid to charge a gravity tank?

pedrocr 9y ago

Have you tried something like this: https://www.aliexpress.com/item/Irrigation-water-timer/1510781067.html https://www.aliexpress.com/item/Irrigation-water-timer/15107... Since it's a ball valve operated by a motor it works with zero pressure. It's a relatively small ball valve but should be enough for almost all applications. I have one of those controlling about 100 meters of drip tubing from a source that's not more than 2 meters high (less if the tank is empty) and it works fine. For better flow I'll be trying one of these ball valves: https://www.aliexpress.com/item/Stainless-Steel-BSP-1-Actuator-Valve-2-Way-DN20-Electric-Motorized-Ball-Valve-DC12V-3-Wires/32802819942.html https://www.aliexpress.com/item/Stainless-Steel-BSP-1-Actuat... It's much less convenient as they don't have an integrated controller. I'll be trying it with this controller: https://www.aliexpress.com/item/NO-NC-220-240V-timer-switch-multipurpose-programmable-digital-timer-module/32692258610.html https://www.aliexpress.com/item/NO-NC-220-240V-timer-switch-... and a 12V battery together in a waterproof casing of some sort. I've been looking for a plastic case similar to the water timer one that's a screw on with an o-ring but haven't found one yet.

catmanjan 9y ago
I used to have the first one, it was garbage - didn't even last an Australian summer, I think it overheated.
- pedrocr 9y ago
  That sucks. I've had good luck with the solenoid version of those. But I can see how the fully enclosed design can cause overheating if it's left in the australian summer sun.
Jedd 9y ago
I actually picked up a few of the first ones there via ebay a while ago, to trial off a smaller tank with around 2 metre head, but haven't plugged them in yet. Winter means frosts, and no great need for automatic watering. I note someone else has had bad experience with them - I've used the normal pressure versions of those with some success - a couple of years, with 9-monthly battery changes, seems reasonable for the price - just frustrating when they go wrong (usually just before a fortnight of 40+ Celsius days). The actuator though, that looks very relevant to my interests. I've just done a google spiral on CR02 (and similar) wiring, to control via an arduino, say. With 3s to close / open, and only 12V required, this seems quite feasible to have a cheap solar charged battery sitting and running a half dozen of these of a manifold. The benefits of a switching solenoid in terms of power consumption, with a simpler control mechanism? The last link you posted seems to imply it will talk to a solenoid (NC or NO) only - would be very curious how that goes. I have several dozen old water timers with the o-ring seal ... where the o-ring seal has failed, and the insides rusted out. I now cover them all in thick plastic bags, and keep them under pit covers / galv steel lean-tos. Probably explains why they tend to last more than one Australian summer, too.

posterboy 9y ago

> but it's too much for the specialised 'water barrel' type valves mentioned here what are you using instead?