Backyard Aquaponics
A place to discuss aquaponics

Where's frank when you need him....
Lots of continuous duty motors see a lot of surge amps during startup, especially if starting under a load. A lot of heat is generated in the windings during startup and with large expensive motors at the plant guidelines were developed to help minimize the amount of life that is consumed from the winding insulation during each startup. They go something like 2 starts for a cold startup and another after 30 minutes with 5 starts in a 12 hr period. Hot restarts allow only 1 immediate restart and subsequent starts after 1-2 hours cool down with 5 restarts in a 12 hr period. Lots of starts are bad regardless of continuous or non continuous. Running a non continuous duty pump continuous I would guess overheats burning out the winding insulation due to its poor ability to dissipate the heat.

Stop/starting motors continuously that are submersed in water is not a problem for the motor windings, water is an excellent conductor of heat so any extra heat generated is quickly dissapated. Mechanical issues could be a problem depending on pump design, the impellers on some magnetic pumps (fish tank style pumps) arn't fixed to the rotor and the contant take-up when started can break the lug which turns the impeller. As suggested previously the back flushing of pump when stopped is a good self cleaning feature for the pump.

The amount of wear on the pump from starting/stopping is also going to be related to the size of the pump. Really honking big industrial size pumps are not going to be all that good for starting/stopping (and I'll point out are probably too big for most little timers to operate anyway.)

Keeping in mind that I run my big system with a continuous pump so I'm not against the idea (main reason for me is that my pump is not self priming and I've found the check valves don't always prevent the loss of prime.) I have a priming pot/leaf catch basket too. Since my pump is drawing from an in ground tank, and it is an in line/non-submersible I'm better off running it continuous. It is a pretty energy efficient pump for the flow it provides so I'm happy with it.

I like the way my system is working but for some one who doesn't want additional failure points (like extra check valves, electronics, funky home build valves and automation, or sensors and switches) I still recommend a pump on a timer for simplicity. Often with such a set up, one might be able to get a second pump and timer to have on had in case of failure for the same price as a single pump plus all the other stuff.

While I sift out fines from my gravel...
I got a Pump Start Relay, a nice outdoor box with provision for 110V in, 24V in for control, and 110V out ready for a pump. It is intended to turn a 15 amp pump ON synchronous with a 24V sprinkler valve.
I figured it would be a safe way to accept a signal from a readily-available sprinkler timer to "simply run the pump off a timer" to index the Spider.

Seems that the sprinkler people don't actually make a one-station sprinkler timer, much less one that has enough on/off sequences to run a fill/drain all day. Unless you want to pay out the wazoo...

Besides Simso, and his retic pressure-drop valve solution is rather elegant, what exactly are folks doing to "run the pump on a timer?"
-> Use a pump relay, Plug a 24V wall-wart transformer into a mechanical or digital lamp timer that has enough on/offs to program 15/45 minutes? (and use it as the control signal?)
-> No relay, Plug their pump straight into one of the above "lamp timers" and weatherproof it somehow?
-> No relay, Modify a rugged sign timer (add a lot more on/off events) and wire the pump right into that timer's weatherproof box?
-> Build a custom 555-based repeat timer on a board (sigh, yet another skill to go learn) and try to make it go with the kitchen decor?

Or something else?

My pump start relay's manual says NOT to use the same circuit for the sprinkler timer and for the pump power itself. Why would this be? It is making me hesitate to just do the first option by tapping an inside outlet.

I just don't like the second option, it's as bad as what I'm bodging right now, extension cord plugged into a spring-door outside outlet.

Want to keep it simple. Otherwise I might as well go back to wiring a 24V reed switch to control this relay box, sequence the Spider when the currently-fed growbed drains. I have a magnet-equipped FLOUT prototype that can do that.

... so what exactly is it that you're trying to do...

What runs your pump now?... all you need to do is put a timer at the end of the current pump lead where it connects to the power point....

Or is it that you want to be able to program the on/off sequences to differing values... or just values other than 15 min intervals?

What is the magnet for? Pictures plz!

Not killing anybody would be a good start! See next.

I want something more permanent than that. I have the pump plugged in to an extension cord that runs across grass and patio to an outdoor outlet that really should not be propped open.
Naw, 15-min is fine. One-time-fits-all is OK too. It's the timers I am finding, that seem bodgy (is that even a word) given the exposure and amps and voltages...
Are you saying the way most folks go is to plug a wall timer in, either in the house or out, and plug the pump in to that? And the really anal ones plug the timer in to a GFI instead?

Outdoor outlets on residential homes are GFI by building code normally. Note that multiple outlets may use a single GFI outlet switch (which may be located inside).

How big is the pump? If it is only like 1/6th to 1/3rd of a HP then I have an outdoor timer that I use for things such as this, does 15 minute intervals. Has a little pig tail that can run into one of those outdoor outlet covers so you can have it plugged in and the outlet covered. It is a GE outdoor timer. Yes mechanical timer and they sometimes become dodgy in their timing but normally still within bounds and you can do intervals the clock round so no messing with only being able to do 28 on/off cycles per day and having to shut down at night or something like that.


the extension cord across the grass isn't so great but it doesn't matter what timer you go with, you will need to get power out to the system some how, I don't think you want to be beaming microwaves across the yard to avoid running wires. Might be best if you have a more perm power point installed out in the right location to avoid the extension cord.

Now where I have had to connect electronics out where I can't have in inside or something like that. I've usually run the cables up a post and mounted stuff up at the top of the post so I can place a bucket over it to keep it dry. This has worked pretty well for me so far, just keep an eye out for wasps building nests up under there.

Oh, and about GFI circuits. By code they are supposed to be installed but in an older house, that might not be the case and also, since the protection switches themselves can become dodgy, some people tend to remove them when doing DIY repairs without permits so don't assume it is a protected outlet. You can only have one GFI outlet on a circuit and it will protect all the outlets on the circuit. Beware that a timer installed before a GFI (like when you get one of those GFI extension cords or three way outlets) will usually cause the GFI to trip so doesn't work very well, the GFI needs to be before the timer.

GFI: Yeah, the 36-year-old houses in my 'hood barely have ANY outdoor outlets, let alone GFIs. Not one on the outside wall where all the action will be. There is a newer, boxed and breakered 220 drop for the air cond. compressor nearby, and a kitchen outlet on the inside of that wall.
So I will be either: Tapping thru the brick to the indoor kitchen outlet, while replacing that one with a GFI outlet (quickest)
-or- Just running a new separate circuit from the main, taking the opportunity to bury appropriate shielded conduit at an appropriate depth for local and national code (mo' proper)
-or- Tapping into one side of the 3-phase? Can that be done? It's already there. Accessible. Substantial!

TCL's Timer: Thanks, Yes that is what I also consider doing if I put in a closer outlet (I like the power post). Plug and play. Well, plug and shield and bury.

I see my Elec. Engineer older brother has sent me a reply via email as well, let me see what he offers, he is good at keeping me within code and safe as well.

I did mean 2-phase regarding the 220v. When I said 3-phase.
I don't know if I will unbalance something by adding a subpanel (with its own 20 amp breaker) for the aquaponics and maybe garden lights.
Can't live in Houston without air conditioning after all. (not since everybody else runs it pumping heat into the air)

I think you do want a circuit run out to the AP system nice and proper. When I called zoning here, the only possible need for a "permit" for a "water garden" was the electrical. If you can plug it right into a covered outdoor outlet, then no need for anything special. So if you can get proper electrical run out there, then your water garden would be all cool according to our zoning officials. (Well technically they want some one to pull a permit to run the electrical and get inspected I guess which is why my system is built right next to the house where I can plug directly into the outdoor outlets right on the wall, we just added the proper covers to them.

Good Luck with it!

I split these often, but mostly when folks have the wire set, but no AC installed. I've also tapped into a well circuit which is also 240V. The main thing is that you should see what the existing power load on the circuit is and decide if you have some extra capacity. Remember that motors (pumps, AC, etc) use more power on startup.

I didn't want to run electrical cable across my yard either. So I am in the process of digging a trench for 2 inch conduit to thread heavy duty extension cord to the green house. This way I can avoid homeowners association and building code restrictions and it can all be undone if I ever move. The cord will be plugged into the gfi outlet on the patio. I'd like solar but this seemed cheaper at the time. I can tell you at this point it most certainly is not quicker as I can only dig so much rock at a time with a pick axe, and I'm only going 30 feet!

I don't envy you the rock. I got sand and I dug the trench to replace the wiring to my well in a morning, that is 70 feet minimum around here since if a house ever has to be tented and treated for termites a well closer than 70 feet would have to be abandoned and capped before tenting. Now I personally would probably go ahead and get heavy duty romex and thread it through smaller conduit, like 3/4" and install a box on the greenhouse end but only do that if you feel confident in your wiring skills. Of course you could probably hire an electrician to come do the wiring on each end for a reasonable price. If you do go with the big conduit go to some extra effort to make sure you don't wind up with water getting down into it, or critters for that matter, a rodent could mess with your wiring if they were to use the 2" conduit as a convenience tunnel between your greenhouse and patio. Some steel wool and cauking over the ends might be a good idea.