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Author Topic: Simple well pump timer  (Read 4603 times)
Jedon
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« on: April 11, 2010, 06:07:22 PM »

I keep forgetting to turn my well off when I turn the generator off. My batteries don't last long with the 240V 8A pump going ( I'm off-grid ). The pump is turned off and on with a breaker at my house panel. It pumps into a 2600g tank that we gravity feed off of. I was thinking of using one of those simple 120V timers for watering etc but I figure they couldn't handle the amps. I'd like to be able to just set it for an hour or two and have it turn off automatically. Eventually I'll have a level sensor on the tank and have the pump turn on and off  according to set of automation rules but I'd like a simple stopgap measure. Any suggestions? Thanks!
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rl71459
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« Reply #1 on: April 11, 2010, 06:23:57 PM »

Jedon

Can you temporarily plug your pump directly into the circuit from the genset? In that way you can't leave it on if the generator is off.

That almost sounds too simple.

Rob

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Jedon
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« Reply #2 on: April 11, 2010, 06:56:48 PM »

The pump does not have wiring that goes anywhere near the generator, the power shed where the generator, inverter and batteries are is on the other side of the house from the well, the power lines from the well go to the house so run off the house power which is controlled by the inverters. 
I didn't even think to just google it first and check Ebay, my bad.
This looks like it might work except for surge?
http://cgi.ebay.com/220V-LCD-Micro-Computer-Timer-Switch-Time-Controller_W0QQitemZ270552479117QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3efe2f358d#ht_2435wt_939
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BruceM
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« Reply #3 on: April 11, 2010, 07:57:01 PM »

Any timer will be fine if you use an appropriately rated contactor (relay) to switch the well pump.
The Hong Kong unit on ebay you listd is rated for 20 inductive amps- if this is above your pump's start surge, then you don't need an additional contactor.

Some well pump controllers already have the contactor - starting about 1 1/2 HP, typically.  In this case you may be able to wire in control of that contactor- but a wiring diagram- from the lid of the contactor- would be needed.  In these types of pump controllers, the pressure switch unit is what normally activates the AC coil of the pump controller relay. 

Pity you have no way of signaling your generator is on-  perhaps some X10 gear?

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Jedon
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« Reply #4 on: April 12, 2010, 11:48:57 AM »

I guess I should not have much surge according to the pump docs:

Quote
The SQ series pump features a permanent magnet motor controlled by an electronic frequency converter developed by Grundfos. It starts slowly, without surge, so it can be run on a much smaller inverter or generator than any conventional AC submersible pump. It is a high-efficiency pump and motor with built-in dry-run protection.

This is the ideal pump to use if you are pumping from a well and into a pressure tank, especially for solar-powered homes. They work on modified sine wave or sine wave inverters. Highest volume pumps run on 240VAC. They can be powered by inverter systems with 240VAC output, or by using an autotransformer to step 115VAC from an inverter to 240 to run the pump. Minimum well diameter of 3" is required. Use 2-conductor with ground pump cable.

I do have a cat5 cable running from the power shed to the house, on one pair I have a shunted voltage meter, I could run some kind of generator on sensor on another pair, how would I do that?

The pump is supposed to shut off when the tank is full since it has a float valve, but it doesn't. The well is 320 ft and then it is another 100ft up to the storage tank.

Pump is Grundfos SQ 1.5HP in a 4" well.
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LowGear
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« Reply #5 on: April 12, 2010, 02:54:08 PM »

X-10 can do some pretty neat stuff, works on 120 AC lines and is fairly cheap. 

Keep It Simple Smarty!

Casey
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Jedon
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« Reply #6 on: April 12, 2010, 03:01:18 PM »

I thought there were issues with X-10 running on inverter power? My Tripplite UPS's don't work on it.
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BruceM
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« Reply #7 on: April 12, 2010, 05:33:33 PM »

Since you have cat5 cable from the generator to the house panel, which serves the well, you could use another pair from that cable to enable a relay for the pump.   I'd use a small 12VDC wall wart off the generator side of the switchover gear- I assume there is something like that. .  Power a small, low coil current 12V relay which trips an AC coil contactor and you're all set.

As for the full float switch- just get out your ohm meter and find out what's broke.  I assume the well float switch isn't carrying full load- so it should be feeding a relay on the pump controller. Get or make a wiring diagram for the pump controller/float switch and I'll try to help.

The timer unit you found should handle your pump.  But really, you want to repair the float switch or correct it if it never worked. 
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Jedon
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« Reply #8 on: April 12, 2010, 05:44:41 PM »

The float switch isn't, it's a valve. It just closes the water inlet off which is supposed to increase the pressure enough to kick the pump off.
I have pipe running from the well to the tank ready to pull wire in for sensors but I haven't done it yet.
I have some automotive 12V relays, would those work? I don't have an outlet hooked between the generator and inverters yet but I could add one easily, I want to wire up another dual 50A breaker box to act as a transfer switch to bypass the inverters in case something goes wrong with them or the batteries we could still run directly off of one of the generators which already have their own switch so I can only run off one or the other but never both.
What is this AC coil contactor you spoke of? Like this? http://cgi.ebay.com/CENTRAL-HEAT-AC-CONTACTOR-RELAY-24-VOLT-COIL-2-POLE_W0QQitemZ250533041383QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a54eed4e7#ht_500wt_956

Goal 1: Have a timer on the well pump so I can set it for an hour or two and it will turn off automatically
Goal 2: The well pump won't run unless the generator is on ( should be able to be overridden or bypassed though )
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LowGear
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« Reply #9 on: April 12, 2010, 08:04:06 PM »

Hi Jedon,

You're kinda right about X-10.  It can have a problem transmitting / receiving across some electric devices.  I have a couple of GFIs that it can't get across and many surge protectors will block the signal as a spike even though it's a tincy-wincy one.  But these are pass through settings and not work along side.

I have used X-10 to sense a float switch and then turn receptacles on or off depending on the need.  One was a sump backup pump and it also turned on the warning light in the front room when the secondary pump was being called into action. 

I think X10.com has a pretty easy return policy if your inverter scrubs the communications even though they wouldn't be passing through it but just along side of it.  If kept simple it can be handy.  Unfortunately their web site is a maze of over selling crap but they're pretty good on the phone.

I'll try and do some testing next week after the taxes are sent in.

Casey
 
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Jedon
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« Reply #10 on: April 12, 2010, 08:26:59 PM »

I have some X-10 stuff, just on/off via remote type things but it would show if it was going to work or not, I'll give it a try.
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BruceM
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« Reply #11 on: April 12, 2010, 09:28:23 PM »

Yes, Jedon, that contactor is way more than you need.  Since you pump does a soft start, you could use a much smaller relay.  Just match your relay contacts to the max load amps.  24VAC coil would be OK, depending on the length of the CAT5 run and the required coil current, you might be OK going direct. 

For your setup, a  float switch would make more sense than your float valve, else you've got to add the pressure switch.  My float switch is wired in series with the remote 12V "on" control which comes over a Cat5 pair. The 12V switches a tiny low current coil relay which switches 240V to a bigger relay.  I will be replacing the 12V relay with one of the new opto-mos chips when I find that 'round toit.  That will get the 12V current requirement down to 2 ma instead of about 40 ma.

I got a float switch at Grainger, but I'm sure they're pretty easy to find, and cheap lots of places.  Mine is attached to a piece of threaded pipe which fit into a female fitting on the top of the tank. A J box there and some conduit to the pump house is all that was involved. 




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LowGear
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« Reply #12 on: April 13, 2010, 02:11:07 AM »

I'm getting good service out of the one I bought at a marine store.  It's sold for bilge pumps.

Casey
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mbryner
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« Reply #13 on: April 16, 2010, 11:24:17 AM »

Hi Jedon,

I have almost the same setup as you, without a mechanical float switch, though.  I didn't want the well pump to be able to come on at night.  My solution is to use a simple pump relay switch (24 V), a electrical on-off float valve in the holding tanks, and a cheap easy-to-find home lighting timer.   (The kind you plug in to the wall to turn on lights so burglers think you're home.)   All the components were relatively cheap and readily available at the plumbing store.  The well pump is a Grundfos SQ pump like yours.  I don't even have an electronic pump controller.  The timer and float switch are in series, so both of them have to complete the circuit for the pump to be able to come on.   If the tank is low, but the timer says it's dark outside (or any programmed "do not pump" time of day), the well pump will stay off until the sun's up.   The timer has battery backup, etc.   Simple setup and quite cheap.   Maybe that logic will work?  You could just use a simple 24 V relay like mine, with a wall-wart plugged into generator power.   No power = relay off = no pumping.

Marcus
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Jedon
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« Reply #14 on: April 16, 2010, 12:19:27 PM »

Mine is currently: well->breaker , super simple no controllers or timers or anything besides a pull out on/off at the well head.
So if I was to wire it like yours, it would be:
Well->pump relay->breaker
pump relay <- timer <- 110V
24V from where?
Thanks!
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