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TandW · 05-26-2022, 11:05 AM

Quote:

Originally Posted by ratherberv

One question if I may.
Why not use a flow switch instead of pressure switch? Pump would not have to run as long to establish flow as apposed to pressure, circuit could be same as pressure switch and flow switch could be mounted just before anti siphon valve to prevent pump from running dry in case of pipe or lake level problems. just a thought.

Flow switches are Dixie Cups. Too problematic on their own. High maintenance item.

153stars · 05-26-2022, 11:37 AM

An inexpensive plc copy of Omron Zen, with LCD screen probably about $100. You can set delays to pressure switches and make many timers and alarms. Wiring of inputs and outputs is simple. If you can get help with ladder logic.

timjet · 05-26-2022, 12:23 PM

Not sure how a flow switch would be better and a pressure switch has no moving parts. When turned on, the pump builds pressure to 60 psi in just a second or two.

timjet · 05-26-2022, 12:32 PM

Quote:

Originally Posted by 153stars

An inexpensive plc copy of Omron Zen, with LCD screen probably about $100. You can set delays to pressure switches and make many timers and alarms. Wiring of inputs and outputs is simple. If you can get help with ladder logic.

There are probably many creative ways to accomplish what we're doing here. I am not a programmer and do not have extensive knowledge of electrical circuits especially when coupled with computers. Someone with knowledge of IFTTT could probably come up with a solution. I was pretty good at programing with DOS back in the late 80's but got away from it when Windows came along. I've got a Raspberry PI and it too could be used by someone who has the knowledge to pair software programing with electrical circuits. Unfortunately I have not learned Python or any language to use my PI, maybe someday.

TandW · 05-26-2022, 12:37 PM

Quote:

Originally Posted by timjet

There are probably many creative ways to accomplish what we're doing here. I am not a programmer and do not have extensive knowledge of electrical circuits especially when coupled with computers. Someone with knowledge of IFTTT could probably come up with a solution. I was pretty good at programing with DOS back in the late 80's but got away from it when Windows came along. I've got a Raspberry PI and it too could be used by someone who has the knowledge to pair software programing with electrical circuits. Unfortunately I have not learned Python or any language to use my PI, maybe someday.

If you put a flow switch ahead of the pump, on the suction side, you had better install a strainer on the pump inlet to catch a wayward flow switch paddle.

ArtJoyce · 05-26-2022, 12:53 PM

My square-d pump control switch does some of the job but not all. It sets the limit low turn on pump, high limit turn off pump and the limits are adjustable.

You want you want at pump startup for there to be a delay and then a low limit switch turn off if the pressure is not at a certain level. Correct?

You might want to check the specs of the pump for how long it can run dry? It might be a mute point.

timjet · 05-26-2022, 02:26 PM

Quote:

Originally Posted by ArtJoyce

My square-d pump control switch does some of the job but not all. It sets the limit low turn on pump, high limit turn off pump and the limits are adjustable.

You want you want at pump startup for there to be a delay and then a low limit switch turn off if the pressure is not at a certain level. Correct? Yup

You might want to check the specs of the pump for how long it can run dry? It might be a mute point. It can run dry, just guessing, for maybe 10 minutes before damage. It is not designed to run dry.

^^^

MrMark52 · 05-26-2022, 02:40 PM

Wiring diagram and parts list attached -

Parts total about $23 on Amazon. MARS relay is not on Prime, pressure switch is.

timjet · 05-26-2022, 04:10 PM

Thanks Mark, Just to confirm the box at the top labeled L1 T1 and L2 T2 is my existing pump start relay.

MrMark52 · 05-26-2022, 05:38 PM

Quote:

Originally Posted by timjet

Thanks Mark, Just to confirm the box at the top labeled L1 T1 and L2 T2 is my existing pump start relay.

Yes

FWIW - I didn’t show ground bonding between components if a bonding screw is provided.

timjet · 05-27-2022, 04:17 AM

Very cool Mark. Using the bypass timer to control the existing pump start relay. My thinking was to use another time delay double pole relay. You obviously have some experience in electronics.

OK, there's just one part missing. How will I know if the pump protection you just designed kicked in? My thinking was to install a small LED light, perhaps 24 volt since that's the control voltage, that would stay on if the pump didn't produce pressure after the time delay. With the current setup I wouldn't know if the protection feature kicked in and the next time the irrigation controller call for a zone to be watered the pump would start and stop again until I realized something was wrong.

MrMark52 · 05-27-2022, 07:45 AM

Quote:

Originally Posted by timjet

Very cool Mark. Using the bypass timer to control the existing pump start relay. My thinking was to use another time delay double pole relay. You obviously have some experience in electronics.

OK, there's just one part missing. How will I know if the pump protection you just designed kicked in? My thinking was to install a small LED light, perhaps 24 volt since that's the control voltage, that would stay on if the pump didn't produce pressure after the time delay. With the current setup I wouldn't know if the protection feature kicked in and the next time the irrigation controller call for a zone to be watered the pump would start and stop again until I realized something was wrong.

Understanding the “physics” of the system operation is probably the more important piece.

What your wanting to do can be done - probably with the addition of another bypass timer and a DPDT relay - BUT, if there is a power failure the system will reset and the cycle will be repeated. This bypass timer would be set for a slightly longer period of time than what has been shown already.
If you want power outage protection I’ll see if I can find a latching relay that requires manual intervention to reset.

I’m not sure I would use a light to tell you the system is triggered - the bulb may have failed for some reason (burned out, loose in its socket, broken wire etc.), and the lockout circuit is triggered.

Thoughts?

timjet · 05-27-2022, 08:32 AM

I don't really think I need power outage protection. In the rare event we loose house power AND the pump lost its prime, the cycle would repeat and that would be OK. I just don't want the cycle to repeat every time the irrigation controller initiated watering which is a couple of times a week. I did add a light to your circuit diagram as shown below. It would flash on until the pump built pressure but that would probably only be a second. The pressure switch has a NO and NC contacts.

However I think the most useful design would be an additional relay that requires manual intervention to reset that would shut control power off to the pump start relay if the pump did not build pressure.

Another issue this may cause however is low voltage on the control circuit. I have been getting "pump fault" messages from the irrigation controller and in talks with the distributor of my controller, that apparently happens when the controller is not sending enough voltage to the pump start relay. This happens about a third of the time.

MrMark52 · 05-27-2022, 09:04 AM

Something doesn’t make sense with your pump controller - and if it’s not seeing enough current now, this circuit isn’t going to make it any better - especially after adding the light.
Usually the pump power originates with the controller. The only reason I can think of that it isn’t providing enough power is the transformer isn’t adequate. How many VA is the transformer rated for?

I agree with your light addition - I would make that a red light - and it tells you the irrigation controller is telling the pump to run but there is no pressure.
But I would add a green light to the NO/bypass relay side of the switch - it will then tell you the pump is running and there is pressure.
The red light would only flash in the moment that it takes to build pressure when the system is working properly. The “Fail-Safe” is - no lights, a) the pump controller is off, or b) the pump controller is on and the red bulb is burned out (otherwise there would be pressure and the green bulb would be lit, or it’s burned out).
And FWIW - the minimum time for the tdr is 8 secs so it’s possible the pump will run dry for 8 seconds. That shouldn’t be a problem though.

Let me think on the manual reset circuit.