DC valve control based on AC boost pump on/off state

Thread Starter

lonex00

Joined Jun 24, 2021
9
I am trying to acquire the hardware needed to implement a valve shut off solution. We have a 220 volt boost pump that controls water pressure. We need to trigger a low volt sprinkler type valve to close when the boost pump is running and open when the boost pump is off. Any ideas and solutions with regards to the hardware, relays etc required in order to accomplish this would be very helpful.
Thanks
 

MaxHeadRoom

Joined Jul 18, 2013
23,381
Simple relay across the pump motor (parallel). to switch the valve on at the same time.
Relay with 220vac coil, SPST or SPDT contacts, minimum.
What voltage and current for the valve?
 

Thread Starter

lonex00

Joined Jun 24, 2021
9
Thanks for the reply MaxHeadRoom.
The voltage for the valve is actually 24vac and 0.2 amps. I thought originally is was going to have a transformer to dc but that is not the case.
 

MaxHeadRoom

Joined Jul 18, 2013
23,381
So you will need a 24vac source for the valve?
Where are you located?
In some places hardware stores carry small transformers that may do the trick, I assume you are in a country where the normal supply is 220v?
 

Thread Starter

lonex00

Joined Jun 24, 2021
9
Yes we would need the 24vac source for the valve which I figured would be a transformer and originally thought it was to dc but that isn't the case. We have a 120v 20 amp wall outlet that we can plug the transformer into. I am located in Canada. Sorry the boost pump power supply is 240v not 220v.
 

Thread Starter

lonex00

Joined Jun 24, 2021
9
what do you have for a pump motor contactor. They frequently have allowance for aux contacts.
We have a Pentek Intellidrive. I will take a look at the manual and see if it can all be accomplished from there. There are a number of unused contacts so it may be an option.
 

LowQCab

Joined Nov 6, 2012
798
It seems that nobody asked about "the Sprinkler-Valve".
What does it do.
Does the Valve open or close when powered ? Many Valves are available with operation either way.

If You use a Valve that Closes when Powered, all You need is a Transformer, and zero other parts.

Does the Valve need to Close before the Pump starts, and Open after the Pump Stops ?
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Thread Starter

lonex00

Joined Jun 24, 2021
9
It seems that nobody asked about "the Sprinkler-Valve".
What does it do.
Does the Valve open or close when powered ? Many Valves are available with operation either way.

If You use a Valve that Closes when Powered, all You need is a Transformer, and zero other parts.

Does the Valve need to Close before the Pump starts, and Open after the Pump Stops ?
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This same thing had just occurred to me as I was looking into the contactor and relay. I will have to connect the one I have to the sprinkler controller and test to see if it opens when powered or closes when powered. I would prefer to have it close when powered as the open state would be the state it would be in for the majority of the time. I will look into getting a valve with that configuration if the one I have is not that type. Thanks for that tip.
 

MaxHeadRoom

Joined Jul 18, 2013
23,381
All the irrigation valves I have used are N/C, i.e. open under power.
Do you have 120v available also?
If so, Home Depot have a variety of transformers, one I believe is 24v.
 

Thread Starter

lonex00

Joined Jun 24, 2021
9
All the irrigation valves I have used are N/C, i.e. open under power.
Do you have 120v available also?
If so, Home Depot have a variety of transformers, one I believe is 24v.
Yes I have 120v available as well. I am now researching to find a suitable electronic valve that is normally open. Once I find that, then a transformer seems it would solve it.
 

MaxHeadRoom

Joined Jul 18, 2013
23,381
Yes I have 120v available as well. I am now researching to find a suitable electronic valve that is normally open. Once I find that, then a transformer seems it would solve it.
I suspect you may have a problem for a irrigation style, as when used it would be permanently open in the even of a power failure.
 

Thread Starter

lonex00

Joined Jun 24, 2021
9
I suspect you may have a problem for a irrigation style, as when used it would be permanently open in the even of a power failure.
Good point. In our case though, it is ok to be in the open position during a power outage. I am isolating a submersible well pump from a gravity fed boost pump system. So the goal here is to stop the submersible pump from running when water is being used and the boost pump is running.

By closing the valve when the boost pump runs (which I thought I could use a sprinkler type valve that I already have), it will allow the pressure to build and the pressure switch will shut off the main submersible well pump. We have a 2500 litre holding tank to draw from. I have found that in rare occasions under certain circumstances the boost pump creates enough low pressure in the line that the pressure falls below the safety tolerance of the well pump and trips its breaker which has to be manually reset. This happens maybe once per month and a bit more often during peak watering time in the summer which is pretty annoying. If I only allow the well pump to run and refill the main holding tank while the boost pump is off, then this problem will be resolved. In the event of a power failure, no pumps will be running and we just have lower pressure gravity fed water so it won't matter if that valve is in the on or off position at that time.
 

LowQCab

Joined Nov 6, 2012
798
I would run the Submersible-Pump directly into the Holding-Tank and
let the Boost-Pump do all of the maintenance of adequate System-Pressure.
This would give you unlimited Water, and the Pumps won't get into a fight with each other.

If your Holding-Tank doesn't hold Pressure, (ie vented), then You can control the
Submersible-Pump with a Washing-Machine Water-Level-Switch, they usually
turn Off when there's around 24" of Head-Pressure above the Switch.
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Thread Starter

lonex00

Joined Jun 24, 2021
9
I would run the Submersible-Pump directly into the Holding-Tank and
let the Boost-Pump do all of the maintenance of adequate System-Pressure.
This would give you unlimited Water, and the Pumps won't get into a fight with each other.

If your Holding-Tank doesn't hold Pressure, (ie vented), then You can control the
Submersible-Pump with a Washing-Machine Water-Level-Switch, they usually
turn Off when there's around 24" of Head-Pressure above the Switch.
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I would but in my brilliance (now not so brilliant) I was able to use the same pipe to feed the tank from the well as I used to gravity feed back to the pressure side. Using a one way check valve at the top and a T to feed the float line in the tank. This saved about 500 ft of extra piping. It seemed like a solid design and works like a charm for the most part but in the rare circumstance, something with having the boost pump sucking water down the pipe that the well pump is pushing up to feed the tank causes the issue. It's rare but still happens every month or so. I figured the best solution is to simply stop the well pump from trying to feed the tank when the boost pump is boosting water usage. Being that the water is mostly not running and the tank is very large, there should never be an issue of running out of water because we would never need to use the entire 2500 litres.

I think the best solution for this will be to install a normally open solenoid valve that is powered by a single leg of the boost pump. At least that is where I am at right now. Something like this https://www.amazon.ca/Normally-110V...ally+Open&qid=1624566819&s=industrial&sr=1-12

The boost pump kicks on, valve closes (mimicking the float closing), main well pump builds pressure and the pressure switch shits off the well pump. Then when the boost pump turns off, the solenoid valve opens and if the float says the tank still needs water, the well pump kicks back in and keeps filling.
 

LowQCab

Joined Nov 6, 2012
798
Your Holding Tank is 500ft from the point of use ?????? Damn !!! That's a lot of restrictive Pipe !!

Seems to me that you could just disable Power to the Submersible-Pump when the Boost-Pump starts.
You probably don't need any extra Valve, just a Relay.

How far apart are the Pumps ?
Where does each Pump get its Power,
and how long are the individual runs to the Panel(s) ?
Do the Pumps operate from Standard-Motor-Starter(s) ?
Most Motor-Starters are designed to accept an add-on SPDT "Pilot-Duty-Switch"
which would do a fine job of turning Off the Submersible-Pump.

But before I get to far down the Rabbit-Hole .............
You say that you have a " Pentek Intellidrive",
is this on one Pump, or both Pumps ?

Have you actually measured the Current being drawn by the Submersible-Pump
when it is running at the same time as the Boost-Pump ?

Is this a Motor-Starter that is tripping ?, or a Circuit-Breaker ?

What is the Max-Current allowed for the Submersible-Pump ?,
is this Current level actually being exceeded ?

You may have an incorrectly sized "Heater" in your Motor-Starter,
or, if it's controlled by an Electronic-Control-Box,
the Current-Setting-Adjustments could be unnecessarily conservative.
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Thread Starter

lonex00

Joined Jun 24, 2021
9
The system has worked great for years but the holding tank is the new component. We are using 2" line so the restriction is minimal for the length. I would consider installing a relay and shut the power off to the well pump when the boost pump runs but the problem with that is that the pressure tank that is on the well side that's controlled by the tank float would then discharge all of it's water into the tank and the pressure would drop too low in the line. If the pressure drops below 40 psi, it has a safety protection feature that trips the pump. (This is the same safety feature that periodically trips that we are trying to resolve). So if we don't have a valve to close and pressurize the line (imitating the float), the pressure tank will discharge the water into the tank and the pressure would drop below 40 and trip every time.

The well pump pressure switch cycles on at 40 psi and off at 60 psi. The boost pump is a variable boost that maintains pressure at 60 psi. My best hunch is that in some scenarios, I think when conditions are just right for example, all water is off, the pressure on the well pump side is sitting just above kick in at 41 psi. Someone flashes on the main 3/4" garden hose full blast and maybe some plumbing fixtures turn on as well at the same time. For a brief second, the boost pump draws a massive haul on the line and causes a quick drop in pressure of 3-4 psi. That puts the well pump pressure line to 37-38 psi and causes the safety feature to kick in and well pump has to be manually reset. That or when the boost pump ramps up, it creates such a low pressure in the line that when the well pump kicks in, it spins up too fast and the system senses that the well pump may have run dry and the safety feature kicks in. Almost like it is sensing a false line break or something because of the effect of the boost pump.

I measured the current on the well pump when the system was reconfigured and it was what was to be expected. I can't remember if I tested it when the boost pump was running as well. I will do that and see if there is a noticeable difference. The Pentek Intellidrive is on the boost pump and that is the brain that controls pressure for the system on the user side. The well pump has a pump tech control box and the safety switch which I believe it is more like a thermal circuit breaker. I can't be sure what the max current for the well pump is as we have never pulled it from the well to verify anything. I am only going by the information passed on to us and the main breaker sizing in the panel of 20 amp and the #12 wire used for the pump.

The pumps themselves are about 300 ft apart if you consider the one down the well 175 ft. The well pump line comes up and then Ts. One side goes over to the well house that holds the pressure tank and all of the controllers and the other boost pump. The other end of the line goes up to the tank. Just before the pipe connects to the tank, there is a another T and a one way valve. The one way valve is at the dischage of the line so that the boost pump can draw when needed. The other line goes into the tank and up to the top where the float is. It may just be this line that is pressurized by the well pump and utilized as the inlet side of the boost pump that is causing some issues.
 
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LowQCab

Joined Nov 6, 2012
798
A Picture would work much better, but anyhow, this is my next consideration.

"WATER-HAMMER"

It's fine that You don't have much flow restriction because You used a 2" Pipe,
but ~500-ft of it weighs a lot.
That 2", 500-foot-long-pipe holds roughly ~680 pounds of Water,
and once you get it moving, it doesn't want to stop.

This can cause all sorts of weirdness,
and could even cause rapid oscillations,
causing a start-stop-start-stop-start-stop cycle that continues until some
safety device shuts-down the Power.

"Several" Surge-Tanks along the various Route(s) will probably solve all your problems.
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