Heavy duty switching relays for well pumps:

This article describes how to find, use, diagnose, install and wire-up or repair the a water pump relay switch (well pump relay).

The page top photo shows a typical wall-mounted Goulds ™ relay switch used to power a submersible well pump. The well pump relay switch is used to turn on and off higher horsepower well pumps. The pump pressure control switch operates the pump relay switch that in turn operates the pump.

Water Pump Relay Control Switch FAQs

These questions and answers about installing, troubleshooting, or replacing a heavy duty or high voltage water pump relay control were posted originally

at WATER PUMP RELAY SWITCH - be sure to see that article.

On 2018-11-02 by (mod) - well pump wont' turn on

Javed

see the diagnostics at

WATER PUMP WON'T START https://inspectapedia.com/water/Water-Pump-Wont-Turn-On.php

On 2018-05-07 by Javed ahmad

Water pump not starting

On 2017-11-30 by (mod) - pump delivers pressure that is fast then slow

Sherry try the diagnostics at WATER PUMP SHORT CYCLING - home https://inspectapedia.com/water/Short_Cycling_Pump.php

On 2017-11-30 by Sherry Adams

I have my own well & septic. My pressure in my home, doing laundry, dishes or showering goes fast then slow. (In spirts) what is the problem? Is it the relay button?0

On 2017-11-01 by Malcolm

Is there a control switch which will turn the pump off when the holding tank is full

On 2017-07-16 by (mod) - cut the well wiring, now the pump won't start

Ivan:

- the repair may be improper, mis-wired, or shorting to earth - VERY DANGEROUS could kill someone

- the short could have blown a fuse or breaker

- the breaker could itself be damaged or defective - tell me the panel and breaker brand

- the pump could have been damaged

- a separate pump control relay could be damaged or a start/run capacitor blown

On 2017-07-16 by Ivan

Cut through both the water well water pipe and the electrical connection with an auger; repaired pipe and wire and well pump would not start.

On 2016-12-30 18:54:26.098623 by (mod) -

David

Please search InspectApedia for SHORT CYCLING WATER PUMP to see the cause and cure for this problem. Check first for a water-logged pressure tank.

On 2016-12-30 04:03:23.197104 by David Markley

My relay is short cycling about every ten seconds and the pressure goes to fifty psi and drops to twenty ten seconds later and starts back up, when the water is running anywhere in the house. I don't want to get robbed by a plumber. Please tell me how to figure out the problem myself or what steps to take to diagnose the specific problem

On 2016-11-11 19:30:20.761497 by Roy

If anybody can help me it would be appreciated. I ran out of water in my holding tank and the booster pump between tank and house will
not automatically start.

I can force start with relay switch but cannot build pressure.

When I ran out of water is it possible that I may
have burnt the pump out? Motor turns on fine with force of relay but could the impellers be fried?

No water is turned on anywhere and it still will not build pressure holding contacts closed.
Thanks to anyone for helping.
Roy

On 2016-09-20 11:05:29.515682 by Andrew

The contacts were a little burned so I wire brushed them.

My next call will be the electrician to see if power is being delivered.

Does it mean anything when this only happens when water hasn't been used for an extended period of time? If we go away for the weekend, its guaranteed to happen when the pump tries to turn on at 20 psi.

Should I be contacting a well pump company or an electrician?

On 2016-09-14 02:16:23.179043 by (mod) -

We'd start by inspecting the contact points in the pressure control switch to see if they are badly burned, working.

I would also have my electrician check to see that when they switch clicks and the points close that in fact power is being delivered to the pump from the switch.

If the switch is working properly

And if there is not a separate control relay that actually switches your pump on and off,
then I would be looking for a loose wire or contact.

On 2016-09-14 00:18:49.878639 by Andrew

When my pressure switch gets to the lowest point (20 psi), I can hear the relay click, but the pump doesn't turn on and pressure drops to 0.

The relay will continue to click up to 8 times or so and then the pump will start returning the water pressure. The problem is intermittent and only happens once every couple of days usually when flushing the toilet or using the shower. What could the problem be?

On 2016-09-09 16:40:53.071210 by (mod) -

Mike search InspectApedia for WELL PUMP WON'T START to read how to diagnose and fix this.

Or for a simple diagnostic table search for DIAGNOSTIC TABLE for WATER PUMPS

On 2016-09-09 02:22:04.605568 by Mike Devereaux

My well pump will not start. I replaced the pressure control switch but it still did not start. Could the relay switch need replaced?

On 2016-04-16 16:15:47.895157 by Brad

I'm off to the hardware store for a new switch seeing they're only $25 I'll replace it and go from there..

As far as the well running dry I have had it run out of water before and every few months when my water pressure gets low I'll have an orange tint to my water.

Thanks for the advice and fast responses I'm sure I'll have more questions along the way

On 2016-04-16 16:08:31.073544 by (mod) -

Brad,

Indeed it makes sense that if one faucet is out of water they all will be, as you're probably in a house served by a single water supply source.

Flipping the side handle on the pressure switch is perhaps re-setting a pump protection control circuit intended to keep from burning up the pump when the water level in the well is so low that the pump either runs continuously or runs dry.

A delay before you turn the switch back on gives a little time for the water level in the well to recover.

So I suspect that either the well is failing OR there is a failure in the pump motor, wiring, or switch. Your well expert can do some test such as measuring current draw by the pump that can help diagnose a pump or switch or wiring problem.

But the fact that the pump can't get above 10 psi, points to what I suggested before: low water, bad pump, or bad pipe leak; If you have not CHANGED the pressure settings of the switch it doesn't sound as if the switch itself is the problem.

On 2016-04-16 16:03:23.542250 by Brad

The past few days I've ran out of water on every faucet in my house.

When it happened I would go the the relay flip the handle on the side to reset it and it would work again now about a week later it happened again so I flipped the switch and the pressure went from 0 psi up to 10 and that's it.

I tried to run water from my sink and it slowly trickled out and stopped now it's not building pressure at all. Any ideas? And thank you for the quick response

On 2016-04-16 12:13:11.897949 by (mod) -

Brad, I don't have a clear idea of your situation: if the pump runs but can't build water pressure above 10 psi I suspect that either the well is out of water or the pump impeller assembly has been damaged

If pressure falls after the pump turns off I'd look for a burst or leaky well pipe.

Only if someone very badly mis-adjusted the pressure control switch would it turn the pump off at such a low pressure. That seems unlikely.

On 2016-04-16 04:08:13.813121 by Brad

I'm trying to figure out if I need a new relay switch or pump. First I checked the bladder tank for air by pushing the valve stem in a little an it seemed fine I tried to reset the breaker to my pump but nothing happened my water pressure was building to 10 psi but now nothing. Any ideas or suggestions would be greatly appreciated thanks

On 2015-03-19 16:54:35.878180 by (mod) -

Darwin

IT sounds as if we need an onsite electrician with a DMM or VOM to perform the appropriate electrical tests. Meanwhile for safety I'd turn off the equipment.

I can't guess from your note if the problem is a bad switch, shorted wires, or a well pump motor that has seized. Some simple voltage and current measurements can help sort that out.

On 2015-03-19 00:55:25.202000 by Darwin

I changed the pressure switch because it was sticking when i put power to it the relay box will hum then go off and the pump will not come on how can i find out if the relay is bad

Question: Pump motor capacitor blows up

(July 6, 2011) RJ said:

The capacitor in my well head control box for my submersible pump at my home was replaced 2 months ago. Last night the new capacitor blew it's top off.

There was an electrical burn mark on the inside of the control box near the lead connections at the capacitor. I purchased and installed a new capacitor this morning.

After 3 hours of lawn watering my wife reports that the water is off again. I can only guess it is the capacitor again. What would cause this and how do I repair it?

Reply:

I am SPECULATING that the unit was wired improperly or there is a short in the system;

Also see CAPACITORS for HARD STARTING MOTORS

Question: can the pump relay switch control a well pump that is quite far away?

(June 7, 2012) Shane said:

Should a well pump relay switch be used to control the power supply to the pump when the power supply to the pump is quite far from where the pressure tank and pressure switch are?

In our situation, water is supplied from well to pressure tank located in house about 60 meters away.

Power to well pump supplied from garage, which is 10 meters away from well. We want to install relay switch in garage next to electrical panel and run signal wire from pressure switch on pressure tank (in house) to trigger relay switch in garage based upon pressure in tank. Subersible pump is older 240 volt 2 wire (plus ground) variety.

Reply:

Shane, the well pump relay switch is usually located quite close to the pressure control relay switch and is installed for higher horsepower pumps that draw higher current - as a way to extend the life of a pressure control switch not designed to handle heavy switching loads.

The problem of distance among electrical controls, switches, relays, and the well pump itself are handled by choosing the proper wire size or gauge as per tables in the NEC.

To avoid overheating an electrical wire when the run is quite long, a larger sized wire may be required.

Question: pump pressure switch keeps burning up

[delete] (June 29, 2012) Mark said:

After reading your page I have the same problem some have. My pressure switch keeps buring up after some us. I need to get a relay switch installed for my above ground water well pump.

The water well pump is 120v. Where can I buy a relay switch for the water well pump?
Mark

Reply:

Mark, plumbing suppliers and well equipment suppliers and some electrical supply houses have well pump relay switches.

But on a 120V above ground pump - I imagine it's a one line or two line jet pump - I wouldn't expect you to need a separate control - those are used when the pump hp is a high amount.

Check to see if your pump can be rewired to run on 240V - it would run better and easier and draw less current which could save your pressure control switch.

Check for low water or damaged pump impeller or a bad pressure control switch - that means the pump relay switch never turns off.

Reader follow-up

Hi, thanks for the reply to my comments. Yes its a flotec 2 line get pump. Pressure switch draws 14 amps. Breaker is a 20 amp 120v system .

Pressure switch burning up especially when pump cycles off /on watering grass etc. Relay switch must help out. Will get electrician to quote converting service to 240v but for now relay switch is what i need, Correct?

Reply:

Mark, not necessarily; short cycling of the pump can burn up switch contacts; I'd be sure that the pressure tank is not waterlogged; And I wouldn't buy a relay switch before I knew what other wiring and voltage changes might be in store.

Question: no water pressure, contacts closed, humming noise

(July 18, 2012) Scott said:

Mark-I have no pressure it is below the cut-in. The contacts on the control switch are closed, when I turn on the breaker there is a hum at the relay switch but no clicking noise. How do I test for a short in the submersible? Or a problem with the relay? thank you

Reply:

Check for electrical power first.

Humming suggests you have power - TURN IT OFF. Something is jammed or burning up, probably a stuck relay or a bad pump motor.

See ELECTRIC MOTOR DIAGNOSTIC GUIDE

Watch out: a submersible pump can be running and you won't know it unless your pump relay includes diagnostic lights or a display. Be sure that there is a pressure relief valve on the water tank lest it burst.

Question: short cycling pump control diagnosis - Costa Rica

(July 20, 2012) A.L. clueless said:

chain of events... short cycling, then the pump shut off, hit the button and again short cycling.

Lasts for a few days, then no water to the house, red button keeps popping when power is turned on to pump, tank has water (not much) on floor, realizing the tank it totally full, opened pipe and released all water, now no power to pump, relay switch pops within seconds .....suggestions?

Reply:

Perhaps the waterlogged water pressure tank that is causing pump short cycling is also overheating the pump motor?

See WATER PUMP SHORT CYCLING DIAGNOSIS TABLE

Question: does it matter what sort orf pump controller I use?

(Aug 9, 2012) Dropframe said:

I have a 240v pump. Does it matter whose pump controller I use? What voltage is required to turn the pump on and off via the controller? I have a water tower that the pump fills. I want to make it automatic with a new pump controller and auto level sensor in tank.

Reply:

No Drop, I don't think so as long as the ampacity and voltage wiring are all correctly matched you can use any of a variety of pump pressure control switches and relays.

I can't answer your voltage question - it depends on your pump motor and how it's wired: for 120V or 240V.

The pressure control switch from most mfgs can also be wired at either voltage level.

(Aug 12, 2012) Dropframe said:

I guessed that they would have a control voltage, like 12volts that triggers the pump controller to turn the pump on.

So if I get an auto level sensor,(which usually gives a low voltage output) you are saying it would need to be connected to an external relay that sends 120v 0r 240v to the pump controller which then turns the pump on.

Is the voltage thru this external relay the voltage that actually powers the pump? (My pump is 240v)

Reply:

Drop.
The pressure control (usually 120v tho some can run 240v) on your system as you describe it is used to switch a heavier duty pump relay that in turn powers the pum from a power feed brought into that relay box, not thru the pressure switch.

Bottom line, the discussion indicates that you should ask for onsite wiring by a licensed electrician.

(Aug 18, 2012) Dropframe said:

Two things. A licensed electrician is not something you find in rural Costa Rica. (electricity here is just like the USA 110/60hz normally with 220v for my well pump)

My system does not have a pressure switch. It is a gravity feed from a water tower. The pump fills the tower and and gravity supplies the water pressure. According to the way I read your comment, the current to trigger the pump controller could be either 110 or 220. That seems excessive to just trigger a relay. Are you sure?

Reply:

About "licensed electrician" the intent is to find someone with some training so that nobody gets electrocuted.

"Current" is amps not volts. Pump controllers are wired as 110V or 220V depending on the supplying circuit voltage level which in turn is of course matched to the type of pump motor (110 or 120V). Some motors are convertible.

For smaller horsepower well pumps the pressure control switch handles the whole job as the current draw (amps) is not more than the pressure switch can handle.

For higher horsepower well pumps the pressure control switch contacts will burn up or the relay will burn up under the high current flow, so the design changes: we use the pressure control switch to operate a heavier-duty separate pump relay switch (the subject of the article above on this page). The pump relay then turns the pump on and off.

Dropframe: in my original reply that I just located I said something similar to the edited reply above:

Typically an above ground well pump is small enough HP and amperage draw that it is switched by a pressure control switch - the switch is operated by water pressure and opens or closes a relay to turn the pump on and off. That switch may be wired for 120V or 240V depending on what the pump calls for.

For higher HP submersible well pumps and for some high horsepower above ground pumps, because the switch I just described is not meant for heavy current loads, the pressure control switch at the water tank is used to operate a separate heavy duty pump relay control like the one at the top of this page - that in turn operates the pump.

Sure you could operate the first pressure control relay in this case with low voltage but the most common switch operates at 120V.

I appreciate that you don't have an expert (licensed) electrician in rural Costa Rica - having spent time there myself. But my caveat had as its underpinning thought, the concern that if you don't know what you're doing you could make a mistake and kill yourself.

Question: pump relay won't switch on

(Sept 6, 2012) Leigh said:

no water so I put in a new pump pressure switch but still no water. The switch is working but the relay switch didn't make it's normal click. My plumber friend says that means the pump is shot, but wouldn't the relay switch on even if the pump was no good?

Reply:

Leigh:

Yes, the pump relay is an independent assembly from the pump itself, and would "click" on (or off) to try to turn a pump on or off regardless of whether or not the pump was operable. However, if a pump motor failed with a dead short, that might ultimately also impact a relay switch.

It's easy and inexpensive to try swapping in a relay switch. But first check the water pressure in the pressure tank and run water to drop the pressure below the cut-in pressure set at the switch so you're sure the switch should be calling for the pump to turn on.

Question: fusing for pump relays

(Feb 10, 2013) Unknown Person said:

Does a pump relay switch have a fuse in them by any chance?

Reply:

The pump relays I'm familiar with are protected by a separate fuse or circuit breaker.

Question: how to test that the pump relay switch is working - how do I test the pump relay?

(Aug 5, 2012) High and Dry said:

How do you test to see if the Pump relay switch is bad vs. the pump being bad? I'm getting full power to the the relay.

And I have full power at the well head, from the relay, feeding the pump wires.....bad pump???

(Feb 10, 2013) Anonymous said:

First off, when the contacts are connected the pump kicks in and when they kick back the pump shuts off right? Assuming that is correct and replacing the pressure switch isolated the problem to either pump relay or pump, should the pump relay make an audible sound as it trys to turn the pump on? Would testing the wires as they come out of the relay box en route to the pump and finding power confirm that the problem is the pump?

Reply:

H&D, sounds as if your pump is not pumping; your well company or plumber will probably use a VOM to check resistance and current draw to see what's going on with the motor.

Anon, you are right: when the pump relay pulls "in" the contacts are "made" the circuit switch is "closed" and current can flow, so the pump motor runs.

Pump relays and their activating little brother, the pressure control switch usually involve a mechanical relay. Typically we hear a little "click" when the relay makes or closes, and if there is no other louder ambient noise we'll hear another little click when the relay opens. Or not. Some switches are a bit quiet.

Some pump relays include indicator lights so that we know when the relay thinks the pump is (or should be) running and some models are much more sophisticated and monitor currrent draw, telling us helpful information such as

• The pump is running dry (low current)
• The pump is running and pumping (normal current draw)
• The pump is in trouble and binding (high current draw or a developing short)
• The pump is off (no current draw)

If you know how to use a VOM or DMM safely you can indeed check for current flow on the wires leaving the pump relay and controlling the pump.

Question: chattering pump control switch

4/29.2014 pete said:

My well pressure switch is chattering when the pump is called to turn on why is it doing that ?

Reply:

Pete

Check first for a clogged filter or closed valve blocking water output from the pump causing rapid on off cycling.

If that's not the problem I suspect burned contacts in the relay - time for a new pump switch, though I suppose low voltage or a loose connection could also be at fault.

Question: missing relay switch? Pump not working properly?

(June 3, 2014) Carol said:
I have a neighbot that bought a home in need of a lot of repairs. One of their complaints was very low water pressure. Since we are on a well system too, we offered to take a look at their setup.

The previous owner did not or could not tell the current owners where the actual well is located.

Upon inspection we could see the wiring from the pump coming into the basement. Black/red/white but no visible ground.

Apparently at some point there had been a relay installed but we found it laying aside not connected at all. The wires coming from the pressure switch were straight connected to the pump wiring...again...with no relay installed. The pressure switch was reading about 18. With water turned on in the house the pressure would slowly drop but a cut in point was never reached.

Once the water was turned off the pressure would build back to about 18. One of their relatives had checked the air in the pressure tank but didn't drain it befoe checking.

It's our understanding it needs to be empty and set 2 psi below cut-in on pressure switch. Now, we are thinking there are multiple problems, obviously, with this setup. One being that the line going into the pressure tank is connected with a washing machine hose...

Oh my Lord!! Anyway, is it possible if we verify the pressure tank psi, after emptying it, and install a new pressure switch that this will raise their water pressure?

One of them did order a new capacitor for the relay (that's not installed). The relay has Black, Red, Yellow/Line 2, Line 1 with a red(trip?) button on it. We are not familir with the wiring for this since ours is a 2-wire pump. And the wiring from their pump is, as mentioned before, red/black/white.

Reply:

It sounds as if someone abandoned a relay intended to turn the pump on and off. The relay in turn would have been operated by the reassure switch. Sounds like a 240V pump circuit. If so idnot expect the relay to last long.

Pressure at the tank is indicated by a pressure gauge mounted on the tank tee or nearby.

If you drain the tank completely tats a fair starting point to get hings inning.

The installation sounds such a mess it may be unsafe. I'd prefer to hear that you brought in an experienced professional plumber.

Don't forget to include a pressure relief valve too.

(June 4, 2014) Carol said:

I totally agree this setup is a mess.

Question: If we turn off all power to the pump, drain the pressure tank and check its psi, adjust pressure, install a new pressure switch, that this would possibly provide them with more water pressure until they can afford an experienced plumber?...

as they are limited on funds right now. Also, if I understand things correctly, since this is apparently a 3-wire pump, shouldn't there be a relay installed?

I was a little confused at your response about the relay not lasting long....please forgive my ignorance on this. I/we wouldn't attempt to install it ourselves for sure as it needs to be like you said an experienced professional plumber.

Question: sparking pressure switch contacts

(Oct 10, 2014) Alison said:
I have a well pump connected to a relay switch, connected to a pressure switch with 2 wires (plus ground).

I recently had to replace the pressure switch because the terminals were sparking (arcing?), usually at cut-off. It wore down the terminals to the point where the switch wouldn't make a connection.

I replaced the switch, checked and recharged the pressure tank to it's pre-charge (38psi - it had fallen to near 0 psi. ? ), and adjusted the pressure switch accordingly to 40/60psi.

Initially things looked good, but after a few cycles, the new pressure switch contacts were sparking. What should I check next?
Thanks in advance,
Alison

Reply:

Dirty contacts, improper voltage, loose connections, or a damaged or loaded well pump drawing high current.

...

Continue reading at WATER PUMP RELAY SWITCH or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• PUMP CONTROL STATUS INDICATORS
• CHATTERING RELAY CONTROL SWITCHES
• WATER PUMP PRESSURE CONTROL SWITCH

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