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A 30/50 well pressure switch can often be adjusted to 40/60 PSI, but only if the switch, pump, pressure tank, relief valve, and plumbing are all suitable for the higher pressure.
The main change is simple: the pump would start at about 40 PSI instead of 30 PSI and stop at about 60 PSI instead of 50 PSI. However, raising the switch setting without checking the rest of the well system can cause poor pump operation, rapid cycling, or a pump that cannot reach the new shutoff pressure.
What 30/50 and 40/60 Mean
A well pressure switch controls when the pump starts and stops.
With a 30/50 switch:
- 30 PSI is the cut-in pressure. The pump starts when pressure falls to about 30 PSI.
- 50 PSI is the cut-out pressure. The pump stops when pressure reaches about 50 PSI.
With a 40/60 setting, the pump starts at about 40 PSI and stops at about 60 PSI.
Moving from 30/50 to 40/60 gives the house higher water pressure throughout the pump cycle. It does not make the pump produce more water.
Can a 30/50 Pressure Switch Be Adjusted to 40/60?
Many common mechanical well pressure switches are adjustable enough to make this change. But you should check the instructions for your exact switch before adjusting it.
For example, Schneider Electric's Square D Pumptrol switches use a larger range adjustment and, on models with two adjustments, a smaller differential adjustment. Schneider says the larger adjustment changes the operating range, while the smaller adjustment changes the difference between cut-in and cut-out pressures. Power should be disconnected before making adjustments.
Do not assume every switch works the same way. Some switches have one adjustment spring, some have two, and electronic controls may use a completely different procedure.
If the switch's listed adjustment range does not include 40/60 PSI, replace it with a switch designed for that pressure range rather than forcing the adjustment.
Check the Pump Before Raising the Pressure
This is one of the most important checks.
Your well pump must be able to reach 60 PSI under actual operating conditions. A pump that could comfortably reach 50 PSI may have much less available flow as pressure rises.
Pump performance depends on head height. Head height is the total resistance the pump has to work against. It includes:
- The vertical distance the water must be lifted
- Pressure required at the pressure tank
- Friction through pipe and fittings
- Filters and treatment equipment
- Other restrictions in the water system
Check the pump's performance curve or specifications if possible.
If the pump cannot reach the new 60 PSI cut-out setting, it may run continuously while trying to satisfy the pressure switch. That can overheat or damage equipment.
A pump that struggles to reach 60 PSI is not a good candidate for a 40/60 setting.
Check the Pressure Tank Rating
The pressure tank also needs to be suitable for the higher pressure.
Look for the tank's maximum working pressure on its label or documentation. Do not operate the tank above its rated pressure.
Also inspect an older tank before adding more air or raising system pressure. Significant corrosion, damage, or unexplained loss of air should be investigated rather than simply repressurizing the tank.
The system should also have an appropriately rated pressure relief valve. Pressure tank manufacturer Amtrol calls for a properly sized relief valve as part of a well system installation.
The Tank Precharge Must Change Too
If you change the pressure switch from 30/50 to 40/60, you normally also need to adjust the air precharge in a bladder or diaphragm pressure tank.
Precharge is the air pressure inside the tank when there is no water pressure acting against the tank's bladder or diaphragm.
A common manufacturer recommendation is to set precharge about 2 PSI below the pump's cut-in pressure.
That means:
| Pressure switch | Typical tank precharge |
|---|---|
| 30/50 PSI | 28 PSI |
| 40/60 PSI | 38 PSI |
Amtrol specifies a 38 PSI precharge for a 40/60 system and says the tank must be empty of water when the precharge is checked or adjusted.
Do not check the tank's true precharge while the plumbing system is still pressurized. Water pressure inside the tank will affect the reading.
Before You Adjust the Switch
Check the whole pressure system first.
Make sure:
- The pressure switch is adjustable to the desired range.
- The pump can comfortably reach more than 60 PSI.
- The pressure tank is rated for the higher pressure.
- The relief valve is correctly rated and working.
- The pressure gauge is trustworthy.
- Filters, water heaters, treatment equipment, and other connected components are suitable for the higher pressure.
- There are no major leaks or plumbing problems.
If the system currently struggles to reach 50 PSI, changing the switch to 40/60 will not solve the problem. Find the cause of the low pressure first.
Possible causes include a worn pump, clogged filter, restricted pipe, failing pressure tank, incorrect switch setting, low well-water level, or another system problem.
How a Typical Mechanical Switch Is Adjusted
The exact method depends on the switch, so follow the manufacturer's instructions.
On a common two-spring mechanical switch, the larger adjustment usually moves the operating range. The smaller adjustment changes the difference between the cut-in and cut-out pressures.
Examine replacing a 20-40 pressure switch with a 30-50 to compare delivery behavior when suction head is inadequate.
For Square D 9013FSG switches, Schneider Electric says to adjust the range first and the differential second. Turning the range nut clockwise raises the cut-in setting. The differential adjustment can then be used to change the cut-out setting. Schneider also recommends checking switch operation several times after adjustment.
Do not rely on a guessed number of turns of the adjustment nut. Spring calibration varies by switch.
Instead, make small adjustments and verify the actual cut-in and cut-out pressures on the system gauge.
Work Safely Around the Pressure Switch
A well pressure switch contains exposed electrical terminals when its cover is removed.
Shut off power to the pump circuit before removing the switch cover or touching the adjustment mechanism. Verify that power is off using appropriate electrical testing equipment.
Make adjustments with the circuit de-energized. Replace the cover before restoring power to test the pump cycle.
If you are not comfortable working around line-voltage electrical equipment, have a qualified electrician or well-pump professional make the adjustment.
Test the New Setting
After adjusting the switch and tank precharge, run several complete pump cycles.
Open a faucet and watch the pressure gauge.
The pressure should fall until the pump starts near 40 PSI. Then close the faucet and allow the pump to build pressure. It should stop near 60 PSI.
Do this several times.
Watch for:
- Pump starting near 40 PSI
- Pump stopping near 60 PSI
- No rapid on-and-off cycling
- No long struggle to reach 60 PSI
- No unusual pressure spikes
- No leaking fittings
- Steady water flow around the cut-in point
Schneider specifically recommends checking switch operation several times after an adjustment.
If the pump runs for an unusually long time as it approaches 60 PSI, return to the previous setting and determine whether the pump is capable of operating at the higher pressure.
Will 40/60 Give You Better Water Pressure?
Usually, yes.
A 40/60 system keeps household pressure about 10 PSI higher than a 30/50 system throughout the pressure cycle. Showers and faucets may feel stronger, especially when system pressure previously fell close to 30 PSI before the pump started.
But pressure and flow are not the same thing.
Flow rate is how much water moves through the system, usually measured in gallons per minute. Raising the pressure switch setting does not increase the amount of water your well can supply.
A restricted pipe, clogged filter, undersized line, or low-producing well can still give poor flow even with a 40/60 switch.
When You Should Not Change to 40/60
Keep the lower setting or have the system inspected if:
- The pump already takes a long time to reach 50 PSI.
- The pump specifications do not support the higher pressure.
- The pressure tank has significant corrosion or damage.
- The tank or other equipment has an inadequate pressure rating.
- The pressure gauge does not work reliably.
- The pump short-cycles.
- The switch is badly corroded or worn.
- The system has unexplained pressure problems.
A pressure-switch adjustment should fine-tune a healthy well system. It should not be used to hide a pump, tank, plumbing, or well problem.
Frequently Asked Questions
Do I need a new pressure switch to change from 30/50 to 40/60?
Not always. Many mechanical well pressure switches have an adjustable range that can cover both settings. Check the model's instructions and pressure limits. If 40/60 is outside its allowed adjustment range, install the correct switch instead.
What should my pressure tank be set at for a 40/60 switch?
For many bladder and diaphragm well tanks, the recommended precharge is 2 PSI below the cut-in pressure. That makes the typical precharge about 38 PSI for a 40/60 system. Check the tank manufacturer's instructions.
Do I have to drain the pressure tank before adjusting its precharge?
Yes. The water side of the tank should be depressurized and emptied before checking or setting the true air precharge. Amtrol specifies checking precharge with the tank empty of water.
Will changing from 30/50 to 40/60 hurt my well pump?
Not if the pump and the rest of the system are designed for that operating pressure. However, a pump that cannot comfortably reach 60 PSI could run too long or fail to shut off. Check the pump's pressure capability before increasing the setting.
Does a 40/60 switch increase water flow?
Not directly. It increases the pressure range at which the system operates. Actual flow still depends on the pump, well output, pipe size, restrictions, elevation, and water-use demand.
Why won't my pump reach 60 PSI after adjusting the switch?
The pump may not have enough pressure capability for the new setting. Other possibilities include a clogged filter, pipe restriction, worn pump, low well-water level, leak, inaccurate gauge, or incorrectly adjusted switch. Do not allow a pump to run continuously while trying to reach an unattainable shutoff pressure.
Can I adjust the pressure switch while the power is on?
Do not work on the adjustment mechanism with exposed energized electrical parts. Disconnect power before removing the switch cover or making adjustments. If you are not comfortable working around line voltage, use a qualified professional.
