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Pentair Pool Heater ERR PS Error: Pressure Switch Fault on IntelliFlo Models

Quick Answer

ERR PS on Pentair pool heaters is the pressure switch fault displayed on IntelliFlo and newer panel models, functionally identical to the E05 code on older MasterTemp LED displays. Low pool pump flow rate is responsible for nearly half of all ERR PS faults. A clogged filter, open bypass valve, or failed pressure switch account for the rest.

ERR PS on Pentair pool heaters is the pressure switch fault displayed on IntelliFlo and newer panel models, functionally identical to the E05 code on older MasterTemp LED displays. Low pool pump flow rate is responsible for nearly half of all ERR PS faults. A clogged filter, open bypass valve, or failed pressure switch account for the rest. Verify the pump is running at heating-speed RPM before replacing any parts.

PentairPoolheaterSeverity: highDifficulty: intermediate80% DIY Success
Time to Fix
20–90 min
Difficulty
intermediate
Parts Cost
$25 – $60
Tools Needed
Multimeter, Pool pressure gauge
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low water flow lockout
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What Does the ERR PS Code Mean?

ERR PS is the IntelliFlo-era display version of the E05 pressure switch fault - low water flow or a failed switch.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Pool pump running at too low an RPM to achieve minimum flow through heater40%
Clogged pool filter increasing system resistance24%
Heater bypass valve open or partially open14%
Air trapped in the plumbing upstream of the heater12%
Pressure switch failure10%

Symptoms You May Notice

  • ERR PS displayed on heater panel
  • Heater locks out immediately on heat attempt
  • Heater ignites briefly then shuts down with ERR PS
  • ERR PS appears on the IntelliFlo pump display or automation controller

Can you reset a Pentair poolheater to clear the ERR PS code?

After resolving the flow issue or replacing the pressure switch, soft reset the heater by pressing ON/OFF, waiting 30 seconds, then pressing ON. If running IntelliFlo integration, also verify the pump program assigned to heating mode is at the correct RPM in the IntelliFlo or EasyTouch controller.

Tools Required for Diagnosis

MultimeterPool pressure gaugeScrewdriver set

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

1

Check the variable-speed pump RPM while the heater is calling for heat

Check the variable-speed pump RPM while the heater is calling for heat. The pump must be at a speed sufficient to deliver 20+ GPM through the heater - for most installations this is 2,400 to 2,800 RPM.

2

Read the filter pressure gauge

3

Confirm the heater bypass valve is fully closed

4

Listen and watch the heater inlet sight glass (if present) or

5

With the pump running at heating speed

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
Pressure switch42001-0060S · $25–$60

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs
Labor Approach
Our Verdict
REPAIR
Estimated Cost: $43 (Parts) vs $3000 (New Machine)

Frequently Asked Questions

What is the difference between ERR PS and E05 on Pentair heaters?
Both indicate a pressure switch fault caused by inadequate water flow, but they appear on different display interfaces. E05 shows on older MasterTemp 3-character LED displays, while ERR PS appears on newer digital panel models and on systems using IntelliFlo integration.
What RPM should my variable-speed pump run at for a Pentair pool heater?
For most residential installations with a MasterTemp 250 to 400, the pump needs to reach 2,400 to 2,800 RPM to supply the required 20 to 25 GPM. Longer pipe runs and additional plumbing resistance may require higher RPM. Program a dedicated high-speed schedule in the pump controller for heating mode.
Can ERR PS cause damage if ignored?
The pressure switch is a safety device. When it stays open, the heater will not fire, so there is no immediate damage risk from the fault itself. However, repeatedly forcing resets without fixing the underlying flow issue can lead to premature pressure switch wear and potential heat exchanger scaling from inconsistent heating.
How do I know if my pressure switch is bad vs. the flow being too low?
With the pump running at heating RPM, test continuity across the pressure switch terminals. If the switch is open and you have confirmed the pump is at adequate speed with a clean filter and closed bypass valve, the switch has failed and needs replacement.
Will ERR PS clear itself once I fix the water flow?
No, you need to manually reset the heater after correcting the flow issue. Press ON/OFF, wait 30 seconds, and press ON. The heater will attempt a new heat cycle; if flow is now adequate the pressure switch will close and the lockout will clear.

Related Pentair Poolheater Error Codes

Code: HUBPentair Pool Heater Error Codes GuideCode: E05Pentair Pool Heater E05 Error CodeCode: RESETHow to Reset a Pentair Pool Heater

Same Fix on Other Brands

Hayward poolheaterLO: Hayward Pool Heater LO Error Code

Models Known to Experience ERR PS Errors

This repair applies to most Pentair poolheaters with this error code. Common model numbers include:

MasterTemp 400, MasterTemp 250, MasterTemp 300, MasterTemp 125

Last verified for technical accuracy on March 14, 2026