- Heat pumps
- Pool heat pump
ER15
Poolex Er 15 on pool heat pump: inlet water sensor fault
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Low
Quick answer
On the Poolex Jetline Selection Fi, code 15 means a fault in the inlet water temperature sensor. Note the code and the F3 reading in the status menu, and call a technician to check the sensor connection.
Safety first
Stop and check this first
- Poolex requires the power supply to be disconnected before any work or maintenance on the heat pump. Do not open the casing: water and mains voltage are together inside.
Safe checks you can perform
- Status values and fault history
- F3 reading against the real temperature
- F3 against F4 with water flowing
Leave these tasks to a qualified professional
- Do not attempt this professional task: Sensor connector check
- Do not attempt this professional task: Sensor measurement
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Sensor connector check
What they doWith the power off, the technician opens the unit and checks the inlet sensor connector on the board and the cable condition.
They must show youa photo of the connector before and after.
In writingwhat was found and whether reconnecting was enough.
Sensor measurement
What they doThe technician measures the disconnected sensor with a multimeter and compares the value with the manufacturer's specification at the water temperature.
They must show youthe measured value against the manufacturer's specification.
In writingthe new sensor reference, the reason and the F3 reading after the change.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Status values and fault history
- Who:
- you, from the heat pump controller.
- How:
- enter status check mode by holding for 3 seconds the button shown in section 5.9 of the manual; step through the parameters and note the inlet (F3) and outlet (F4) water temperatures and codes HE1 to HE4 (fault history).
- Result that matters:
- knowing whether the code repeats in the history and which values the unit showed.
- If the history shows the same code several times:
- it is not a one off; show it to the technician.
- If it is the first time and it clears once the water is corrected:
- watch it for a few days before calling.
- Evidence to keep:
- a photo of each value on the screen, with the date.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
F3 reading against the real temperature
- Who:
- you, with a pool thermometer.
- How:
- with the filtration running, measure the pool water with a thermometer and compare it with F3 in the status menu.
- Result that matters:
- whether F3 shows a sensible value or an impossible one.
- If F3 is absurd or missing:
- it points to the sensor or its connection; tell the technician.
- If F3 matches the thermometer:
- the fault may be intermittent; note when the code appears.
- Evidence to keep:
- a photo of F3 and the thermometer together.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
F3 against F4 with water flowing
- Who:
- you, from the status menu.
- How:
- with the filtration running and the heat pump not heating (on standby), compare the inlet temperature F3 with the outlet temperature F4.
- Result that matters:
- whether both readings are similar, as expected when water just passes through without being heated.
- If F3 is far from F4 or jumps around:
- it points to the inlet sensor or its connection.
- If they are similar:
- note when the 15 appears so the technician can look for an intermittent fault.
- Evidence to keep:
- photos of F3 and F4 taken one after the other.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Heat pumps
- Brand
- Poolex
- Product type
- Pool heat pump
Known code variants
- Er 15
- Poolex 15
- Poolex E15
- Poolex error 15
- Poolex inlet water temperature sensor
- Poolex Jetline Selection Fi 15
- Poolex sonda temperatura agua entrada
What it means
The inlet sensor measures the temperature of the water coming from the pool; the controller uses it to decide when to heat and to protect the unit. For 15, Poolex gives one cause on the Jetline Selection Fi: sensor disconnected or defective, and the action is to reconnect or replace it. A loose sensor and a failed one give the same code, so a 15 does not prove the sensor must be replaced: the connector is checked first, then the sensor is measured.
Warnings and stop conditions
- Highsource verified
Poolex requires the power supply to be disconnected before any work or maintenance on the heat pump. Do not open the casing: water and mains voltage are together inside.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
Symptoms and causes
Probable causes · in order
- Sensor disconnected or poorly connectedCommon
The sensor connector on the board is loose, corroded or the cable is damaged. It is fixed by reconnecting, without a new part.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
- Defective sensorPossible
The connection is fine but the sensor gives an impossible or out of range value. Poolex says to replace it.
Evidence: Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
Virtual technician
Does ER15 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Poolex Jetline Selection Fi: installation and user manual (multilingual, 08-2025)
Poolstar (Poolex) · 2025 · official_doc
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