E4 — Low pressure
The pressure does not build up; the unit detected dry running from the pressure.
What does fault E4 mean?
The pressure does not build up; the unit detected dry running from the pressure.
How is fault E4 cleared?
- Make sure water reaches the pump inlet.
- Check F10; it must be lower than the normal working pressure.
- Check where the sensor is fitted; it must sit after the check valve.
- Check the bypass valve — it may look closed but still leak.
To clear a fault, press the Cancel key on the main screen.
Notes from the manual
- This fault clears by itself once the water returns; the unit retries every F6 minutes.
Which model is right for the pump?
Several HYDROSET PM821 faults appear when the unit's rating does not match the pump's nameplate current. The table below gives the right model for each pump current.
Frequently asked questions
How is a fault cleared?
To clear a fault, press the Cancel key on the main screen.
What does fault E4 mean?
The pressure does not build up; the unit detected dry running from the pressure.
Does fault E4 clear by itself?
This fault clears by itself once the water returns; the unit retries every F6 minutes.
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