E3 — Dry running

Water is not reaching the pump; the unit detected it from the drop in current.

What does fault E3 mean?

Water is not reaching the pump; the unit detected it from the drop in current.

How is fault E3 cleared?

Make sure water reaches the pump inlet.
Open the pump inlet valve fully.
Bleed the pump.
If there is water and the fault keeps returning, reduce F4 slightly.

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.
If the output drives a contactor, the pump current does not pass through the unit. Set F4 to 0 so E3 is ignored and detect dry running by pressure (F10).

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.

Model selection table
Pump current	Pump power	Model	Typical use
up to 8 A	up to 1.5 kW	PM821-8	1–4 floors, homes and shops
8 – 16 A	up to 3 kW	PM821-16	5–10 floors, booster sets
up to 25 A	up to 4 hp	PM821-25	Residential, commercial and agricultural

The current on the pump nameplate decides the model, nothing else.

Frequently asked questions

How is a fault cleared?

To clear a fault, press the Cancel key on the main screen.

What does fault E3 mean?

Water is not reaching the pump; the unit detected it from the drop in current.

Does fault E3 clear by itself?

This fault clears by itself once the water returns; the unit retries every F6 minutes.

All fault codes HYDROSET PM821 user manual

Last updated: 7 September 2026