How much does it cost to fix ECA error code 391?

Typical repair cost for the ECA 391 fault is £90-200 including labour.

391 Medium

ECA 391 Fault Code

Q: What does the ECA 391 fault code mean?

Your boiler has lost its connection to the remote thermostat or controller you use to set your heating temperature.

The ECA 391 fault code means: your boiler has lost its connection to the remote thermostat or controller you use to set your heating temperature.. It appears on 1 ECA model in our database.

Technical description: Room kontrol device 1

Typical repair cost £90-200 (including labour)

DIY fix possible

Check if the batteries in your room thermostat need replacingEnsure the wireless thermostat is not out of range or blocked by new large furnitureTurn the boiler off at the fused spur for 60 seconds to reset the connection, then turn it back on

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like 391: no call-out fees, no surprise bills.

Approved partner

Domestic Appliance Guard

Unlimited call-outs, 24/7 helpline, no price-hike promise

Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

ECA models that show the 391 fault code

Click a model for the full fault code list and model-specific repair notes.

FELiS FL 50 HM Repair: £90-200

Source

ECA 391 fault code information on this page is sourced and cross-checked against the official ECA service / installation manuals for each affected model.

ECA FELiS FL 50 HM manual (PDF)

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026