Low
dE on Viessmann Vitodens 222-F

Your boiler is currently operating on a fixed schedule and is ignoring temperature adjustments from your room thermostat or smart controller.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Control mode without room influence

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 222 F installation & service manual, page 96.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's control system can no longer detect a signal from the temperature sensor assigned to your second heating zone. It is usually caused by a loose electrical connection, a break in the thin sensor wiring, or the internal component of the sensor failing due to age.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like dE: 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.

Related fault codes

dEView →bCView →

All 92 fault codes on the Vitodens 222-F

Seeing a different code? Every code this model can display, in one place.

00:100:200:300:400:500:60A0F1A1F2E:0050606:...9B9C9F1011:9182021:023:02526283030:032:034:0353840485051585980:0929394A2A5A7A8A9b0b1b4b5b7b8bAbcbdbebFC2C4C5C6C7CdCECFdAdbE4E5E8E9EAEbECEdELF0F1F2F3F4F7F8F9FAFCFdFEFillingVenting

Related guides you might find useful

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →