Low
S.20 on Vaillant ecoTEC plus Regular

Your boiler is perfectly healthy and is simply letting you know that it is currently preparing or providing heat to your radiators or hot water cylinder.

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

Hotwaterhandlingmode:Requirement

From this model's manual
Verified against the Vaillant Ecotec Plus Regular installation & service manual, page 32.
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 status occurs when the boiler receives a signal from your thermostat or timer that the house needs heating or the hot water tank needs warming. It indicates that the internal controls have successfully registered this request and the boiler is now initiating its firing sequence. It is the standard starting point for normal operation rather than a mechanical failure.

DIY fix possible

No action is required as this is a normal status message and not a fault.Ensure your hot water taps are closed if you do not require water.Check your external controls or timer if the message stays on when no water is being used.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

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

Related guides you might find useful