Tap crossed out: hot water off
The boiler’s hot-water function is switched off: it will not heat tap water, or will not heat the cylinder. Heating can still be on.
What the manual says to do
To bring hot water back, use the tap key or the mode button. Worcester Bosch: press the tap key and set hot-water mode on. Ideal Logic Combi2: press Mode until there is no cross through the tap. Vaillant (current ecoTEC plus): from the basic display, holding the hot-water button for at least five seconds switches hot-water mode off, so check that first.
Only your boiler’s own manual says exactly what a symbol means on your model. The manuals let the householder reset a fault once, top up the pressure through the filling loop and change the settings; anything else on a gas boiler is a job for a qualified heating engineer (Gas Safe registered in the UK), as the manuals themselves say.
What it does not mean
It does not mean the boiler is off or faulty, and with a cylinder it does not stop the cylinder’s frost protection: Vaillant and Viessmann both say that stays active.
- What it looks like
- The tap symbol with a line or cross through it, or the tap missing from the display.
- Names used
- Hot water mode Off (Worcester Bosch); Domestic hot water mode switched off (Vaillant); DHW not active (Viessmann); Cross through the tap (Ideal)
Where makers differ
Ideal draws crosses through both the tap and the radiator when the whole boiler is off. Worcester Bosch’s Greenstar 4000 shows ‘Off (eco)’ when only the hot-water pre-heat is off, which is different from hot water off.
Other symbols with the same shapes
Sources
No public standard defines this boiler symbol, so its meaning is taken from the manuals of 4 different maker groups (Worcester Bosch, Ideal Heating, Vaillant, Viessmann), each fetched and read on the date shown:
- Worcester Bosch, Greenstar 2000 combi (GR2301iW): Greenstar 2000 user instructions, 6 721 839 343 (2023/04) UK/IE (PDF) — Screen display, domestic hot water: “Hot water mode On” and “Hot water mode Off”. Checked 2026-09-27.
- Worcester Bosch, Greenstar 4000 combi (GR4700iW C): Greenstar 4000 user instructions, 6 720 891 170 (2020/09) UK/IE (PDF) — Symbols on the display: “Off (eco): Hot water preheat off (boiler in eco mode)” and a separate “Hot water off” symbol. Checked 2026-09-27.
- Ideal Heating, Logic Combi2 C24, C30, C35: Logic Combi2 user guide, UIN 237664 A01 (10/2023) (PDF) — “BOILER OFF — Press the mode button until crosses are shown through both the tap and radiator symbols”; summer: a cross through the radiator but not through the tap. Checked 2026-09-27.
- Vaillant, ecoTEC plus VU../VUW../VUI.. (current range): Operating instructions ecoTEC plus, 0020308119_03 (28.11.2023) (PDF) — “Starting from the basic display, press … for at least five seconds. The domestic hot water mode is switched off.” Checked 2026-09-27.
- Vaillant, ecoTEC plus VU, VUW, VUI ..6/5-5: Operating instructions ecoTEC plus, 0020245033_02 (26.05.2021) GB, IE (PDF) — Switching off hot water generation with a cylinder: “Cylinder charging is switched off. Only the frost protection function for the cylinder remains active.” Checked 2026-09-27.
- Viessmann, Vitodens 100-W/111-W/111-F/141-F (black/white screen): Operating instructions for the system user, 6167584 GB (12/2020) (PDF) — “DHW is not active: No DHW heating; Frost protection for the DHW cylinder is active.” Checked 2026-09-27.
Written in our own words; quotations are the makers’ wording.