Smell gas? Leave the property and call the National Gas Emergency line on 0800 111 999
BoilerCodes
L1
Ideal fault code

Ideal L1: no water flow or overheat, or a condensate pipe blockage, depending on the model

Check these first, then call an engineer

Ideal uses L1 for different faults on different models. On the Logic Combi it's a flow temperature overheat lockout, which Ideal's general guide describes as flow temperature overheat or no water flow. On the Ideal Exclusive 2, L1 means a condensate pipe blockage. The checks below cover both.

What you can safely do

  1. Check the pressure gauge reads between 1 and 1.5 bar, and top up if it is low.
  2. Make sure your radiator valves are open.
  3. Check the condensate pipe outside for a blockage or ice, and thaw it with warm water or a hot water bottle if frozen.
  4. Reset the boiler.

Call a Gas Safe engineer if

  • L1 comes back after these checks.
  • You smell gas at any point. Leave the property and call 0800 111 999.
Find a Gas Safe engineer near you Opens the official Gas Safe Register search.

Applies to: Logic Combi (ESP1), Exclusive 2. Codes can differ between models, so check your manual.

What L1 means on each Ideal model

From Ideal's own fault tables. Your model name is usually on the front of the boiler or in the user manual.

ModelMeaning
Logic Combi (ESP1)Flow temperature overheat lockout
Exclusive 2Condensate pipe blockage

Common questions about Ideal L1

Why do different websites give different meanings for Ideal L1?

Because Ideal uses L1 differently on different models. Ideal's general guide says overheat or no water flow; the Exclusive 2 user guide says condensate pipe blockage. Your own user guide is the final word.

Nearby Ideal codes

See all 19 Ideal codes

Sources