F1 is a very common problem on Ideal boilers and can be easily fixed without the help of a professional.
Contents
What is an F1 fault?
An F1 fault is caused by low water pressure in the boiler / central heating system with an Ideal boiler.
When the pressure is too low the boiler won’t work at all so you’ll have no heating or hot water.
What causes an F1 fault?
F1 faults are caused by a drop in system pressure. The main reasons for this among others are:
Leaking radiators.
Leaking boiler components.
A faulty expansion vessel.
Bleeding radiators without replacing the lost water/air.
Initially setting the system pressure too high or low.
Faulty pressure relief (safety) valve.
Cracked or damaged main heat exchanger.
Faulty internal pressure sensor.
Faulty pressure gauge.
How do I repair an F1 fault?
Using the reset button or switch has no effect on F1 faults. The fault can only be cleared by increasing the pressure.
Check the pressure by using the pressure gauge. On older models it is hidden under the boiler on the left. On more modern versions it is on the front of the boiler.
The pressure is increased using the filling loop. On most Ideal logics this is built in under the boiler on the right hand side. There may be an external filling loop, this guide can help you identify it.
Before starting make a note of the positions of the valves. When you are finished return them to the original position.
Turn the left hand blue valve toward you. Next slowly turn the right hand blue valve toward you until you can hear water running. Carefully watch the needle on the pressure gauge go up.
Be aware that the water pressure may go up very quickly so open the valve very slowly.
When the pressure gets between 1 and 1.5 turn the right hand back to where it was and do the same with the left hand valve.
The fault should be clear now, the boiler should go through its startup sequence.
If the pressure is between 1 and 1.5 and the boiler still displays F1 the pressure sensor may be faulty which requires a gas safe engineer to repair it.
What should I do next?
For a week or two keep an eye on the pressure gauge of the boiler.
For the first week there may be some pressure loss as air is released from the system. You may have to top it up again.
If the fault reoccurs there may be a problem either in the boiler itself or on the radiators.
If F1 is displayed on your boiler and you have to top up the pressure regularly you may have a leak on your heating system.
This should be investigated by a plumber or heating engineer.