A common problem I am often called to solve is Low Pressure in Boilers. Some boilers start with a blinking alert some others stop working all together.
Is an easy problem to solve by integrating the circuit with water. While a plumber may solve this problem and while there may do a good maintenance of the boiler in question rates differ enormously whit the ones I offer as Handyman.
While there I may also check for air trapped in the radiators.
When radiators are cold at the top in normally a sign of air in the system. By bleeding the air in each radiator the problem is being eliminated.
Once there if the problem requires a professional plumber I will advice so and explain you why.
Remember I move by motorbikes around Central London Chelsea& Kensington so no parking and no congestion charges.
Helped many solve the issue of low pressure in boilers at with a minimal expenditure in Central London Chelsea & Kensington