This is what we recommend.
- First call the person who installed it or last serviced it.
- Second look at the website of your boiler manufacturer - they may have good tips.
- Third call the boiler manufacturer.
For example Worcester Bosch ( tel: 0844 892 3000 or email via their website) currently charge a flat rate of £230 for a call out which includes ALL parts & labour. The others do something similar and this is a good deal.
There comes a point when it is better to save the money and get it replaced. A boiler should usually last more than 10-12- may be 14 years.
They can be replaced with a budget model in a typical small family home for little over £1,000 or the replacement cost could easily be over £2,000. There are so many factors to consider, not least what type of boiler and temperature controls.