Ensure that your boiler is happy and health with an annual boiler service get in touch to book with us today! Book your free no obligation survey now. It is good to know a good plumber i have used these guys several times and have had a good experience timely and a job well done! So how do you know what size boiler you need? well, the most accurate way to size your home’s boiler is to. They’re there when you call to make an appointment, they call you to make sure you remember to make it.