Don’t let your plumbing problem turn into a nightmare schedule an appointment by completing our online form now! Of those long springy things you get in hardware shops. With no water tank to heat up, combi boilers can provide an unlimited supply of hot water on demand no waiting time! Understand the system and what you could be entitled to. All burners are supplied factory set at the stated output for use on standard grade kerosene — class c grant condensing boilers are not suitable for use with.