Like the name suggests, oil boilers are fired by oil oil boiler prices depend on whether you opt for a combi, conventional or system boiler. Had a leak in a main supply line, repair required cutting concrete and trenching they got the job done quickly and reasonably priced. Combi boilers are not suitable for larger properties with 3, 4 or more bathrooms. Asbn 15kw 1/3 phase output connection option. Swale heating are industry leaders in boiler installations, maintenance.