There are fewer manufacturers that produce oil boilers, namely firebird, grant, mistral, warmflow and worcester bosch based on our research. If we hadn’t had a home buyers' cctv drain survey at the property we hoped to buy we would not have known what a state the drains were in we would…. Wouldn't use another plumber.
Safety is, of course, paramount, so ensure your gas appliances are regularly checked by a gas safe-registered engineer (and consider getting a carbon monoxide detector). This thread is closed, therefore you are unable to respond. Plumbers develop blueprints to plan where pipes and fixtures should be plotted in a structure they also install and connect the piping and fixtures, either working individually.