If I was putting the design out to an installer than there would be a full set of drawings and not just a rough sketch. That said I woud have expected an expert in heating to have been able to interpret that sketch using his or her experience and knowledge.miss half the details from the drawings & leave the installer to guess the design!
No!! You get the fees to design. So you should provide the FULL design!! Jeez!!! You are so typical BG, half a design & expect the installer to do the rest. Totally useless fag packet design. That's why tradesmen get more respect than 'fag packet design Johnnies'.