need sum expert advice

[bobby101]

hi all i hope you can help me out i recently went to a job to solve the fault within a housing flat the setup to me is a bit hard to follw as i can t find a wiring schmatic for this type of installation as follws : a seperate mains fed 3kw backup clynder for hot water a communal gas main supply with a 3 port valve and pump i feel competent enough to follow a drawing of said type of systems also the supply for the ch controller is off the light cct.. part of the fault is in the living room there is a d/p sw which is fed from the controller but i have not as yet identified its purpose, it definetly is fed from the controller but it does not appear to control anything. i have not got a lot of experience with these type of systems dont know if the problems are becuse it is a commual gas supply if anybody has worked on said systems on the glasgow housing association systems ... other main fault is the controller has reqd to be replaced 7 times so far

 

[pmac10]

i have one of those switchs in my living room, took me ages to figure out what it was for (no it wasnt for the lights), it turns on an auxiliary boost pump so if i want quick hot water, i close a ball valve and flick this switch and it gets pumped direct to a tank in the roofspace. its a very old system obviously, hope this helps.