As Adam says, some things aren't a quick fix on the web! Any competent plumber will have fitted at least a 3-port valve (or seperate zone valves) to allow Hot Water only or (usually) Hot Water and Central heating radiators. It also needs a suitable time-clock/programmer to control these functions. Look at your programmer - does it have switches for the two main functions? If not the system was done 'on the cheap' by an incompetent plumber! If the boiler still works OK it's worth having a 3-port or zone valves fitted plus a suitable control unit. Anything is better than a complete boiler change! "If it ain't broke - don't fix it".
I designed and built my own system, using the Potterton Flamingo RS50 (with the one-piece heat exchanger - not long before they brought out the sectional exchanger!), in 1978. I used 3 seperate zone valves and 2 programmers so I could have the upstairs heating independently controlled. I had the gas connected by a CORGI qualified fitter. (I am a competent DiY plumber but not CORGI). Apart from replacing valve motors periodically and cleaning the burner and jets, it has needed no replacement parts in 30 years! Not even a thermocouple, even though I have a new one just in case.
The pilot light occasionally blew out so I adjusted the jet to give a slightly bigger flame. The fact that the thermocouple is still the original proves that I haven't overdone it!
Lionel Y, September 2008
