replacing boiler controller

[jobel]

hi, recently moved into a new house, my boiler is an old one that was converted from oil to gas. the controller is not working, its a very old mechanical landys and gyr. the system is a little strange, the hw is for sure gravity and the ch is pumped however what is strange is there is a 3 port valve on the ch circuit which appears to either be closed, bypass to the boiler or heating. i want to replace the controller, and think i can ignore this valve as i have a bypass radiator in the bathroom in case all the room thermostats are closed. second can i control the pump direct from the relays in the ch timer if i can do both of the above can anyone reccomend a suitable controller there are lots out there for gravity and pumped systems my main concern is selecting one that can turn on the pump and boiler, oh the boiler has its own thermostat so i was going to run it off that rather than introduce something else.

 

[naveedsahil]

I am facing same situation..

 

[jobel]

so i think the valve is closed heating or just circulation, and i have found a temp sensor on the ch pipe, i assume the valve is moved to circulate if the system is at temperature. if i leave this in the fully open position then i think i have a c plan system just without the thermostat on the hw gravity circuit. so i think they honeywell st699 in its basic gravity wiring should do the trick. i would enhance maybe with a themostat valve on the hw and it be a full cplan system i think. is there any point in trying to bring this old motorised valve back into action?