Programmer Help

[Vehlin]

I opted to fit a 2 channel programmer and wireless room stat to my antiquated heating system and have run into a bit of a snag.

The central heating system is set up currently such that when the hot water is on the boiler fires up and heats the hot water tank. When the CH is switched on the boiler also fires up and the radiators heat up in addition to the HW heating up.

The previous programmer automatically turned on the HW side when you turned the heating on. My assumption is that the HW ON connection tells the boiler to fire and the CH on tells the diverter valve to switch.

Herein lies the problem, the Programmer I've bought (Heatmiser PRT/HW-WTS) has independent channels, there's no way to turn the HW on with the heating without creating a hot water program to mirror the CH one (which makes turning the heating on manually a pain).

So I have two wires which were connected to CH ON and HW ON on the old Invensys controller, I've connected these both to NO1 and NO2 respectively on the Heatmiser controller. What I seem to really need to do is to have either channel turn on the boiler, but to have the CH channel turn actuate the diverter. The only way I can think to do this is to connect the boiler connection to both NO1 and NO2 via an optoisolator and then have the diverter on NO1 only.

Am I overcomplicating this?

 

[Ihavenojob]

Was there a wire in the H/W off terminal?Doesnt look like it will work as it should without it.I had a Heatmiser control a few years ago which would only work with a diverter valve by wiring in a relay,it was in the instructions,ended up putting 2 2port valves in.You need the grey wire on the div valve to go to the hot water off on the cylinder stat and NC2 on your receiver.

 

[ianmcd]

Afraid you have a gravity hot water/pumped central heating system and you have tried to convert it to fully pumped, basically your origionall controls you could have HW on its own or HW and CH together but you have installed controls that can select CH on its own without a demand for HW , this isnt achievable on your system it would require pipe work alterations and additional Zoning valves to be installed

 

[Vehlin]

I realise that I won't be able to have CH without HW on the current system, what I'm trying to accomplish is to get a HW channel and a HW/CH channel which should be doable.

I just need to work out the relay logic to make the following work

NO1 NO2 - CH HW
..0......0........0....0
..0......1........0....1
..1......0........1....1
..1......1........1....1