Greenstar Comfort Twin Channel Programmer Forgets Programme

I have a Worcester Greenstar Heatslave II oil fired boiler, around 4-5 years old. It was fitted with a Comfort Twin Channel Programmer with remote thermostat about 2-3 years ago.

Everything was working OK. Recently, however, the programmer has, when the power is lost/turned off (we suffer frequent power cuts), been forgetting the programme and I have to redo the whole programme.

I presume there is a battery somewhere? Inside the main boiler or inside the programmer?

I can't find any information about changing this battery and I'd prefer not to spend a £100 or so replacing the whole unit. I guess the battery is supposed to last at least as long as the unit ....

Information please on replacing the battery, please?

The batteries are inside the actual room thermostat, you may have to re-bind the thermostat with the receiver when you have changed the batteries but not always, everything you need to know here.

file:///C:/Users/user/Downloads/Greenstar_Comfort_II_RF_Installation_and_Operating_Instructions.pdf

No, the room thermostat works fine. It is only powered by a battery and isn't a problem. How would the mains going off affect a battery-only device? It wouldn't.

The problem is the controller, which forgets the programme when the mains goes off. There is a battery somewhere inside the controller to ensure the programme is remembered in the event of a mains failure. Unless the programmer unit has non-volatile memory?

the controller doesnt have any kind of memory, all settings are stored in the battery powered Thermostat, I think what is happening is that when the power is cut the thermostat and the receiver are unpairing so stop talking to each other

Some have a small 3.6v NiCad rechargeable battery to maintain the clock running and the memory, soldered on the PCB, which used to often be used on PC motherboards. Could be the NiCad is failing. They are not a user serviceable item usually, but if you have a soldering iron and nothing to loose...

ianmcd said:

the controller doesnt have any kind of memory, all settings are stored in the battery powered Thermostat, I think what is happening is that when the power is cut the thermostat and the receiver are unpairing so stop talking to each other

Click to expand...

The power isn't cut to the thermostat - it is battery powered and remains active when there is a power cut or the mains is turned off. And when the power comes back on, the room thermostat and programmer reconnect without any problem.

The programme is almost certainly not stored within the battery powered room thermostat:

1. I have changed batteries in the room thermostat - this had no effect on the programme, despite the room thermostat being without power for several minutes.

2. The programmer will operate perfectly well without a room thermostat - the room thermostat is an option for the programmer.

Harry Bloomfield said:

Some have a small 3.6v NiCad rechargeable battery to maintain the clock running and the memory, soldered on the PCB, which used to often be used on PC motherboards. Could be the NiCad is failing. They are not a user serviceable item usually, but if you have a soldering iron and nothing to loose...

Click to expand...

As you say, nothing to lose from opening up the programmer if I'm going to have to buy a new programmer anyway ... The problem I've come across in the past with this sort of problem is that sometimes the connections to the NiCad are spot welds rather than solder joints. I have no problem with soldering but micro spot welds need equipment I don't have.