Replace analog timer?

[Welshgasman]

Hi all,
Looking for some advice please?

I have an old Ideal Concord WRS boiler circa 1979. Not sure if is a 230A/240A/255A. I am also not sure if it is gravity fed or fully pumped. There is a small pump to the right of the boiler
It has the programmer in the attached picture. Google Lens showed this as a Landis & Gyr RWB2, but looking for that on the net I see very different interfaces?
In looking for a replacment I found the Siemens RWB29SI?

In several threads on here, it is mentioned that the backplate is the same and that it is a straight swap. Siemens themselves state that. However in mine all the wires appear to go in vertically to the right side of the unit as you look at it's face.

Now I am not sure mine is indeed an RWB2, how hard would it be to replace this old timer please.
I do not intend to do it myself more than likely, but have a friend who could fashion some sort of mounting plate for the new programmer, then get an electrician in.
The current one is bolted to the boiler front panel with two screws.

Thank you

 

[CountryFan]

I doubt that's a universal backplate being part of the boiler. It would probably be better a new one and new/altered wiring at the boiler.

 

[ericmark]

I note either central heating and hot water or only hot water, which points to a C Plan. There is no option for central heating only.

Back when CFL lights first came out, I realised there was a problem. With tungsten lamps the inferred from the lamp resulted in the evening when one was just sitting you still felt comfortable as one was getting this inferred, as they were replaced, we well at least I wanted the room warmer in the evening to during the day, so I wanted a programmable thermostat.

Combining the timer function and thermostatic function into one device, needed so alteration in the wiring, Nest Gen 3 allowed in with N/O contacts and out from the com contact, and Hive had a special configuration for C Plan with one set of contacts for the pump and another for the boiler.

However, I am jumping ahead, step one is to decide if you want DHW heated by the boiler in summer?

What we have to consider, is the cost to fire up the boiler before it heats even one pint of domestic hot water, in the winter heating DHW when boiler also heating radiators is generally good, but in summer, often the immersion heater is as cheap or cheaper to run to the gas or oil boiler, even when gas is cheaper than electric, so much energy wasted each time the boiler turns off/on.

So next is to look at 5 to 10 years time, as TRV heads can be added latter, but you likely want a thermostat/hub or thermostat and hub that will accept TRV heads to be added later.

I like the Wiser system, but it will not work direct with C plan, where the Hive will, so although I have C Plan in summer I heat DHW with solar, or off-peak, not with my oil boiler. But oil boiler does heat it in winter.

So your looking at the future as much as now, and allowing for changes in the future to make it better.

Distance boiler to cylinder makes a difference, in my case boiler two floors below the cylinder, so there is a lot of pipework to heat.

I found to use oil to heat DHW in the summer needed 5 times the energy to heat it with electric, since electric was 5 times the price of oil, sadly no longer the case, but it would have worked out even in summer using oil or electric, and once I had off-peak and solar, much cheaper to use electric.

Next is the timer where you would want to measure temperature, some systems the programmable thermostat and hub are the same item, others the hub and the thermostat are separate items connected together wireless. Can't really advise on a system without knowing if both can be combined or not.

I am not saying spend a fortune now on the best smart system, what I am saying is select one which you can if you wish expand on.