Need to Replace Worcester Wireless Digistat Mk1

[Redlander]

I have a Worcester 28CDi combi-boiler witted with a wireless thermostat which has stopped working. The model numbers are: Receiver 7716 192 005, Transmitter 7716 192 004, Complete system 7716 192 006.

The transmitter and the receiver have stopped communicating with each other, so I have investigated replacing the thermostat system. The reply I got from Worcester/Bosch is that the model number of the Mk2 replacement is 7716 192 049. I have found two problems with this:
1. The Mk2 component does not seem to be available online except secondhand on ebay, suggesting it has been discontinued, despite what Worcester tells me.
2. The old and the new receivers seem to have different electrical connectors, as can be seen in these two pictures:

https://flic.kr/p/2oMSyro

Worcester Bosch DT10 RF Digistat Optimiser with receiver Used | eBay

Find many great new & used options and get the best deals for Worcester Bosch DT10 RF Digistat Optimiser with receiver Used at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

It appears that the Mk2 receiver is not compatible with my existing boiler.

So it appears that Worcester/Bosch's advice is erroneous. Can anybody advise how I can proceed?

 

[Avo Mk8]

Silly question I know, but have you replaced the batteries in the transmitter?

https://www.worcester-bosch.co.uk/support/literature/download/8716145055

 

[Redlander]

Silly question I know, but have you replaced the batteries in the transmitter?

https://www.worcester-bosch.co.uk/support/literature/download/8716145055

Not a silly question but yes, I've installed new batteries.

One thing I'd like to establish is: supposing that it is just the transmitter that is faulty, if I replaced it with a with a different type of transmitter- either a Worcester one or some other make - would it still work with the existing receiver?

 

[Avo Mk8]

One thing I'd like to establish is: supposing that it is just the transmitter that is faulty, if I replaced it with a with a different type of transmitter- either a Worcester one or some other make - would it still work with the existing receiver?

I think a different transmitter is unlikely to work with your existing receiver, though someone here may know if there is a compatible one still available.
The trade seem to advertise a compatible unit, eg:

Heating Spare Parts

Worcester part no. 77161920040 - NOW USE 87161144610 CDI-DIGISTAT TRANSMITTER-SO24T1

www.heatingspareparts.com

if you can get the old model on Ebay at a reasonable price, might be worth a punt - eg:

WORCESTER 77161920040 DIGISTAT TRANSMITTER CDI 4010009207870 | eBay

Find many great new & used options and get the best deals for WORCESTER 77161920040 DIGISTAT TRANSMITTER CDI at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

One could in theory replace both tx and rx with any suitable system by rewiring the boiler control connections to an external receiver. An electrical schematic of the boiler would help, but you would need to be confident in what you were doing!