replacing switchmaster 300 to a siemens rwb29

[fandango1978]

Hi I was told I could use a siemens RWB29 as a digital replacment for my old and very noisy switchmaster 300.
I followed new diagram and put mains feed (3amp fused) into live I have a twin and earth and a single live and a single neg connection from glowworm boiler down stairs, I put twin and earth live into connector 3 and pump live in 4 all my negs go into the N block as instructions illustraight, my problem is I have no clue as to where i put the single live cause when I put it in any of the lives it blows if I leave it out timer works but blows fuse after about an hour and also although pump works on CH no hot water comes out so i'm guessing my boiler hasn't got a live feed also the single live is not a permanent live any help would be appreciated thanks as programmer is very close to being at top of the garden in more pieces than i got it with.

 

[D_Hailsham]

The switchmaster has Volt free switching while the RWB29 switches 230v.

Which glowworm boiler do you have?

 

[fandango1978]

Hi thanks for the reply my boiler is a glowworm fuelsaver mkll it has a connection block with the twin and earth and the single live and single neg have a yellow and white wire goin into cable that also has the normal brown live ,blue neg and earth that all go into boiler will this programmer work with the wires i have or do i need a different programmer

 

[D_Hailsham]

Unfortunately you will need to change the RWB29 for a programmer with volt-free switching.

The reason for this is that your boiler has a permanent 230v supply which is needed so the pump overrun can work. Turning the boiler on and off is then just a case of connecting two terminals on the boiler together, which is done by running a cable to the volt free terminals on the programmer.

Your old programmer should have 5 wires: Live, Neutral, Earth? (supply) (these just run the clock); a live feed from the boiler; a switched live to the wall stat (or, if you have no wall stat, back to the boiler).

The live, neutral and earth supply for the clock may come from the boiler.

The boiler will have: live neutral and earth(supply); live to programmer and switched live back from programmer or wall stat. It should also have a cable (LNE) going to the pump.

 

[fandango1978]

Thanks for explaining that really appreciate it