drayton RF2 change to Salus receiver.

[tombell]

Firstly, I am new to this forum, so apologies for any errors I make in this post.

I have been having a few problems with my viessmann boiler recently, which gas man will be sorting ( once he returns from holiday ) however he did also suggest the old receiver was on its last legs and could do with replacing.

There is a 5 core cable that comes from the boiler. Now the live/neutral/earth are easy to deal with, the other 2 cables are a grey one and a black one. The receiver has connections common and NO, and one connects to a L1 connection in the boiler and one to ( I think a Live ). From my limited knowledge, this is related to call for heat. My problem is that the old RF2 had different names for the terminals and I want to confirm which of the 2 wires connects to the L1 connection ( common or NO ), ( thereby the remaining one would connect to the other terminal ).

I'm sure this is probably a simple question for someone who is used to fitting boilers / or thermostats to answer, but countless google searches have not provided me with the answer I need. The last thing I want is for the gas man ( when he returns ) to mis-diagnose the boiler problem because I have the two wires the wrong way round.

Thanks in advance.

 

[ScottishGasMan]

You know if you change recivers you will also need to change the thermosats as well? Stupid question but you might not be aware of that first.

Given the damage that can be done when something that has been incorrectly wired and the fact its summmer time, could you not wait until your gas man is back, it is a two minute job for someone who works with these things and next to zero risk if he does it as opposed to yourself.

For example, do you know if the switching wires on the reciver are 24v or 240v? a mistake here can end up requiring a new (expensive) PCB for the boiler.

 

[tombell]

I bought both the receiver and thermostat together... not an issue.

The Boiler, as I understand it ( reading the Viessmann install instructions ) is 230v, but no-volt switching required on the circuit.

Just really need to know which wire goes to the common and which to the NO terminal.

Thank you for your quick initial response

 

[D_Hailsham]

Are the terminals on the RF2 numbered 1, 2 and 3 (ignoring the obvious L and N terminals)?

If so:

1 = Common
3 = NO

If there is a link between L and 1 on the RF2, you need to put a link between L and Common on the Salus.

 

[tombell]

there was no link wire on the RF2 as it is volts free connection.

The PCB power connections on the viessmann are in 2 sections. 1 is the standard Live neutral and Earth, the other is for the boiler controls. When the boiler is delivered it has a jumper between the terminals in this second section of L and L1, this is in case you are not going to install a thermostat. When the thermostat is installed, the jumper is removed and 1 cable is connected to the L and one connected to the L1. These go to the receiver, 1 to common and 1 to NO. The operation of the thermostat receiver will facilitate the connection when the thermostat is calling for heat, ( and block it when not ) . So basically the signal ( current ) comes from the boiler, goes through the receiver then back to the boiler.

If this is a " simple circuit ", in theory it wouldn't matter which way round the wires were as the on/off function of the receiver would still work to block/allow the signal ( current ) through. I was hoping someone familiar with Viessmanns, Salus, or just general boiler/stat installations would be able to advise me whether it does matter, and if so, which way round it goes. Eg L to com, L1 to NO or L to NO and L1 to com.

 

[D_Hailsham]

It makes no difference which way round they are connected.