Salus rt500bc thermostat not sending signal to boiler

[Zak K]

Hi all

Thermostat is driving me crazy! Any advice would be good. Whilst using the boiler in my sisters place found that the wireless thermostat does not seem to be working correctly.

When the temp is higher then set it will switch the reciever on the boiler off but the CH stays on. On further investigation found that the CH is always on! Not matter what the thermostat does. I've attached photos of the back of the receiver as well as the wiring into the boiler and was wondering if anyone can see any obvious wiring issues that would explain why the thermostat reciever is not sending a signal to the boiler to switch off the CH.

Many thanks in advance.

Boiler: Ferolli Modena 38c

 

[dilalio]

More chance picking up a signal from Voyager than from Salus.

 

[stem]

Assuming that it has worked when it was originally installed, then.

1. The first check is to make sure that the boiler receiver switch is set to 'Auto' if it is set to 'Manual' the heating will be permanently on.

2. There is a red led on the boiler receiver, see if turning the thermostat up an down switches it on and off. (There may be a time lag before it does, so be patient when doing this) If the led stays permanently 'on' then the thermostat is not communicating with the thermostat. Does the thermostat need new batteries?

3. Remove the thermostat from its wall bracket and move it close to the boiler receiver. Try it now, does it switch the light on and off? If not, then try resetting and then re-synchronising the thermostat and receiver following the instructions in the manual. If you don't have the instructions you can find them here. Make sure that you follow all of the steps to the letter.

 

[Zak K]

Really appreciate the reply.

The thermostat receiver is on Auto and switches on and off (red light comes on/off) dependent upon temp set. Problem seems to be even though the receiver turns off the central heating continues. It’s as if the receiver isn’t telling the boiler to shut down the CH.

 

[stem]

Has it ever worked? I'm trying to ascertain if the unit has become faulty, or if it has been incorrectly installed.

 

[Zak K]

Hi... it’s never worked correctly whilst I’ve beem here (4 weeks) currently just having to turn the whole boiler on and off when needed.

Does the wiring look correct in the pics?

If it’s faulty what part would need replacing?

 

[stem]

Sorry, I can't see the wiring clearly enough in your photos, to confirm, but I can give you some pointers:

The Salus receiver connections are as follows:

So, Salus receiver terminals 1 and 2 should connect to the boiler N & L for the 230V supply to operate the receiver. This is probably correct as according to your description, the unit is receiving power.

Salus receiver terminals 3 and 4 would normally connect to the bottom two boiler terminals shown below left, it doesn't matter which way around they go. If there is still presently a link between them, the link should be removed. Nothing else should be connected to these terminals.

Post back if you have something different.

 

[dilalio]

Op: sounds like faulty wiring if the receiver doesn’t control the boiler correctly.

AND... make sure you give @stem a massive thanks for his efforts... he really does go beyond the call in helping people with stat wiring issues on this forum.

 

[Zak K]

A huge thanks @stem for going the extra mile to help out a stranger.

In terms of the wiring. I’ve seen that diagram in the manual but in reality it’s different.

There are 4 wires (2 yellow, 2 pink) going into the box.

Tried all sorts of combinations to get it working with the receiver ( white wires together, 1 white into the box, 2 white etc) but seems to switch on CH permanently no matter what the thermostat is doing. I’ve attached photos. Including the 2 white wires coming from the boiler and 2 from the receiver.

Could you tell me how it should be wired please and if it still doesn’t work would I need a whole new thermostat or a specific part.

Many thanks in advance.

 

[stem]

Sorry but the photos of the wires don't really help, I need to know what each of the wires is actually connected to. It should have been installed as per the diagrams in my previous post.

So lets start with the Salus receiver.

From your photo 3 showing the back of the Salus receiver, I would expect that:

Terminal 1 'N' is connected to the green wire
Terminal 2 'L' is connected to the brown wire
Terminal 3 'COM' is connected to one of the white wires
Terminal 4 'N.O' is connected to the other white wire.

Can you confirm this is correct or not please.

Also I recommend that you do not continue the adhoc trial and error method of connecting wires you could cause some damage.

 

[Zak K]

Yup I won’t be doing anymore trial and error.

I can confirm that the

brown wire goes to terminal 1.
Blue wire goes to terminal 2
White wires goes to terminal 3 and 4

Not sure why the brown is in the wrong place. Should I switch them?

 

[stem]

If the L & N are transposed, then yes, you should switch them over. As the UK mains is 230V ac it shouldn't have harmed it.

With the white wires disconnected, does the boiler still operate?

Do you have a multimeter, or any other means of continuity testing? before we go any further, if possible, I would like to check that the Salus receiver is working