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Help with why my combi boiler has a dual programmer?

Discussion in 'Plumbing and Central Heating' started by Shane-tj, 16 Nov 2020.

  1. Shane-tj

    Shane-tj

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    Hi all,
    so I’ve purchased a property and was looking to install a hive heating system on my combi boiler to replace the old programmer. I have found it’s a dual system Siemens rwb29 which I’m a little confused about.

    Few issues with the system is that the heating/hot water can’t be turned off completely via the programmer, and the boiler is in the loft so this is annoying.

    Can anyone shed some light on why they think this is, I don’t have the best of knowledge about these things. I’ll show some pictures of the setup.
     

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  3. muggles

    muggles

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    What make/ model boiler is it?
     
  4. Shane-tj

    Shane-tj

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    Cheers for the reply, it’s an older Worcester boiler. I’m currently at work and not 100% sure the model I’ll have to get back to you on that one. Pretty sure it’s a green star one not sure which version off the top of my head.
     
  5. CBW

    CBW

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    Possibly a system boiler. Do you have a hot water tank?
     
  6. Shane-tj

    Shane-tj

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    No I don’t have a separate hot water tank, also if you look at the wiring in the picture the hot water isn’t wired up if I’m not mistaken?

    I also had my boiler serviced yesterday and the engineer was just as confused why it was on a two way.
     
    Last edited: 17 Nov 2020
  7. CBW

    CBW

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    I couldn’t see the wiring properly as photo is a little dark, but yes appears to be not wired in. Perhaps a conversion took place and they didn’t want/couldn’t afford an upgrade on controls?

    However, looks easy enough to change to a Hive single channel programmer.
     
    Last edited: 17 Nov 2020
  8. Shane-tj

    Shane-tj

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    Thanks for the reply, when we moved in the guy who we bought the property from told us the thermostat we have in the front room was set to just control the front room only, but then when I asked the engineer who come round yesterday about it, he was adamant it would be for the whole house.

    my thinking is he had either purchased the dual one by mistake and just wired it up so it ran atleast, or he had one lying around and thought he’d save the money.

    so your saying it should be pretty easy to swap this over to the single channel receiver from hive?
     

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  9. CBW

    CBW

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    Yes, just a case of copying wires over
     
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  11. Shane-tj

    Shane-tj

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    Yea the only thing putting me off is that people are having issues getting the hive to work if they also have a separate thermostat. So it would mean disconnecting that from the mains box I’m guessing. I’ve had a quick look in the mains box it looks like it’s not going to be an easy job finding that.
     
    Last edited: 17 Nov 2020
  12. Madrab

    Madrab

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    When you say the CH cannot be turned off properly how do you mean? If it can't then it would suggest that the wiring isn't quite right and would need to be checked.
    That being said if it's just a combi then it should just have a constant power with the bridge/switched live wired as a simple on and off through the programmer.
     
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  13. Shane-tj

    Shane-tj

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    As far as I’m aware there’s no CH off option on the programmer, we have it set on a timer to come on and then go off.

    from the way it’s wired up and the diagram from Siemens the off function is 2 and there’s no wires running to 2. Unless I’m mistaken?

    On the picture 1 & 2 is free , 3/4 is being used as the ch on and ch function just to clear up the mess of the wires.
     
  14. Madrab

    Madrab

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    Yup, depending on the boiler requirements the wire from 3 + 4 is CH off and CH on. All a combi boiler should need is the SL (CH on) on 4 connected to the SL terminal on the boiler, as the programmer has internal 240V switching. Do you have a wall thermostat?

    Ideally you need to see what the grey and brown wires (3&4) are connected to/through.
     
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  15. Shane-tj

    Shane-tj

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    Yea so when we viewed the house the guy pointed out the front room thermostat, he said it was set to control the heat in the front room only. But there’s no other thermostats in the house. I also asked the engineer regarding it and he was sure it would be for the whole of the house.

    I’m just going to order a hive setup direct from hive whilst they’re reduced and get their installation and let them have a look at it, seems the best option for £52 installation fee.
     
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  16. CBW

    CBW

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    That seems logical and not a bad price either.
     
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  17. Madrab

    Madrab

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    Apologies, you said that in a previous post didn't you.

    Unless the thermostat controls a wireless TRV or a 2 port valve that just zones the front room then yes it would control the whole system.
     
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