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Ideal Vogue Gen 2 Boiler Temperature Won't Exceed 26 Degrees

Discussion in 'Plumbing and Central Heating' started by stem, 20 Apr 2018.

  1. stem

    stem

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    Instead of answering a Nest question, I am going to ask one for a change.

    The Nest is fitted to a newly installed Ideal Vogue Gen 2 using the OpenTherm system.

    The timer plug and socket were connected together and the OpenTherm connection made as per the Ideal manual below:

    ot.JPG

    Also, initially the factory fitted red link in the Room stat / timer terminals shown in the photo below was removed, based on the boiler instructions which state:

    "The Vogue Combi GEN2 boiler comes pre-fitted with a link wire between the Room Thermostat/Timer connections on the terminal strip. This creates a permanent call for heat and must be removed when adding a Room Thermostat/Timer"

    Capture.JPG

    Obviously though, Ideal don't consider the Nest to be a Room Thermostat or timer, because when the Nest was calling for heat the boiler display continually showed "Timer or Room Thermostat off"

    As the Nest uses the OpenTherm terminals and wasn't actually wired to the Timer or Room Thermostat terminals, I wondered about the link and so it was reinstated. Now the Nest will turn the heating 'on' and 'off' correctly.

    The next problem is that with the actual room temperature shown by the Nest as 24 degrees, a set room temperature of 30 degrees and the boiler humming away nicely showing that the Heating is 'ON', it only fires up for a few seconds at a time with the display showing that it is maintaining a water temperature of 26 to 27 degrees. The flow pipe leaving the boiler and radiators remain cold to the touch.

    Additional Info

    The boilers heating thermostat is set to 80 degrees (Max)

    When running hot water, the boiler temperature quickly reaches the set 60 degrees, but when it returns to heating mode the temperature drops rapidly back to 27. This is then maintained by a firing of the boiler for just a few seconds once every 15 to 20 minutes or so.

    The system was initially tested prior to the installation of the controls and the radiators heated up OK.

    No other controls or outside sensor are fitted.

    So now for the question. With a set room temperature of 30 degrees and an actual room temperature of 24 degrees, why aren't the radiators heating up?
     
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  3. muggles

    muggles

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    Did you select OpenTherm as the control method in the Nest setup menu?

    Nest's OpenTherm logic isn't very sophisticated, and the installer setup options are very limited, so that may be a factor if you have selected OT control. Setting the boiler stat to 80 doesn't make a difference though, OT will always override that, even not very sophisticated OT. That's how it works - it aims to reduce the flow temperature to the minimum possible to achieve the desired room temperature.
     
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  4. stem

    stem

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    Yep, OpenTherm was selected at the Nest and it shows as such in 'my system'

    The boiler heating stat was set to Maximum because the boiler display tells you to set it to Maximum, which I assumed was because it had sensed OpenTherm and setting it to max would allow it to be regulated down as required.
     
  5. D_Hailsham

    D_Hailsham

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    The online manual says:

    (F) OPENTHERM PROGRAMMABLE ROOM STAT
    1. Remove the link wire between the Room Stat/Timer terminals
    2. Connect the OpenTherm Programmable Room Stat across the terminals as shown in the Diagram.
    3. Unclip the 3 way connector from the back of the internal timer plastics and connect to the 3 way connector adjacent to the plastics.
     
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  6. stem

    stem

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    I found that manual when we originally had the problem, but they are the instructions for the original Vogue boiler. This one is the new 'Gen2' version. The manual that came with it doesn't include that instruction for removing the link with OpenTherm. It has a separate plug that is removed.

    ot.JPG


    Only the when wiring to the 'standard' relay type external controls, is the instruction to remove the link given.

    external.JPG

    However I have tried it with the link both 'in' and 'out'. With the link 'out' and the Nest calling for heat, nothing happens. The display shows:

    display.JPG

    With the link inserted, the Nest will switch the heating 'on' and 'off', but when it's 'on' the boiler temperature goes as high as 30 degrees....

    30.JPG

    ....and that's where it stays. Firing for a few seconds every 15 minutes or so to maintain it. On Friday it was maintaining a boiler temperature of 27, On Saturday it was 30.

    Eventually, the control was changed from OpenTherm to using the Nest Heating 'Common' and 'Call for Heat' relay contact, and it now works perfectly.... Except that the client is not too happy as he specifically wanted to have OpenTherm.
     
  7. muggles

    muggles

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    Honeywell T6 has much better OT control, for future reference ;)
     
  8. stem

    stem

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    It was all specified and installed before I got involved, which was only when the installer couldn't get the controls to work. He's going to try and get in touch with Ideal today to see if it can be resolved. I suspect that they may suggest that he contact Nest, who will then probably suggest he contact Ideal!

    Looks to me that their interpretations of OpenTherm may be different from each other. Which if so, goes a bit against the 'open' concept.
     
  9. D_Hailsham

    D_Hailsham

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    I was quoting from the only manual available online. There is no Gen 2 manual listed online. In fact the Vogue GEN2 doesn't exist so far as the Ideal web-site is concerned.

    However I Googled for "ideal vogue gen 2 combi installation manual" and, guess what - it came up with one on the Ideal website! (If only manufacturers would keep their sites up to date!). I know it's the correct manual as it says GEN2 on the cover. The instructions are as you quoted.

    I see you have realized that the link wire (230V instructions) is not the same as the link plug (OT instructions). Have you joined the plug and socket together as in item 2 of the OT instructions? If you don't join them the OT terminals on the boiler go nowhere. Look at the wiring diagram on page 35.
     
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  11. stem

    stem

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    Yes. The installer told me he'd done it, and when I checked later I can confirm that it had been done.

    I know the Nest was sensing the OpenTherm connection. When being set up, it searched for, and confirmed that it had found OpenTherm. I suspect Muggles is right that the problem is with the "logic" ie the software. [not to be confused with an Ideal Logic, which is another boiler altogether :)]

    IMHO, I think that the instruction manual from an electrical viewpoint is very poor. As well as the ambiguity about the 'link', the function of the two room thermostat terminals is not shown. One terminal will be the live supply out to the external controls, and the other will be the switched live back from the external controls. However,

    From one of the optional installation methods, the diagram below shows the left of the two room thermostat terminals as the switched live coming from the controls.

    1.JPG

    Yet under 'Fault Finding' it states:

    "If not 230V on 'A' there is no voltage from the timer / room stat"


    Which is identifying the right of the two terminals as the switched live from the controls. To make it worse, the photo doesn't even show any controls connected, but the link firmly in place instead, which would mean that there would always be a live on 'A' as it's linked to the permanent live next to it. :rolleyes:

    a.JPG
     
  12. shambolic

    shambolic

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    Try putting up temperature to 35 if Nest goes that high and see what the flow temp is then.
    It may be the boiler is saying that with 6 deg difference it only needs to come on at a very low flow temp to achieve your set point.
    If opentherm fitted the boiler stat does nothing.
     
  13. stem

    stem

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    Nest goes up to 30 max, which was the setting we used for testing. [Nest does also have a test function which we tried briefly, but that didn't seem to change anything.]
    • On Friday afternoon, the ambient was 24, so giving a 6 degree differential, and the boiler water temp was maintaining 27.
    • On Saturday morning the ambient had fallen to 21 giving an 9 degree differential and the boiler water temp increased to 30.
    The flow pipe from the boiler didn't actually feel warm at all, but the water temperature was only 3 degrees above the ambient temperature it would have been at before the heating was turned on.
     
  14. polesapart

    polesapart

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    edit
     
    Last edited: 24 Apr 2018
  15. vulcancontinental

    vulcancontinental

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    I haven't got the Nest instructions with me but wasn't one of the options (I've only trialled one at my place and it's gone now) in the setup to choose the max and min htg flow temps?

    If OpenTherm is broken (open circuit) it's supposed to revert to ON max AFAIR.
     
  16. stem

    stem

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    Can't say that I've seen the facility to select max and min flow temps, and I'm not able to check it now. When the installer makes enquiries of Ideal / Nest hopefully that will be revealed. It would sound reasonable though.
     
  17. Paulj48

    Paulj48

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    I have a Nest V3 connected via Opentherm and you only set the maximum CH flow temperature in the Nest itself.

    The minimum flow temperature in my case is set at the boiler, you also set if the minimum requested is lower than that value then the Nest either ignores the request or the boiler supplies at the user set temperature instead.
     
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