Upgrading analogue thermostat to programostat

Discussion in 'Electrics UK' started by DIYAmelia, 4 Nov 2021.

  1. DIYAmelia

    DIYAmelia

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    Hi All,

    I read this plus many more posts, but I have more Qs.

    Read more: https://www.diynot.com/diy/threads/...digital-room-thermostat.534659/#ixzz7BFIjBGwC

    Current system is a Baxi Platinum 30 gas boiler heat only. I have a Drayton LP722 (dual - hot water and central heating control separate) programmer/controller next to boiler and a mechanical/analogue thermostat in the hallway of 2 storey house circa build 2002.

    The system is working, but I can't set the heating to a higher temp ie. 20C from 15C without getting out of bed and coming downstairs first thing in morning.

    Reading around it is suggested that people use the existing controller set to 24hour-7days CH on all time and use the controller just for hot water.
    The analogue thermostat is then replaced by a 'programostat'.

    I have seen 'smart' controllers etc but given issues with WiFi eg resets of cache I would prefer to kept heating a separate/ offline/standalone system. The system heats up quickly enough when I get home etc not to need geofencing etc.

    My options seem to be what I have described or a Radio Frequency box that is situated where thermostat is currently and a remote wireless programme box. Is this correct?

    I am leaning towards the former option.

    Thermostat is 3core plus earth.
    Lp722 controller is 4 wire (CH on, CH off, HW on, HW off) and both have industry std plate.

    What products do people recommend as a programostat?
    Accurate thermostat, backlight, wired / mains, reliable are important considerations.

    Looked at these

    Wireless options

    https://www.screwfix.com/p/danfoss-...rc=aw.ds#product_additional_details_container

    https://www.toolstation.com/drayton...kubbGCEWAdYBP1NYpv4aArK1EALw_wcB&gclsrc=aw.ds


    Wired options
    0.2 C temperature increment - accurate temp monitoring? This looks like it fits the bill? Neostat
    https://www.elementshop.co.uk/heatm...L4CmraI7fri_w10HasafsKbmqHbBlY0RoCYoYQAvD_BwE

    https://www.toolstation.com/honeywell-home-t4-7-day-programmable-thermostat/p76955


    Anyone recommend or discourage me from above?

    I probably don't need RF wireless controller. Is it possible to have two controllers (1 for up and 1 for downstairs) that communicate with each other IE settings altered?
     
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  3. Taylortwocities

    Taylortwocities

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    personally, if you already have a wired stat, and it has live, neutral and switched live (the 3-core&earth would suggest that is what you have) then I would go for a wired option. I quite like the Heatmiser range, but note that you'll also need a hub (£100+!) if you want to control things from your bedside.. The Digistat 3+ is a decent programmable stat. battery powered and easy to use. But no remote option.

    If you want to go full tech (ie control via wifi) then the
    MoesGo Smart Thermostat is pretty good. You can control that with an app (SmartLife) and alexa, google etc..

    re
    Much more complicated. Your house is one whole heating zone, two stats are usually used for when there are separate zones.
    Another option is to fit smart TRV valves to every radiator.

    Our friend @ericmark will be along shortly with a 5-page treatise on a myriad of heating options, including somethig called OpenTherm. So, get a compfy chair, and a pot of tea....he'll be along soon..



     
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  4. CBW

    CBW

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    Not forgetting referencing his own heating system :LOL:

    @DIYAmelia I’m inclined to agree with TTC, you can easily go for a WiFi version, or just a wireless room thermostat, which the receiver could just go in place of wired thermostat.
     
  5. ericmark

    ericmark

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    I found what I think are the boiler installation instructions and a find command does not find ebus or OpenTherm so it seems you don't have the option of using a analogue thermostat, the analogue is better, but your stuck with digital it seems, i.e. on/off.

    I found cheap hard wired programmable thermostats work well, ae235.jpg around £35, but with wireless had problems with lack of fail safe, if RF is lost, you want boiler to turn off, not just keep on heating. So with wireless we jump from £35 to £100 in the main.

    I would agree, they seem to work well, think there are around three versions, one for electric UFH, one for standard gas boiler, and can't remember the part numbers.

    However I want to swing my legs out of bed to a warm room, so by time any wifi linking to phone has turned on heating and warmed room it is too late, so only want timed control.

    These EQ-3 Bluetooth Smart Radiator Thermostat.jpg cost me £15 each and they allow me to set temperature in each room at different times of the day, but they do not tell the boiler when to fire up. Hive TRV heads link to the Hive wall thermostat, so if we for example have two rooms, one which catches morning sun, so some times one room heats up first and on another day it is other room, a Hive wall thermostat with one linked TRV head can ensure the boiler runs when either room is cool.

    Some systems have algorithms to work out what is the likely result, so Drayton Wiser have TRV heads that work out how long it takes to heat the room so it adjusts how far in advance to start heating the room.

    It is hard to keep up, when Hive first came out it did not link to TRV heads and compared to Nest was rubbish as Nest had the algorithms, but now Nest has no remote sensing so only monitors one room, so Hive is better, but in USA Nest has released satellite units so can work with 4 rooms, when this comes to UK Nest may work better.

    My brother-in-law's house had around £20,000 worth of control, it was installed when house was built, to be frank that is the only way, as reinforced floor required for the water tanks used, but the point is you can spend silly money to control the central heating.

    In spite of having Nest Gen 3 fitted to my house, likely the best for both me and you is Hive, with two Hive TRV heads and rest cheap eQ-3 heads. There are better, but I do not use geofencing.

    MoesGo Smart Thermostat does not link to TRV heads, but it depends on your house, my last house was open plan and it would have worked fine.
     
  6. DIYAmelia

    DIYAmelia

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    Thanks for all the replies!

    I enjoy tech, but a smart system is a step too far. I already replaced all the TRVs (4 ended up leaking after 12 years old) and replaced everything with 10mm radiator valves with or without drain. At £1.30 they offered economy over £15 TRVs. The house is a 4 bedroom with single fin rads in most rooms. The rads are turned down somewhat upstairs and fully open downstairs. Previously all TRVs were fully open or near full. Given the cube like shape of house, this setup works. I can see use of TRVs when house is unusual shape (cooler rooms due to excess losses) or if output of some rads is bigger output than needed for room)

    All rads have been off wall to flush out sludge with power washer.

    So, I don't really want to touch the rad valves with smart valves.

    20k on tech! Wow! That's my energy bill over 20years. But, might be my bill over a shorter time having lost my energy supplier I had a nice priced deal with.

    I think a wired all in one controller and thermostat fits the bill. I have a predictable routine, so I can set it up with times in advance.

    The current thermostat is supplied with L, Red, N, Black, Switched live, Yellow and Earth, Yellow/Green.
    See photo.

    Any advice on what to do with the Drayton LP722 controller? If it fails, it appears they still sell this model. About £40 to £60.

    Taylor two - I noticed that hub was pricey!
    What do you like about the Heatmiser programostat? I'm comparing with the Honeywell model above. Accurate thermostat would be good. I can twist the analogue thermostat dial 2C either way before it switches on/off (slack in dial)

    I read up on OpenTherm. I don't think my boiler has that communication.

    Thanks
     

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  8. DIYAmelia

    DIYAmelia

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    IMG_20211102_190502_2.jpg drayton lp722 controller for reference IMG_20211102_191657_2.jpg
     
  9. Taylortwocities

    Taylortwocities

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    Keep it (I have one too). You’ll need it to control timing for the hot water. Just set the heating side to always on and use the time function on the new stat.
    I’ve installed a lot of the Heatmiser NeoStat range for a number of customer projects.
    They are solid and accurate, easy to install and to programme and understand. They look better than most too.
     
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  10. DIYAmelia

    DIYAmelia

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    Drayton Digistat + 3 7 Day Programmable Room Thermostat (240 Volts - Mains) looks promising. Not backlit LCD display, but plenty of options. 3 wire installation, so like for like.

    The Heatmiser needs a 35mm back box according to reviews I read, so this would protrude too far out of the hallway wall.

    Thanks
     
  11. CBW

    CBW

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    I’m confused, are you getting an RF version? Otherwise you’re just replacing a mechanical stat for a digital one, but still having to up the temperature getting out of bed? :confused:
     
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