Could use some help to gain efficiency (35%)

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Good evening all

I am seeking some of the help to get my setup right. I got Ideal Vogue 32 Max in my 3-bedroom house. I run it with a total of 11 radiators. My heat loss calculation seems to be (if I have done it right) at about 6.7kW.

I got Tado Wireless kit (EU version) and it is plugged in and configured for OT. I do run it with Auto Geofencing which I do know some people got mixed feelings but it does work for me. I got 4 TRV valves (2 most used bedrooms, kitchen and living room). My main sensor is installed in hallway where we got two radiators - one a bottom landing and one at the top.

Why am I seeking higher efficiency? As per title my boiler is showing 35% efficiency which prior to installing Tado, it was showing a shocking 25%!! Since I configured scheduling and times I am happy I get enough heat and I tend to run 19.5C max at times I need to heat (30min in AM and about 3h between 5PM - 8PM.

From checking the system and all "signs" I do not think I take advantage of the condensation mode as much as I should.

My max flow temp settings are 50C but yet my return temperature is still very high.

I bought 10x LCD temp probes to measure return and feed temperatures across radiators. What I have found on initial readouts is:

At time of the checks it was 8C deg outside.

  • Loundge rad is running 38.5 deg on feed and 23.7 on return while TRV setting where at 19.5C. Am I right in saying it is DT15C?
  • At boiler pipes I had 45.8deg on feed and 40.1 on return which gathering from the picture below something might be off by 2deg as the boiler screen was reading 48 and 42.

Please let me know where do I start with getting this system right. I gather it might need balancing but before I start making any adjustments I would like to explore all first.



Comments

  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited February 2023
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    Yes, balance the radiators as a priority. If you've got dT15 on one radiator and dT5 on the primaries then it suggests one or more radiators are passing too much water. If you have some particularly small radiators then the lock shields on these will probably need screwing in most of the way. You want dT12 - dT20 on each radiator which should give you a similar value on the primaries.

    Note that the minimum output on your boiler is 4.9KW. If you're concerned about efficiency then you don't want the load to be less than this value. Meaning you don't want too many radiators to be closed at any time. Depending on size the output of your radiators is likely to be in the range of 400W to 1500W each.

    Also, you'll need one med/large radiator without a TRV to act as the bypass i.e. it is always in circuit and giving out heat when the boiler is on.

  • BOG73
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    As @GrilledCheese2 stated you need to balance your radiators and I suggest to look at HeatGeek site for boiler pump speed,you mite need to lower your pump speed first and after play with return flow via return lockshield valve.Give it a try and see how your radiators get heat at lower speed,look for the further ones from your boiler. In my case,i have adjusted the return valves so many times without getting more then 7-8°C differential flow-return and only after reading HeatGeek article about setting boiler speed pump i've managed to see 15°C+ to 20°C differential flow/return. My boiler is a Viessmann 100 35Kw(2019 model) running 13 radiators and the range of pump speed can be adjusted from 72 to 100 and gradually lowering the speed i have foud the best speed at 80,so i am somewhere bettween low and middle speed pump. I am not a tech and just share my experiences with Tado and heating.

  • allias3g
    allias3g
    edited February 2023
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    @GrilledCheese2 thank you for what you pointed out. After what you said I realized I was running it with one rad heating. That way I can not have better efficiency and I lie myself about how well the heat is being distributed inside the house.

    @BOG73 you both right I need to balance system as I was able to tell as my 2 rads are all over with settings.

    That just proove how full was my plumber who said "I did balance your system" once he finished his work last time.🤕