Radiator without TRV
Just installed and have had my Tado running for over 3 weeks now. However I wanted to understand why two of the radiators in the rooms (hallways and master bedroom) where the wired thermostats are installed (that replaced the old wired one) have no Thermostatic Valves.
I read somewhere that it’s to balance temperature but in a smart system that’s not needed.
The reason I ask is that I I think when the TRV using the wired thermostat in say the master bedroom to call for heat; the radiator in the master bedroom gets warm too as it’s not “smart”.
Comments
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The two radiators without TRVs are probably intended to act as bypasses so that the pump never has to operate on a fully closed system. The necessity for this is sometimes debated and can be avoided by fitting an external boiler bypass but I imagine it was an intended design feature of your system . . .0
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It’s a design flaw for modern living. Heating ‘off’ in the bedroom during the day means the upstairs spare room is cold when used as WFH office. Similarly, the nursery is cold; or the bedroom is baking overnight to keep the nursery warm.
Worth investigating if the boiler needs the bedroom rad as as a bypass or could fit a TRV.0 -
I was reading about an ABV (Automatic Bypass Valve) and appear to have at least one (bottom circle), not sure what the top circle is for.
Reading the manual, it says this:
When thermostatic radiator valves are used, the space heating temperature control over a living / dining area or hallway having a heating requirement of at least 10% of the minimum boiler heat output should be achieved using a room thermostat, whilst other rooms are individually controlled by thermostatic radiator valves. However, if the system employs thermostatic radiator valves on all radiators, or two port valves, then a bypass circuit must be fitted with an automatic bypass valve to ensure a flow of water should all valves be in the closed position.
Page 13 https://idealheating.com/uploads/documents/logic-heat-h-installation-and-servicing.pdf
So now to figure out if I have this automatic bypass valve
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The top circle is an automatic bleed valve to allow trapped air in the system to escape.
A bypass is essential in all systems to prevent possible serious damage to the boiler and/or pump. Generally, a radiator used as a bypass can be identified by having lockshield valves fitted at both ends of the rad. This is to prevent the radiator being turned off without using tools.
Most likely in the op senario, trv's are never fitted in rooms with a room stat. Obviously, the valve could close before the stat reaches temperature meaning the heating would never switch off. It has nothing to do with system balance.
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This is to stop the TRV fighting the thermostat in scenarios where someone has turned the manual TRV to a low level (say 3) but then try calling for 23oC. In this scenario the heating would remain on forever.
To stop this happening they often don't put TRV's in the same place as the thermostat. Obviously with Tado you can stop this happening with the way you setup the TRV's and thermostats. However, in a property with manual controls this is a failsafe.
Usually, bathrooms are used for bypass purposes (if the plumber is too cheap to do it right :)). Combi's also have an internal bypass (however you don't want to rely solely on that with Tado installed, else the boiler will be having a real bad day!)
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Thanks for all the feedback and it makes logical sense. I’ll probably see if I can move the non-TRV into a bathroom as am finding the hallway gets overly warm … but that’s a job for the summer.0
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You don't necessarily need a TRV on the hallway, you can adjust the flow to the that radiator with the valve on the opposite side. This is used for balancing the system.
Try turning the hall rad valve down towards the - symbol 1 turn. This just reduces the amount of hot water flowing to that radiator.
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