Central heating not getting to temperature
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Hi All,
I wonder if anyone can help or has experienced a similar issue.
We have a system boiler that is likely 20 years old and a water tank on the second floor for storing hot water, which has its own thermostat. The central heating had a wall mounted thermostat in the living room before we replaced it with a wireless tado thermostat, wireless receiver and internet bridge.
We have noticed that the central heating only comes on when the hot water is also on, when the hot water is off (for example over night) the temperature drops until it turns back on again. The other thing we have noticed is that the central heating will rarely get to the required temperature unless we turn up the thermostat on the water tank.
Regardless of whether there is a demand for central heating tado does not seem to turn the boiler on, when the hot water is either off or presumably, at temperature - meaning the house rarely gets to the 21C we set it at.
Is there any settings with in the software or hardware that are likely to make a difference or could it be a mechanical fault with the boiler?
I wonder if anyone can help or has experienced a similar issue.
We have a system boiler that is likely 20 years old and a water tank on the second floor for storing hot water, which has its own thermostat. The central heating had a wall mounted thermostat in the living room before we replaced it with a wireless tado thermostat, wireless receiver and internet bridge.
We have noticed that the central heating only comes on when the hot water is also on, when the hot water is off (for example over night) the temperature drops until it turns back on again. The other thing we have noticed is that the central heating will rarely get to the required temperature unless we turn up the thermostat on the water tank.
Regardless of whether there is a demand for central heating tado does not seem to turn the boiler on, when the hot water is either off or presumably, at temperature - meaning the house rarely gets to the 21C we set it at.
Is there any settings with in the software or hardware that are likely to make a difference or could it be a mechanical fault with the boiler?
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Answers
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Do you have a 3-port motorised valve to divert hot water between the cylinder and radiators? If you do, and Tado has previously worked OK, then I suspect your valve may be faulty. If the Tado system has never worked properly then it could be a wiring issue.
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Thanks @GrilledCheese2. The honest is I really don’t know without opening up the boiler.
Just looking back at the graphs for when it was first installed it looks like it was working correctly (I.e maintaining the target temperature irrespective of whether the hot water was on or off). However, after around a month of use it looks like it stopped doing so reliably. It’s a shame I can’t share the graphs really! For at least the last three months it’s only worked in the way I have described above.
I suppose this sounds like it could be a valve slowly failing, eventually failing completely?
I have checked and double checked the wiring according to tado instructions for my boiler and controller.
Is there a simple way to check operation of the valve, if I did open up the boiler?0 -
If you have a system boiler the motorised valve will be inside, so not really accessible. Even with access they’re not easy to test without the right tools. The reason I wrote it might be a faulty valve is due to the default unpowered position being HW only. There’s a spring inside the motor housing that will pull the valve to the HW only position. The motor has be energised and overcome the spring’s resistance to get the valve to the mid-position or CH only.
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