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Why is my Hot Water not getting up to the temperature?

Before explaining the steps to check why is your Hot Water not getting up to the temperature we need to make the difference between the Hot Water ON / OFF control and the Hot Water temperature control. With the first type of water control you can only switch ON / OFF the Hot Water and the second type gives you the temperature control on top of the ON / OFF control.

Our Dual Channel Receiver is a direct swap with a non-automated timer as is switching on or off the boiler. Replacing the Dual Channel receiver with any other time would not solve the problem to how long takes for the hot water to warm up.

For ON/OFF & Temperature Hot Water controlled


  1. Check if the channel of the Dual Channel receiver (the part that controls the boiler) is assigned to the Hot Water Zone. Usually, Channel 2 (bottom button) of the receiver will be controlling the Hot Water but you will need to double check the label on the device itself if this is right. Here is some help for assigning the Dual Channel Receiver in the case is not assigned.  
  2. Check the schedule of your heating period. Sometimes for the Hot Water to get to the temperature you might need to extend the heating period. So for example, if you are having the hot water on for 30 minutes try the extend the period for 60 minutes and see if the temperature is getting to the temperature you want. One more thing to consider is it can be that the boiler would prioritise the Hot Water for the radiators but this must be checked with a plumber.  

For Temperature Hot Water controlled

  • Check that a temperature is being displayed for your hot water zones. If you do not have a temperature displayed. Check this article
  • If the above is correct you will need to check if the Cylinder Stat temperature is higher than what is on the app and if the temperature coming out the Boiler is higher than what is in the app. To do this, check the physical, wired cylinder stat on your hot water tank and ensure that the limit temperature is set slightly above the uppermost temperature you have set on your schedule.
  • Check the location of the Temperature Probe. If this is not properly affixed to the hot water tank or is reading in the wrong place, the temperature displayed on the app will be wrong.

According to building regulations, a mechanical cylinder stat must be left in place when the new temperature probe is added for health and safety reasons in event of a failure in the wireless communication, and so this is shown on all of our wiring diagrams.

How to attach the Temperature Probe (Floor/Tank) to the hot water cylinder

To get the best results you must ensure that your Temperature Probe is positioned correctly against the side of the hot water tank or ideally inside the pocket on the hot water tank.

If there is a pocket on the side of the hot water tank, you should place the Temperature Probe inside this pocket. 

If you do not have a pocket in the side of the hot water tank:

  • Using silicone thermal paste, adhere the end of the Temperature Probe to the tank in the place specified by the hot water tank manufacturer.
    • Unfortunately, we cannot give specific advice as to the best location of the temperature probe as this is dependent on the design of hot water tank. As a general rule of thumb, the higher the probe is located the closer it reads to the tap temperature, however, the temperature reading may vary more depending on the location and size of the heating coils in the tank.
  • Make sure that the probe is touching the metal of the side of the tank and there is nothing in between it
  • Cover the probe in insulation so that no heat can escape from above the probe.
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