How to fix fluctuating water temperature in shower?

Question

Hi

Since installing a water saving shower head we have had widely fluctuating water temperatures in our shower. It is the only shower in our flat. We do not have this temperature fluctuation problem with the water anywhere else in our flat. Thank you in advance for your assistance.

MitchellMc · Answer

Hi @mungkinfay ,

If your current shower head is restricted to around 6L/min, then replacing it with the 9L/min flow regulator included in a set such as the Kinetic Water Saving Discs might provide enough flow for your hot water system to operate consistently. However, if your continuous flow unit requires more than 9L/min to remain activated, that alone won't resolve the issue.

The best approach is to check the specifications for your hot water unit, or have a licensed plumber confirm the minimum flow rate it requires to operate correctly. You can then choose a WELS-rated shower head or flow regulator that's compatible with that requirement.

I wouldn't recommend removing the flow restrictor altogether, as doing so can significantly increase your water consumption without necessarily improving the performance of your hot water system.

Mitchell

mungkinfay · Answer

Hi

In a previous post I made about temperature fluctuations in water in our shower , Mitchell suggested that we may need to remove the flow restrictor. Is there any way we can do that ourselves? Thank you for your time.

MitchellMc · Answer

Thanks for confirming those details, @mungkinfay .

As you have a gas continuous flow hot water system with separate hot and cold taps, and the temperature fluctuates even when no one else is using water, the new water-saving shower head is the most likely cause.

Water-saving shower heads reduce the flow rate, and if the flow drops below what your continuous flow hot water system needs to stay operating consistently, the burner can cycle on and off. That causes the water to alternate between hot and cold while you're showering.

Since it's a standard water-saving shower head installed as part of a government scheme, there may also be a flow restrictor fitted inside it that's reducing the flow even further.

As a simple test, I'd recommend temporarily fitting a standard shower head with a higher flow rate (if you have access to one) and seeing whether the temperature remains stable. If it does, you've identified the cause.

If you need to keep the current shower head, it would be worth having a licensed plumber inspect it. They can check whether the flow restrictor is appropriate for your hot water system or whether an alternative WELS-rated shower head that provides a slightly higher flow would be a better match.

Please let us know how you go, as it will be helpful to hear what resolves the issue.

Mitchell