This problem generally relates to a restriction of water flow at the outlet

All Continuous Flow Hot Water Systems require water flow passing through them to keep them activated

Things change depending on cold water temperature /Hot water temperature / set temperature / flow rate

Here is an example

If you have a 6 LPM Water saver shower head

And you have to achieve a minimum flow rate through the hot water system generally min. 3lpm

To keep the appliance running

This means the max. Avail cold is 3 lpm

3 of hot and 3 of cold = 6lpm

So our calculation looks like this

Winter equation, Temperature when mixing hot and cold

Hot water 3 lpm x 60c = 180

Cold water 3 lpm x 15c = 45

3 + 3 = 6 (mixed flow rate)

180 + 60 = 240

240 Divided by 6 = 40c (approx. showering temp.)

Summer equation, Temperature when mixing hot and cold

Hot water 3 lpm x 60c = 180

Cold water 5 lpm x 28c =140

3 + 5 = 8 (mixed flow rate)

180 +140 = 320

320 Divided by 8 = 40c (approx. showering temp.)

So you can see from these calculations that during winter the mixed flow rate is 6 lpm

However through summer the mixed flow rate is 8 lpm to achieve 40c

The problem is if you have a 6 lpm water saver shower head you will need to replace it with one that allows at least 8 lpm based on this calculation to operate the same way during summer

Basically you need more water flow to pass through your shower head through summer opposed to winter to ensure that the Continuous Flow Hot Water System stays on

Or reduce the temperature coming out of the hot water system

This is a very basic understanding of this principle

These dynamics are the same for all makes and models of Continuous Flow Hot Water Systems

It is not related to any particular manufacturer’s product

What you can do

1. Check your shower head for blockages or restrictions

2. Reduce the outlet temperature from your hot water system

or

Please call our office and arrange for one of our qualified service technicians to test and rectify this problem for you

Hot Water Repairs