My gas water heater heats water in its tank to about 60 C for use which is great. But I don't know how to set a minimum temperature so that water does not cool below 30 C. Please help me.

  • While it's not likely that you can set a minimum, providing the make & model of the water heater would help us confirm that. Please edit that into your post.
    – FreeMan
    Dec 2, 2020 at 11:58
  • If your water heater set to 60°C is cooling below 30°C, options are: you are exceeding it's capacity to heat water, or it's broken. More likely the former. A water heater stores a certain amount of hot water, and can heat water at a certain rate. When you draw more hot water than it has stored, at a rate faster than it can heat water, the delivered temperature of the water will fall, even though the thermostat is running the burner full-bore.
    – Ecnerwal
    Dec 2, 2020 at 15:14
  • What is your water heater model. Mine never fluctuates low enough for me to tell a difference. Mine is at 54 C and it always feels constant. Do you have some sort of WiFi enabled system? Maybe someone is messing with you. Quite honestly the water heater sounds faulty.
    – MonkeyZeus
    Dec 2, 2020 at 17:50
  • Is this a pressurized hot water tank that fills automatically as hot water is drawn? Or is this a batch tank which does not automatically replace hot water as it is used? Dec 3, 2020 at 1:11

1 Answer 1


In a standard gas water heater there is no way to set a minimum hot water temperature. The thermostatic control has a pre set on/off differential.

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