Tankless Water Heater Sometimes Loses Hot Water for 1-2 Min

[Astroguy]

Hi everyone! I have a Takagi tankless water heater. Occasionally (especially now that it has turned warmer) I will notice the water turning suddenly cold in our bathroom faucet. This normally happens after 10 min or so of water running, but not every day. If I turn the other bathroom faucet on it will normally come back in 1-2 min.

Only rarely do I notice this on other faucets. Any ideas on how to fix this? When bathing our new baby the sudden cold water is not pleasant for anyone!

Thanks,
Michael

 

[Dana]

Try increasing the flow or lowering the programmed output temperature of the Takagi.

With warmer seasonal incoming temperatures it takes less 120-140F water to mix down to a more reasonable 105F temperature at the tap. When the flow through the water heater drops below ~0.5 gpm it turns off the burner. With a lower output temperature, say 110-115F (still hot enough for a tub fill) there will be marginally more water flowing through the water heater.