Can a Tankless Freeze

Posted on Feb 1, 2013 | 0 comments

There are some interesting issues that develop with tankless water heaters and cold weather.  In general you can get build up on exhaust vents due to freezing condensation.  A tankless also has built in freeze protection for any outdoor models.  Lastly, there is a little trick to ensure your tankless pipes don’t freeze during a cold spell.

For home owners in Toronto, Hamilton, Mississauga and all towns around southern Ontario with a tankless you should keep an eye out for extremely cold weather.  We have had a few calls to address an issue with a tankless system not running or starting up.  It turns out that the exhaust vent can actually freeze closed from the condensation building up.  Do note that each situation was on a commercial tankless application that required the system run for extended periods.  This also only proves to be an issue when temperatures plunge below -20 Celsius.  As a home owner with a tankless, if you happen to find that your system is not running and the temperatures are really cold it may save you the expense of a service call to take a quick peek at the tankless exhaust vent.

Tankless systems are built well, internally most have tankless freeze protection systems.  Basically it is a heat trace line applied to all areas that have the potential to freeze and crack.  There is a simple thermometer inside your tankless constantly assessing ambient temperature.  If for some reason it happens to dip below 0 the tankless will automatically protect itself by applying heat to its vital organs.  In Ontario all of our tankless water heaters are installed indoors so it’s not very probably that the tankless freeze protection will ever be used.  Well, I guess if its winter, you’re away on vacation, and the furnace happens to fail… Your tankless will be safe though!!

Last little trick for those that have in outdoor tankless at their cottage or somewhere more exposed.  If you know that the temperatures are headed down into the dangerous negative temperatures you can simply turn your tap on to a trickle.  A tankless requires a flow of ½ a gallon a minute to fire up the burner.  If this is not met the system will not burn, this little flow rate will help prevent (in reasonably cold temperatures) the water from freezing in your pipes.  This is just an emergency technique and shouldn’t be relied upon to prtect from a tankless freeze up.