Gallons per Minute

When shopping
for a tankless water heater the first thing people check out is how much hot
water is the unit can provide. Next, they often look at the various features
the units have and try to get the ones wtih the most high-tech features for the
lowest price. The size and maximum hot water capacity are very important
indeed. So are the additional features. Yet, what does not get the attention it
deserves is the minimum flow rate of tankless water heaters. A low minimum flow
rate can make a tankless machine stand out as better than the rest. Let us now
see what exactly it is.
Tankless Water
Heater Minimum Flow Rate
Tankless water
heaters do not heat water all the time. They just stand there on your wall
burning no gas until you open a hot water tap. This is when water starts moving
through the unit’s heat exchangers and once the unit’s sensors see a certain
rate of water flow in the system, the tankless water heater will start heating
up with tremendous power. The amount of water that must be passing through the
water heater to trigger the heat exchangers is called the minimum flow rate or
the activation flow rate. If you open the tap so little that only drops of
water are coming out, the heater will not sense it and stay cold because the
minimum flow rate threshold has not been exceeded.
A High
Activation Flow Rate Can Ruin Your Shower
There are
countless manufacturers and brand names to choose from when it comes to
tankless water heaters. You can get a tankless water heater for as low as $200
but it is not going to work as well as you expect. This is because it probably
has an activation flow rate of about 1 gallons per minute, which is a lot. You
would get cold water very often with such a unit because it will not sense that
cold water is actually passing through. The sensors that tell the units brain
that water has started to flow are not that simple to manufacture and not every
company can make them sensitive enough.

 

What are Some Tankless Brand Names with Low Minimum Flows

Better
tankless water heater models have lower thresholds. Rheem and Rinnai are two
brand names that offer the best possible thresholds for starting to heat the
water. The water heaters fron both of these manufactures start running once you
pass 0.4 gallons per minute and they run as long as you do not fall below 0.25
gallons. This is the best you can get in the market and it is one of the
several points that makes them the two tankless brand names.