Water Heater Condensation
What
causes condensation in water heaters
How to reduce condensate in heating
Water heater condensation is not a leaking. When the gas water heating appliance is working condensate is the normal occurrence. How to recognize condensation in water heaters, what to do and how to troubleshoot is what you will find in this article.
What is water heater condensation?
When gas is burning, there is a lot of moisture in products of
combustion, and when the flue gas product, water vapor, is chilled
below the dew point, water heater condensation occurs. The dew point is
the temperature at which water vapor turns into the liquid state,
called condensate.
Why it condensates in water heaters?
In order to troubleshoot the water heater that has problems
with condensation you have to recognize the symptoms first and which
part of the unit condensates.
Shortly after the start-up, when the gas heater is filled with
cold water and the main burner is ON, the heater will release the
condensate. One of the main symptoms of condensation you will notice is
a puddle of water on the floor just below the unit.
Water heater condensation is happening especially when dealing
with the new heating appliances and for the first time.
You will also see a condensate after a long draw of hot water
in a short time and when the refill water is very cold.
When the temperature setting is set too low, condensation
might occur also. The solution is to increase the temperature.
An undersized heater is also the reason for more condensation,
and even with a heater properly sized you can expect some condensation.
The heater should be properly sized, to meet your family demand for hot
water, for shower, dishwashing and cloth washing.
Problems and how to solve water heater condensation
Excessive water heater condensation is not normal, but it may
be noticed during the winter and early spring when the outside
temperatures are the lowest. This is what can cause the pilot light
outage, premature corrosion of the burner area and tank itself. Small
black or red granules can be seen on the main burner and top of the
heater.
Hydrocarbons and carbonic acid are found in the condensate and
they will corrode the heater. The most exposed parts to the
condensation are flue tubes, baffles and burners.
Moisture from the combustion products will condense on the
cooler tank and form water drops which may drip onto the burner or any
other hot surface, resulting in the characteristic sizzling, frying or
popping noise within the burner area.
Continual exposure to the condensation will weaken the flue
tube. It can also affect the gas combustion producing a carbon monoxide.
Because of the suddenness and the amount of condensate, this
problem might be diagnosed as the leaking. Keep in mind that one half
of the gallon of condensate during every hour of operation is a typical
for home heater. It takes 1-2 hours for the tank to warm up so the
condensation should disappear.
Since new high efficient heaters and Energy Star models are
using powerful gas burners; and combining it with the latest technology
to extract even more heat from the flues and flames, they will
condensate more than the older heaters that are utilizing less energy.
One of the solution when troubleshooting condensation in the
heater is a good venting so the gas appliances will operate efficiently
and vent the products of combustion together with the water vapor
properly.
As the cooler flue gases are part of the reason for the
condensing problem, suggestion is to raise the supply air temperature,
increase the stored water temperature or increase the size of the tank.
A suitable metal drain pan, at least 2" wider than the heater
should be installed under the heater to collect the condensate and not
to damage the area.
How to distinguish between condensation water heater and
leaking
-
Make sure there is no water under the heater. If there is any wipe it up.
-
Turn the thermostat on the gas control valve to the pilot position.
-
Wait for a few hours, one day approximately, to check is there any water accumulated under the unit.
-
When the heater is heated above 110 F condensation should stop.
-
If there is no water under the heater than you have condensation. If there is a puddle, check for leaking.
Condensing water heaters and condensate
Condensing water heater, Vertex from AO Smith for example,
requires a drain located close to the unit so condensate can drain
safely. This heater has three places where the condensate drains from,
bottom of the unit and where the blower assembly is installed.
Ensure that the condensate flow is free and clear of debris
and the drain will not allow backflow through the hose. This is
important especially during the winter and freezing days.
On the power vent units, to prevent problems during water heater condensation, the vent pipe should always slope downward away from the blower. If this is not possible than an adequate water heater condensation trap or drain should be provided.
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