Why proper venting on gas water heaters is important?

by Zee from water heater reviews
(Canada)

Did you ask yourself is the room where your gas water heater is installed, properly vented? Does it produce the pilot outage or improper gas burning?

Carbon monoxide is the worst what can happened if the venting is blocked or if it works with problems.

I will explain here what are the reasons for the venting issues. One problem is related to the negative air pressure, inside the room where your gas water heater is installed, and the other is if your unit is located in places like the attic.

Negative pressure and venting

Negative pressure inside the room is happening when there is an air movement from outside to the inside, i.e when the air pressure outside is higher than the pressure inside the room.

Kitchens and laundry rooms are the worst spots for your gas water heater as the venting devices will pull the air out and create negative pressure. This is why you should make sure that if one cubic of air leaves the room, the same amount has to be brought in to replace it.

If there is a negative air pressure, products of combustion, made by the gas water heater, will reverse its direction, and cause the problem.

The most common symptoms of the improper venting associated with the negative air pressure are:

- The combustion of products are pulled into the room and there is a higher concentration of CO2 and CO.
- Pilot light outage.
- Sooting.
- Poor water heater performance.
-Slow recovery of the gas water heater.
- Flame rollout.

Solution for this problem is to provide the proper venting by removing the obstruction, providing a lot of fresh air or install the unit in a room (without other devices) which is not subjected to the negative air pressure.

Attic location and improper venting

If your gas water heater is installed in the attic, you might have experienced problems with your heater due to the inadequate venting.

The heat in the attic can build up to extremely hot during the period of time and that can cause the problems.

Most of the heat comes from solar heat transmitted through the roof. Due to the increased attic temperature, the pressure will increase also and less oxygen will be available for gas combustion.

Pilot outage is the most common problem that you will see on the gas fired water heaters installed in the attic. Since the temperature in the attic can fluctuate due to the weather conditions, water heater pilot can go out occasionally.

Solution for this problem is to supply the attic with sufficient fresh air.