Ventilation and Heat Exchanger Testing

The part five in a series of special reports discussed the multiple step-by-step instructions for ventilation and heat exchanger testing. Although the combustion analyzer does not measure them, proper ventilation/infiltration air, sufficient combustion air, and a safe heat exchanger are critical to proper operation of a gas- or oil-fired appliance. No combustion test or appliance inspection is complete without addressing these concerns. The ventilation air test is a worst-case test used to determine whether or not enough indoor air and infiltration air is coming into the building. If the building does not have enough infiltration air, provisions must be made to bring in outdoor air to replace the air used in the combustion and ventilation process. You can use a flue gas combustion analyzer effectively for finding leaking cracks or holes in a furnace heat exchanger. On all furnaces, the static pressure achieved by the system blower can overcome any positive pressure in an atmospheric draft appliance.