Retrotec Residential Pressure & Air Leakage - Manual (Page 33)

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house, and the presence of large leaks in the duct system. Ultimately, a measurement of 0 Pa would indicate no
leakage from the duct system because it shows that the ducts are at the same pressure as the house (0 Pa
difference).
Figure 11 Small and Large Pressure Pans
To test registers using a pressure pan
1. Connect a pressure tube from the “Input A” (blue) port on the gauge to the port on the pressure
pan.
2. Place the pressure pan over the register, so that it is completely blocked. If the register is too large
and cannot be totally covered by the pressure pan, seal around the register with Grill Mask, until the
remaining hole can be covered by the pressure pan.
Channel A displays the pressure difference between the house and the duct system behind the register.
4.2.5. In a pressurized house, smoke will be pulled quickly into the duct near the
leaks
One of the simplest ways to identify leaky sections of duct is with a smoke tester while the house is pressurized.
Large duct leaks will pull a lot of air into the duct system nearby the leaky sections. This test works because
when the house is pressurized, the ducts should be similarly pressurized. However, when there are large leaks
to the outdoors in the duct system, the area around the leak will be at a smaller pressure than the rest of the
house/duct system. Air, therefore, will be pulled into the lower pressure area, and out through the leak.
To perform a smoke test for leaky ducts
1. Turn off the air handler, and open all registers. The air filter should be removed.
2. Setup the Blower Door for a basic air leakage test, and pressurize the building to about 25 Pa.
3. Squirt a small amount of chemical smoke near each register. If the smoke is pulled into the register
quickly, it is an indication that there is a significant leak to the outdoors in the nearby ducts. If the
smoke does not enter the ducts, or does so slowly, there is little to no leakage in the area.
4.3 Closed bedroom door test to check pressure balance
Some rooms, especially large master bedrooms, can cause pressure balancing problems when the door to the
room is closed. In some cases, a room may be more connected to the outdoors than to the rest of the house
when air isn’t able to pass through the doorway.
To conduct a closed room door test