Home » Business » The HRV emerges as a possible culprit

The HRV emerges as a possible culprit

Agnew continues to study the problem, going as far as buying a manometer to see how much negative pressure is produced by his bathroom fan, dryer and range hood.

In the process, he stumbles on a problem he hadn’t considered. When a defrost cycle in the HRV kicks in, the stove back drafts.

“I was not aware that the defrost cycle actually circulated air, but was under the impression that it was an electrical element that defrosted the core,” Agnew says. “I am kind of amazed that they would engineer a negative pressure cycle into the HRV knowing the kind of houses it is meant for Wood Fire Direct Melbourne.

“It would make sense that this was the reason the stove back drafted two times initially (seemingly at random times) since we were running the stove because it was particularly cold out (-10°F),” he adds. “The temperature difference creates condensation/frost in the core and that would trigger a defrost cycle.”

A dryer vent booster fan with a pressure sensor might help, Agnew says, by bringing in additional fresh air when there is a sudden negative pressure in the house. The booster could be wired to a switch so it was used only when a fire was burning in the stove, but Agnew isn’t convinced the arrangement would work.

Heating Consultant Melbourne Actually, Holiday adds, there is a control device on the market that would supply more air to the indoors when the house became depressurized. Holiday reviewed the control, the Exhaust EBC 14, back in 2008.

“The main disadvantage of the EBC is its high price; it lists for $300, although contractors will pay significantly less,” Holiday wrote in his original review published in Energy Design Update. “Moreover, a complete makeup air system will require several other components in addition to the EBC 14 control: the outdoor sensor, a supply air fan, and, in some cases, a heating coil to condition the makeup air Wood heaters Melbourne.”

Our expert’s opinion

Here’s what GBA technical director Peter Cost had to say: Since the issues involved with this GBA Spotlight are not part of my expertise, I asked around our industry, and three different colleagues said, “You really ought to check in with Skip Hayden.”


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