Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Energy Recovery Ventilators
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## A recovery device exists to pre-condition outdoor air using energy that would otherwise be discarded with the exhaust, so that the downstream cooling and heating equipment is smaller and the annual ventilation energy is lower; the device's certified effectiveness, its cross-stream leakage, and its frost behavior are the central engineering decisions, not accessories. {note}
−## Where moisture transfer between the two air streams is unacceptable for reasons of contamination, the recovery device must keep the streams physically separated, which restricts the technology choice and is treated as a hard constraint in this standard rather than a preference. {note}
+## Where moisture transfer between the two air streams is unacceptable for reasons of contamination, the recovery device must keep the streams physically separated, which restricts the technology choice and is treated as a hard constraint in this standard rather than a preference.
## Equipment shall be certified or rated in accordance with AHRI 1060, tested in accordance with ASHRAE 84, and selected to satisfy the exhaust-air energy recovery provisions of ASHRAE 90.1 and the air-stream classification and cross-leakage limits of ASHRAE 62.1.
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## Where conflicts exist between referenced standards, the adopted energy and mechanical codes, the equipment manufacturer's instructions, or the contract documents, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## The energy code and ventilation standard editions adopted by the authority having jurisdiction shall be confirmed before selection, because the energy recovery mandate thresholds and the cross-leakage limits differ between editions. {note}
+## The energy code and ventilation standard editions adopted by the authority having jurisdiction shall be confirmed before selection, because the energy recovery mandate thresholds and the cross-leakage limits differ between editions.
## Referenced standards list {toc}
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### An undersized or unadjusted purge sector allows more exhaust air to be carried across the wheel than the certified EATR assumes, which is why the purge setting is a commissioning item, not a factory-only setting. {note}
+### The served exhaust air stream class shall be specified per ASHRAE 62.1, and the purge sector shall be commissioned to keep exhaust air transfer within the certified limit.
+
```datasheet
label: Exhaust Air Class and Leakage Limits — Served exhaust air class (ASHRAE 62.1)
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### The outdoor air correction factor shall not exceed 1.10, and the certified OACF shall be reported with the effectiveness ratings.
−### The outdoor air quantity calculation shall apply the certified OACF so that the certified intake airflow at the building exterior is sufficient to deliver the required outdoor air to the spaces after device leakage.
−
−### Omitting the OACF from the outdoor air quantity calculation causes the building to draw less outdoor air than the ventilation requirement demands, because some of the air entering the intake is lost to leakage within the device before it reaches the supply duct. {note}
−
```datasheet
label: Outdoor Air Correction Factor
…6 unchanged lines
```
+### The outdoor air quantity calculation shall apply the certified OACF so that the certified intake airflow at the building exterior is sufficient to deliver the required outdoor air to the spaces after device leakage.
+
+### Omitting the OACF from the outdoor air quantity calculation causes the building to draw less outdoor air than the ventilation requirement demands, because some of the air entering the intake is lost to leakage within the device before it reaches the supply duct. {note}
+
# Device Configuration and Selection {toc}
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### A rotary wheel shall include a purge sector, variable-speed or modulating wheel drive where capacity control is required, and an accessible drive belt and seal set.
−### The wheel rotation shall be confirmed during startup, because a wheel that has stopped or is rotating against a failed drive delivers essentially no recovery while the unit appears to operate normally. {note}
+### The wheel rotation shall be confirmed during startup, because a wheel that has stopped or is rotating against a failed drive delivers essentially no recovery while the unit appears to operate normally.
## Fixed-Plate and Heat-Pipe Devices {toc}
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### A large imbalance between the supply and exhaust airflows changes the actual effectiveness and the cross-leakage from their certified values and can pressurize or depressurize the building, so the design and balancing shall hold the streams within the device's rated imbalance limit. {note}
+### The fan arrangement shall be specified as integral to the packaged unit or external in a separate air handler, and shall be balanced within the device's rated imbalance limit.
+
```datasheet
label: Fans and Airflow — Fan arrangement
…5 unchanged lines
```
+### The design supply (outdoor) airflow shall be specified, and it shall be balanced with the exhaust airflow to remain within the device's rated imbalance limit.
+
```datasheet
label: Fans and Airflow — Design supply (outdoor) airflow
…7 unchanged lines
```
+### The design exhaust airflow shall be specified, and it shall be balanced with the supply airflow to remain within the device's rated imbalance limit.
+
```datasheet
label: Fans and Airflow — Design exhaust airflow
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## The sequence of operation shall be submitted and shall define the priority among recovery, economizer bypass, and frost control when their conditions overlap.
−### When the outdoor temperature is low enough to call for frost control at the same time the device would otherwise be in economizer bypass, the sequence shall make clear which mode governs, because the two are mutually exclusive and an ambiguous sequence leaves the device oscillating. {note}
+### When the outdoor temperature is low enough to call for frost control at the same time the device would otherwise be in economizer bypass, the sequence shall make clear which mode governs, because the two are mutually exclusive and an ambiguous sequence leaves the device oscillating.
# Testing {toc}
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default: "One complete set of replacement filters per device"
```