Retrotec Flow Box - Exhaust Fan Flow Meter & Pressure Pan

Retrotec Flow Box - Exhaust Fan Flow Meter & Pressure Pan

The FlowBox is a passive exhaust fan flow meter that utilizes the DM32 manometer to measure exhaust only flows. This tool is perfect for measuring flow for bath fans, kitchen exhaust, room returns and whole-house ventilation. It uses the same type of range plugs that are found on our DucTesters and Model 5000 and 6000 blower doors. In addition, you can use the FlowBox as a pressure pan by simply using all blank range plugs.

The FlowBox has several unique design features that put it in a class of its own, including:

• A large 16.5" x 16.5" x 8" coverage area that can measure larger bath fan models with light assemblies
• No moving parts that will break later on
• A sturdier plastic that will last. We noticed that many testers use their exhaust fan flow meters to carry things, causing inferior products to break over time. So we made ours stronger. After all, it is a box. You’ll naturally want to put things in it.
• The ability to use it as a Pressure Pan without adding tape

With all of the holes completely plugged, the FlowBox can also be used as a pressure pan to locating leaks with a blower door. This is the only exhaust fan flow meter that can be used as a pressure pan without the need for tape.

Instructions for use

To use the FlowBox, make sure you update the firmware on your DM32. If you haven’t yet, you can download the DM32 configurator on the Retrotec website.

Once your firmware update is complete, click on the device you have selected on the home screen and tap "Change Device" in the bottom left hand corner. Then use the "…" key to cycle through the options until you see the Hole Flow mode or device.

A sticker attached on the side of the FlowBox (also shown directly below) indicates the effective open area you'll need to enter into the DM32 or DM2 gauge for the selected ranges and flow capacities.

FlowBox Flow Ranges Simply select the appropriate range below and enter the Effective Area into the DM32 using the Hole Flow Mode Device

Standard Ranges	Effective Area (sq in)	Effective Area (sq cm)	Min Flow (CFM)	Max Flow (CFM)
4 Openings	60.0	387.1	66.3	200.7
3 Openings	45.0	290.3	50.4	152.7
2 Openings	30.0	193.5	33.7	94.4
1 Opening	15.0	96.8	18.8	50.3
74 Plug	6.7	43.2	7.1	23.3
Optional
47 Plug	2.7	17.4	3.3	9.9
29 Plug	1.0	6.5	2.3	3.7

Those using the FlowBox with a non-Retrotec Gauge can use the "Retrotec FlowBox Lookup Table" under the Resources tab on this page.