Constant flow damper lindab | dampers and measure units VRL1 Technical data Setting and installation Set the desired flow rate before mounting the constant flow damper VRL1 into the duct sytem. The desired flow is set with the pointer (1) on the scale (2). To set the desired flow the adjustment screw (3) needs to tightened (screw head size TX8). 4 4 6 After fire damper min. 1 dim From larger dimension to smaller min. 1 dim From smaller dimension to larger min. 1 dim min. 1 dim 5 2 13 When the damper is mounted into the duct system the flow direction (4) of the damper must match the direction of the flow in the duct system. Make sure that the ducts have the necessary concentricity and that the installation is tension-free. The lip seals (5) must be in contact with the duct walls, as shown, and inserted against the direction of air flow (4). The damper blade must move easily all of the time. Each VRL1 flow regulator has a sticker where the set flow rate (6) should be specified. Regulating accuracy The units are calibrated from factory within their whole working range. In this the units keep the flow constant within approximately ±5 to ±10% of the set flow. Greater devia- tions occur at the lower flows, aspecially for small sizes. Flow setting The units can not be delivered from factory with a preset flow. You can set the flow yourself very easy following to the instruction for each product. Change of direction The units are independent of their mounting direction and one may deviate from the specified direction and mount them in any direction without affecting the accuracy. Disturbance tolerance In order to achieve the stated accuracy for the pre-set flow a straight distance before and after the unit are required. A mounting close to a source of disturbance (bend, reducer, t- piece etc.) decreases the regulation accuracy and the flow may diverge from the set value. After bend min. 4 dim min. 1 dim min. 1 dim After t-piece min. 1 dim min. 1 dim min. 1 dim In combined installation with a plenum box Supply min. 0 dim Exhaust min. 1 dim Lindab reserves the right to make changes without prior notice 2 2020-09-10
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