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QVE1900U

Technical Instructions

Document No. 155-778

May 14, 2013

Flow Switch

Siemens Industry, Inc.

Description

The QVE1900U Flow Switch is used in HVAC installations to monitor the flow of fluids in

hydronic heating and cooling systems.

Product Number

QVE1900U

Operation

There are three terminals inside the enclosure:

• Red = Common

• Blue = Normally Closed (NC)

• White = Normally Open (NO)

When there is no flow, or when the flow rate is insufficient to activate the switch, the circuit

between the red and blue terminals is closed, and the circuit between the red and white

terminals is open. When the flow rate increases to a level sufficient to activate the switch

mechanism, the circuit between the red and blue terminals will open, and the circuit between

the red and white terminals will close.

The switch activation points can be adjusted via the + / - screw inside the enclosure.

Mechanical Design

The unit consists of a base, paddle, and body with a 1" MNPT system connection.

The base houses the microswitch, electrical terminals, and adjusting screw (for switch-

on/switch-off point), a paddle holder, and an opening for the cable entry. Four paddles are

included that can be trimmed to accommodate different pipe diameters.

The cover is secured to the base with two screws.

Summary of content (6 pages)

PAGE 1
Technical Instructions Document No. 155-778 May 14, 2013 QVE1900U Flow Switch Description The QVE1900U Flow Switch is used in HVAC installations to monitor the flow of fluids in hydronic heating and cooling systems.
PAGE 2
Technical Instructions Document Number 155-778 May 14, 2013 QVE1900U Flow Switch Mechanical Design, Continued Setting Element and Connection Terminals Connection Terminals COMMON 2 3 Adjusting Screw for Switch-on/off Values SEN0622R1 + - Figure 1. • The unit is supplied with the switch point values set to the minimum (See Notes). Notes • Unit must be installed in a 1-inch tee with FNPT threads. The recommended length is one inch.
PAGE 3
QVE1900U Flow Switch Technical Instructions Document Number 155-778 May 14, 2013 Commissioning, Continued Line Size Inches (mm) 1.25 (32) 1.50 (40) 2.00 (50) 2.56 (65) 3.00 (80) 4.00 (100) 5.00 (125) 6.00 (150) 8.00 (200) Qmax gpm (m3/h) 25.9 (5.9) 44.0 (10.0) 38.4 (8.7) 60.8 (13.8) 58.9 (13.4) 112.4 (25.5) 136.7 (31.0) 196.0 (44.5) 394.3 (89.5) ≤ 5.2 (1.2) ≤ 4.8 (1.1) ≤ 4.4 (1.0) ≤ 4.8 (1.1) ≤ 7.9 (1.8) ≤ 19.4 (4.4) ≤ 38.0 (8.7) ≤ 44.0 (10.0) ≤ 104.0 (23.7) ≤ 21.5 (4.9) ≤ 34.0 (7.8) ≤ 30.0 (6.
PAGE 4
Technical Instructions Document Number 155-778 May 14, 2013 QVE1900U Flow Switch Specifications, Continued Protective data Degree of protection IP 65 per EN 60 529 (≅ NEMA 4) Environmental conditions General environmental conditions Operation and storage –4°F to 185°F (– 20°C to 85°C) Norms and standards conformity to Low-voltage directive Product standard 2006/95/EEC DIN EN 60335-1:2010/VDE0700-1 Materials and colors Housing base Cover Screw-in body 1" NPT Paddle Flow switch, overall Bayblend
PAGE 5
QVE1900U Flow Switch Technical Instructions Document Number 155-778 May 14, 2013 Dimensions Cutting the Paddles NOTE: Cut Paddle No. 4 as required (see below) Line Size Inches (mm) 1.25 (32) 1.50 (40) 2.00 (50) 2.56 (65) 3.00 (80) 4.00 (100) 5.00 (125) 6.00 (150) 8.00 (200) Siemens Industry, Inc.
PAGE 6
Technical Instructions Document Number 155-778 May 14, 2013 QVE1900U Flow Switch Dimensions, Continued Figure 4. Dimensions in Inches (Millimeters). Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as design improvements are introduced. Product or company names mentioned herein may be the trademarks of their respective owners. © 2013 Siemens Industry, Inc. Siemens Industry, Inc.