9
Customer Service
(704) 841-6000
backflow.apollovalves.com
ES1597 REV A.
BFMMDC4ANLBF
The Double Check Detector Assembly (DCDA Type 1) contains a mainline DC incorporating two spring loaded check valves and a bypass line
consisting of an approved DC assembly and a water meter. The DCDA Type 2 contains a mainline DC incorporating two spring loaded check
valves and a bypass line consisting of a single check valve and a water meter. Each device is equipped with test cocks for periodic field
testing and is normally supplied with inlet and outlet shut-off valves. NOTE: UL and FM installations must include indicating type shut-off
valves.
During no flow conditions, the mainline and by-pass check valves will remain closed. If there is a low flow demand (up to a minimum of 2
gpm) of water downstream, the flow is routed through the water meter to monitor such consumption. If the downstream pressure increases
above the supply pressure or there is a reduction in the inlet pressure, the mainline and bypass check valves will close to prevent backflow.
VI.
DESCRIPTION AND OPERATION
VII. INSTALLATION
1. The DCDA must be installed in an accessible location to facilitate periodic field testing and maintenance.
2. Flush all upstream POST INDICATORPOST INDICATORng thoroughly to remove foreign matter prior to installing the device.
3. The device may be installed in the n-flow position. A clearance of 12” to 30” between the lower most portion of the device and flood grade or floor
should be provided for ease of maintenance.
4. After installing the assembly and with downstream (#2) shut-off valve closed, pressurize the device and bleed air through test cock #4. Then
open #2 shut-off valve.
OTHER INSTALLATION TIPS
• Installing this device in a POST INDICATORt requires consideration for future maintenance and repair. Along with necessary clearances, there
must be adequate drainage within the POST INDICATORt to deter potential accumulation of standing water. Also, check with local codes and/or
inspectors prior to making such installations.
• Do not install in areas subject to freezing without using a properly designed enclosure.
• As in any POST INDICATORPOST INDICATORng system, provisions should be made to minimize water hammer and pressure rise due to thermal
expansion, as these conditions can create damaging and dangerously high internal pressures.
