Single Check Valve (SCV)
To prevent excessive water pressure force the water back into the water source at from the flush valves, all flush valve for water closets must incorporate with a check valves / vacuum breakers that comply with requirements and standards stipulated by the Authority,
Handheld bidet spray
To prevent water being drain back into the water source when the hand-held bidet spray (connected to a flexible hose) submerge into the water closet reservoir, thus all hand-held bidet spray (connected to a flexible hose) located next to a water closet shall be installed with a check valve and vacuum breaker.
Draw-off taps near a pond or drain
To prevent water being drain back into the water source when the hand-held spray (connected to a hose) submerge into the pond from a draw-off tap, all draw-off tap installed near to a pond or drain shall be installed with a check valve and vacuum breaker.
Picture of SCV & VB
Double Check Valves (DCV)
Most of the kitchen equipment, including dish washer, refrigerator, ice maker and washing machine are installed with mechanical pump to discharge unwanted water out from the equipment. In-order to prevent water contamination when its pump malfunction, double check valves (DCV) must be provided along the pipe(s) line before the tap which is connecting to any kitchen equipment. This is to prevent back-flow which will contaminate the water source.
Storage Water Heater
To prevent mixing of hot water in the storage water heater and back flow of water which will contaminate the water source a double check valve is to be install after a stop valve before the inlet of the storage water heater.
For all property having two source of water supply (potable water & NEWater) a double check valve is required to install at the potable water pipe line to prevent mixing with NEWater during switching over. There shall be no cross connection between the PUB and NEWater supply pipelines.
A double check valves with drain-out test cocks shall be provided to prevent contamination, the double check valves shall be installed immediately after the branch-off from the potable water pipe to serve the firefighting system.
Drinking fountains/water coolers
Drinking fountains or water coolers shall have an inclined and hooded jet to prevent contamination. Double check valves are to be installed at the pipe supplying water to the drinking fountain/water cooler.
Balancing tank for swimming pool filtration plant
A double check valves are to be installed at the water supply pipe to the balancing tank, this is to prevent back flow and contamination of water source.
1. Clean your DCV once a month
Picture of DCV
Temperature / Pressure Relief Valve (TPRV)
The Temperature / Pressure Relief Valve (TPRV) used in storage water heater should be tested at least once a year. This valve is a safety device is to prevent your hot water heater from exploding. Most are designed to activate if the water temperature in your tank exceeds 70 Degrees Celsius, or the pressure in your tank exceeds 7 bars (115 psi).
When your water heater is functioning properly, the TPRV valve and surrounding area should be dry.
Should you see water around the TPRV valve, your TPRV valve is fulfilling its role as a safety device. But it is important to find out what caused the TPRV valve to trigger. There can be several reasons for water discharge, but it is clearly an indication of an abnormal condition, and should be immediately addressed.
Some of the causes could be due to thermal expansion (when water is heated it expands), high system pressure, high temperature relief, temperature gauge set too high, or something else in the water heater causing the temperatures to exceed a safe limit.
1. Test your TPRV once a year
2. Replace your TPRV once a year
Picture of TPRV