In some instances, yes. However, these considerations are based on concerns regarding external sources of heat. The hot water from the heater will not affect FlowGuard Plus CPVC if the temperature exceeds 95℃.
When connecting to a gas water heater, FlowGuard Plus CPVC should not be located within 50 cm of the heater's flue, if the flue has no insulation. A metal nipple or flexible appliance connector should be used.
This measure eliminates the potential for damage to plastic piping that might result from excessive radiant heat from the flue. If the flue is insulated, the instructions of the flue manufacturer should be followed.