Backflow Preventer; System Water Piping Methods; Circulator Pumps - Pioneer PHR100-55 Instruction Manual

C. BACKFLOW PREVENTER
Use a backflow preventer specifically designed for hydronic heater installations. This valve should be
installed on the cold water fill supply line per local codes (see Piping Details).
D. SYSTEM WATER PIPING METHODS
EXPANSION TANK AND MAKE-UP WATER
1. Ensure that the expansion tank is sized to correctly handle heater and system water volume and
temperature. The heater volume is 55 gallons.
Undersized expansion tanks cause system water to be lost from the relief valve, causing make-up water
to be added. Eventual heater failure can result due to excessive make-up water addition. SUCH
FAILURE IS NOT COVERED BY WARRANTY.
2. The expansion tank must be located as shown in the Heater Piping Details, or following recognized
design methods. See expansion tank manufacturer's instructions for details.
3. Connect the expansion tank on the suction side of the circulator. Always install the system fill
connection at the same point as the expansion tank connection to the system.
4. Most chilled water systems are piped using a closed type expansion tank.
E. CIRCULATOR PUMPS
DO NOT install automatic air vents on closed type expansion tank systems. Air must remain in the system
and return to the tank to provide an air cushion. An automatic air vent would cause air to leave the
system, resulting in improper operation of the expansion tank.
SIZING SPACE HEAT SYSTEM PIPING
1. See piping details in this manual. Special attention must be paid when connecting an indirect storage
tank, as temperature delivered to low temperature circuits may be higher than desired. The use of
thermostatic mixing valves is required to protect these circuits.
To control the temperature of low temperature heating circuits when using an indirect fired water heater, a
thermostatic mixing valve is required. Failure to install a thermostatic mixing valve when using an indirect
fired water heater could result in serious personal injury or death due to scalds.
2. Size the piping and components in the space heating system using recognized design methods.
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