Primera 400B Installation & Maintenance Manual page 29

Piping Schematic for Two PRIMERA® Water Heaters and Two Storage Tanks
Circulator (confirm proper sizing)
Full Port Isolation Ball Valve
Swing Check Valve
Union
Temperature and Pressure Relief Valve
PRIMERA
2
Return temperature
to the water heater
must be = 130°F
Low Temperature
Bypass with Valve.
Size bypass piping and
valve for 2 inches
2.5" dia. for
models 1000W
and 2000W.
All other
models 2" dia.
Main Header Sizing for Two Heaters
Models Total GPM Min. Pipe Size
400W / 540W 60
750W 122
1000W 152
1200W 92
1600W 122
2000W 152
Notes:
1. All piping to the storage tanks must be balanced; this include cold inlet, hot outlet to
2. Piping shared by multiple PRIMERA heaters, must be sized for the total anticipated
3. Pump sizing must be confirmed for the required heater flow rate (gpm) against the
4. Low temperature bypass from hot outlet to the cold inlet is required on each heater.
5. Operating probes are moved to storage tank after water heater flow rate setup.
6. Pipe all temperature and pressure relief valves to drain with no restrictions or valves.
Operating Probes
7. Refer to heater installation manual (form 34-50) for more details.
PRIMERA
1
Use the outlet
piping isolation
valve to set
water heater ΔT
and flow rate.
NOTE: Pipe size from this T
2" dia.
to each storage tank can be
3" dia.
reduced from the main header
3.5" dia.
size, but doing so limits the
2.5" dia.
number of heaters that can
3" dia.
operate if one of the tanks is
3.5" dia. valved off for maintenance.
Size pipe for a velocity of 6
feet per second at the antici-
pated flow rate.
the building and the piping to and from the water heater main headers.
flow of approximately 6 feet per second as required for type L copper.
head loss of the water heater-to-tank piping, as well as the water heater itself.
3/4" fitting required and multiple-probe thermowell (part no. 102561).
Storage
Tank 1
Storage
Tank 2
29
Hot Outlet
Cold Inlet
Exp.
Tank
Building Return
34-50 04/02/2010