Laarsen Associates PW - Manual (Page 15)

Mighty Therm Volume Water Heater Page 15
Figure 17. Two-Temperature Hot Water Supply System with Vertical Tank for Models VW and PW Water Heaters.
Legend
B - Check Valve
C - Check Valve
D - Tempering Valve
H - Throttling Valves in Building Loop Returns
J - Circulating Pump for Return Loop
K - Service Valves to Isolate Heater and Pump
for Service