36
WHL-060 REV. 1.6.16
Figure 28
– Water Heater with Thermal Bypass Valve – NOTE: There is a Built-In Flow Check in the Internal Recirculation
Pump Loop
Using the Optional Crossover (Thermal Bypass) Valve
In piping applications where a dedicated recirculation line is not available or too costly to install, the water heater can use a crossover
(thermal bypass) valve as a method of recirculation. The water heater uses its Internal Recirculation Pump, internal bypass line, and a
crossover valve installed between the hot and cold supply lines at the furthest fixture in the plumbing line from the water heater to
temporarily use the cold water line to recirculate hot water through the system. A thermal bypass valve may be purchased at your local
plumbing supplier.
When using an optional Crossover (Thermal Bypass) Valve, the Internal Recirculation Pump circulates hot water through the system to
the thermal bypass valve, where it is directed back to the water heater through the cold water line when hot water is not in use.
NOTE:
When using an optional Crossover (Thermal Bypass) Valve, it is required to set the water heater Installer Mode parameter 0:RC
to InRC
– Internal Recirculation Mode.
NOTE:
The Crossover Valve must only allow flow rates less than 0.4 GPM. If the flow rate is greater than 0.4 GPM the unit will not
operate properly.
NOTE:
Westinghouse approves the use of TACO HLV-1 Crossover Valve in its installations. It allows a maximum flow rate of 0.25
GPM.
PIPING NOTES:
1. Minimum pipe size should match connection size. Upsize pipe accordingly if greater flow is required.
2. A thermal expansion tank suitable for potable water must be sized and installed within this piping system between the backflow
preventer and the cold water inlet.
3. All circulators should have an integral flow check.
4. Drains and check valve between unit and storage tank will assist in purging air from system.
5. These drawings are meant to demonstrate system piping only. The installer is responsible for all equipment and detailing required by
local codes. In Massachusetts, you must install a vacuum relief valve per 248 CMR.
6. Mixing valve application is optional, but recommended to help prevent scalding.
7. Always shut off power to the water heater or isolate the heater from the system if ANY plumbing work is to be done. Running the
water heater without water will result in dry-firing.
