Retrotec USACE - Manual (Page 271)

Appendix D D141
D.7.10.13 Unnecessarily High Hot Water Temperature Setpoint
(Waste)
Figure D231. Reduce water heater temperature setpoint to the required level; check waster
temperature (left), then reset thermostat (right).
Calibrate the hot water heater temperature setpoint in accordance with the re-
quirements of the dish washer—typically 60 °C (140 °F) for high-temperature
machines and 51.7 °C (125 °F) for low-temperature machines (Figure D231).
In the absence of a dishwasher, the minimum hot water temperature setpoint
for hand washing sinks is 48.9 °C (120 °F). Even a small temperature reduc-
tion—12.2 °C (10 °F)—can signifi cantly reduce water heating costs. Potential
annual operating cost savings are $500 for 12.2 °C (10 °F) water temperature
reduction at 3,785.4 L (1,000 gal) hot water use per day.
D.7.10.14 Heat Escapes from the Hot Water Storage Tank through
the Water Heater Flue (Waste)
Figure D232. Heat loss through water heater
fl ue (left); water heater with automated fl ue
damper (right).
Most commonly found on newer model water heaters, the automated fl ue
damper is a simple device that closes a damper atop the water heater fl ue
when the burners are off, preventing heat from the storage tank from escaping
(Figure D232). The dampers motor has two positions: hold open damper and
automatic operation. The switch should be placed in the automatic position.
Potential annual operating cost savings ranges between $100 and $300.