INSTALLATION AND OPERATION INSTRUCTIONS
1-22
SFT 199 TANKLESS WATER HEATER
1.7.2 Domestic Hot Water Piping
The domestic water piping connections are located at the bottom of the unit,
see
Figure 23 - Gas Piping.
The connections are
¾
" male NPT threads. The cold water
inlet is on the right side and the hot water outlet is on the left side.
A pressure relief valve must be installed:
•
With a maximum pressure setting of 150PSI and rated for a minimum capacity
of not less than the rated input of the unit (NOT supplied with the unit) on the
domestic hot water outlet piping within 6" of the unit.
•
Between the unit’s outlet and any isolation valve to ensure the pressure relief
valve cannot be isolated by closing a valve. We recommend a valve kit designed
for this purpose to reduce installation time and to reduce the space required.
The SFT series units can be connected to the pressurized 1/2" or larger domestic
cold water supply piping and the domestic hot water piping in the home. The
minimum domestic water pressure required is 40PSI and recommended to be 50PSI
or higher. Generating domestic hot water with a water pressure lower than 40PSI
reduces the amount of hot water generated and increases the risk of scaling in the
heat exchanger.
The domestic water piping must be installed with isolation valves and fl ushing taps
installed on both the cold and hot domestic connections.
Thermal expansion of the water in the domestic hot water piping and unit can cause
excessive pressures to build in the piping system. This can cause the pressure relief
valve to discharge on a regular basis. This condition must be prevented with the
installation of a properly sized and installed domestic water expansion tank or other
device designed for the purpose.
Table 6: Water Heater Pressure Drop
A fi lter is required where contaminants are present in the supply water (see A in
Figure 21).
WARNING
- Bacteria growth can develop
in domestic hot water tanks
and indirect water heaters if the
minimum water temperature is
not set high enough to prevent
its growth.
