Bock Water heaters 119ST, Instruction Manual

Page: 4 / 12

Page 4 Storage Tanks
WHEN YOU RECEIVE YOUR NEW STORAGE TANK
Check the new equipment to see if all components are in good condition. The T&P valves,
aquastat and immersion well are supplied by the installer.
TEMPERATURE CONTROLS
Bock storage tanks are equipped with
3
⁄
4
'' tappings for the installation of immersion
temperature controls. Any temperature control approved for use in hot water systems is
acceptable. Bock recommends the use of a control with an adjustable differential so that the
differential can be adjusted to match that of your heat source controls. Setting the storage
tank temperature control 5
° lower than the water heater temperature control is also
recommended. This is to ensure that when the storage tank calls for heat and the circulator is
turned on, the water being circulated is cool enough to cause the water heater to start. If the
burner does not start then the circulator could run for long periods of time, wasting energy.
Note: The recommended water temperature for domestic use is 120 ° . Higher water
temperatures can result in scalding. If higher or lower water temperatures are needed, point
of use tempering devices are recommended.
T&P VALVES
Temperature and pressure relief valves must be installed on all storage tanks by the installer.
All Bock storage tanks are also equipped with
3
⁄
4
'' or 1'' tappings for the installation of
properly sized temperature and pressure relief valves. These are located on the side near the
top of vertical tanks and on the top surface of horizontal storage tanks. Relief valves are rated
for maximum system pressure and temperature as well as Btu input of the heating appliance.
This information is normally supplied on a metal tag attached to the end of the valve. For a
normal domestic water system maximum system pressure is 150 psi and temperature limit is
210
°F . The Btu per hour rating will be listed next to the AGA or CSA logo on the tag under
the temperature and pressure data. Be certain to use a relief valve that is rated for the Btu per
hour input of the heating appliance. For example, if you are connecting a storage tank to a
water heater with a 50,000 Btu per hour input then the relief valve installed in the storage
tank must be rated for a minimum of 50,000 Btu per hour.
PIPING
Bock storage tanks are equipped with many different fitting sizes and configurations
depending on intended use. However, all storage tanks will have some common features. All
Bock storage tanks will have two or more anode rods installed through the top of the storage
tank. Bock storage tanks typically have three large tappings, normally 2 inches NPT or larger,
in the side of the tank. The exact location of these fittings will vary depending on tank
model and any special options ordered. The tapping nearest the bottom of the tank is used
as a cold water inlet and/or a connection to return water from the storage tank to the heat
source. A second tapping of similar size located higher up the side of the tank is used to
return heated water from the heat source. A hot water outlet is located on the top of the tank.