How It Works - Ace Heating Solutions Mini-Pack Operating And Maintenance Instruction Manual

ACE BOILER INC.
Page 6

How It Works!

The Mini-Pack is designed to heat domestic hot water using existing plant steam or hot boiler water, and
regulates the domestic hot water outlet temperature to a close tolerance of +4qF from the set point. The
advantage of this system is it replaces the need for large hot water storage tanks and is much more
efficient.
As there is a demand for domestic hot water, the temperature control bulb will sense the drop in water
temperature. The temperature bulb sends a signal to the control valve to open and allow steam or hot
boiler water into the heat exchanger tube bundle. As the steam or hot boiler water passes through the
tubes, the domestic water in the shell is rapidly heated. Above the tube bundle, a minimal water volume
storage area is provided to give the controls sufficient time to react to the changes in water temperature.
The circulator constantly rotates the water in the shell, eliminating any hot spots, which could cause false
readings at the control valve.
As the steam or boiler water passes through the tubes, it is sub-cooled by the incoming domestic cold
water. As the demand for hot water fluctuates, the control valve will respond accordingly, quickly reacting
to keep the water temperature within +4qF. In the event the water temperature in the Mini-Pack continues
to climb, the high limit control will trip, cutting the electrical current to the solenoid valve on the control
panel, which in turn relieves the air signal to the control valve and causes it to close.
On units equipped with a double safety solenoid valve, the system is designed to dump the overheated
water through the solenoid dump valve when the high limit is tripped.