T-M50 / T-M50 ASME Service Manual
Ver. 1.05
64
CONFIDENTIAL
12-11. Pump control ON/OFF Conditions
To run circulation pumps efficiently and effectively, the T-M50 offers four different modes of pump
control. The following table shows the pump control ON/OFF conditions for different modes. To change
pump control modes, see section 12-7 for dipswitch settings.
“Normal mode” and “Storage tank circulation mode”
There are no specific ON/OFF conditions for these two modes. The circulation pump will receive a
constant “ON” signal from the pump terminal on the central computer board, and will run
continuously.
“Re-circulation mode” and “Energy conserving re-circulation mode”
These functions enable the re-circulation pump to be controlled by the following conditions.
ON/OFF Conditions
Re-circulation mode
Energy conserving re-circulation mode
Conditions that activate
the pump
The BTU requirement is more than
14,880 BTU/h*
OR
30 minutes have elapsed after
previous operation
Inlet water temperature is less than
95°F(35°C) and flow rate is less than
0.8GPM
OR
20 minutes have elapsed after
previous operation
Conditions that
deactivate the pump
When the central computer board detects the following conditions, it will stop
the pump 60 sec. after detection.
The BTU requirement is less than 5,950 BTU/h
OR
Inlet temperature is higher than the set temperature
OR
Outlet temperature is over 194°F
OR
The water flow rate is less than 0.4 GPM
*The computer records the inlet temperature and the flow rate of the pump during the final minute of
its previous operation when calculating the BTU requirement.
