Multi-Unit System On/Off Conditions - A.O. Smith T-M50 ASME Service Manual

12-12. Multi-unit system ON/OFF conditions

In Easy-link system and Multiple-system, the amount of T-M50 called on to activate depends on the
FLOW RATE and the OUTPUT SET TEMPERATURE.
1. Condition required to activate an additional T-M50:
Flow rate required to activate additional T-M50 = A × n
Where n= number of currently activated T-M50's
and A is dependent on the output set temperature. See table below:
2. Condition required to reduce the number of activated T-M50's:
In the case of reducing down from two units T-M50's to one T-M50
A.
Flow rate = A / 1.7
All other cases: Flow rate = A × (n - 2)
B.
(One T-M50 has two combustion sections.)
Output set temperature
˚F
100 - 120 38 - 49
125,130 52 - 54
140
145,150 63 - 66
155 - 185 68 - 85
T-M50 / T-M50 ASME Service Manual
Factor "A"
˚C GPM
3.2
2.9
60 2.6
2.4
2.1
65
CONFIDENTIAL
Ver. 1.05
L/min
12
11
10
9
8