19
the Indirect Supply sensor (S6) and the Target Max
setting when using the Indirect DHW sensor (S5). The
Boiler/Injection Pump (P1) runs during all heat calls
regardless of priority. The Indirect DHW Pump (P3)
runs during an indirect call for heat with no “off” delay.
The Boiler/Injection Pump (P1) is delayed “off” as user
defined in the
BOILER
menu and the System Pump
(P2) is delayed “off” in the
ADJUST
menu. The system
pump (P2) runs whenever the system is enabled for
heating and the outdoor air temperature is lower than
the WWSD temperature setting (if utilized) unless an
indirect call for heat is present.
WH – Direct DHW Configuration
When the unit is ordered as a “WH” configuration, the
only application available to it is direct DHW with sin-
gle or multiple heaters (Maximum 4 heaters). The tank
temperature is controlled by the System sensor (S3).
The Boiler/Injection Pump (P1) runs during any call for
heat. The System Pump (P2) output is active whenev-
er the system is enabled. The Boiler Pump is delayed
“off” as user-defined in the
BOILER
menu.
Fig. 21: WH Units - Single Water Heater with Tank
H Units - Single Boiler with Process Tank
NOTE:
A Tank Aquastat can be used in lieu of the
Indirect DHW Sensor (S5). See the VERSA IC man-
ual for additional details.
Domestic Hot Water
When designing the water piping system for domes-
tic hot water applications, water hardness should be
con-sidered. Table H indicates the suggested flow
rates for soft, medium and hard water. Water hardness
is ex-pressed in grains per gallon.
Model 2505
Model 3005
Sys Ret
Temp
(F)
Soft (2-4)
Med (5-15)
Hard (16-25)
Pipe max eq ft
Soft (2-4)
Med (5-15)
Hard (16-25)
Pipe max eq ft
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
3”
4”
3”
4”
80
144
74
139
81
137
83
100
350
148
84
139
97
139
97
110
100
144
108
139
122
137
128
100
350
148
119
139
146
139
146
110
120
149
164
149
164
149
164
100
350
150
190
150
190
150
190
110
140
169
164
169
164
169
164
100
350
170
190
170
190
170
190
110
Model 3505
Model 4005
Sys Ret
Temp
(F)
Soft (2-4)
Med (5-15)
Hard (16-25)
Pipe max eq ft
Soft (2-4)
Med (5-15)
Hard (16-25)
Pipe max eq ft
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
Supply
Temp
(F)
Sys
Flow
GPM
3”
4”
3”
4”
80
148
98
143
106
143
106
100
148
112
146
115
146
115
100
100
148
139
143
155
143
155
100
148
158
146
165
146
165
100
120
150
222
150
222
150
222
100
150
253
150
253
150
253
100
140
170
222
170
222
170
222
100
170
253
170
253
170
253
100
HIGH FIRE CONDITIONS
Flow rates determined based on max temperature rise of 30ºF. Pipe size selected based on 7.5 ft per sec maximum velocity.
*Must utilize optional cupro-nickel tubes. If over 25 grains per gallon, a water softener/treatment system must be utilized.
**Caution:
For scale-free operation with “Hard Water” (16-25 grains per gallon of total hardness), the operating control must NOT be set
higher than 130ºF. For higher than 130ºF operation, a water softener/treatment system must be utilized.
***Care should be given to prevent over-softening of the water as over-softened water can become aggressive. Cupro-nickel tubes are
recommended for water softened below 5 grains per gallon.
Table H: Domestic Water Heater Flow Rate Requirements
