LAARS Heating Systems
Page 22
SECTION 4 Water Flow and Headloss Data
4.A General Water Flow Information
Table 14. Boiler Water Flow and Headloss
Table 15. Minimum Allowable Water Flow Rates
4.B Boiler Water Flow & Headloss Data
SECTION 4 Water Flow and Headloss Data
4.A. General Water Flow Information
MagnaTherm units are water-tube type units that
require water flow for operation. Boilers are
generally used in closed systems, so Laars bases
the water flow data on temperature rise
(difference between boiler inlet and outlet
temperature.) Water heaters are used in open
systems, with new water constantly being
introduced to the system. This brings a constant
supply of new minerals into the system, as well.
Minerals can cause scale to form on the inside
surfaces of water heater systems (heaters, tanks,
pipes, valves, and other components). Laars uses
the water-tube design to its advantage by basing
the water flow data on water hardness, to assist in
minimizing mineral buildup in the heater's
waterways.
4.B. Boiler Water Flow and Headloss Data
The water flow and headloss data shown in Table
15 is based on full input of the boiler. The boiler
has a 20:1 turndown, meaning it modulates from
5% to 100% of full input. Table 16 shows the water
flow required at the the boiler's minimum input,
and this is the minimum water flow allowed
through the boiler. Running in this condition is
very rare, and if the system requires this minimum
water flow, the water flow switch may need to be
adjusted or replaced. Contact the factory if you
have such a system.
Model
25°F
30°F
35°F
40°F
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
1600
122
19.4
100
14.0
87
10.0
76
8.0
2000
150
30.0
128
24.5
109
17.1
95
13.6
2500
190
34.0
158
24.6
136
17.6
119
13.6
3000
226
47.0
190
34.2
164
25.8
142
18.9
3500
266
41.0
222
31.6
190
23.6
166
18.6
4000
300
48.0
255
38.2
218
28.5
190
22.5
*Headloss is for boiler only (no piping)
Model
14°F
17°F
19°F
22°F
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
1600
462
5.9
379
4.3
329
3.0
288
2.4
2000
568
9.1
485
7.5
413
5.2
360
4.1
2500
719
10.4
598
7.5
515
5.4
451
4.1
3000
856
14.3
719
10.4
621
7.9
538
5.8
3500
1007
12.5
840
9.6
719
7.2
628
5.7
4000
1136
14.6
965
11.6
825
8.7
719
6.9
*Headloss is for boiler only (no piping)
Table 15. Boiler Water Flow and Headloss
Model Water Flow
(gpm)
Water Flow
(l/m)
1600
8
30
2000
11
42
2500
13
49
3000
16
61
3500
18
68
4000
21
79
SECTION 4 Water Flow and Headloss Data
4.A. General Water Flow Information
MagnaTherm units are water-tube type units that
require water flow for operation. Boilers are
generally used in closed systems, so Laars bases
the water flow data on temperature rise
(difference between boiler inlet and outlet
temperature.) Water heaters are used in open
systems, with new water constantly being
introduced to the system. This brings a constant
supply of new minerals into the system, as well.
Minerals can cause scale to form on the inside
surfaces of water heater systems (heaters, tanks,
pipes, valves, and other components). Laars uses
the water-tube design to its advantage by basing
the water flow data on water hardness, to assist in
minimizing mineral buildup in the heater's
waterways.
4.B. Boiler Water Flow and Headloss Data
The water flow and headloss data shown in Table
15 is based on full input of the boiler. The boiler
has a 20:1 turndown, meaning it modulates from
5% to 100% of full input. Table 16 shows the water
flow required at the the boiler's minimum input,
and this is the minimum water flow allowed
through the boiler. Running in this condition is
very rare, and if the system requires this minimum
water flow, the water flow switch may need to be
adjusted or replaced. Contact the factory if you
have such a system.
Model
25°F
30°F
35°F
40°F
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
Water
Flow
(gpm)
Headloss
* (ft)
1600
122
19.4
100
14.0
87
10.0
76
8.0
2000
150
30.0
128
24.5
109
17.1
95
13.6
2500
190
34.0
158
24.6
136
17.6
119
13.6
3000
226
47.0
190
34.2
164
25.8
142
18.9
3500
266
41.0
222
31.6
190
23.6
166
18.6
4000
300
48.0
255
38.2
218
28.5
190
22.5
*Headloss is for boiler only (no piping)
Model
14°F
17°F
19°F
22°F
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
Water
Flow (l/m)
Headloss
* (m)
1600
462
5.9
379
4.3
329
3.0
288
2.4
2000
568
9.1
485
7.5
413
5.2
360
4.1
2500
719
10.4
598
7.5
515
5.4
451
4.1
3000
856
14.3
719
10.4
621
7.9
538
5.8
3500
1007
12.5
840
9.6
719
7.2
628
5.7
4000
1136
14.6
965
11.6
825
8.7
719
6.9
*Headloss is for boiler only (no piping)
Table 15. Boiler Water Flow and Headloss
Model Water Flow
(gpm)
Water Flow
(l/m)
1600
8
30
2000
11
42
2500
13
49
3000
16
61
3500
18
68
4000
21
79
This appliance is a water-tube design that requires
water flow for operation. Boilers are generally used in
closed systems, so Laars bases the water flow data on
temperature rise (difference between boiler inlet and
outlet temperature.) Water heaters are used in open
systems, with new water constantly being introduced
to the system. This brings a constant supply of new
minerals into the system, as well. Minerals can cause
scale to form on the inside surfaces of water heater
systems (heaters, tanks, pipes, valves, and other
components). Laars uses the water-tube design to
its advantage by basing the water flow data on water
hardness, to assist in minimizing mineral buildup in the
heater’s waterways.
The water flow and headloss data shown in Table 14 is
based on full input of the boiler. The boiler has a 20:1
turndown, meaning it modulates from 5% to 100% of
full input. Table 15 shows the water flow required at
the the boiler’s minimum input, and this is the minimum
water flow allowed through the boiler. Running in this
condition is very rare, and if the system requires this
minimum water flow, the water flow switch may need
to be adjusted or replaced. Contact the factory if you
have such a system.
