LAARS Mighty Therm VW-PW (Sizes 175-400) - Installation, Operation and Maintenance Instructions User Manual
Page 12
LAARS Heating Systems
Page 12
Heat
Flow
Pressure*
Water Temp
Exch.
Water
Rate
Drop
Rise
Model
Passes
Category
gpm
L/s
ft.
m
°
F
°
C
175
2
Soft
22
1.4
5.8
1.8
13
7
Normal
34
2.1
11.2
3.4
8
4
Hard
46
2.9
19.1
5.8
6
3
4
Soft
11
0.7
4.9
1.5
25
14
Normal
17
1.1
9.3
2.8
16
9
Hard
23
1.5
15.9
4.8
12
7
250
2
Soft
22
1.4
5.8
1.8
18
10
Normal
34
2.1
11.2
3.4
12
7
Hard
46
2.9
19.1
5.8
9
5
4
Soft
11
0.7
4.9
1.5
35
19
Normal
17
1.1
9.3
2.8
33
18
Hard
23
1.5
15.9
4.8
17
9
325
2
Soft
34
2.1
12.5
3.8
18
10
Normal
34
2.1
12.5
3.8
18
10
Hard
46
2.9
21.7
6.6
11
6
4
Soft
17
0.7
10.4
3.2
36
20
Normal
17
0.7
10.4
3.2
30
17
Hard
23
1.5
18.1
5.5
22
12
400
2
Soft
34
2.1
13.3
4.1
19
11
Normal
34
2.1
13.3
4.1
19
11
Hard
46
2.9
23.4
7.1
14
8
4
Soft
17
0.7
11.1
3.4
37
21
Normal
17
0.7
11.1
3.4
37
21
Hard
23
1.5
19.5
5.9
27
15
*Pressure drop includes head loss of heat exchanger and through 30 feet (9.1 m) of pipe and normal fittings when
heater is installed with storage tank. Pipe and fittings are assumed to be 1-1/2 inch (38 mm).
Main Circulating Loop
(With Own Pump)
Water Maintained
Less Than 110°F (43°C)
Adjustment Procedure
1.
Turn on heater and open gate
valves A and B.
2.
After 15 minutes, read T
1
.
3.
If T
1
is less than 110°F (43°C),
slowly close valve B until T
1
climbs to 110°F (43°C).
4.
If T
1
is greater than 110°F (43°C),
slowly close valve A until T
1
drops to 110°F (43°C).
5.
Check after 5 minutes
operation and make final
adjustments.
Figure 20. Cold water application.
Table 4. Pump Performance Requirements.