Mighty Max Volume Water Heater
Page 9
2G-5. Pump Requirements
Table 5 specifies water flow rates for the
Mighty Max VW heaters, and the pumping head
required for typical piping configurations. Table 5
allows for 30 feet (9.1m) of piping and typical
fittings (see Figure 5). Piping with a shorter length or
larger diameter may reduce the head requirement and
pump power consumption. Contact a Laars
representative for assistance.
The correct flow rate can be verified by checking
the temperature rise of water as it passes through the
heater. To check the temperature rise, measure the
difference in water temperature between the heater
inlet and outlet to determine flow. For example: If a
Size 320M VW heater is installed and normal water is
used; the inlet water temperature is 160°F (71°C); the
outlet water temperature is 171°F (77°C). Then there
is a 11°F (6°C) degree temperature rise. Per Table 3,
this is essentially correct for normal water. If a higher
temperature rise is measured, flow must be increased
by changing the piping or pump.
2G-6. Combined Space Heating/Potable
Water Heating Systems
When using the Mighty Max VW heater as a
source of heat for a combined space heating/potable
water heating system, be sure to follow the
instructions of the space heating system.
Do not use water piping, fittings, valves, pumps,
and any other components which are not compatible
with potable water.
Do not connect the heater, which will be used to
supply potable water, to any heating system or
components previously used with a nonpotable water
heating system.
Do not add boiler treatment or any chemicals to
the heating system piping, since the piping contains
water for potable use.
Do not use solder containing lead in the potable
water lines.
If the space heating system requires water
temperatures greater than the water temperature for
potable hot water use, a tempering valve (see Figure
6) or other means should be installed in the potable
hot water supply line to limit the risk of scald injury.
Table 5. Pump Requirements for Mighty Max VW Heaters.
Soft or Normal Water
Hard Water
Pipe Size
Flow
Headloss
Temp, Rise
Flow
Headloss
Temp. Rise
Model
in.
mm
gpm
L/m
ft.
m
°F
°C
gpm
L/m
ft.
m
°F
°C
0320M
1.5
38
51
193
25.9
8
10.5
6
68
257
46.0
14
7.9
4
2.0
51
51
193
13.9
4
10.5
6
68
257
24.7
8
7.9
4
0400M
1.5
38
51
193
26.0
8
13.1
7
68
257
46.3
14
9.8
5
2.0
51
51
193
14.1
4
13.1
7
68
257
25.0
8
9.8
5
0520M
2.0
51
85
322
22.4
7
10.2
6
114
431
39.5
12
7.7
4
2.5
64
85
322
14.0
4
10.2
6
114
431
24.9
8
7.7
4
0625M
2.0
51
85
322
22.4
7
12.3
7
114
431
39.8
12
9.2
5
2.5
64
85
322
14.2
4
12.3
7
114
431
25.2
8
9.2
5
0775M
2.0
51
85
322
22.6
7
15.2
8
114
431
40.2
12
11.4
6
2.5
64
85
322
14.4
4
15.2
8
114
431
25.6
8
11.4
6
1000M
2.5
64
85
322
14.6
4
20.0
11
114
431
26.1
8
14.9
8
3.0
76
85
322
11.3
3
20.0
11
114
431
18.8
6
14.9
8
Note: 1. Pressure dop includes allowance for 30 feet 9.1m of piping and normal fittings. If piping is shorter or of larger
diameter, pump power may be reduced substantially. Contact Laars Representative for assistance.
2. Heaters for soft water application should be equipped with cupronickel heat exchangers.
Soft Water: 0 to 7.5 Grains/gallon
Normal Water: 7.5 to 17 Grains/gallon
Hard Water: More than 17 Grains/gallon
Figure 6. Installation of Tempering Valve.
Mixing Valve
Out -
Mixed Water
For Potable Use
Hot Water
From Water Heater
or Storage Tank
Cold Water
Supply
Summary of Contents for Mighty Max VW Series
Page 25: ...Mighty Max Volume Water Heater Page 25 Figure 19 Troubleshooting Chart...
Page 27: ...Mighty Max Volume Water Heater Page 27 Front View Right Side View...
Page 28: ...Page 28 LAARS HEATING SYSTEMS Front View Rear View Right Side View Left Side View...
