NOTE:
Failure of a heat exchanger due to lime
scale build-up on the heating surface, low pH or
other chemical imbalance is non-warrantable.
NOTE:
High chemical concentrates from feeders
that are out of adjustment will cause rapid corrosion
to the heat exchanger. Such damage is not covered
under the warranty.
18
Potable Water and Space Heating
1. All piping materials and components connected to
the water heater for the space heating application
shall be suitable for use with potable water.
2. Toxic chemicals, such as used for boiler treatment,
shall not be introduced into the potable water used
for space heating.
3. If the heater will be used to supply potable water,
it shall not be connected to any heating system or
components previously used with a non-potable
water heating appliance.
4. When the system requires water for space heating
at temperatures higher than 140°F (60°C), a
means such as a mixing valve shall be installed to
temper the water in order to reduce scald hazard
potential.
CAUTION:
When this heater is used for both
potable water and space heating, observe the
following to ensure proper operation.
∆T = Temperature rise, °F
∆P = Pressure drop through heat exchanger, ft
SHL = System head loss, ft (based on heater and tank connections of no more than 100 eq. ft. of tubing)
gpm = Gallons per minute, flow rate
MTS = Minimum tubing size
*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 130 F. For higher than 130 F 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 G: Domestic Water Heater Flow Rate Requirements
CAUTION:
Combustion air must not be
contaminated by corrosive chemical fumes which
can damage the heater and void the warranty.
Automatic Chemical Feeders
All chemicals must be introduced and completely dilut-
ed into the water before being circulated through the
heater. High chemical concentrations will result when
the pump is not running (e.g. overnight).
WATER HARDNESS
SOFT*
MEDIUM
HARD*
3-4 Grains Per Gallon
5-15 Grains Per Gallon
16-25** Grains Per Gallon
MVB
Model
T
(ºF)
GPM
P
(ft wc)
MTS
(in)
SHL
(ft wc) T (ºF) GPM
P
(ft wc)
MTS
(in)
SHL
(ft wc) T (ºF) GPM
P
(ft wc)
MTS
(in)
SHL
(ft wc)
503A
17
50
3.6
2
8.3
17
50
3.6
2
8.3
9
95
10.4
2
25.7
753A
26
50
4.0
2
8.7
18
73
7.8
2
17.3
15
90
11.4
2
25.3
1003A
20
85
11.5
2 1/2
16.2
20
85
11.5
2 1/2
16.2
15
116
19.6
2 1/2
27.8
1253A
27
80
12.2
2 1/2
16.3
20
109
21.0
2 1/2
28.3
20
109
21.0
2 1/2
28.3
1503A
28
94
18.4
2 1/2
24.0
25
105
22.5
2 1/2
29.3
23
115
26.5
2 1/2
34.6
1753A
29
104
23.6
2 1/2
30.3
27
113
27.4
2 1/2
35.2
27
113
27.4
2 1/2
35.2
2003A
29
118
33.0
2 1/2
41.5
29
118
33.0
2 1/2
41.5
29
118
33.0
2 1/2
41.5
Summary of Contents for 503A
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