Installation Instructions

whl-590 Rev. 003 Rel. 003 Date 3.22.18
27
Number of
Units
∆T = 77
o
F ∆T = 45
o
F ∆T = 35
o
F
Flow Rate
(GPM)
Water
Velocity (ft/s)
Pipe Dia.
(In.)
Flow Rate
(GPM)
Water Velocity
(ft/s)
Pipe Dia.
(In.)
Flow Rate
(GPM)
Water
Velocity (ft/s)
Pipe Dia.
(In.)
1 5 3.75 3/4 9 3.61 1 11 4.64 1
2 10 4.22 1 18 3.21
1 1/2
23 4.13 1 1/2
3 16 4.05 1 1/4 27 4.82 34 3.48
2
4 21 3.75
1 1/2
35 3.61
2
45 4.64
5 26 4.69 44 4.52 57 3.72
2 1/2
6 31 3.17
2
53 3.47
2 1/2
68 4.46
7 36 3.69 62 4.05 80 3.61
38 41 4.22 71 4.62 91 4.13
9 47 4.75 80 3.61
3
102 4.64
10 52 3.38
2 1/2
88 4.01 114 3.79
3 1/2
11 57 3.72 97 4.42 125 4.17
12 62 4.05 106 4.82 136 4.55
13 67 4.39 115 3.83
3 1/2
148 4.93
14 72 4.73 124 4.13 159 4.06
4
15 78 3.52
3
133 4.42 171 4.35
16 83 3.75 142 4.72 182 4.64
17 88 3.99 150 3.84
4
193 4.94
18 93 4.22 159 4.06 205 5.23
Table 11 - Recommended Water Pipe Size
NOTE: The above pipe sizes are recommended based on water velocity of 5 ft/s and a maximum water
temperature of 140
o
F.
G. Pressure Relief Valve
An external pressure relief valve must be installed on this water
heater. When installing, observe the following guidelines. Failure
to comply with these guidelines can result in substantial property
damage, personal injury, or death.
This water heater must be provided with an approved 150 psi, ¾”
ASME HV Valve that must be installed on the DHW outlet line. The
150 psi Pressure Relief Valve must be installed on the DHW outlet
line to ensure a compliant installation and safe operation.
This water heater has a high-temperature shut-o switch built in
as a standard safety feature. Therefore, a “pressure only” relief valve
is required. DO NOT operate this water heater before the supplied
pressure relief valve is installed with sucient relieving capacity in
accordance with the rating plate on the water heater.
Pressure relief valves must be installed as close to the water heater
as possible. No other valves should be placed between the pressure
relief valve and the appliance. DO NOT install a relief valve with a
pressure rating greater than 150 psi. This is the maximum allowable
relief valve setting for this water heater.
After installing the relief valve and lling and pressurizing the
system, test the operation of the valve by lifting the lever. Make
sure the valve discharges freely. If the valve fails to operate correctly,
replace it with a new relief valve. Ensure that the maximum BTU/H
rating on the pressure relief valve is equal to or greater than the
maximum input BTU/H rating of the combination water heater.
To avoid water damage or scalding due to relief valve operation:
t Discharge line must be connected to relief valve outlet and
run to a safe place of disposal. Terminate the discharge line
in a manner that will prevent possibility of severe burns or
property damage should the relief valve discharge.
t Discharge line must be as short as possible and the same
size as the valve discharge connection throughout its entire
length.
t Discharge line must pitch downward from the valve and
terminate at least 6” above the oor drain, making discharge
clearly visible.
t Discharge line shall terminate plain, not threaded, with a
material serviceable for temperatures of 375
o
F or greater.
t Do not pipe discharge to any location where freezing could
occur.
t No shuto valve may be installed between the relief valve
and water heater or in the discharge line. Do not plug or place
any obstruction in the discharge line.
t Test the operation of the relief valve after lling and
pressurizing the system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate correctly,
replace it with a new relief valve.
t Test relief valve at least once annually to ensure the waterway
is clear. If valve does not operate, turn the water heater “o”
and call a plumber immediately.
t Take care whenever operating relief valve to avoid scalding
injury or property damage.
t For water heaters installed with only a pressure relief valve,
the separate storage vessel must have a temperature and
pressure relief valve installed. This relief valve shall comply
with Relief Valves for Hot Water Supply Systems, ANSI Z21.22
CSA4.4.
FAILURE TO COMPLY WITH THE ABOVE GUIDELINES COULD
RESULT IN FAILURE OF RELIEF VALVE OPERATION, RESULTING
IN POSSIBILITY OF SUBSTANTIAL PROPERTY DAMAGE, SEVERE
PERSONAL INJURY, OR DEATH.