Installation Instructions
whl-590 Rev. 003 Rel. 003 Date 3.22.18
16
more or less energy. The negative regulated gas valve provides only
the amount of fuel required to ensure clean combustion. The mixer
accurately regulates the combination of gas and air throughout the
modulating range to ensure high reliability. The burner is constructed
of durable ceramic metal ber for long service life.
Water Heater Sensors (Inlet – Outlet – Flue) - Sensors provide highly
accurate temperature monitoring to assure accurate system control.
These sensor inputs can be monitored through the water heater
control system and display.
Pressure Gauge – Allows the user to monitor system pressure.
System Safeties – The water heater is provided with many safety
features to ensure reliable and safe operation. Each safety is connected
to the water heater control. The water heater will alert the user if an
unsafe condition occurs and needs to be addressed. The following
are provided safeties: Flue Pressure Switch (monitors ue pressure),
Burner High Limit (monitors burner plate temperature), High Limit
Water Switch (monitors water heater water temperature), Low
Water Sensor (monitors water level in the heat exchanger), optic
ame sensor (monitors ame quality), Flue Sensor (monitors ue
temperature), Condensate Pressure Switch (monitors pressure to
ensure condensation does not back up into water heater).
Manual Air Vent – Each water heater is equipped with an air vent to
discharge air from the system during start–up.
Intake and Exhaust Adapters – The water heater is equipped with
adapters to ease connection to the vent system. The adapters are
provided with clamps and seals to secure eld supplied piping, and
test ports to ease monitoring of the combustion system. Each water
heater is supplied with a 6 inch piece of CPVC that must be connected
into the exhaust vent adapter.
3/4” Inlet and Outlet Connections – Water heaters are equipped with
bottom piping connections for greater installation exibility.
Gas Connection – The water heater is equipped with a ¾” gas
connection to connect the incoming gas supply.
Field Wiring and Power Switch – Each water heater is supplied with a
power switch to cut o power. The water heater is also equipped with
two front mounted terminal strips. These terminal strips are separated
into low and line voltage to ease system wiring.
Condensate Trap and Hose Assembly – Each water heater has a built-
in condensate trap to control the discharge of condensate produced by
the water heater during normal operation. A corrugated condensate
hose is also provided to ensure proper drainage of condensate into
the pump or drain.
Low Water Cut O Probe – LWCO is provide with each water heater
to assure the water heater has adequate water level to eliminate
overheating and even damaging the water heater heat exchanger .
Pump Service Mode – Allows manual operation of pumps to
commission system and check pump operation.
Cascade Operation - This water heater can be congured to run with
multiple units in a Cascade System. In a Cascade System, multiple
water heaters are installed, piped, and wired to cooperate in a single
system. This provides many advantages over a single large capacity
water heater, including increased turndown, system redundancy, and
increased eciency. A maximum of sixteen (16) water heaters can be
controlled by a single water heater designated as the “Master”. Other
connected water heaters are designated as “Followers”.
J. Wall-Mounting
The water heater may be installed on any suitable internal wall
(suitable sound-proong may be required when installing onto a
stud partition wall).
The water heater must be installed on a wall that can bear its
weight (more than 100 lbs. when fully plumbed and full of water).
Installing the water heater on a wall which cannot support its
weight could result in property damage, personal injury, or death.
This water heater is too heavy for one person to lift. It is highly
recommended to install the water heater with two people. Use
caution as to not drop the water heater, which could damage the
water heater and cause property damage and/or severe personal
injury. Verify that the water heater is properly and securely
mounted before leaving unsupervised. Failure to comply with
the above and properly mount the water heater could result in
substantial property damage, severe personal injury, or death.
This wall mounting system is not seismic rated and should not be
applied as such. Failure to comply with the above and properly
mount the water heater could result in substantial property
damage, severe personal injury, or death.
Positioning the Water Heater on the Wall
1. Attach the wall bracket on the location where you want to
install the water heater. Ensure it is level and on stud (16”
centers) before proceeding.
2. Mark the four drill holes with a pencil or marker. Remove the
wall bracket.
3. Drill four (4) holes using a 5/32 drill bit at the marked hole
locations.
4. Mount the wall bracket to the wall with the four (4) included
anchor bolts. Ensure the mounted bracket is level. See Figure
6A.
5. Align the heater bracket grooves on the back of the water
heater with the tongues on the wall bracket and hang the
water heater on the bracket. See Figure 6B.
Figure 6 - Wall-Mounting the Water Heater
The Master controls the operational run time of the connected
Followers and modulates the connected units up or down to ensure
the units are putting only the needed energy into the connected
storage tank, and also to ensure all connected units get even run
time to balance out service requirements.
When the Master water heater receives a DHW demand, the Master
will energize the lead water heater in the cascade system. In a new
system start-up this will be the Master. The water heater will re at
its ignition speed and then modulate its ring rate to maintain the
set point. If the rst water heater reaches 80% of its ring rate, the
Master will modulate down and split the load in half with the next
unit in the system service rotation. At this point, the Master will re
the second water heater in the system. If there are more than two
water heaters in the system, the same principle will be applied. Once
the lead water heater reaches 80% of its ring rate, it will modulate
down and split the total amount of load by the total number of units
in the cascaded system.
If the set point still cannot be met, the Master will continue ring
more Followers until either the DHW demand is met or all water
heaters in the cascade system are ring at the maximum rate. As the
heat demand decreases, all operating water heaters will modulate
down according to the heating load. The rst water heater to
modulate down to 30% will shut o. The same principle will be
applied to the remaining water heaters in operation until the DHW
demand is satised. When the demand is satised, the water heaters
will turn o.