Page 1
100273038_2000529317 Rev A
Installation & Operation
Manual
Models: SIT040DW - SIT119DW
LOW LEAD CONTENT
WARNING
Save this manual for future reference.
This manual must only be used by
a qualified heating installer / service
technician. Read all instructions
before installing. Perform steps in
the order given. Failure to comply
could result in severe personal
injury, death, or substantial property
damage.
Page 2
Contents
HAZARD DEFINITIONS .................................................... 2
PLEASE READ BEFORE PROCEEDING ........................ 3
1. GENERAL INFORMATION
Operating Restrictions ........................................................ 4
Double-Wall Heat Exchanger ............................................. 4
2. PRE-INSTALLATION
Locating the Tank ............................................................... 5
Recommended Clearances ................................................ 5
3. BOILER SIDE PIPING
Zone with Circulator to Aquastat ........................................ 6
Zone with Valve to Aquastat .............................................. 6
DHW Prioritization .............................................................. 6
Multiple Tank Connections (Boiler Side) ............................ 6
Table 3A - Pressure Drop Chart ................................... 6
Table 3B - Pressure Drop Values ................................. 6
Piping Diagrams ............................................................ 7-10
4. DOMESTIC SIDE (TANK) PIPING
Basic Domestic Piping ................................................. 11
Multiple Tank Domestic Water Piping .......................... 11
Domestic Water Piping for Distant Fixtures ..................11
Hazard definitions
Anti-scald Valves (Mixing Valves) ............................. 12
Install Drain Valve ...................................................... 12
Temperature and Pressure (T&P) Relief Valve .......... 12
Table 4A - Minimum Relief Valve (AGA Rating) ... 13
5. WIRING
Indirect Water Heater Sensor Setup (Knight Boiler) ........ 14
Install and Connect Tank Sensor ............................... 14
Indirect Water Heater Controlled Using Aquastat and
Zone Circulator ................................................................. 15
6. START-UP AND CHECK-OUT .................................. 16
7. MAINTENANCE
Maintenance Schedule ..................................................... 17
To Fill the Water Heater ............................................. 17
To Drain the Water Heater ......................................... 17
8. PERFORMANCE DATA
AHRI Chart ....................................................................... 18
How to Properly Size Your Indirect Water Heater ........... 19
Performance Data Charts ........................................... 20-22
REVISION NOTES ............................................ Back Cover
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels
or to important information concerning the life of the product.
DANGER
WARNING
CAUTION
CAUTION
NOTICE
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious
injury.
CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or
moderate injury.
CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.
NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.
2
Page 3
Please read before proceeding
Installation & Operation Manual
WARNING
NOTICE
WARNING
Installer – Read all instructions before
installing. Perform steps in the order given.
Have this indirect water heater serviced/
inspected by a qualified service technician, at
least annually.
Failure to comply with the above could
result in severe personal injury, death or
substantial property damage.
When calling or writing about the appliance
– Please have the indirect water heater model
and serial number from the indirect water
heater rating plate.
Consider piping and installation when
determining appliance location.
Any claims for damage or shortage in
shipment must be filed immediately
against the transportation company by the
consignee.
Factory warranty (shipped with appliance)
does not apply to appliances improperly
installed or improperly operated.
If the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.
This appliance MUST NOT be installed in
any location where gasoline or flammable
vapors are likely to be present.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch; do not
use any phone in your building.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
• Installation and service must be performed by a qualified
installer, service agency, or the gas supplier.
WARNING
Failure to adhere to the guidelines on this
page can result in severe personal injury,
death, or substantial property damage.
When servicing the indirect water heater –
• To avoid severe burns, allow the appliance to cool
before performing maintenance.
Indirect water heater operation –
• Should overheating occur or gas supply fail to shut off,
do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location
external to the appliance.
• Do not use this appliance if any part has been under
water. The possible damage to a flooded appliance can
be extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.
The following chart details the relationship of water temperature
and time with regard to scald injury and may be used as a
guide in determining the safest water temperature for your
applications.
APPROXIMATE TIME / TEMPERATURE
RELATIONSHIPS IN SCALDS
120°F More than 5 minutes
125°F 1 1/2 to 2 minutes
130°F About 30 seconds
135°F About 10 seconds
140°F Less than 5 seconds
145°F Less than 3 seconds
150°F About 1 1/2 seconds
155°F About 1 second
Hot Water Can Scald!
• Water heated to temperatures for clothes washing, dish washing, and other sanitizing needs can
scald and cause permanent injury.
• Children, elderly, and infirm or physically handicapped persons are more likely to be
permanently injured by hot water. Never leave them unattended in a bathtub or shower.
Never allow small children to use a hot water tap or draw their own bath.
• If anyone using hot water in the building fits the above description, or if state laws or local
codes require certain water temperatures at hot water taps, you must take special
precautions:
• Use lowest possible temperature setting.
• Install some type of tempering device, such as an automatic mixing
valve, at hot water tap or water heater. Automatic mixing valve must be selected and
installed according to valve manufacturer’s recommendations and instructions.
• Water passing out of drain valves may be extremely hot. To avoid injury:
• Make sure all connections are tight.
• Direct water flow away from any person.
Protection Must Be Taken Against Excessive Temperature and Pressure!
--Installation of a Temperature & Pressure (T&P) relief valve is required.
3
Page 4
1 General information
Installation & Operation Manual
The Lochinvar SIT DW series indirect water heater (FIG. 1-1)
is designed to generate domestic hot water in conjunction
with a hot water boiler using forced boiler water circulation.
This indirect water heater consists of a 316L Stainless Steel
tank in which a smooth 316L stainless steel coil is located
(Table 1A). Boiler water is pumped through the coil and
heats the water in the tank. This tank is not intended for use
in pool heating applications or for heating any fluid other
than water. It is also not intended for use in gravity hot water
heating systems.
Operating restrictions:
• Maximum domestic hot water temperature is 194°F.
• Maximum boiler water temperature is 210°F.
• Maximum working pressure for the vessel tank is
150 psig.
Table 1A
Component Materials
Component Material
Tank 316L Stainless Steel
Coil 316L Stainless Steel
Double-wall heat exchanger
Uniform plumbing code
Heat exchangers used for heat transfer or heat recovery shall be
separated from the potable water by a double-wall construction
with a space open to the atmosphere between the two (2) walls.
Insulation Polyurethane
Jacket Polypropylene / ABS
Figure 1-1 Lochinvar SIT DW Series Indirect Water Heater
PAR T NO.
“F”
SIT040DW
SIT050DW
SIT065DW
SIT080DW
SIT119DW
NOTES:
22.5°
45°
1” FPT (SEE NOTE 1)
“E”
“D”
1. 1” FPT ON MODELS SIT040DW - 050DW
2. 1-1/2” MPT ON MODELS SIT065DW - 119DW
2
1
3/4” FPT
1” MPT
3
AQUASTAT/SENSOR WELL
“A”
(in.)
3 7/16
3 3/8
3 1/8
3 1/8
3 1/8
“B”
(in.)
8 7/8
9 1/4
9 1/4
9 1/2
9 1/2
“C”
(in.)
25 1/8
25 3/8
29 1/4
29 1/4
29 1/4
“D”
(in.)
30 7/8
39 3/8
53
61 1/2
59 7/8
1. RELIEF VALVE CONNECTION
2. HOT WATER OUTLET
3. BOILER WATER IN
4. BOILER WATER OUT
5. DRAIN/COLD WATER INLET
“E”
(in.)
38 1/8
48 3/8
59 3/8
68 7/8
67 5/8
WEIGHT
“F”
FULL OF WATER
(in.)
24
24
24
24
28
(lbs.)
463
581
775
900
1250
1” MPT
“C”
“B”
“A”
4
1” MPT (SEE NOTE 2)
5
SIT040DW - SIT119DW
4
Page 5
2 Pre-installation
Installation & Operation Manual
1. The installation must conform to the instructions
in this manual and all applicable local, state,
provincial, and national codes, laws, regulations, and
ordinances. Installations in Canada must conform to
B149.2 Installation Code.
2. Be certain the domestic water supply to the tank has
physical and chemical characteristics that fall within
the limits shown in Table 2A. Where questions exist
as to the composition of the water on the job, a
qualified water treatment expert should be consulted.
CAUTION
3. Read and understand all installation requirements in
this manual.
Water with characteristics outside the
limits shown in Table 2A may severely
shorten the life of the tank due to
corrosion. Damage to tanks in such
cases is not covered under warranty.
Table 2A
Water Chemistry Requirements
Water used in the tank must have characteristics falling
within the following limits:
Characteristic Min. Max.
Ph 6.0 8.0
Locating the tank
1. Choose a location for your water heater centralized to the
piping system. You must also locate the SIT DW water heater
where it will not be exposed to freezing temperatures.
Additionally, you will need to place the water heater so that
the controls, drain, and inlet/outlets are easily accessible.
This appliance must not be installed outdoors, as it is
certified as an indoor appliance, and must also be kept
vertical on a level surface.
2. Keep distance between boiler and water heater to a
minimum to:
a. reduce piping heat loss
b. provide minimal friction loss
3. Figure 1-1 on page 4 shows the weights of all the tanks filled
with water. Make sure that the location chosen for the tank
is capable of supporting it.
CAUTION
This appliance must be placed where leakage
from the relief valve, leakage from the
related piping, or leakage from the tank or
connections, will not result in damage to the
surrounding areas, or to the lower floors of
the building. A water heater should always
be located in an area with a floor drain or
installed in a drain pan suitable for water
heaters. Lochinvar shall not be held liable for
any such water damage.
Chloride (PPM) -- 80
4. The tank may be located some distance from the boiler
provided the pump is designed to provide the flow
called for in Table 3B - Pressure Drop Values, through
the coil. Also, the further the tank is from the boiler, the
longer the response of the boiler will be to a call from the
tank zone. Insulate piping between the boiler and the tank.
WARNING
Failure to properly support the tank could
result in property damage or personal injury.
Recommended clearances
The installation location must provide adequate clearances
for servicing and proper operation of the water heater. A 12
inch vertical clearance is recommended from the top of the
water heater. A zero clearance is allowed for the sides of the
water heater. However, boiler and servicing clearances must be
figured when locating the water heater.
5
Page 6
3 Boiler side piping
0
5
10
15
20
25
0 5 10 15 20 25 30 35
Foot Of Head
Flow
Pressure Drop Coil
36.5
44
44'
36.5'
Installation & Operation Manual
Figures 3-1 thru 3-4 show typical boiler side piping for
several common situations. Regardless of which system is
used it is imperative that the flow rates called for in Table
3B are developed through the coil. This requires properly
sized piping and a properly sized pump.
The system shown in FIG’s 3-1 thru 3-4 are described
below:
Zone with circulator to Aquastat
This system is like the circulator zone system on a straight
heat job except that one of the zones goes to the tank
instead of radiation. As on any circulator zone system
check valves should be installed in each zone to prevent
unwanted circulation through zones which are not calling
for heat. Figure 3-1 on page 7 illustrates typical circulator
zone piping.
Zone with valve to Aquastat
As with the circulator zone system, this system is just like a
standard heating zone system except that one of the zones
is connected to the tank coil as shown in FIG. 3-2. The
system circulator must be large enough to move boiler
water through the coil regardless of the flow rate required
through the heating zones.
DHW prioritization
This piping system is designed to provide direct hot water
priority over the other zones in the heating system. When
there is a Domestic Hot Water (DHW) call for heat, the
Knight control will shut off the boiler circulator and activate
the domestic hot water circulator. Once the DHW demand
is satisfied, the boiler circulator will be readjusted as demand
requires. The circulator must be large enough to move the
boiler water through the coils. The recommended piping for a
DHW priority system is depicted in FIG. 3-3 on page 9.
Multiple tank connections (boiler side)
Multiple tank installations must be done in the “reverse-return”
manner. The reason for this is to create the same pressure drop
(and therefore, the same flow) through the coil of each tank.
The boiler manifold piping must be sized so that each coil has
the flow rate called for in Table 3B.
Because the pressure drop through tank coils varies from size
to size, it is hard to predict the flow rate that will be developed
through each coil when two tanks of different sizes are placed
in the same manifold. For this reason it is best not to mix tanks
of different sizes in the same zone if their recovery is critical.
WATER
MODEL
SIT040 1 1 1 36.5 12.05 0.87 1.99 4.05 6.00 9.89 14.62 20.11
SIT050 1 1 1 36.5 12.05 0.87 1.99 4.05 6.00 9.89 14.62 20.11
SIT065 1.5 1.5 1 44 15.03 0.94 2.14 4.35 7.20 10.64 15.72 21.63
SIT080 1.5 1.5 1 44 15.03 0.94 2.14 4.35 7.20 10.64 15.72 21.63
SIT119 1.5 1.5 1 44 15.03 0.94 2.14 4.35 7.20 10.64 15.72 21.63
INLET
NPT
6
WATER
OUTLET
NPT
Pressure Drop Coil Chart
COIL
CONNECTION
NPT
Table 3A
Table 3B
Pressure Drop Values
COIL
LENGTH
FT
SQ FT
SURFACE
AREA
GPM8 GPM
PRESSURE DROP
FT/HD
5
12
GPM16GPM
20
GPM25GPM
30
GPM
Page 7
3 Boiler side piping (continued)
Figure 3-1 Piping Diagram Zoned with Circulators
ZONE #1
Installation & Operation Manual
MAKE UP WATER
DRAIN POINT
(TYPICAL)
BALL VALVE
(TYPICAL)
PRESSURE
REDUCING VALVE
BACKFLOW
PREVENTER
AIR SEPARATOR
EXPANSION
TANK
PRESSURE
GAUGE
SYSTEM SUPPLY
SENSOR
(WHEN USED)
NOT TO EXCEED 4 PIPE DIA.
OR A MAXIMUM OF 12" APART
Y-STRAINER
FLOW CHECK
BOILER
CIRCULATOR
VALVE
ZONE #2
HOT
WATER
OUT
ZONE #3
ANTI-SCALD
MIXING VALVE
ZONE #4
COLD
WATER
IN
ZONE CIRCULATORS
(TYPICAL)
NOTICE
NOTICE
RELIEF VALVE
TANK SENSOR/
AQUASTAT
UNION
(TYPICAL)
TEMPERATURE /
PRESSURE
GAUGE
RELIEF VALVE
DRAIN
PRESSURE
SOLUTION
BOILER
SQUIRE
DRAIN
( FIELD SUPPLY )
RECIRCULATION
CHECK VALVE
PUMP
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
Please note that the installer is responsible for ensuring DHW prioritization when piped as a zone.
7
Page 8
3 Boiler side piping
Figure 3-2 Piping Diagram Zoned with Valves
Installation & Operation Manual
ZONE #1
REDUCING VALVE
BACKFLOW
PREVENTER
DRAIN POINT
(TYPICAL)
BALL VALVE
(TYPICAL)
PRESSURE
MAKE UP WATER
AIR SEPARATOR
EXPANSION
TANK
PRESSURE
GAUGE
SYSTEM SUPPLY
SENSOR
(WHEN USED)
NOT TO EXCEED 4 PIPE DIA.
OR A MAXIMUM OF 12" APART
Y-STRAINER
BOILER
CIRCULATOR
CIRCULATOR
ZONE #2
ZONE #3
HOT
WATER
OUT
ZONE #4
ANTI-SCALD
MIXING VALVE
COLD
WATER
IN
ZONE VALVES
(TYPICAL)
DIFFERENTIAL
PRESSURE BYPASS
VALVE (IF USED)SYSTEM
TEMPERATURE /
PRESSURE
NOTICE
NOTICE
8
RELIEF VALVE
TANK SENSOR/
AQUASTAT
UNION
(TYPICAL)
GAUGE
DRAIN
PRESSURE
RELIEF VALVE
SOLUTION
BOILER
SQUIRE
DRAIN
( FIELD SUPPLY )
RECIRCULATION
PUMP
CHECK VALVE
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
Please note that the installer is responsible for ensuring DHW prioritization when piped as a zone.
Page 9
3 Boiler side piping (continued)
Figure 3-3 Knight Boiler Primary / Secondary Piping
PRESSURE
AIR
REDUCING VALVE
PRESSURE
GAUGE
BACKFLOW
PREVENTER
MAKE UP WATER
SYSTEM SUPPLY
SENSOR
SEPARATOR
Installation & Operation Manual
TO
SYSTEM
BALL VALVE
(TYPICAL)
SYSTEM
CIRCULATOR
EXPANSION
TANK
DRAIN POINT
(TYPICAL)
UNION
(TYPICAL)
TEMPERATURE /
PRESSURE
GAUGE
BOILER
CIRCULATOR
DRAIN
PRESSURE
RELIEF VALVE
Y-STRAINER
(RECOMMENDED)
DOMESTIC
HOT WATER
CIRCULATOR
KNIGHT
BOILER
FROM
SYSTEM
ANTI-SCALD
MIXING VALVE
SQUIRE
HOT
WATER
OUT
COLD
WATER
IN
TANK SENSOR/
AQUASTAT
CHECK VALVE
RECIRCULATION
DRAIN
( FIELD SUPPLY )
PUMP
NOTICE
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
9
Page 10
3 Boiler side piping
Figure 3-4 Multiple Tank Connections
PRESSURE
BACKFLOW
PREVENTER
REDUCING VALVE
PRESSURE
GAUGE
Installation & Operation Manual
SYSTEM SUPPLY
TO
SYSTEM
BALL VALVE
(TYPICAL)
MAKEUP WATER
SENSOR
CIRCULATOR
EXPANSION
AIR
SEPARATOR
SYSTEM
TAN K
DRAIN POINT
(TYPICAL)
UNION
(TYPICAL)
TEMPERATURE/
PRESSURE GAUGE
NOT TO EXCEED 4 PIPE DIA.
OR A MAXIMUM OF 12” APART
Y-STRAINER
(RECOMMENDED)
BOILER
CIRCULATOR
DRAIN
PRESSURE
RELIEF VALVE
DOMESTIC
HOT WATER
CIRCULATOR
KNIGHT
BOILER
FROM
SYSTEM
SQUIRE
HOT
WATER
OUT
SQUIRE
ANTI-SCALD
MIXING VALVE
RELIEF VALVE
(TYPICAL)
TANK SENSOR/
AQUASTAT
(TYPICAL)
COLD
WATER
IN
RECIRCULATION
PUMP
CHECK VALVE
DRAIN
(FIELD SUPPLY)
NOTICE
10
IMG00184
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
Page 11
Installation & Operation Manual
4 Domestic side (tank) piping
Basic domestic piping
Figure 4-2 on page 13 shows typical domestic water piping
for a tank. The function of the components shown are as
follows:
a. Shut-off valves (recommended) - Used to isolate the
tank for servicing.
b. Backflow Preventer (required by some codes) - Used to
prevent water from backing out of the tank and into
the main potable water supply in the event that inlet
water pressure drops.
c. Expansion Tank (required for thermal expansion) This expansion tank absorbs the increased volume
caused by heating water.
Use an expansion tank designed for use on domestic
water systems. Refer to the expansion tank
manufacturer’s literature for the proper size expansion
tank to use.
NOTICE
d. Unions (optional) - Used to disconnect the tank in the
unlikely event that this is necessary.
If an expansion tank is used, do not put
any valves between the expansion tank
and tank inlet.
Domestic water piping for distant fixtures
In some cases the furthest fixture may be quite distant from
the tank. Such an installation would result in an unacceptable
delay before hot water reaches these distant fixtures. Even if all
the fixtures are relatively close to the tank, the building owner
may want hot water at all fixtures as soon as they are opened.
To prevent delays, return circulation piping with a check valve
that allows flow to the inlet of the tank. This should be installed
on each branch circuit at the farthest fixture or device, so that
hot water is supplied upon demand.
Because hot water is always circulating in the hot water branch,
the entire branch should be insulated to prevent excessive heat
loss.
e. Drain (required) - Used to drain the tank for
inspection or servicing.
Multiple tank domestic water piping
The two pipe reverse return piping uses more pipe than the
two pipe direct return piping, but the flow is more balanced
and even in the two pipe reverse return piping layout (see
FIG. 3-4).
Each tank must have its own T&P valve. It is recommended
that each tank be equipped with its own isolation valves,
unions, and drains so that one tank may be removed from
the system. If local codes require a backflow preventer,
check with the appropriate authority to find out whether
one backflow preventer may be used for tanks or each tank
must be equipped with its own backflow preventer. If each
tank must have its own backflow preventer, each tank must
also have its own expansion tank. If a common backflow
preventer is permitted, an expansion tank must be sized to
accommodate the expansion volume of all tanks.
11
Page 12
Installation & Operation Manual
4 Domestic side (tank) piping
Anti-scald valves (mixing valves)
Anti-scald valves used with water heaters are also called
tempering valves or mixing valves. An anti-scald valve
mixes cold water in with the outgoing hot water to assure
that hot water reaching a building fixture is at a temperature
low enough to be safe. ASSE1017 and ASSE1070 certified
valves are recommended.
Usually, the maximum temperature of the outlet water will
stay near the setting of the tank control. In some cases,
however, hot water usage patterns can cause the outlet
water temperature to rise significantly above the control
setting.
The temperature of water going to the fixtures may be
more carefully controlled through the use of a thermostatic
mixing valve. This device blends a controlled amount of
cold water with the hot water leaving the tank so that water
at a more constant temperature exits the mixing valve.
Anti-scald mixing valve piping is illustrated in FIG.’s 3-1
thru 3-4.
WARNING
An anti-scald mixing valve does not
eliminate the risk of scalding.
* Set the tank thermostat as low as
practical.
* Feel water before bathing or
showering.
* If anti-scald or anti-chill protection
is required, use devices specifically
designed for such service. Install
these devices in accordance with
their manufacturer’s instructions.
Install drain valve
Drain valve and fittings are supplied by others.
Standard Installation
• Install a tee connection at the domestic cold water
inlet (FIG. 4-1).
Figure 4-1 Drain Valve Installed
Temperature & pressure (T&P) relief valve
WARNING
NOTICE
Do not place a valve between the combination T&P relief valve
and the tank.
Determine T&P relief valve size by the following specifications,
unless they conflict with local codes:
- SIT040/050DW - 3/4" NPT with a minimum CSA
Rating of 105,000 Btu/hr.
For protection against excessive
temperatures and pressure, install
temperature and pressure protective
equipment required by local codes.
This equipment shall not be less than a
combination temperature and pressure relief
valve certified by a nationally recognized
testing laboratory that maintains periodic
inspection of production of listed equipment
or materials as meeting the requirements for
Relief Valves and Automatic Gas Shutoff
Devices for Hot Water Supply Systems,
ANSI Z21.22 and the Standard CAN1-4.4,
Temperature, Pressure, Temperature and
Pressure Relief Valves and Vacuum Relief
Valves. The combination temperature and
pressure relief valve shall be marked with
a maximum set pressure not to exceed the
maximum working pressure of the water
heater. The combination temperature and
pressure relief valve shall also have an hourly
rated temperature steam BTU discharge
capacity not less than shown in Table 4A.
Install the combination temperature and
pressure relief valve into the opening
provided and marked for this purpose on
the water heater.
Verify that the combination temperature
and pressure relief valve complies with local
codes. If the combination temperature and
pressure relief valve does not comply with
local codes, replace it with one that does.
Follow the installation instructions in this
section.
12
DRAIN
VALV E
- SIT065/080/119DW - 3/4" NPT with a minimum CSA
Rating of 200,000 Btu/hr.
NOTICE
The Lochinvar SIT DW series water heaters
will absorb/store less than 200,000 Btu/hr when
domestic water outlet temperature is 210°F
and boiler water supply temperature is
240°F. Listed outputs are based on ASME
Section VIII Interpretation VIII-1-86-136.
Check with local codes for applicability.
Page 13
Installation & Operation Manual
4 Domestic side (tank) piping (continued)
Table 4A
Minimum Relief Valve (CSA Rating)
Model Btu/hr
SIT040DW 105,000
SIT050DW 105,000
SIT065DW 205,000
SIT080DW 205,000
SIT119DW 205,000
Standard installation
• Install the T&P relief valve in the connection marked
“Relief Valve”.
T&P relief valve discharge piping
T&P relief valve discharge piping MUST be:
- made of material serviceable for a temperature of
250°F or greater.
- directed so that hot water flows away from all
persons.
- directed to a suitable place for disposal.
- installed so as to allow complete draining of the
T&P relief valve and discharge line.
- terminated within 6" of the floor.
T&P relief valve discharge piping MUST NOT be:
- excessively long. Using more than two (2) elbows or 15
feet of piping can reduce discharge capacity.
- directly connected to a drain. Refer to local codes.
- subject to freezing.
WARNING
Do not install any valve between the T&P
relief valve and the tank connection or
on the T&P relief valve discharge piping.
Improper placement and piping of T&P
relief valve can cause severe personal injury,
death or substantial property damage.
CAUTION
The T&P relief valve is not intended for
constant duty, such as relief of pressure
due to repeated normal system expansion.
Correct this condition by installing a
properly sized expansion tank in a domestic
water system. Refer to the expansion tank
manufacturer’s installation instructions for
proper sizing.
WARNING
Failure to install and maintain a new, listed
3/4" X 3/4" T&P relief valve will release
the manufacturer from any claim which
might result from excessive temperature
and pressures.
Figure 4-2 Recommended Domestic Water Piping
SHOCK ARRESTOR
UNION
(TYPICAL)
ANTI-SCALD
MIXING VALVE
TO BOILER
FROM BOILER
SQUIRE
TANK SENSOR/
AQUASTAT
CHECK VALVE
DRAIN
( FIELD SUPPLY)
SHUT-OFF VALVE
SHUT-OFF
VALVE
SHUT-OFF
VALVE
EXPANSION
TANK
RECIRCULATION
PUMP
SHUT-OFF
VALVE
BACKFLOW
PREVENTOR
NOTICE
Please note that these illustrations are meant to show system piping concept only, the installer
is responsible for all equipment and detailing required by local codes.
13
Page 14
Installation & Operation Manual
5 Wiring
Indirect water heater sensor setup (Knight boiler)
CAUTION
NOTICE
Install tank sensor
The tank sensor is a dual sensor which controls the
temperature of the tank from the boiler(see FIG. 5-1). The
tank sensor has a built-in high temperature limit set at
194°F.
1. Install the sensor inside the tank as depicted
in FIG. 5-1.
2. Connect the wire leads to the DHW Tank Sensor
(AUX) connection point on the Knight boiler
connection board (see FIG. 5-1).
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and
dangerous operation.
The sensor supplied contains an Auto Reset High Limit (194°F).
Connect tank sensor
1. Turn OFF the power to the unit. Use wire strippers to strip
one inch of insulation from the ends of each wire that
will be spliced.
2. Splice the two ends of bare wire by twisting them together
with a pair of electrical pliers. Turn the pliers three or
four times to make a sufficient connection.
3. Attach a wire nut at the point where the two wires have been
twisted together. Twist the wire nut until it fits snugly, or
until it cannot be twisted any more.
3. The Knight boiler will automatically read the sensor
and default the tank temperature setting to 125°F.
4. Wrap the wire nut and the two wires with electrical tape to
secure the connection. Cover any exposed wiring with
4. Adjust the tank setpoint program. Reference the
electrical tape.
Knight Installation and Operation Manual for a
detailed explanation of the tank setpoint program.
Figure 5-1 Indirect Water Heater Controlled Using Tank Sensor
TANK BULBWELL
DHW TANK SENSOR / AUTO RESET HIGH LIMIT
(PLACE SENSOR IN
TANK BULBWELL & SNAP
CLIP OVER BULBWELL)
DHW TANK
SENSOR
KNIGHT LOW VOLTAGE
TERMINAL STRIP
14
INDIRECT TANK
KNIGHT BOILER
Page 15
Installation & Operation Manual
5 Wiring (continued)
Indirect water heater controlled using Aquastat and zone circulator / valve
1. Install Aquastat to tank. Aquastat control (100208546) can be ordered from your local Lochinvar distributor.
2. Connect Aquastat to the zone controller for the Indirect Water Heater Zone.
3. Adjust Aquastat to the desired temperature.
Figure 5-2 Wiring for Zone Control
100208546
TEMPERATURE
ADJUSTMENT
ZONE CONTROL BOX
OR
WIRE
CONNECTIONS
ZONE VALVE
OR
ZONE CIRCULATOR
INDIRECT TANK
AQUASTAT
CONTROL
15
Page 16
6 Start-up and check-out
1. Make sure the system is free of leaks and that air is
purged from the system.
Installation & Operation Manual
CAUTION
2. Many soldering fluxes contain Zinc Chloride which can
cause severe corrosion damage to stainless steel. After
completing all domestic water connections, flush the
indirect water heater thoroughly before leaving the
installation. This is particularly important if the
indirect water heater will be unused for an extended
period of time after installation. Flush the indirect
water heater by drawing at least three times its volume
from the tank.
3. Make sure that all electrical connections are made
correctly and that no exposed high voltage wiring is
present.
4. Make sure that each zone valve or circulator operates
when, and only when, its thermostat calls for heat. Let
each zone operate long enough to purge any remaining
air from the system.
5. Set the indirect water heater to the desired temperature.
Because hot water presents a scald hazard, it is best to set
the thermostat at 120°F or lower and raise it only if
necessary to provide adequate hot water.
Fix any leaks found before proceeding
further. Leakage from the boiler piping
can result in severe damage to the boiler.
6. Re-enable the burner and allow the boiler to operate.
Make sure that the boiler shuts down when the indirect
water heater is satisfied.
16
Page 17
7 Maintenance
Installation & Operation Manual
The Lochinvar SIT DW series indirect water heater is an
extremely simple device and as such requires very little
maintenance. There are, however, several items which
should be checked out on an annual or as needed basis to
ensure a reliable supply of hot water:
* Make sure that the rest of the boiler and domestic
water piping is free of leaks.
* If there is an oil lubricated circulator in the system,
make sure it is lubricated as called for by the
circulator manufacturer.
* Make sure that the boiler is maintained in accordance
with the boiler manufacturer’s instructions.
* If a water treatment system is required to keep the
water chemistry within the parameters shown in
Table 2A (see Section 2 - Pre-Installation), make sure
that this system is properly maintained.
Maintenance Schedule
Annual service by a qualified service technician
should include the following:
Any procedure required by local codes.
Verify system pressure. Air venting procedure may
require adding water to bring boiler system up to
pressure, typically 12 psig.
Manually operate T&P relief valve at least once a year.
This will release some hot water.
WARNING
Move operating lever to open position for a few
seconds and then move it back, allowing it to snap
closed. After the T&P relief valve is operated, if it
continues to release water, close the cold water inlet to
the water heater immediately. Follow the draining
instructions, and replace the T&P relief valve. If the
T&P relief valve weeps periodically, it may be due to
thermal expansion. Do not plug the T&P relief valve or
discharge piping.
DANGER
Follow instructions on circulator to oil, if required.
Check mixing valve, valves, pipes, and fittings for leaks.
Check function of the field-installed controls and valves.
See component manufacturer’s instructions.
Review homeowner’s maintenance responsibilities and
their frequencies, including any not listed in the
following section.
Before operating a T&P relief valve, make
sure no one is in front of or around the
T&P relief valve discharge piping. Hot
discharge water can cause severe personal
injury or substantial property damage.
Plugging the T&P relief valve or discharge
piping can cause excessive pressure in the
water heater, resulting in severe personal
injury, death, or substantial property
damage.
Homeowner monthly maintenance to include:
Visually check valves, pipes, and fittings for leaks. Call a
qualified service technician to repair leaks.
To Fill the Water Heater
1. Close the water heater drain valve by turning the knob
clockwise.
2. Open the cold water supply shutoff valve.
3. Open several hot water faucets to allow air to escape from
the system.
4. When a steady stream of water flows from the faucets, the
water heater is filled. Close the faucets and check for water
leaks at the water heater drain valve, combination
temperature and pressure relief valve and the hot and cold
water connections.
WARNING
To Drain the Water Heater
Should it become necessary to completely drain the water
heater, be sure to follow the steps below:
1. Disconnect the power supply to the heat source. Consult
the plumbing professional or electric company in your area
for service.
2. Close the cold water supply shutoff valve.
3. Open the drain valve on the water heater.
4. Open a hot water faucet to allow air to enter the system.
Drain the water heater if it will be shut off and exposed to
freezing temperatures. Freezing water will expand and damage
the water heater.
• If boiler water contains sufficient antifreeze, then
only the domestic water needs to be drained.
Water from opened drain valves, unions and
other connections may be extremely hot.
To avoid severe personal injury, death, or
substantial property damage:
- Tighten all drain hose connections.
- Direct hot water away from all
persons.
• If boiler water does not contain sufficient
antifreeze, the boiler water and the domestic water
must be drained.
If antifreeze is used in the boiler water, check concentration.
Boiler water (including additives) must be practically non-toxic,
having a toxicity rating or class of 1, as listed in the “Clinical
Toxicology of Commercial Products”. A maximum 50/50
mixture of inhibited propylene glycol is recommended. Follow
the antifreeze manufacturer’s instructions.
WARNING
Do not use automotive, ethylene glycol
or petroleum-based antifreeze. Do not use
any undiluted antifreeze. This can cause
severe personal injury, death, or substantial
property damage.
17
Page 18
Installation & Operation Manual
8 Performance data
Table 8A AHRI Chart
Squire Indirect DW Water Heater
AHRI Rating
Minimum Heat
Output Rate
from
Heat Source
Btu/hr
Minimum
Heat Source
Flow Rate
GPM
Tank Heat
Source
Friction Loss
Feet W.C.
Indirect
Water Heater
Model Number
SIT040DW
SIT050DW
SIT065DW
SIT080DW
SIT119DW
Potable
Water
Volume
Gal.
38 1.6 1.5 153 120 90,000 14.00 5.3
50 1.6 0.9 165 120 90,000 14.00 5.3
63 2.5 0.7 235 174 120,000 14.00 5.7
80 2.5 0.6 249 174 120,000 14.00 5.7
113 2.5 0.5 280 174 120,000 14.00 5.7
Heat Source
Water
Volume
Gal.
Standby
Heat Loss
F/hr
First Hour
Rating Gal/hr
Continuous
Draw Rating
Gal/hr
• These ratings were obtained with a heat source output and heat source flow rate as listed in the chart using the parameters of the
Domestic Cold Water Inlet at 58°F, Domestic Temperature Rise of 77°F, and a Boiler Temperature Output of 180°F. Other results
will be obtained under different conditions.
18
Page 19
Installation & Operation Manual
8 Performance data (continued)
How to properly Size Your Indirect Water Heater
Use the First Hour Rating (FHR) to properly size your Indirect Water Heater. The First Hour Rating is the amount of hot water
in gallons the heater can supply per hour (starting with a tank full of hot water), depending on tank capacity, source of heat, and
the size of the burner.
Estimate your peak hour demand as follows:
• Determine what time of day (morning, noon, evening) you use the most hot water in your home. Keep in mind the
number of people living in your home.
• Use the worksheet below to estimate your maximum usage of hot water during this one hour of the day -- this is your peak
hour demand. Note: The worksheet does not estimate total daily hot water usage.
The worksheet example shows a total peak hour demand of 165 gallons; therefore, this household would need a water heater with
a First Hour Rating of no less than 165 gallons.
Fixture Count Guide
To quickly estimate the minimum gallons of hot water required based on a family size number of baths and hot water appliances
the First Hour Rating of the Squire must be equal to or exceed the total first hour requirements.
Peak Hour Demand Worksheet
Description Fill in the Blank Example
40 Gallons for the first 2 people
10 Gallons for each additional person
20 Gallons for each bath after the first
(consecutive bath)
10 Gallons if dishwasher is used
20 Gallons if clothes washer is used
TOTAL
Heavy Usage Buffer
Use if family members take longer than average showers, etc.
First Hour Rating
Proceed to pages 21 – 23 of this manual to locate your Indirect Water Heater and Boiler in the sizing charts. Using the First Hour
Rating calculated in this worksheet, locate your Indirect Water Heater and Boiler along with your First Hour Rating. This will also
determine the flow needed between the Indirect Water Heater and Boiler.
x 1.5 x 1.5
Gals. 40 Gals.
Gals. 20 Gals.
Gals. 20 Gals.
Gals. 10 Gals.
Gals. 20 Gals.
Gals. 110 Gals.
Gals. 165 Gals.
19
Page 20
Installation & Operation Manual
8 Performance data
Table 8B First Hour Rating - 180°F Boiler Loop Water (Knight Boiler)
First Hour Rating - 180°F Boiler Loop Water
(Knight Boiler - Models SIT040DW - SIT050DW)
Model SIT040DW SIT050DW SIT065DW
Circulator Flow GPM 5 8 12 16 20 25 30 5 8 12 16 20 25 30 5 8 12 16 20 25 30
Domestic Outlet
52,500 WH/KH55
76,000 KB81
80,750 WH85
99,750 KB106
104,500 WH110
Boiler Output Capacity
142,500 KB151
MAX BTU INPUT 47,144 57,327 62,606 67,133 73,108 81,841 89,761 47,144 57,327 62,606 67,133 73,108 81,841 89,761 70,904 77,315 87,876 98,059 100,699 113,899 124,459
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140115140115 140 115 140 115 140 115 140 115 140 115 140
141 110 152 118 153 122 164 130 226 178
164 126 175 135 186 142 199 151 203 154 176 138 187 147 198 154 211 163 215 166 285 220 301 231 302 232
214 162 226 174 305 234 317 242
216 163 236 178 228 175 248 190 339 258 371 281 376 284
379 287 392 296
421 317 454 340
First Hour Rating - 180°F Boiler Loop Water
(Knight Boiler - Models SIT080DW - SIT119DW)
Model SIT080DW SIT119DW
Circulator Flow GPM 5 8 12 16 20 25 30 5 8 12 16 20 25 30
Domestic Outlet
52,500 WH/KH55
76,000 KB81
80,750 WH85
99,750 KB106
104,500 WH110
142,500 KB151
Boiler Output Capacity
MAX BTU INPUT 70,904 77,315 87,876 98,059 100,699 113,899 124,459 70,904 77,315 87,876 98,059 100,699 113,899 124,459
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
243 195 271 223
302 237 318 248 330 265 346 276 347 277
322 251 334 259 362 287 362 287
356 275 388 298 393 301 416 326 421 329 422 330
396 304 409 313 424 332 437 341 436 340
438 334 471 357 466 362 499 385
NOTICE
NOTICE
20
All data was generated under lab conditions. ere is no extra bene t in the shaded out areas on the tables. Results will
vary under individual applications.
It is not recommended to have a unit that is 400,000 Btu input or greater on the SIT040DW and SIT050DW models.
Page 21
Installation & Operation Manual
8 Performance data (continued)
Table 8C First Hour Rating - 180°F Boiler Loop Water (Universal Sizing)
First Hour Rating - 180°F Boiler Loop Water
(Universal Sizing - 45,000 - 140,000 Btu/hr)
Model SIT040DW SIT050DW SIT065DW
Circulator Flow
GPM
Domestic Outlet
45,000
60,000
75,000
95,000
115,000
Boiler Output Capacity
140,000
MAX BTU INPUT 47,144 57,327 62,606 67,133 73,108 81,841 89,761 47,144 57,327 62,606 67,133 73,108 81,841 89,761 70,904 77,315 87,876 98,059 100,699 113,899 124,459
5 8 12 16 20 25 30 5 8 12 16 20 25 30 5 8 12 16 20 25 30
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140115140115 140 115 140 115 140 115 140 115 140 115 140
138 109 148 119 207166
141 110 164 126 172 132 153 122 176 138 182 143 254199
175 135 186 142 199 151 203 155 187 147 198 154 211 163213 165 285 220 302 233
216 163 236 178 228 175 248 190 305 234 339 258 365 278
371 281 379 287 421 317 428 322
454 340
First Hour Rating - 180°F Boiler Loop Water
(Universal Sizing - 45,000 - 140,000 Btu/hr)
Model SIT080DW SIT119DW
Circulator Flow
GPM
Domestic Outlet
45,000
60,000
75,000
95,000
115,000
Boiler Output Capacity
140,000
MAX BTU INPUT 70,904 77,315 87,876 98,059 100,699 113,899 124,459 70,904 77,315 87,876 98,059 100,699 113,899 124,459
5 8 12 16 20 25 30 5 8 12 16 20 25 30
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
218 177 252 211
266 211 300 245 300 245
302 237 313 244 347 278
322 251 356 275 377 289 350 279 384 303 411 323
388 298 396 304 438 334 440 334 416 326 424 332 466 362 474 368
471 357 499 385
21
Page 22
Installation & Operation Manual
8 Performance data
Table 8D First Hour Rating - 200°F Boiler Loop Water (Universal Sizing)
First Hour Rating - 200°F Boiler Loop Water
(Universal Sizing - 45,000 - 225,000 Btu/hr)
Model SIT040DW SIT050DW SIT065DW
Circulator Flow
GPM
Domestic Outlet
45,000
60,000
75,000
95,000
115,000
140,000
165,000
Boiler Output CapacityBoiler Output Capacity
195,000
225,000
MAX BTU INPUT 81,087 98,603 107,683 115,469 125,746 140,766 154,389 81,087 98,603 107,683 115,469 125,746 140,766 154,389 121,955 132,982 151,146 168,661 173,202 195,905 214,070
5 8 12 16 20 25 30 5 8 12 16 20 25 30 5 8 12 16 20 25 30
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140115 140 115 140 115 140 115 140 115 140 115 140 115 140
134 109 145 119 202 166
167 132 177 143 248 199
199 156 210 167 293 233
210 164 243 188 222 176 253 199 354 278
248 192 268 206 285 219 286 220 260 204 280 218 296 230 415 323
307 235 335 256 340 260 297 231 319 247346 267 350 270433 334 467 359 492 379
369 281 347 268 381 293 523 401 569 435
576 440 589 449 659 501 659 502
714 541
First Hour Rating - 200°F Boiler Loop Water
(Universal Sizing - 45,000 - 225,000 Btu/hr)
Model SIT080DW SIT119DW
Circulator Flow
GPM
Domestic Outlet
45,000
60,000
75,000
95,000
115,000
140,000
165,000
195,000
225,000
MAX BTU INPUT 121,955 132,982 151,146 168,661 173,202 195,905 214,070 121,955 132,982 151,146 168,661 173,202 195,905 214,070
5 8 12 16 20 25 30 5 8 12 16 20 25 30
115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
213 177 247 211
259 211 293 245
305 244 339 278
366 289 400 323
427 334 461 368
450 351 484 376 504 391 478 379 512 404 538
540 418 580 447 568 446 614 481
593 457 606 466 671 514 621 485 634 494 704 546 705 547
676 518 731 558 759 586
22
Page 23
Notes
Installation & Operation Manual
23
Page 24
Revision Notes: Revision A (Process #3000001798_Change
#500002025) initial release.
MM #100273038_DIR #2000529317 Rev A
08/16 - Printed in U.S.A.
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