Page 1
CAUTION: The heat transfer medium
must be water or other nontoxic fluid having
a toxicity rating or class of 1, as listed in
Clinical Toxicology of Commercial Products,
5th edition.
SIT-I-O Rev H
Installation & Operation
Manual
Models: SIT030 - SIT119
The pressure of the heat transfer medium
must be limited to a maximum of 30 PSIG by
an approved safety or relief valve.
WARNING
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.
Save this manual for future reference.
Page 2
Contents
HAZARD DEFINITIONS .................................................... 2
PLEASE READ BEFORE PROCEEDING ........................ 3
1. GENERAL INFORMATION
Operating Restrictions ........................................................ 4
Single-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) ........ 15
Install and Connect Tank Sensor ............................... 15
Indirect Water Heater Controlled Using Aquastat and
Zone Circulator ................................................................. 16
6. START-UP AND CHECK-OUT .................................. 17
7. MAINTENANCE
Maintenance Schedule ..................................................... 18
To Fill the Water Heater ............................................. 18
To Drain the Water Heater ......................................... 18
8. PERFORMANCE DATA
IBR Chart.......................................................................... 19
How to Properly Size Your Indirect Water Heater ........... 20
Performance Data Charts ........................................... 21-23
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 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 304L 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 Steel Stainless Steel
Coil 304L Stainless Steel
Insulation Polyurethane
Single-wall heat exchanger
Uniform plumbing code
Single-wall heat exchangers are permitted if they satisfy all of
the following requirements --
1. The heat transfer medium is potable water or contains only
substances which are recognized as safe by the U.S. Food
and Drug Administration.
2. The pressure of the heat transfer medium is maintained less
than the normal minimum operating pressure of the
potable water system.
3. The equipment is permanently labeled to indicate that
only additives recognized as safe by the FDA shall be used
in the heat transfer medium.
Other heat exchanger designs may be permitted where approved
by the Administrative Authority.
Jacket Polypropylene / ABS
Figure 1-1 Lochinvar SIT Series Indirect Water Heater
PAR T NO.
“F”
22.5°
45°
1” FPT (SEE NOTE 1)
“E”
“D”
SIT030
SIT040
SIT050
SIT065
SIT080
SIT119
NOTES:
1. 1-1/2” FPT ON MODELS SIT065 - 119 .
2. 1-1/2” MPT ON MODELS SIT065 - 119 .
2
1
3/4” FPT
3
1” MPT
AQUASTAT/SENSOR WELL
“A”
(in.)
3 1/16
3 1/16
3 5/8
3 5/16
3 5/16
3 5/16
“B”
(in.)
8 3/16
8 3/16
9 1/8
9 1/8
9 1/8
9 3/8
“C”
(in.)
21 3/4
25 1/4
24 7/16
27 15/16
27 15/16
31 11/16
“D”
(in.)
32 1/4
48 1/2
39 3/4
52 1/4
61 3/4
60 1/4
1. RELIEF VALVE CONNECTION
2. HOT WATER OUTLET
3. BOILER WATER IN
4. BOILER WATER OUT
5. DRAIN/COLD WATER INLET
“E”
(in.)
39 1/2
55 9/16
47 1/4
59 7/8
69 3/8
68 3/16
WEIGHT
“F”
FULL OF WATER
(in.)
(lbs.)
20
20
24
24
24
28
393
515
614
820
921
1268
4
“C”
“B”
“A”
1” MPT
1” MPT (SEE NOTE 2)
5
SIT030 - SIT119
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 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
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
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.
Table 3A
Pressure Drop Chart
SIT030 -119 FRICTION LOSS
SIT030 -119 FRICTION LOSS
SIT119,
SIT065
&
080,
SIT050
SIT040
SIT030
FOOT HEAD
12.00
12.00
10.00
8.00
6.00
4.00
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
2.00
0.00
5 8 12 16 20
GPM
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.
Table 3B
Pressure Drop Values
PRESSURE DROP
5
(FT/HD)
12
GPM16GPM
MODEL
WATER
INLET
(NPT)
WATER
OUTLET
(NPT)
COIL
CONNECTION
(NPT)
COIL
LENGTH
(FT)
SQ FT
SURFACE
AREA
GPM8 GPM
SIT030 1 1 1 24 8.0 .36 .91 2.06 3.66 5.71
SIT040 1 1 1 30.8 10.0 .41 1.04 2.34 4.16 6.49
SIT050 1 1 1 36.5 12.0 .46 1.18 2.67 4.74 7.4
SIT065 1.5 1.5 1 41.5 13.5 .61 1.57 3.53 6.27 9.8
SIT080 1.5 1.5 1 41.5 13.5 .61 1.57 3.53 6.27 9.8
20
GPM
SIT119 1.5 1.5 1 67.3 22.0 .73 1.87 4.22 7.5 11.71
6
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
WATER
ZONE #3
HOT
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
TO
SYSTEM
BALL VALVE
(TYPICAL)
MAKE UP WATER
SEPARATOR
SYSTEM SUPPLY
SENSOR
SYSTEM
CIRCULATOR
EXPANSION
TANK
AIR
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 SQUIRE
HOT
WATER
OUT
ANTI-SCALD
MIXING VALVE
RELIEF VALVE
TANK SENSOR/AQUASTAT
COLD
WATER
IN
(TYPICAL)
(TYPICAL)
RECIRCULATION
PUMP
CHECK VALVE
DRAIN
( FIELD SUPPLY )
NOTICE
10
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 14 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.
Temperature & pressure (T&P) relief valve
WARNING
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.
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
DRAIN
VALV E
12
Page 13
Installation & Operation Manual
4 Domestic side (tank) piping (continued)
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:
- SIT030/040/050 - 3/4" NPT with a minimum CSA
Rating of 105,000 Btu/hr.
- SIT065/080/119 - 3/4" NPT with a minimum CSA
Rating of 200,000 Btu/hr.
NOTICE
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.
The Lochinvar SIT 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.
Table 4A
Minimum Relief Valve (CSA Rating)
Model Btu/hr
SIT030 105,000
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
CAUTION
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.
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.
SIT040 105,000
SIT050 105,000
SIT065 200,000
SIT080 200,000
SIT119 200,000
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.
13
Page 14
4 Domestic side (tank) piping
Figure 4-2 Recommended Domestic Water Piping
SHOCK ARRESTOR
UNION
(TYPICAL)
Installation & Operation Manual
SHUT-OFF VALVE
TO BOILER
FROM BOILER
ANTI-SCALD
MIXING VALVE
SQUIRE
TANK SENSOR/
AQUASTAT
CHECK VALVE
DRAIN
( FIELD SUPPLY)
SHUT-OFF
VALVE
SHUT-OFF
VALVE
EXPANSION
TANK
RECIRCULATION
PUMP
SHUT-OFF
VALVE
BACKFLOW
PREVENTOR
NOTICE
14
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 15
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. 4-1). 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
INDIRECT TANK
KNIGHT BOILER
15
Page 16
Installation & Operation Manual
5 Wiring
Indirect water heater controlled using Aquastat and zone circulator / valve
1. Install Aquastat to tank. Aquastat control (TST20016) 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
TST20016
TEMPERATURE
ADJUSTMENT
ZONE CONTROL BOX
WIRE
CONNECTIONS
ZONE CIRCULATOR
OR
ZONE VALVE
OR
16
AQUASTAT
CONTROL
INDIRECT TANK
Page 17
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.
17
Page 18
7 Maintenance
Installation & Operation Manual
The Lochinvar SIT 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.
18
Page 19
Installation & Operation Manual
8 Performance data
Table 8A IBR Chart
Squire Indirect Water Heater
I=B=R Rating
Indirect
Water
Heater
Model
Number
SIT030
SIT040
SIT050
SIT065
SIT080
SIT119
• 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.
Potable
Water
Volume
Gal.
27.0 1.1 1.5 160 183 99,000 14.0 3.9
40.0 1.6 0.9 181 208 115,000 14.0 4.5
51.6 1.7 0.8 209 255 133,000 14.0 5.3
67.0 1.9 0.7 263 327 154,000 14.0 5.7
81.5 2.1 0.6 266 347 160,000 14.0 5.7
113.4 3.2 0.5 349 459 216,000 14.0 6.5
Heat
Source
Water
Volume
Gal.
Standby
Heat Loss
F/hr
Continuous
Draw Rating
Gal/hr
First Hour
Rating Gal/
hr
Minimum Heat
Output Rate
from
Heat Source
Btu/hr
Minimum
Heat Source
Flow Rate
GPM
Tank Heat
Source
Friction
Loss Feet
W.C.
19
Page 20
Installation & Operation Manual
8 Performance data
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.
20
Page 21
Installation & Operation Manual
-
8 Performance data (continued)
Table 8B First Hour Rating - 180°F Boiler Loop Water (Knight Boiler)
First Hour Rating - 180°F Boiler Loop Water
(Knight Boiler - Models SIT030 - SIT050)
Model SIT030 SIT040 SIT050
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
WB050 108 83 108 83 122 97 122 97 135 110 135 110
K/WB080 159 119 159 119 173 133 173 133 188 147 188 147
K/WB105 171 128 191 142 217 165 217 165 231 178 231 178
K/WB150 191 142 223 165 252 189 267 200 268 204 292 221
K/WB210 223 165 240 177 267 200 282 211 292 221 307 232
KB285 223 165 240 177 267 196 267 200 282 211 286 213 292 221 307 232 334 251
Boiler Heating Capacity
KB399 267 196 286 213 334 251
KB500 267 196 286 213 334 251
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
77008 89165 105532 114761 129676 92998 112972 123331 129574 132764 94115 114116 125111 134044 146207
First Hour Rating - 180°F Boiler Loop Water
(Knight Boiler - SIT065 - SIT119)
Model SIT065 SIT080 SIT119
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
WB050 153 128 153 128 163 138 163 138 197 172 197 172
K/WB080 207 165 207 165 216 175 216 175 250 209 250 209
K/WB105 250 196 250 196 259 206 259 206 292 239 292 239
K/WB150 319 245 328 252 338 262 338 262 372 296 372 296
K/WB210 356 271 386 293 374 288 409 312 476 371 476 371
KB285 356 271 386 293 388 294 374 288 409 312 424 323 501 388 573 438 596 454
Boiler Heating Capacity
KB399 388 294 424 323 596 454
KB500 388 294 424 323 596 454
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
118488 129139 146864 163768 167924 115860 139106 154002 171229 181544 141419 190161 204795 237649 253504
21
Page 22
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 - 295,000 Btu/hr)
Model SIT030 SIT040 SIT050
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
45,000 108 83 108 83 122 97 122 97 135 110 135 110
60,000 136 103 136 103 150 118 150 118 164 131 164 131
75,000 165 123 165 123 179 138 179 138 194 151 194 151
95,000 171 128 191 142 202 150 217 165 217 165 217 165 233 179 233 179 233 179
115,000 171 128 191 142 223 165 240 177 217 165 252 189 252 189 252 189 233 179 268 204 273 207 273 207
140,000 191 142 223 165 240 177 267 196 252 189 267 200 282 211 286 208 268 204 292 221 307 232 322 242
165,000 240 177 267 196 267 200 282 211 286 213 292 221 307 232 334 251
195,000 334 251
Boiler Heating Capacity
225,000
260,000
295,000
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
77008 89165 105532 114761 129676 92998 112972 123331 129574 132764 94115 114116 125111 134044 146207
First Hour Rating - 180°F Boiler Loop Water
(Universal Sizing - 45,000 - 295,000 Btu/hr)
Model SIT065 SIT080 SIT119
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
45,000 153 128 153 128 163 138 163 138 197 172 197 172
60,000 183 149 183 149 193 159 193 159 226 193 226 193
75,000 213 170 213 170 222 180 222 180 255 213 255 213
95,000 252 197 252 197 252 197 261 207 261 207 261 207 294 241 294 241 294 241
115,000 291 226 291 226 291 226 291 226 300 235 300 235 300 235 300 235 333 268 333 268 333 268 333 268
140,000 305 235 319 245 338 259 338 259 338 259 304 238 347 268 347 268 347 268 347 268 384 302 382 302 382 302 382 302 382 302
165,000 305 235 319 245 356 271 386 293 388 294 304 238 349 270 374 288 395 302 395 302 387 306 429 337 429 337 429 337 429 337
195,000 319 245 356 271 386 293 388 294 349 270 374 288 409 312 424 323 483 375 485 376 485 376 485 376
Boiler Heating Capacity
225,000 356 271 386 293 388 294 374 288 409 312 424 323 501 388 548 421 541 416
260,000 388 294 424 323 573 438 596 454
295,000 596 454
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
118488 129139 146864 163768 167924 115860 139106 154002 171229 181544 141419 190161 204795 237649 253504
22
Page 23
Installation & Operation Manual
8 Performance data (continued)
Table 8D First Hour Rating 200°F Boiler Loop Water (Universal Sizing)
First Hour Rating - 200°F Boiler Loop Water
(Universal Sizing - 45,000 - 295,000)
Model SIT030 SIT040 SIT050
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
45,000 105 84 105 84 118 97 118 97 132 109 132 109
60,000 133 104 133 104 145 117 145 117 160 130 160 130
75,000 160 124 160 124 173 137 173 137 188 151 188 151
95,000 197 151 197 151 197 151 209 163 209 163 209 163 226 179 226 179 226 179
115,000 224 171 233 176 233 176 233 176 245 190 245 190 245 190 245 190 263 206 263 206 263 206 263 206
140,000 255 194 277 210 277 210 277 210 271 209 291 224 291 224 291 224 291 224 295 230 311 241 311 241 311 241 311 241
165,000 277 210 308 232 317 240 335 256 335 256 335 256 295 230 329 254 358 276 358 276 358 276
Boiler Heating Capacity
195,000 308 232 352 265 335 256 362 276 375 285 329 254 375 288 399 306 404 309
225,000 375 288 399 306 404 309
260,000 404 309
295,000
325,000
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
107695 126355 140102 153900 184539 129980 151466 164149 178059 186356 131965 159672 172739 187562 189713
First Hour Rating - 200°F Boiler Loop Water
(Universal Sizing - 45,000 - 295,000)
Model SIT065 SIT080 SIT119
Circulator Flow
GPM
Domestic Outlet 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140 115 140
45,000 150 127 150 127 161 138 161 138 194 171 194 171
60,000 179 148 179 148 189 159 189 159 222 192 222 192
75,000 207 169 207 169 218 180 218 180 250 213 250 213
95,000 245 197 245 197 245 197 255 208 255 208 255 208 288 241 288 241 288 241
115,000 283 225 283 225 283 225 283 225 293 236 293 236 293 236 325 268 325 268 325 268
140,000 331 260 331 260 331 260 331 260 331 260 341 270 341 270 341 270 341 270 373 303 373 303 373 303 373 303
165,000 350 274 377 294 377 294 377 294 377 294 374 295 386 304 386 304 386 304 386 304 419 337 419 337 419 337 419 337 419 337
195,000 350 274 391 305 432 337 432 338 432 329 374 295 440 343 440 343 440 343 440 343 479 381 479 381 479 381 479 381 479 381
Boiler Heating Capacity
225,000 391 305 445 345 487 375 487 375 440 343 475 369 498 386 498 386 533 422 533 422 533 422 533 422
260,000 495 381 499 384 475 369 525 406 536 414 601 470 601 470 601 470
295,000 536 414 667 519 667 519
325,000 536 414 688 534 695 540
MAX BTU INPUT
5 8 12 16 20 5 8 12 16 20 5 8 12 16 20
146842 171693 200077 225514 235239 154198 192471 211523 237540 247474 194143 245777 282047 305766 319025
23
Page 24
Revision Notes: Revision A (ECO C05265) initial release.
Revision B (ECO C05399) reflects the addition of the Pressure Drop
Chart and updates made to the Performance Data Charts.
Revision C (ECO C05587) reflects the update of tables 3A and 3B
(Pressure Drop charts) on page 6, table 4A on page 13, the update of
the “Domestic water piping” paragraph on page 11, and the update of
Performance data table 8A on page 19.
Revision D (ECO C05788) reflects new images for section 3 “Boiler Side
Piping” FIG. 3-1 -- 3-4, a new image for section 4 “Domestic Side (Tank)
Piping” FIG. 4-2, and the update of the Pressure Drop chart on page 6.
Revision E (ECO C06035) reflects the update of FIG. 1-1 on page 4 to
revise listed dimensions.
Revision F (ECO C06300) reflects the update of images and additional
CSA cautions on manual cover and “Connect tank sensor” section
added to “Wiring” on page 15.
Revision G (ECO C06670) reflects the update of the IBR chart
information on page 19.
Revision H (ECO C08396) reflects the addition of the First Hour Ratings
of SIT080 at 20GPM for 115°F to Table 8B on page 21.
07/11 - Printed in U.S.A.
SIT-I-O Rev H
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