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.
Winterizing the System ............................................... 23
To Drain/Flush the System ......................................... 23
7. PERFORMANCE DATA
Performance Data Charts ........................................... 24-27
REVISION NOTES ............................................ Back Cover
Hazard definitions
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 storage tank 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 model and serial number
from the tank 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 Strato-Therm+ –
• To avoid severe burns, allow the appliance to cool
before performing maintenance.
Appliance operation –
• 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°FMore than 5 minutes
125°F1 1/2 to 2 minutes
130°FAbout 30 seconds
135°FAbout 10 seconds
140°FLess than 5 seconds
145°FLess than 3 seconds
150°FAbout 1 1/2 seconds
155°FAbout 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
Installation & Operation Manual
1 General information
The Lochinvar Strato-Therm+ solar stratified tank (FIG. 1-1, page 5) is designed to use a solar collector system, in conjunction
with a back-up heat source, to generate domestic hot water. This solar tank consists of a spherical heat exchanger attached to an
unlined tank containing a corrugated 316L stainless steel coil. Tank components and specifications are detailed in FIG.’s 1-1 and
1-2 (pages 5 and 6), as well as Tables 1A - 1D.
Solar heated water is pumped through the spherical heat exchanger to heat the water in the tank. A backup heat source is used to
maintain desired tank temperature in the event that solar heated water is not available. The tank may be used to heat domestic
potable water which runs through the stainless steel coil. In addition to generating domestic hot water, this tank can have many
other applications including indirect pool heating and space heating. Consult the factory if your specific application is not
covered in this manual. The tank is not intended for use in gravity water heating applications.
Operating Restrictions:
• Maximum domestic hot water temperature is 194°F.
• Maximum boiler water temperature is 210°F.
• Maximum working pressure for the vessel is 125 psig.
Tank shipment
Tanks taller than 7.5 feet will be shipped horizontally. Four
shipping legs are used to secure the tank to a pallet, and holes
are provided in the top cover for access to lifting lugs. The
shipping legs should be removed when the tank is removed
from the shipping crate.
Use field-supplied insulation to pack the shipping and lug
compartments, then use the factory provided covers to
conceal compartments upon final installation.
Table 1A
Strato-Therm+
Tank Component Materials
ComponentMaterial
TankSteel SA414-G
Coil316L Stainless Steel
Insulation Polyurethane Foam
JacketPre-paint Sheet Metal
Table 1B
Spherical Heat Exchanger
Component Materials
ComponentMaterial
HousingSteel S 235 JR
Heat Exchanger CoilCopper
InsulationPolyurethane Foam
JacketPolypropylene
4
Page 5
1 General information (continued)
Figure 1-1 Strato-Therm+ solar stratified tank components
The Strato-Therm+ uses a copper finned tube spherical heat
exchanger to provide optimum solar stratified charging.
The spherical exchanger helps maintain optimal use of solar
energy for hot water and space heating. The multi-functional
design improves efficiency in every system. Insulated with
polyurethane foam, the spherical heat exchanger and tank
maintain a space-saving design with minimal heat loss. Refer
to FIG. 1-3 and Tables 1E and 1F for additional spherical heat
exchanger information and measurements.
Figure 1-3 Spherical heat exchanger w/ tank
B
Table 1E
Tank with Spherical Measurements
Model
STU150SHX4000044 1/228
STU200SHX4000048 1/432
STU257SHX4000150 1/434
STU350SHX4000156 1/440
STU423SHX4000256 1/440
STU504SHX4000262 1/446
STU650SHX4000371 1/452
STU752SHX4000371 1/452
STU940SHX4000471 1/452
Spherical
Model
A
(in.)
(in.)
B
A
IMG00054
Table 1F
Spherical Heat Exchanger Specifications
Tank
Model
SHX400008 1/214610.75"280.557.98.45
SHX400018 1/214610.75"420.657.88.45
SHX400028 1/214611"591.17.358.45
SHX4000311 3/417611.25"1022.015.817.8
SHX4000411 3/417801.25"1022.015.817.8
Diameter
(in)
Jacket
Diameter
(in)
Jacket
Height
(in)
Solar
Inlet
Return
(NPT)
HEX
Surface
Area
(ft2)
HEX
Water
Volume
(gal)
Tank
Water
Volume
(gal)
Total
Water
Volume
(gal)
7
Page 8
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. Ensure that the domestic water supply to the stainless
steel coil 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 site, 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 domestic water coil due to
corrosion. Damage in such cases is not
covered under warranty.
Table 2A
Water Chemistry Requirements
Domestic potable water must have characteristics falling
within the following limits:
CharacteristicMin.Max.
pH6.59.5
Chloride (PPM)--200
Locating the Tank
1. Choose a location for the Strato-Therm+ centralized to
the piping system. You must also locate the Strato-Therm+
where it will not be exposed to freezing temperatures.
Additionally, you will need to place the appliance 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. Table 1C on page 5 shows the weight of all the tanks filled
with water. Ensure that the location chosen for the tank
is capable of supporting the weight.
CAUTION
3. The tank may be located some distance from the heat
source provided that the pump is designed to to provide
enough flow for both units to perform properly. The
further the distance from the tank to the heat source, the
longer the response time will be to provide sufficient heat
to the tank. Insulate piping between the heat source and
the tank.
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.
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 appliance.
A 12-inch vertical clearance is recommended from the top of
the appliance. A zero clearance is allowed for the sides of the
appliance. However, boiler and servicing clearances must be
figured when locating the appliance.
8
Page 9
0
5
10
15
20
25
30
02468101214
Pressure Drop, psi
Flow Rate, gpm
STU150
STU200 /
SHX40000
STU257
STU350 /
SHX40001
STU423
STU504 /
SHX40002
STU650
STU752 /
SHX40003
STU940 /
SHX40004
Installation & Operation Manual
3 Solar connections
A solar thermal system consists of several components selected to work together to convert solar energy into hot water for various
applications. A controller is used to turn on a pump when the fluid in the solar collectors is warmer than the water in the StratoTherm+ tank. The pump will transport hot fluid from the collector to the heat exchanger and replace it with cooler fluid returning.
The collectors, pump station and heat exchanger are connected with supply and return piping that is insulated to minimize heat
losses (FIG. 3-1, page 10). The system is equipped with over-temperature and over-pressure devices that prevent unsafe operating
conditions. When multiple heat exchangers are used, they should connected in reverse-return arrangement (FIG. 3-2, page 10). This
will help ensure that solar heated water is distributed evenly between the heat exchangers. Pressure drop and maximum operating
values for the Strato-Therm+ spherical heat exchanger are listed in Tables 3A - 3C.
Installation and commissioning must be carried out by a licensed contractor. Take appropriate safety measures when carrying
out any installation work on the roof and observe all relevant accident prevention regulations. It is the installer’s responsibility to
comply with the building and installation codes in effect and all regulations that apply to the operation of a solar hot water system.
MODEL
STU150
STU200
STU257
STU350
STU423
STU504
STU650
STU752
STU940
Table 3A
Spherical Heat Exchanger
Pressure Drop Values
PRESSURE DROP PSI)
SPHERICAL
MODEL
SHX400000.200.682.294.667.71 11.39 15.67 20.52
SHX400010.240.812.715.529.13 13.49 18.56 24.31
SHX400020.070.230.781.592.643.90 5.367.02
SHX400030.030.090.300.611.011.50 2.062.70
SHX400040.030.090.300.611.011.50 2.062.70
1
GPM2 GPM4GPM6GPM8GPM10GPM12GPM14GPM
Table 3C
Spherical Heat Exchanger Pressure Drop Chart
Table 3B
Spherical Maximum Operating
Conditions
Copper Heat
Exchanger
Temperature230°F230°F
Pressure145 psi125 psi
Tank
9
Page 10
3 Solar connections
Installation & Operation Manual
Figure 3-1 Solar System Piping
TEMPERATURE GAUGE
SOLAR PUMP
STATION / CONTROLLER
COLLECTOR
(TYPICAL)
SOLAR
PRESSURE
RELIEF VALVE
FILL AND
FLUSH VALVE
EXPANSION
TAN K
SOLAR AIR
RELEASE VENT
(OPTIONAL)
TEMPERATURE
GAUGE
SPHERICAL
HEAT EXCHANGER
SOLAR
SENSOR
IMG00040
Figure 3-2 Solar System Piping with Multiple Heat Exchangers
SOLAR AIR
RELEASE VENT
EXPANSION
TAN K
(OPTIONAL)
TEMPERATURE
GAUGE
SOLAR
COLLECTOR
TEMPERATURE
GAUGE
(TYPICAL)
SOLAR PUMP
STATION /
CONTROLLER
PRESSURE
RELIEF VALVE
T&P
RELIEF
VALV E
SPHERICAL
HEAT EXCHANGER
SOLAR
SENSOR
IMG00094
10
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.
Page 11
4 Domestic side piping
Installation & Operation Manual
Basic domestic piping
Figure 4-4 on page 17 shows typical domestic water and space
heating piping for a Strato-Therm+ tank. The stainless steel coil
requires properly sized piping and a properly sized pump to
maintain adequate domestic hot water delivery. Refer to Tables
4D and 4E on page 14 and 15 for domestic coil pressure drop.
The functions of the components shown are as follows:
a. Shut-off valves (recommended) - Used to isolate the
appliance for servicing.
b. Backflow Preventer (required by some codes) - Used to
prevent water from backing out of the indirect coil and
into the main potable water supply in the event that inlet
water pressure drops.
c. Expansion Tank (required for thermal 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
instructions for proper sizing and use.
NOTICE
d. Shock Arrestor (required by some codes) - Used to allow
water to accelerate or decelerate without a sudden change in
pressure.
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 located far from the
tank. This may result in an unacceptable delay before hot water
reaches these distant fixtures. Even if all the fixtures are located
relatively close to the tank, it may be desired that hot water be
instantly available to all fixtures.
To prevent delays, return circulation piping with a check valve
that allows flow to the domestic hot water outlet. This should
be installed on each branch circuit at the farthest fixture or
device, so that hot water is supplied upon demand. Traditional
recirculation piping is illustrated in FIG. 4-1, page 12.
Because hot water is always circulating in the hot water branch,
the entire branch should be insulated to prevent excessive heat
loss.
When a hot water recirculation system is used there are two
piping arrangements that can be applied to the Strato-Therm+.
The first arrangement is for use in systems with up to 2 gal/
min circulation and requires the purchase of a recirculation
lance assembly (FIG. 4-5, page 18). The second arrangement
is for use in systems with greater than 2 gal/min circulation
that require higher performance and temperature (FIG. 4-6,
page 18).
e. Circulation Pump (recommended) - Used to circulate
and maintain hot water within the piping system.
f. Check Valve (required by some codes) - Used to allow
water to flow in only one direction, preventing back-flow.
g. Drain (required) - Used to drain the tank for inspection or
servicing.
h. Mixing valve (required) - Used to mix hot water with cold
water to ensure constant, safe outlet temperatures.
i. Unions (optional) - Used to disconnect the tank in the
unlikely event that this is necessary for service.
NOTICE
Be sure to field-install plugs or caps on any
tank tappings that are not in use.
11
Page 12
4 Domestic side piping
0
1
2
3
4
5
6
0.00.51.01.52.02.5
Installation & Operation Manual
Recirculation lance
Recirculation systems with up to 2 gal/min circulation
require the use of a recirculation lance assembly (TUB30000)
(FIG. 4-1). The lance is a stainless steel tube that is inserted
directly into the hot water connection of the tank and into the
stainless steel coil. As part of a continuous, slow-moving loop,
warm water is circulated directly back into the coil, via the lance,
maintaining tank stratification. Reference FIG. 4-5 on page 18
for typical recirculation lance piping.
Table 4A
Recirculation Lance Pressure Drop Values
Flow Rate (gpm)Pressure Drop (psi)
0.20.07
0.40.25
0.60.5
0.80.83
11.22
1.21.68
1.321.98
1.42.2
1.62.78
1.83.41
24.11
2.24.85
Figure 4-1 Recirculation lance assembly
RECIRCULATION
WATER LINE
1/2" NPT
REDUCER
BUSHING
RECIRCULATION
LANCE
HOT WATER
1 1/2" NPT
1 1/2" NPT
DOMESTIC
1" NPT
1 1/2" NPT
NIPPLE
1 1/2" NPT
STAINLESS STEEL
REDUCER BUSHING
STAINLESS STEEL
1" NPT NIPPLE
1" NPT DOMESTIC
HOT WATER TUBE
1" NPT
1 1/2" NPT
T&P
RELIEF
VALVE
BRASS NIPPLE
1" NPT
1 1/2" NPT
DOMESTIC
HOT WATER
IMG00013
Table 4B
Recirculation Lance Pressure Drop Chart
PRESSURE, PSI
12
FLOW RATE, GPM
Page 13
4 Domestic side piping (continued)
Installation & Operation Manual
Direct piping to cold water inlet
When a re-circulation lance is not used, it is acceptable to
connect a building recirculation loop directly to the cold water
inlet of the Strato-Therm+ when flows are greater than 2 gal/
min returning to the tank. This method of building recirulation
will use the entire indirect coil to heat the recirulation loop. See
Figure 4-6 on page 18 for typical piping arrangement.
Multiple tank domestic water piping
Multiple tank installations must be done in the reverse-return
arrangement. This helps maintain the same flow and pressure
drop through the coil of each tank. Because the pressure drop
through tank coils varies from size to size, it is recommended
not to mix tanks with different coil sizes within the same zone.
Multiple tank domestic piping is illustrated in FIG. 4-7 on
page 19.
When high volume supply of hot water at a constant outlet
temperature is required, the Strato-Therm+ can be paired
with a large capacity storage tank (FIG. 4-8, page 19). In this
configuration the Strato-Therm+ will be able to meet high
demands with its instantaneous delivery rate. An Aquastat
control is used to control the water temperature between the
two tanks with a circulation pump. If a building recirculation
system is installed, the return water is brought back to the
storage tank so as not to disturb the stratification of the
Strato-Therm+.
Anti-scald mixing valves
Anti-scald valves used with water heaters are also called
tempering valves or mixing valves. An anti-scald valve mixes
cold water with the outgoing hot water to assure that hot water
reaching a building fixture is at the correct temperature.
NOTICE
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 4-4 thru 4-8, pages 17 - 19.
Always consult the mixing valve manufacturer’s instructions
and guidelines for correct piping and usage.
WARNING
WARNING
ASSE1017 and ASSE1070 certified mixing
valves are required.
Hot water can scald! To avoid scalding
potential, mixing valves must be selected and
installed according to valve manufacturer’s
instructions and recommendations. Mixing
valves should be installed by a licensed
contractor.
An anti-scald mixing valve does not
eliminate the risk of scalding.
* 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.
13
Page 14
4 Domestic side piping
0
5
10
15
20
05101520253035
Pressure, psi
Flow Rate, gpm
STU150
STU200
STU257
STU350
STU423
STU504
STU650
STU752
STU940
Domestic Coil Pressure Drop Values
MODEL
STU1500.10.61.62.84.46.28.310.713.314.7
STU200
STU257
STU350
STU4230.10.82.03.65.67.910.613.616.918.7
STU5040.10.82.13.75.88.211.014.217.719.5
STU650
STU752
STU940
2
GPM
6
GPM
10
GPM
0.10.71.83.25.07.19.512.215.116.7
0.10.92.24.06.28.811.715.118.720.7
Table 4C
PRESSURE DROP
14
GPM
GPM22GPM26GPM30GPM34GPM36GPM
18
(PSI)
Installation & Operation Manual
Table 4D
Domestic Coil Pressure Drop Chart
14
Page 15
4 Domestic side piping (continued)
Installation & Operation Manual
Temperature & Pressure (T&P) Relief Valve
WARNING
The T&P relief valve is installed in the vertical position and
mounted in the outlet of the indirect coil as shown in FIG. 4-2.
Do not place a valve between the relief valve and the coil. To
prevent water damage, the discharge from the relief valve shall
be piped to a suitable floor drain for proper drainage when relief
occurs. Do not install reducing couplings or other restrictions
in the discharge line. The discharge line shall allow complete
drainage of the valve and line. Relief valves should be manually
operated at least once per year.
For protection against excessive
temperatures and pressure, install
temperature and pressure protective
equipment required by local codes. A
T&P relief valve must be certified by a
nationally recognized testing laboratory
that maintains periodic inspection of listed
equipment or materials. The equipment
and materials must meet the requirements
for Relief Valves and Automatic Gas Shutoff
Devices for Hot Water Supply Systems,
ANSI Z21.22, as well as the standard
CAN1-4.4, Temperature, Pressure,
Temperature and Pressure Relief Valves and
Vacuum Relief Valves. The combination
T&P relief valve shall be marked with a
maximum set pressure, not to exceed the
maximum working pressure of the water
heater. It shall also have an hourly rated
discharge capacity not less than shown in
Table 4E.
Figure 4-2 Relief valve
PRESSURE
RELIEF VALVE
(FIELD SUPPLIED)
NOTICE
Verify that the combination temperature
and pressure relief valve complies with local
codes. If the combination T&P relief valve
does not comply with local codes, replace it
with one that does. Follow the installation
instructions in this section.
Do not place a valve between the
combination T&P relief valve and the tank.
Minimum Domestic Coil Relief Valve
Model
Table 4E
ASME
Btu/hr
Pressure
psi
T&P RELIEF
VALV E
(PROVIDED)
Lochinvar
Part No.
IMG00105
Pressure Only (POV) Relief Valve
A connection is provided for a pressure relief valve on the
top of the tank. The tank containing the hydronic water shall
have a pressure only relief valve in addition to the T&P relief
valve installed in the stainless steel coil. The POV should be
sized in accordance with the maximum working pressure of
the tank and the BTU output of the backup heat source. It is
recommended to have a relief valve sized in accordance with
ASME Boiler and Pressure Vessel Code, Section IV “Heating
Boilers”. ASME states in Section VIII, Division 1, paragraph
UG-125 (a) “All pressure vessels within the scope of this
division, irrespective of size or pressure, shall be provided with
pressure relief devices in accordance with the requirements of
UG-125 through UG-137.”
STU150 - STU9402,610,000125RLV20015
15
Page 16
4 Domestic side piping
Installation & Operation Manual
Standard Installation
• Connect a factory-supplied straight tee, reducing bushing
and close nipple to the coil opening provided. Install the
T&P relief valve vertically (FIG. 4-3). Install a field-supplied
POV into the nipple provided.
T&P Relief Valve and POV Discharge Piping
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
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 relief
valve and its connection or on the relief
valve discharge piping. Improper placement
and piping of relief valve can cause severe
personal injury, death or substantial
property damage.
Figure 4-3 Relief valve Assembly
T&P RELIEF
VALV E
1” NPT
CLOSE NIPPLE
1 - 1/2” NPT
STRAIGHT TEE
1 - 1/2” X 1” NPT
REDUCER BUSHING
HOT WATER
OUTLET
1” NPT
STAINLESS STEEL
CLOSE NIPPLE
IMG00012
CAUTION
WARNING
The T&P relief valve or POV 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.
Failure to install and maintain a new, listed
and properly sized relief valve will relieve
the manufacturer from any claim which
might result from excessive temperature
and pressure.
16
Page 17
4 Domestic side piping (continued)
Figure 4-4 Domestic Piping with Hydronic Heating
Installation & Operation Manual
BACKFLOW
PREVENTER
BALL VALVE
(TYPICAL)
PRESSURE
REDUCING
AIR
SEPARATOR
VALVE
SYSTEM SUPPLY
SENSOR
(WHEN USED)
PRESSURE
GAUGE
ZONE CIRCULATORS
(TYPICAL)
EXPANSION
TANK
MIXING
VALVE
LOW TEMP
ZONE
SPACE HEAT SUPPLY
HIGH TEMP RETURN
LOW TEMP RETURN
HIGH TEMP
ZONE #1
TEMPERATURE
BACKUP
HEAT SOURCE
GAUGE
HIGH TEMP
ZONE #2
CIRCULATION
MIXING
VALVE
PUMP
SHOCK
ARRESTOR
RECIRCULATION
LINE
CHECK
VALVE
DOMESTIC
HOT WATER
SHUTOFF
VALVE
DOMESTIC
COLD WATER
NOTICE
DRAIN
IMG00042
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.
17
Page 18
4 Domestic side piping
Figure 4-5 Recirculation Lance Piping: Flow Up to 2 gal/min
CIRCULATION
PUMP
RECIRCULATION
LINE
RECIRCULATION
LANCE
SHOCK
ARRESTOR
Installation & Operation Manual
SHUTOFF
VALV E
DOMESTIC
HOT WATER
TEMPERATURE
GAUGE
BACKUP HEAT
SOURCE SENSOR
Figure 4-6 Recirculation Piping: Flow Over 2 gal/min
CIRCULATION
PUMP
RECIRCULATION
LINE
TEMPERATURE
GAUGE
MIXING
VALV E
IMG00043
MIXING
VALV E
SHOCK
ARRESTOR
CHECK
VALV E
HOT WATER
SHUTOFF
VALV E
DOMESTIC
COLD WATER
DOMESTIC
HEAT SOURCE
18
BACKUP
SENSOR
NOTICE
CHECK
VALV E
DOMESTIC
COLD WATER
IMG00089
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 19
4 Domestic side piping (continued)
Installation & Operation Manual
Figure 4-7 Multiple Tank Domestic Piping
RECIRCULATION
LINE
TEMPERATURE
GAUGE
BACKUP
HEAT SOURCE
SENSOR
CIRCULATION
PUMP
ARRESTOR
MIXING
VALV E
SHOCK
DOMESTIC
HOT WATER
SHUTOFF
VALV E
CHECK
VALV E
DOMESTIC
COLD WATER
Figure 4-8 Domestic Piping with Storage Tank
BUILDING
RETURN LINE
DOMESTIC
WATER OUTLET
DOMESTIC
WATER INLET
CIRCULATION
PUMP
IMG00087
SHOCK
ARRESTOR
MIXING
VALV E
AQUASTAT
(TO CONTROL
CIRCULATION
SENSOR
PUMP)
IMG00093
DOMESTIC
HOT WATER
SHUTOFF
VALV E
CHECK
VALV E
DOMESTIC
COLD WATER
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.
19
Page 20
Installation & Operation Manual
5 Boiler side piping
Figures 5-1 and 5-2 show typical boiler piping for single and multi-tank situations. A pressure relief valve must be installed on each
boiler and each tank, as regulations require. The tank pressure relief valve should be sized to meet the working pressure of the tank
according to local codes.
Multiple tank connections (boiler side)
Boiler piping works most efficiently when it is done in the reverse-return application. This method uses more piping than direct
return systems, but the pressure drop and boiler flow are more balanced throughout each tank. To ensure even charging and
discharging of each tank, it is recommended that only tanks of the same size are placed in the same manifold. 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
necessary.
Figure 5-1 Backup Heat Source Connection
PRESSURE
RELIEF VALVE
TEMPERATURE
GAUGE
BACKUP
HEAT SOURCE
SENSOR
NOTICE
FILL
VALV E
AIR
SEPARATOR
Y-STRAINER
(TYPICAL)
CHECK
VALV E
PRESSURE
BOILER
CIRCULATOR
T&P
GAUGE
DRAIN
RELIEF
VALV E
IMG00086
BACKUP
HEAT SOURCE
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.
20
Page 21
5 Boiler side piping (continued)
Figure 5-2 Multiple Tank Backup Heat Source Connection
PRESSURE
RELIEF VALVE
TEMPERATURE
GAUGE
BACKUP
HEAT
SOURCE
SENSOR
AIR
SEPARATOR
Installation & Operation Manual
PRESSURE
RELIEF VALVE
BOILER
CIRCULATOR
BACKUP
HEAT SOURCE
NOTICE
FILL
VALV E
EXPANSION
TAN K
Y-STRAINER
(TYPICAL)
CHECK
VALV E
TEMPERATURE /
PRESSURE
GAUGE
DRAIN
IMG00091
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.
21
Page 22
6 Startup and maintenance
Installation & Operation Manual
System startup
1. Make sure the system is free of leaks and that air is
purged from the system.
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
Strato-Therm+ tank and indirect coil thoroughly before
leaving the installation. This is particularly important if the
Strato-Therm+ will be unused for an extended period of
time after installation. Flush the storage tank by drawing at
least three times its volume from the tank.
3. 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.
Refer to the heat source and solar Installation and Operation
Manuals for additional start-up information.
Fix any leaks found before proceeding
further. Leakage from the heat source and
solar piping can result in severe damage to
the system.
Maintenance Schedule
The Lochinvar Strato-Therm+ solar tank is an extremely simple
device and as such requires very little maintenance. There are,
however, several items which should be inspected on an annual
or as needed basis to ensure a reliable supply of hot water:
* Ensure that the boiler and solar water piping are 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 heat source is maintained in accordance
with the 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.
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 minimum.
Manually operate T&P relief valve at least once a year.
This will release some hot water.
WARNING
Verify that expansion tank pressure is equal to system
pressure.
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. In this case, ensure that the
expansion tank is properly sized and charged to the
appropriate pressure.
DANGER
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.
22
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6 Startup and maintenance (continued)
Installation & Operation Manual
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 owner’s maintenance responsibilities and their
frequencies, including any not listed in the following
section.
Owner monthly maintenance to include:
Visually check valves, pipes, and fittings for leaks. Call a
qualified service technician to repair leaks.
Winterizing the system
Drain the tank and coil if it will be off and exposed to freezing
temperatures. Freezing water will expand and damage the water
heater.
• If the tank, spherical heat exchanger and heat source
water contain sufficient antifreeze, then only the
domestic coil water needs to be drained.
• If the tank, spherical heat exchanger and heat source
water do not contain sufficient antifreeze, they must be
drained in addition to domestic water.
If antifreeze is used in the heat source water, check the
concentration. Heat source 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.
To drain/flush the system
1. Turn OFF main electrical power to the tank, solar collectors
and any other heat source connected to the tank.
2. Turn OFF the main manual gas shutoff for any heat source
connected to the tank.
3. Turn OFF electrical power to the circulating pump (if used).
4. Close off the boiler or heat source inlet connection.
5. Ensure that the drain (located on the bottom of the tank)
is routed to a floor drain with adequate capacity to allow
the tank to be flushed.
6. Open the drain valve and allow the incoming cold water
“Boiler Return” to flush the soft sediment out of the bottom
of the storage tank.
CAUTION
7. Observe the color of the water initially discharged from
the tank drain. This water will generally be milky or
slightly discolored by the sediment discharge. Allow the
drain to run until the water runs clear.
8. Close the drain valve on the tank.
9. Open the hot water relief/air valve on the top of the
tank.
10. Turn ON main electrical power for the heat source, solar
collectors, tank and circulating pump.
11. Turn ON gas supply to the heat source(s).
12. Observe heat source and solar piping to ensure that all
components are functioning properly.
Hot water will be released under pressure.
Avoid contact with hot discharge water to
prevent the risk of severe scald injury.
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.
23
Page 24
Installation & Operation Manual
7 Performance data
Table 7A
First Hour Ratings at Maximum Coil Capacity
180°F Boiler Input140°F Boiler Input
140°F Mixed DHW115°F Mixed DHW115°F Mixed DHW
Max. Capacity
Model
STU15016103523151615997
STU200191244271774181125
STU257191365271965181250
STU350191550272223181395
STU423271690362451261600
STU504281816362569271783
STU650312036362737281952
STU752312042362869281983
STU940312072363011282032
Flow Rate
(gpm)
First Hour
Rating
gal/hr
Max. Capacity
Flow Rate
(gpm)
First Hour
Rating
gal/hr
Max. Capacity
Flow Rate
(gpm)
First Hour
Rating
gal/hr
Table 7B
Standby Heat Loss
Model
STU1500.61
STU2000.52
STU2570.44
STU3500.39
STU4230.31
STU5040.30
STU6500.27
STU7520.25
STU9400.23
Heat Loss
°F/hr
24
Page 25
716,548
716,548
716,548
716,548
716,548
716,548
716,548
716,548
Installation & Operation Manual
7 Performance data (continued)
Table 7C
Maximum Coil Capacity 180°F Boiler Input, 115°F DHW