HTP HP-30SC User manual

120 Braley Rd. P.O. Box 429 East Freetown, MA 02717-0429 www.htproducts.com
Evacuated Tube
Solar Collector
INSTALLATION
MANUAL
HP-30SC
NOTICE: HTP reserves the right to make product changes or updates without notice and will not be held
liable for typographical errors in literature.

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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 product.
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.
FOREWORD
This manual is intended to be used in conjunction with other literature provided with the Evacuated Tube
Solar Collector. This includes all related control information. It is important that this manual, all other
documents included with this system, and additional publications including Solar Water Heating System
Design and Installation Guidelines, be reviewed in their entirety before beginning any work.
“The solar energy system described in this manual, when properly installed and maintained, meets the
minimum standards established by the SRCC. This certification does not imply endorsement or warranty
of this product by the SRCC.”
Installation should be made in accordance with the regulations of the local code authorities and utility
companies which pertain to this type of water heating equipment.
NOTE TO CONSUMER: PLEASE KEEP ALL INSTRUCTIONS FOR FUTURE REFERENCE.

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FOR THE INSTALLER
For your safety, please read through this manual carefully before installation to minimize the risk of fire,
property damage, and personal injury. Solar hot water system shall be properly installed in accordance
with this manual before use.
INSTALLATION OR SERVICE OF THESE SOLAR PANELS IS REQUIRED TO BE PERFORMED BY
LICENSED PROFESSIONALS WHERE SOLAR, PLUMBING AND ELECTRICAL WORK IS REQUIRED.
The installer should be guided by the instructions furnished with the tank, local codes and utility company
requirements. Preference should be given to codes and requirements where they differ from the furnished
instructions.
Additional publications which should guide the installer include:
Solar Water Heating System Design and Installation Guidelines, SRCC OG-300, from Solar Rating and
Certification Corporation, 1679 Clearlake Road, Cocoa, FL 32922-5703.
Code for the installation of Heat Producing Appliances (latest version), is available from American
Insurance Association, 85 John Street, New York, NY 11038.
The latest version of the National Electrical Code, NFPA No. 70.
In Canada, refer to Canadian Electrical Code C 22.1, from Canadian Standards Association, 5060
Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6.

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TABLE OF CONTENTS
INTRODUCTION...........................................................................................................................................7
ABOUT YOUR EVACUATED TUBE SOLAR COLLECTOR ..................................................................7
PART 1: GENERAL SAFETY INFORMATION............................................................................................7
A. METALLIC COMPONENTS .................................................................................................................7
B. EVACUATED TUBES...........................................................................................................................7
C. HIGH TEMPERATURES......................................................................................................................8
D. HEALTH AND SAFETY........................................................................................................................8
PART 2: IMPORTANT INFORMATION .......................................................................................................9
A. SCOPE OF MANUAL...........................................................................................................................9
B. LOCAL STANDARDS...........................................................................................................................9
C. AUTHORIZED PERSONS....................................................................................................................9
D. TERMINOLOGY...................................................................................................................................9
E. POSSIBLE SYSTEM DESIGNS...........................................................................................................9
1. OPEN LOOP SYSTEMS...................................................................................................................9
2. CLOSED LOOP SYSTEMS..............................................................................................................9
3. DRAIN BACK SYSTEMS................................................................................................................10
F. FLUID QUALITY.................................................................................................................................10
G. METALLIC CORROSION...................................................................................................................10
H. FREEZE PROTECTION.....................................................................................................................11
I. COLLECTOR DIMENSIONS & WEIGHTS..........................................................................................11
J. WIND STRESS ...................................................................................................................................11
K. SNOW LOAD......................................................................................................................................12
L. STORAGE TANKS..............................................................................................................................12
M. HAIL RESISTANCE...........................................................................................................................12
PART 3: INSTALLATION INFORMATION................................................................................................12
A. TRANSPORT, UNPACKING, AND INSPECTION .............................................................................12
1. COMPONENT LIST ........................................................................................................................12
2. TUBE AND HEAT PIPE INSPECTION...........................................................................................14
B. SYSTEM DESIGN..............................................................................................................................15
C. DELTA-T CONTROLLER SETTINGS................................................................................................15
D. STAGNATION AND OVERHEATING................................................................................................15
E. CORRECT SYSTEM SIZING TO AVOID OVERHEATING ...............................................................15
F. SOLAR FOR CENTRAL HEATING – PREVENTING OVERHEATING .............................................16
G. COLLECTOR ANGLE, PLANE, AND DIRECTION............................................................................16

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1. COLLECTOR ANGLE.....................................................................................................................16
2. COLLECTOR PLANE .....................................................................................................................16
3. COLLECTOR DIRECTION .............................................................................................................16
4. TO EASE OVERHEATING .............................................................................................................16
H. AVOID SHADE...................................................................................................................................16
I. LOCATION...........................................................................................................................................16
J. EXPANSION TANK: MINIMIZING WATER WASTAGE .....................................................................17
1. OPEN LOOP SYSTEMS.................................................................................................................17
2. CLOSED LOOP SYSTEMS............................................................................................................17
3. DRAIN BACK SYSTEMS................................................................................................................17
K. LIGHTNING PROTECTION................................................................................................................17
L. PIPE CONNECTIONS AND PIPE SIZE .............................................................................................17
M. CONNECTION OF MULTIPLE COLLECTORS.................................................................................17
N. POTABLE WATER.............................................................................................................................17
O. MOUNTING FRAME..........................................................................................................................18
P. CUSTOMIZING THE FRAME.............................................................................................................18
Q. GALVANIC REACTION BETWEEN STAINLESS AND ZINC GALVANIZED STEEL.......................18
PART 4 – COLLECTOR INSTALLATION .................................................................................................18
A. INSTALLING CLAMP TO MANIFOLD................................................................................................18
B. INSTALLING CLAMP TO BASE TUBE FRAME ................................................................................19
C. INSTALLING MANIFOLD AND BASE TUBE FRAME TO MANIFOLD ARMS..................................19
D. INSTALLING TRIANGLE PLATE ASSEMBLY...................................................................................20
E. INSTALLING LEGS TO ASSEMBLY..................................................................................................21
F. INSTALLING FEET TO ASSEMBLY..................................................................................................21
G. INSTALLING THE SUPPORTS .........................................................................................................22
H. FLUSH / FLAT MOUNTING ...............................................................................................................23
I. INSTALLING EVACUATED TUBES....................................................................................................23
PART 5 – ROOF/WALL ATTACHMENT SUGGESTIONS........................................................................24
A. ROOF ATTACHMENT........................................................................................................................24
B. FLUSH PITCHED ROOF INSTALLATION.........................................................................................25
1. TILED ROOF ATTACHMENT.........................................................................................................25
2. CORRUGATED IRON ROOF ATTACHMENT ...............................................................................25
3. ASPHALT SHINGLE ROOF............................................................................................................25
C. LOW PITCHED ROOF INSTALLATION ............................................................................................25
D. FLAT ROOF INSTALLATION.............................................................................................................26

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E. WALL MOUNTING .............................................................................................................................26
PART 6 – PLUMBING CONNECTIONS ....................................................................................................26
A. TEMPERATURE SENSOR INSERTION............................................................................................26
B. HEADER CONNECTION....................................................................................................................27
C. AIR PURGE........................................................................................................................................27
D. PLUMBING CHECK...........................................................................................................................27
E. GLYCOL FREEZE PROTECTION .....................................................................................................28
F. INSULATION ......................................................................................................................................28
G. PUMP SELECTION............................................................................................................................28
PART 7 – SYSTEM PIPING DIAGRAMS...................................................................................................30
A. DRAINBACK TANK WITH BACKUP WATER HEATER ....................................................................30
B. CLOSED LOOP SYSTEM WITH ELECTRIC BACKUP AND STORAGE TANK...............................31
PART 8 – MAINTENANCE.........................................................................................................................32
A. CLEANING .........................................................................................................................................32
B. LEAVES..............................................................................................................................................32
C. BROKEN TUBE..................................................................................................................................32
D. INSULATION......................................................................................................................................32
E. DRAINING THE COLLECTOR...........................................................................................................32
F. OTHER COMPONENTS.....................................................................................................................33
G. STAGNATION....................................................................................................................................33
PART 9 – TROUBLESHOOTING...............................................................................................................33
A. NO HOT WATER................................................................................................................................34
B. REDUCED SOLAR CONTRIBUTION................................................................................................34
C. REGULAR WATER DUMPING..........................................................................................................34
D. INSTALLED COLLECTOR DETAIL...................................................................................................35
1. ANGLED COLLECTOR ..................................................................................................................35
2. FLUSH COLLECTOR .....................................................................................................................35
PART 10 – INSTALLATION CHECKLIST .................................................................................................36
MAINTENANCE NOTES ............................................................................................................................37
HTP CUSTOMER INSTALLATION RECORD FORM........................................................................38

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INTRODUCTION
ABOUT YOUR EVACUATED TUBE SOLAR COLLECTOR
Your Evacuated Tube Solar Collector is designed to offer reliable hot water heating in mild to cold
climates. Evacuated tubes provide insulation around heat pipes, and work with both glycol and drain back
solar systems, making these solar collectors an ideal choice in cold climates where flat panel collectors
are not an option.
Perhaps most important of all, if an evacuated tube (or tubes) should break, there is no need to shut
down your system. The Evacuated Tube Solar Collector will continue to function until the damaged
tube(s) can be replaced.
Job site conditions will require your installation contractor to supply some or all of the following:
•Plumbing Connections
•Piping and Insulation
•Valves Between Your Backup Water System and the Solar System
NOTE: HTP reserves the right to make product changes or updates without notice and will not be held
liable for typographical errors in literature.
PART 1: GENERAL SAFETY INFORMATION
NOTE: OBTAIN ALL APPLICABLE PERMITS AND OBEY ALL LOCAL CODES.
Only use this solar hot water system as intended and described in the installation manual; use other than
described will void warranty and may lead to fire, property damage, and personal injury.
Install all system components and piping in such a way that does not reduce the performance of any fired
rated assembly.
A. METALLIC COMPONENTS
Always wear leather protective gloves when handling solar collector components. All efforts have been
made to make the metal components safe to handle, but there may still be some sharp edges.
B. EVACUATED TUBES
Be careful when handling the evacuated tubes, as they will break if knocked heavily or dropped.
If exposed to sunlight, hot, and have internal pressure built up, the tubes may explode rather than
implode if knocked and broken. This is a rare occurrence, but safety precautions should be taken.
When installed, evacuated tubes may break if struck by a hard object with enough force (e.g. branch
falling on roof). DURING INSTALLATION, CONSIDERATION SHOULD BE TAKEN AS TO THE

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POSSIBLE PATH ANY BROKEN GLASS MAY TAKE. Where possible, protection should be provided to
prevent broken glass from reaching ground level where somebody could walk on it.
THE HOMEOWNER SHOULD BE MADE AWARE BY THE INSTALLER THE LOCATION OF THE
SOLAR COLLECTOR AND THE POSSIBLE VICINITY OF BROKEN GLASS IN THE EVENT OF AN
EXTREME STORM OR OBJECT FALLING ON THE COLLECTOR.
C. HIGH TEMPERATURES
In good sunlight, the heat pipe tip on the evacuated tube can reach temperatures in excess of 392oF.
Thick leather gloves must be worn when handling hot tubes and heat pipes to prevent serious burns.
Keep solar hot water system and components away from children and animals.
In an installed, fully plumbed system, if the pump is stopped during good sunlight, the collector header
and piping close to the solar manifold can easily reach temperatures in excess of 320o F. Caution should
be taken when handling such components.
DO NOT STORE COMBUSTIBLE MATERIALS (DRY LEAVES, TREE BRANCHES, GASOLINE, ETC) IN
VICINITY OF THE SYSTEM.
D. HEALTH AND SAFETY
•ALWAYS WEAR SAFETY GLASSES WHEN HANDLING EVACUATED TUBES.
•WEAR LEATHER GLOVES WHEN HANDLING METAL COMPONENTS.
•WEAR THICK LEATHER GLOVES IF HANDLING HOT HEAT PIPES.
•ADHERE TO SAFETY REGULATIONS WHEN WORKING ON ROOFS (OR AT A HEIGHT).
•ALWAYS OBTAIN ENGINEER APPROVAL FOR INSTALLATIONS IN HIGH WIND REGIONS.
•ASSEMBLY OF THE SOLAR HOT WATER SYSTEM REQUIRES TWO PERSONS WITH THE
ABILITY TO LIFT 50 POUNDS EACH.
•BEST TO INSTALL ON A COOL, CLOUDY DAY.
•STORE EVACUATED TUBES IN DARK OR SHADED PLACES UNTIL INSERTION INTO THE
MANIFOLD.
If any system components are exposed to the following, do not operate until the affected component has
been inspected by a qualified serviceman.
1. FIRE
2. DAMAGE
3. SUBMERSION IN WATER
Any claims for damage or shortage in shipment must be filed immediately against the transportation
company by the consignee.
Use of lead solder is expressly prohibited. Use of galvanized steel, CPVC, PVC, PEX, or any other type
of plastic pipe is prohibited.

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PART 2: IMPORTANT INFORMATION
A. SCOPE OF MANUAL
This manual pertains only to the installation and operation of the HTP Solar Collector. Details for the
installation, operation and maintenance of the complete solar gas/electric water heating system including,
but not limited to storage tank, gas/electric booster, pump, system controller, valves and other plumbing
components should be provided separately by their respective manufacturers.
NOTE: This manual is primarily a reference document for installation officers, as the solar collector is not
permitted to be installed by non-authorized persons.
B. LOCAL STANDARDS
Installation must be completed in accordance with local standards and regulations.
C. AUTHORIZED PERSONS
Installation must be completed by a qualified tradesperson who holds relevant industry licenses or
certificates. The term “authorized person(s)” used throughout this document refers to a suitably qualified
professional. Unless otherwise specified in section 3, no part of the HTP solar collector may be inspected,
repaired, or maintained by anybody other than an authorized person.
D. TERMINOLOGY
The terminology used from region to region differs. To avoid confusion please note the following:
Supply - The plumbing line running from the outlet of the collector back to the tank.
Return - The plumbing line running from the tank (or heat exchanger) to the inlet of the collector. This
line incorporates the circulation pump.
Insulation - Solar radiation level, expressed in kWh/m2/day or Btu/ft2/day
E. POSSIBLE SYSTEM DESIGNS
1. OPEN LOOP SYSTEMS
For open loop systems, the normal operating pressure should be < 72.5 psi via use of a pressure limiting
(pressure reduction) valve on the main cold supply line.
It is acceptable for the system design to allow the solar collector to stagnate to prevent additional heating
of the storage tank (i.e. pump stoppage once tank temperature reaches 177o F). The pressure relief valve
must be able to release the pressure increase that occurs when the manifold stagnates, and should be
rated to meet the maximum possible heat output of the solar collector(s). Please see Part 6, Section F
regarding insulation of piping for high temperatures, and Part 3 for sections regarding overheating.
2. CLOSED LOOP SYSTEMS
For closed loop systems, the solar loop must operate at < 72.5 psi, and have an expansion vessel
installed to control water expansion. The system design MUST NOT allow stagnation of the collector as a
standard form of controlling tank temperature, as this may cause damage to the glycol.
Any system design must provide means for allowing pressure release at no more than 113 psi. It is
recommended that the lever on pressure and temperature relief valves (PTRV) on main pressure hot
water storage tanks be operated once every 6 months to ensure reliable operation. It is important to raise
and lower the lever gently, and be careful as the water released will be HOT. Failure to operate the

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PTRV on a regular basis could lead to failure of the component and the possibility of the storage tank
exploding.
It is recommended, and may also be a local regulation, that the PTRV have a copper pipe connected,
running the expelled hot water or air to a safe and appropriate drainage location. The PRTV and the drain
outlet pipe must not be sealed or blocked. It is normal for the valve to release small amounts of water
during heating cycles.
3. DRAIN BACK SYSTEMS
For drain back systems, the solar loop usually operates at < 25 psi, far lower than open or closed loop
systems. Drain back systems require larger pumps to move water up and into the solar collectors. But
when storage water temperature settings are reached, or freezing outdoor temperatures are detected, the
pump shuts off, allowing the heat transfer fluid to drain back into the tank. Thus, the drain back method
provides effective overheating and freeze protection, making these systems well-suited for cold and mild
climate operation.
Since drain back systems don’t operate at high pressures, an expansion vessel is not required. Install a
PTRV on the drain back tank, with a copper pipe running expelled hot water and air to a safe and
appropriate drainage location. The PRTV and drain outlet pipe must never be sealed or blocked.
NOTE: The collector and collector plumbing should be sloped down toward the drain back reservoir at ¼”
per foot minimum to allow the system to drain.
F. FLUID QUALITY
Water in direct flow through the manifold header must first meet potable water requirements and, in
addition, the following:
TOTAL DISSOLVED SOLIDS <600 ppm
TOTAL HARDNESS <200 ppm ÷ 17.1 = 11.7 grains
CHLORIDE
<40 ppm
FREE CHLORINE <5 ppm
MAGNESIUM
<10 ppm
Table 1
In areas with “hard” water (> 200 ppm), lime scale may form inside the header pipe (where a direct flow
format is used). In such regions, it is advisable to install a water softening device to ensure the long term
efficient operation of the collector, or use a closed loop for the solar circulation loop.
In order to meet health and safety regulations, glycol used should be food grade polypropylene glycol,
FDA rated as “generally recognized as safe” (GRAS). If using a glycol/water mix, the water must meet the
above requirements, and the glycol content of the liquid must not exceed 50%, unless the manufacture
specifies that a different ratio is recommended for use with solar water heaters. Glycol should be
checked periodically to prevent it from becoming acidic; please refer to the guidelines provided by the
glycol manufacturer regarding maintenance of glycol.
G. METALLIC CORROSION
Both copper & stainless steel are susceptible to corrosion when, amongst other factors, high
concentrations of chloride are present. The solar collector may be used for heating of spa or pool water,
but levels of free chlorine must not exceed 5ppm, otherwise the copper header could corrode.
NOTE: HTP DOES NOT WARRANT THE SOLAR COLLECTOR AGAINST CORROSION RELATED
DAMAGE.

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H. FREEZE PROTECTION
Freeze protection must be implemented in any regions that experience freezing conditions at any time
throughout the year.
“Freeze tolerance limits are based upon an assumed set of environmental conditions. Extended periods
of cold weather, including ambient air temperatures above the specified limit, may cause freezing in
exposed parts of the system. It is the owner’s responsibility to protect the system in accordance with the
Supplier’s instructions if the air temperature is expected to approach the specified freeze tolerance limit.”
For areas with temperatures not falling below –5oC / 23oF, a simple low temperature controller based
freeze protection may be used (e.g. pump circulates if the manifold temperature approaches freezing). If
possible, backup protection in the form of uninterrupted power supply (UPS) or freeze valves (which open
to allow water to dribble out) should also be installed.
For areas with temperatures below –5oC / 23oF, a closed loop filled with a polypropylene glycol-water mix
should be used to provide freeze protection. Please refer to glycol manufacturer’s specifications about
the temperature ranges the liquid can withstand. Only food grade polypropylene-glycol, FDA rated as
GRAS, should be used.
Evacuated tubes are not susceptible to damage in cold weather, and heat pipes are protected against
damage that could result from the freezing of the water inside.
NOTE: HTP DOES NOT WARRANT THE SOLAR COLLECTOR AGAINST FREEZE RELATED
DAMAGE.
I. COLLECTOR DIMENSIONS & WEIGHTS
MODEL
HP30SC
# OF TUBES 30
WEIGHT (LBS)
252
DIMENSIONS (INCHES) 101 X 79 X 58
NET APERTURE AREA (FT
2
) 30.04
STORAGE TANK SIZE (GALLONS)
70 +
NOMINAL FLOW RATE (GAL/MIN) 0.84
Table 2
J. WIND STRESS
When installing the collector, please consider the issue of wind resistance and the resultant stress on
attachment points. Adhere to relevant building codes/regulations regarding installation of such objects.
For flush mounting on a pitched roof, a minimum of two attachment points per front track must be made,
each with minimum pull strength of 100kg / 220lb. If this cannot be achieved, additional attachment
points must be made to achieve minimum strength levels.
If installing the low, mid, high or fixed angle roof frames, a minimum of two attachment points per front
track must be made, each with a minimum pull strength of 150kg / 330lbs. If this cannot be achieved,
additional attachment points must be made to achieve minimum strength levels.
It is the responsibility of the installation contractor to ensure that the frame mounting is of suitable
strength. Where applicable, inspection by building department officer or equivalent should be completed
to ensure the installation is in accordance with relevant regulations.

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K. SNOW LOAD
In areas prone to heavy snowfall, the solar collectors should ideally be installed at an angle of 50oor
greater to help promote snow sliding off the tubes. In addition, it is advisable to raise the front of the
collector frame 15 – 20 cm off the roof surface, as this sits the collector above moderate snowfall and
allows snow to more easily slide out from under the collector. A front track extension can be used for this
purpose.
Please refer to local regulations regarding snow loading precautions.
L. STORAGE TANKS
Glass lined storage tanks: Please note that if the water heater is left in an operating condition and not
used for two weeks or more, a quantity of highly flammable hydrogen may accumulate in the top of the
water cylinder.
To dissipate hydrogen safely, it is recommend that a hot water tap be turned on for several minutes at a
sink, basin or bath, but not a dishwasher, clothes washer or other appliance. During this process there
must be no smoking or open flame or any other electrical appliance operating nearby. If hydrogen is
discharged through the tap it will usually sound like air escaping.
M. HAIL RESISTANCE
Glass evacuated tubes are surprisingly strong and able to handle significant impact stresses once
installed. Testing and impact stress modelling proves that evacuated tubes, when installed at an angle of
40oor greater, are able to withstand impact from hail larger than 1” in diameter. The ability of evacuated
tubes to withstand hail impact is greatly influenced by the angle of impact, so installing the collectors at
low angles does reduce their impact resistance.
It is recommended that in areas prone to large hail (> 3/4”) the solar collector should be installed at an
angle of 40o or greater to provide optimum protection. This is generally a common installation angle, as
many populated areas in the world fall within 30-70olatitude.
If a tube should break, it can be easily replaced. Though a reduction in heat output will result, the solar
collector can still function properly with one or more broken tubes (heat reduction depends upon how
many tubes are broken). A broken tube should be replaced by authorized persons only.
PART 3: INSTALLATION INFORMATION
A. TRANSPORT, UNPACKING, AND INSPECTION
When possible, transport the boxes of evacuated tubes standing upright, taking notice of the THIS WAY
UP arrows. If the boxes can only be laid down, always place on a flat, firm surface such as compressed
wooden board. If stacking the boxes, do not exceed 3 layers and strap in place to avoid movement.
Straps should be padded with thick cardboard or similar padding at corners to avoid cutting into the
boxes.
1. COMPONENT LIST
Please familiarize yourself with the components listed on the packing list included in the collector manifold
packing box. If any components are missing, and/or additional part(s) are required, please contact your
supplier.

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PART A:
MANIFOLD LEG (3)
(SHORTER THAN PART
D)
PART B:
BACK BRACE (4)
(LONGER THAN PART
C)
PART C:
HORIZONTAL SUPPORT
BRACE (3)
(SHORTER THAN PART
B)
PART D:
MANIFOLD ARM (3)
(LONGER THAN PART
A)
PART E:
CLAMP (6)
PART F:
TRIANGLE PLATE (3)
PART G:
FEET (6)
PART H:
NUT (50)
PART I-1:
SMALL BOLT (40)
PART I-2:
LARGE BOLT (10)
PART J:
BASE TUBE FRAME (1)

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PART K-1:
PLASTIC END CAP
(FEMALE)
PART K-2:
PLASTIC END CAP
(MALE)
PART L:
EVACUATED TUBE
PART M:
MANIFOLD
PART N: FIT RING
Table 3
2. TUBE AND HEAT PIPE INSPECTION
Open the tube boxes, which contain the evacuated tubes with inserted heat pipes. Make certain all tubes
are intact, and the bottom of each tube is silver. If a tube has a white or clear bottom, it is damaged and
should be replaced. The heat pipe should be removed from the damaged tube and inserted into a
replacement tube, available at your local HTP dealer.
Heat pipes are bright and shiny when newly manufactured, but will dull and may form dark-grey surface
discoloration over time. This mild surface oxidation happens when the pipe is exposed to air. This
reaction is completely normal and does not affect the integrity of the pipe.
Do not remove and/or expose the tubes to sunlight until ready to install, otherwise the heat pipe tip will
become hot enough to cause serious burns.
NOTE: HTP DOES NOT WARRANT THE TUBE OR HEAT PIPES AGAINST FAILURE AS A RESULT
OF DAMAGE INCURRED DURING TRANSPORT OR INSTALLATION.
3. TOOLS AND MATERIALS
NOTE: Make sure you have all necessary tools, materials and accessories before beginning work on the
drain back solar system.
Electric Drill Torch and Striker
Drill Index (w/ ½” and ¾” Wood Bits) Putty Knife
Hack Saw High Temperature Joint Compound
Tubing Cutter Wire Nuts or Connectors
Tin Snips Miscellaneous Copper Pipe & Fittings (3/4”)
Solder Flux 1” Copper Tee
16’ Tape Measure 1” by ½” Bush

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Emory Paper 1’ Reducer – ½” or ¾”
24” Level 5/8” x ½” wall & 7/8” x ½” wall insulation
Flashlight Silicon Caulk and Roof Tar
Extension Cord ½” I.D. and ¾” I.D. Type M Copper Tubing
Slip Joint Pliers Needle Nose Pliers
Pipe Wrenches, 10” and 14” Angle Iron
Open End Wrenches, 9/16 & 7/16 Threaded Rod, Nuts, & Washers
Screw Driver 6” Flat Blade Stainless Screw Clamps
Screw Driver 6” Philips Thermal Adhesive
Wire Stripper or Knife Aluminum Flashing Sheet
Wire Cutters Black Latex Outdoor Paint
Adjustable Wrenches 8” & 10”
B. SYSTEM DESIGN
System design should be completed prior to installation. Solar collectors need to be installed correctly to
ensure high efficiency, and, most importantly, safe and reliable operation. Please seek professional
advice for the design and installation of your solar heating system. Only authorized licensed contractors
are permitted to install the solar collector.
C. DELTA-T CONTROLLER SETTINGS
Usually a Delta-T ON value of 4-6oC / 7-11oF and Delta-T OFF value of 2oC / 3.6oF is appropriate. These
settings may need to be altered slightly according to location and system design. Refer to the instruction
manual provided with the chosen solar controller for appropriate settings.
D. STAGNATION AND OVERHEATING
Stagnation refers to the condition that occurs when the pump stops running. This can be due to pump
failure, power blackout, or as a result of a high tank temperature protection feature built into the controller,
which turns the pump off.
If the system is designed to allow stagnation as a means of preventing tank overheating, the collector and
plumbing in close proximity may reach temperatures of >200oC / 395oF; components that may be
exposed to these high temperatures, such as valves, plumbing or insulation, should be suitably rated.
If the system is designed to allow stagnation of the collector when the tank reaches a set maximum level,
steam may form in the header. In such a system, a temperature relief valve or auto air vent should NOT
be installed on the collector outlet, as these options may not be able to withstand the high temperatures
and will not allow stable stagnation of the collector (may dump hot water).
The pressure and temperature relief valve on the tank may open to release pressure or heat as required.
Under such conditions the collector manifold will normally reach a maximum temperature of around 160oC
/ 320oF. Any heat returning from the collector is generally not hot enough to cause a continued increase
in tank temperatures (i.e. heat input is less than tank heat losses), and therefore is able to meet
requirements in force in some regions limiting tank hot water dumping. A crackling noise may be heard
down the supply line when hot water is used, as the pressure in the system drops and steam forms. This
is normal.
E. CORRECT SYSTEM SIZING TO AVOID OVERHEATING
The system should be sized so that overheating of the tank is difficult to achieve in a single day, even
during hot, sunny periods. If the system is over-sized, such that excessive heat is often produced during
summer months, a heat dissipater unit, or alternative cooling/dissipation system should be installed.

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F. SOLAR FOR CENTRAL HEATING – PREVENTING OVERHEATING
If a system has been designed to provide a contribution to space heating, it will sometimes provide more
heat in the summer than is required for hot water supply alone. In such cases, it is advisable for the
home to have a hot-tub, Jacuzzi or pool, a large storage tank or underground thermal store. If these
options are not viable, a heat dissipater unit(s) should be installed. Drain back systems provide the best
solution to overheating by allowing the heat transfer fluid to drain back into the tank when domestic
heating needs have been satisfied. See also the following point regarding reduction of summer heat
output.
G. COLLECTOR ANGLE, PLANE, AND DIRECTION
1. COLLECTOR ANGLE
It is common for collectors to be installed at an angle that corresponds to the latitude of the location.
While adhering to this guideline, an angle of latitude +/- 10o is acceptable, and will not greatly reduce solar
output. The solar collector should be installed at an angle of between 20-80oto ensure optimal heat pipe
operation.
2. COLLECTOR PLANE
The collector manifold is normally installed on the flat horizontal plane, but may be installed at an angle,
such as sideways on a pitched roof. The collector must not be installed up-side-down (tubes pointing
upwards) or with tubes lying horizontally. The heat pipes will not function.
3. COLLECTOR DIRECTION
The collector should face the equator. In the Northern hemisphere this is due south, and vice versa.
Facing the collector in the correct direction and correct angle is important to ensure optimal heat output. A
deviation of up to 10ofrom due North or South is acceptable, and will have minimal effect on heat output.
Given the formula above, a solar collector installed at 30oN latitude should face due south at an angle of
40o.
4. TO EASE OVERHEATING
Apart from installing a smaller collector, a good method of reducing summer heat output is to angle the
collector for optimal winter absorption. This is achieved by installing the collector at an angle of around
15oabove the latitude angle (e.g. 45oat 30oN latitude). This angle corresponds closely to the angle of the
sun in the sky during the winter months, thus maximizing winter output.
Conversely, during the summer when the sun is high in the sky, the relative surface area of the collector
exposed to sunlight is reduced, in effect reducing overall heat production considerably (by about 15%).
This option is ideal for installations where solar thermal is being used for space heating.
H. AVOID SHADE
Collectors should be located so that shading does not occur between 9 AM and 3 PM local time. Partial
shading, due to small objects such as antennas and flues, is not of great concern.
I. LOCATION
To avoid long pipe runs, the collector should be positioned as close as possible to the storage tank.
Storage tank location should therefore be considered part of the location requirements of the solar
collector. The storage tank should be located as close as possible to the most frequent draw off points in
the building.

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J. EXPANSION TANK: MINIMIZING WATER WASTAGE
In any hot water system, expansion of water will occur as it heats. When water expands, it has to be
controlled, as it cannot be compressed like air. See below for requirements pertaining to your application.
1. OPEN LOOP SYSTEMS
Open loop systems have a check valve/non-return valve on the cold main. This expanded water is
released via the pressure relief valve, which is mounted on the tank or solar collector loop. To prevent this
wasteful dumping of water, it is recommended to install an expansion vessel.
2. CLOSED LOOP SYSTEMS
Closed loop systems should always be installed with an expansion vessel. Refer to the solar expansion
vessel manufacturers’ guidelines regarding correct sizing.
3. DRAIN BACK SYSTEMS
Expansion tanks are not required in drain back system design.
K. LIGHTNING PROTECTION
To avoid lightning related damage or electrical safety issues, it is advisable to earth/ground the copper
circulation loop of the collector.
L. PIPE CONNECTIONS AND PIPE SIZE
HTP solar collectors are provided as standard with 1” NPT copper pipe inlet and outlet. For domestic
heating applications with 1 or 2 collectors, nominal ½” piping is suitable. For applications using 2 or more
solar collectors in series, it is advised to use nominal 3/4” piping. For connection of banks of collectors,
larger pipe sizes should be used as required for the given application, with consideration made to flow
rates, pressure drop and pump sizing.
The material used for the solar loop must be able to withstand the operating temperatures and pressures
to which the system may be exposed, due to normal or extraordinary conditions (e.g. pump failure or
power outage). Copper pipe is the most widely used piping material for solar applications. If it is decided
to use synthetic piping for the plumbing, HTP strongly recommends that copper pipe is used for at least
the most first 12feet of line connecting to both the inlet and outlet of the collector.
M. CONNECTION OF MULTIPLE COLLECTORS
When connecting collectors in series (maximum of 150 tubes), flexible connections should be used
between each collector in order to allow for expansion and contraction of the copper header with
temperature changes. Failure to use flexible connections between consecutive END port collectors may
result in damage to the header if the system stagnates.
NOTE: The collector and collector plumbing should be sloped down toward the drain back reservoir at ¼”
per foot minimum to allow the system to drain.
NOTE: HTP DOES NOT WARRANT THE COLLECTOR AGAINST DAMAGE RESULTING FROM
POORLY MANAGED HEADER EXPANSION AND CONTRACTION.
N. POTABLE WATER
If the system is direct flow, meaning that potable water is flowing through the collector, any components
used in the system must meet potable water requirements.

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O. MOUNTING FRAME
HTP solar collectors are supplied with an adjustable, extruded aluminum frame, which allows installers to
change the angle of the collector to maximize efficiency. Feet are supplied to fasten the panel securely to
the roof. It is important that frame attachment points and externally supplied fasteners are of suitable
structural strength and corrosion resistance. Be sure to tighten all hardware securely.
P. CUSTOMIZING THE FRAME
The standard frame can be adjusted to various angles and used creatively to suit a range of different
installation formats.
Q. GALVANIC REACTION BETWEEN STAINLESS AND ZINC GALVANIZED STEEL
Zinc galvanized components should NOT be installed in direct contact with stainless steel, as galvanic
reaction between the two metals can cause premature oxidation of the zinc coating and steel underneath.
1. If roof surface is galvanized steel, refer to Corrugated Roof installation guidelines.
2. Avoid using galvanized steel bolts. Use stainless steel components instead.
However, if galvanized components ARE used, avoid direct contact between the two metals by
using rubber/plastic separators.
PART 4: COLLECTOR INSTALLATION
A. INSTALLING CLAMP TO MANIFOLD
1. Place the manifold flat so the bolts are
facing up.
2. Remove nuts attached to bolts on manifold.
3. Secure clamps to the bottom of the manifold
using a ½” ratchet.
Figure 1 – Clamp to Manifold

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Ensure the surface is solid and able to withstand in excess of 150kg / 330lbs of pull force that may be
encountered during high winds. Consult a structural engineer if in doubt.
B. INSTALLING CLAMP TO BASE TUBE FRAME
1. Secure clamps to the base tube frame
using short bolts.
2. Tighten the bolts with ½” ratchet.
C. INSTALLING MANIFOLD AND BASE TUBE FRAME TO MANIFOLD ARMS
1. Space out manifold arms so the rails line up
with the clamps on the manifold and the base
tube frame.
2. Slide in the short bolts in the arms first.
3. Slide small bolts into the rail before securing
any nuts. Align so the ends of the clamps are
flush along the end of the rails.
4. Secure manifold to manifold arms.
Figure 2 – Clamp to Base Tube
Figure 3 – Manifold and Base Tube Frame to Manifold
Arms

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5. Secure the bolts with nuts and tighten with
ratchet.
6. Line up the clamps on the base tube frame
to the manifold arms.
7. Slide in short bolts in the arms first.
8. Secure the bolts with nuts and tighten with
ratchet.
D. INSTALLING TRIANGLE PLATE ASSEMBLY
1. Slide two short bolts in the manifold arm.
2. Align the edge of the triangle plate to the edge
of the manifold arm.
3. Secure the triangle plate to the manifold arm
with nut, tighten with ratchet.
4. Repeat for the next two arms.
Figure 4 – Manifold to Base Tube Detail
Figure 5 – Assembly and Detail
Figure 6 – Triangle Plate Assembly Detail