The Florida Solar Energy Center Logo
Home > Research > Photovoltaics > Virgin Islands Energy Office > Specifications and Vendor Forms > Solar Hot Water Requirements

Stylized Text: Specifications and Vendor Forms.

Solar Water Heating System Component, Installation, Warranty, and Vendor Requirements


1.1. Solar collectors

All solar domestic water heating collectors installed under this program must be certified by the Florida Solar Energy Center (FSEC), per guidelines outlined in the FSEC document "Test Methods and Minimum Standards for Certifying Solar Collectors," [99KB, Adobe Acrobat PDF] and "Operation of the Collector Certification Program," [232KB, Adobe Acrobat PDF].

1.2 Solar systems

All solar domestic water heating systems installed under this program must be approved by the Florida Solar Energy Center (FSEC), per guidelines outlined in the FSEC document " Florida System Standards for Design & Installation of Solar Thermal Systems," [183KB, Adobe Acrobat PDF] and " Operation of the Solar Thermal Systems Certification Program," [232KB, Adobe Acrobat PDF] or equivalent.

A listing of FSEC approved solar systems is provided at the FSEC Approved Solar Energy Systems web site.

1.3 Site specific requirements

Additional specific requirements for each site's defined system and specific requirements must also be followed. These specific requirements are listed in the individual site listing documents. Note that the site listing web page includes the specifications for each system as well as additional photographs of the sites. The intent of the photographs are to provide interested contractors with additional visual information on the sites. Nevertheless, it is recommended that contractors visit each site before providing system installation quotes.

These listings include the following solar water heating system sites:

St. Croix
St. Thomas
Mt. Victory
7th Day Adventist School
VI Energy Office Power at Work Facility

Note that the web site listings also provide additional photographs of the sites. The intent of theses photographs is to provide interested contractors with additional visual information of the sites. Nevertheless, it is recommended that interested contractors visit each site before providing system installation quotes.

For those sites that require only specific components versus complete systems, those components must also meet the additional requirements listed below:


2.1 Storage Tank

The solar and/or auxiliary hot water storage vessel shall be constructed of durable, corrosion resistant materials such as glass-lined steel or stone-lined tanks.

For single "solar" storage tank systems, a maximum 4500-watt electric element in the upper third of the storage tank will provide backup hot water. For systems using electrical auxiliary water heaters, the auxiliary hot water storage tank will have two maximum 4500-watt interlocked electric elements. The insulation on the solar storage tank and the auxiliary hot water tank will be no less than R-16 to minimize standby heat losses. An insulation blanket may be added to storage tanks to meet the R-16 requirements.

2.2 Solar Circulating Pump

The solar circulating pump, when applicable, shall be the seal-less, magnetic drive type with a 12-volt direct current (DC) motor. The circulating pump body shall be bronze or stainless steel construction to prevent corrosion.

2.3 Solar controller

The solar system controller shall be in the range of a 5 to 10 Watt DC photovoltaic (PC) panel that provides direct current to the DC solar circulating pump. The variable current output of the panel shall be matched to the starting current of the circulating pump such that the DC pump motor starts when solar radiation on the PV panel is no more than 350 watts per square meter. (Note: On FSEC approved systems, this requirement is already met.)

Control circuit wiring and terminals shall be identified and marked or color-coded. Control wiring shall be protected from environmental influence and degradation such as wind, moisture, temperature or other factors which may alter their intended function.

The system controls shall include such provision for bypass, adjustment or override of manual or automatic controls as required to facilitate installation, startup, operation, shutdown and maintenance. For PV/DC pump controlled systems, this will include a disconnect switch between the PV module and the DC pump.

2.4 Owner's Manual

FSEC system approval requires that an owner's manual be developed. Since solar system used under this program must be FSEC approved, a manual will have been produced. Nevertheless, this section reemphasizes the major information that must be included in the manual for those systems that require completion of partial installation and therefore will also require an owners manual.

The manual shall contain the name and address of the seller and the system model name or number and shall describe the operation of the system and its components and the procedures for installation, operation, and maintenance.

The manual shall describe clearly the operation of the SWH system, explaining the function of each subsystem and component. The manual shall include a system diagram showing the components and their relationships in the typical installed system. Major components shall be described in a separate section or by enclosed descriptive material furnished by the manufacturer of the components.

The manual shall describe procedures for system startup, shutdown, routine maintenance and special conditional operations such as draindown. The manual should specify temperature, pressure and flow condition expected at various access points to allow simple operational check and troubleshooting.

The manual shall include a parts list giving a sufficient description of each part for ordering a replacement. Parts, components and equipment required for service, repair or replacement shall be commercially available or available from the system or subsystem manufacturer or supplier. The manual shall include the name and address of at least one company that offers service on the system.


3.1 General

All solar water heating systems installed under the U.S. Virgin Islands Solar Program will meet the criteria set forth in Chapter VII, Installation, of the "Florida System Standards for Design & Installation of Solar Thermal Systems", [183KB, Adobe Acrobat PDF]. This will include all criteria listed in Chapter VII as well as the specific supplemental requirements listed below. See also Section 8.0 System Inspections.

3.2 Orientation

Installed collectors must be oriented within 45° west or east of due south and mounted at an angle plus or minus 15° from local latitude. It is recommended that an 18° orientation be achieved whenever possible. It is important to consider aesthetics during the mounting of the solar collector and system.

All flat plate solar collector as well as ICS and thermosiphon system locations shall provide, throughout the year, a minimum of six (6) hours of unobstructed sunshine daily inclusive of solar noon; e.g., 9 a.m. to 3 p.m. or 10 a.m. to 4 p.m. A "solar window" or eight (8) hours of unobstructed sunshine is preferred.

3.3 Collector mounting

The collectors, ICS and thermosiphon system, shall be mounted to permit exposed system drainage as necessary. No external wood mounting members will be permitted. All mounting components shall be aluminum or stainless steel and installed to minimize potential galvanic corrosion.

Ground mount systems will incorporate concrete footers sunk into the ground. These footers will be a minimum of 5-gallon bucket size for proper structural support. Ground mounted collectors and systems will allow a reasonable clearance under the unit. This clearance should be enough to allow the use of a standard lawn mower under the collector/system.

Other ground mounting methods that exceed the structural capabilities of the above requirement can be submitted. The will be reviewed on a case by case basis to determine acceptance by program managers.

Rack frames used will consist of a material that is structurally stable for the loads as well as resistant to environmental degradation.

The location and orientation of the collector shall be such that it is not shaded by external obstructions or mutual shadowing more than the specified period allowed in the design.

3.4 Roof Penetrations

All roof penetrations will be watertight and flashed at least three (3) inches on all sides of the penetration. All pipe penetrations will utilize copper roof flashings. There shall be at least one and a half (1 1/2) inches of clearance between the solar collectors or ICS and thermosiphon system and the roof surface. Sealant used shall be appropriate roof flashing sealant material.

Escutcheons will cover all collector loop piping interior ceiling penetrations.

3.5 Plumbing and Materials

Both supply and return lines in the solar collector circuit shall be at least 5/8 inch (O.D.) Type L or K Soft copper tube for active and thermosiphon - and 3/4 inch (O.D.) Type L or K Soft copper tube for ICS units. The piping in the potable water circuit will be a minimum of 5/8 inch O.D. copper tube. All fittings will be copper, brass, or bronze. One continuous run of soft copper tubing shall be used from the water heater connection to the solar system. There shall be no soldered joints within enclosed attics.

All soldered connections in the solar collector piping shall be made with lead-free, silver bearing solder. All soldered connections in the potable water piping will be made with lead-free, antimony-free solder.

Since the complete drainage of both the solar collectors and the connecting lines is necessary, the entire exposed system will be pitched no less than 1/4 inch per running foot to insure proper drainage.

Hangers shall provide adequate support and correct pitch of pipes. Hangers or supports for insulated pipes or components shall be designed to avoid compressing or damaging the insulation material. If pipe or component hangers are installed over the insulation material, sleeves or plates should be used to avoid damaging the insulation.

Means shall be provided to isolate the solar loop in SWH systems for servicing, manual draindown, or emergencies. Such isolation shall not interrupt water service.

Incompatible dissimilar materials shall be isolated or treated to prevent degradation to the extent that their function could be significantly impaired under in-service conditions.


4.1 Check valve

The solar system check valve will be of bronze with its sealing surfaces made of either nitrite rubber (Buna-N), Teflon, chlorsulfonated polyethylene (Hypalon), and/or Viton. Its purpose is to prevent reverse circulation of heated storage tank water during the night. The check valve must be a low-pressure design to permit satisfactory operation.

4.2 Isolation and drain valve

All isolation and drain valves shall be of bronze construction. Ball valves will be used as isolation valves.

4.3 Air vent

The air vent, when incorporated in a system design, shall be of brass construction and include a polypropylene float mechanism to automatically purge air from the system. The air vent will be installed at the highest point of the system and in a true north vertical position.

4.4 Pressure relief valve

The pressure relief valve shall be bronze, self-closing, and preset to a value compatible with other components and the safe operation of the system.

4.5 Temperature pressure relief valve

The solar storage or auxiliary storage tank temperature/pressure relief valve shall be self-closing and not exceed the tank manufacture rated working pressure and temperature. The discharge of the solar system pressure relief valve and the tank pressure temperature relief valve will be piped to a safe point of discharge as per local codes.

4.6 Vacuum relief valve

Closed storage tanks (ICS included) and piping shall be protected against damage from vacuum-induced pressure. Such components shall be designed to withstand such pressures or have vacuum-relief protection.


Insulation rated at R-2.4 or greater is to be installed on all interconnecting hot and cold water piping installed in attics, unconditioned garages other unconditioned indoor spaces, as well as all conditioned spaces.

The insulation on the pipes of the solar collector circuit shall be of either elastomeric closed cell or polyisocyanurate foam with an insulation value of no less than R-2.4. The exterior insulation will be protected by a covering such as aluminum jacketing or ultraviolet-inhibited synthetic material that will be resistant to moisture, weathering, and sunlight over the anticipated life of the installation.

Underground installations shall be given special consideration to prevent deterioration of insulating properties by compression, water penetration, and chemical or bacterial actions.


The wiring between the PV panel and the circulating pump should be sized to handle 150 percent of the panel's short-circuit current. An accessible disconnecting means shall also be provided between the panel and pump. This disconnect may be a polarized cord-and-plug connection wired such that there are no exposed live contacts.

In addition, an "On/Off" electrical switch shall be installed at the water heater. (See Attached example.) The switch will be rated for 240V, 30 amps.

Wiring from the PV module to the DC pump shall not be routed between the copper piping and the pipe insulation.

The exterior wiring shall be protected from UV ray degradation.


The solar water heating systems will include a BTU meter and, for those sites that have electrically connected solar or auxiliary tanks, a separate watthour meter. The installer will be responsible for procuring both the BTU meter kit and the watthour meter. Please see the attached Monitoring Information document for procurement information.

The installer will install the flow meter (which comes with the specified BTU meter) into the cold service line. The installer will also be responsible for installing a watthour meter, if applicable, at the auxiliary water heater. FSEC will provide specific instructions for the installation of the BTU meter, flow meter and watthour meter to the chosen installer(s).

Therefore, installers must include in the system quote the cost for procuring both the BTU meter kit (which includes the flow meter) and the watthour meter and for installing the flow meter and watthour meter. Note that some sites may not require the watthour meter. Please see the individual site listings.


All solar water heating systems installed under this program will be inspected by FSEC AND VIEO staff. The inspection process will include verification that FSEC approved systems (and the approved systems listed components) have been installed and are operating as designed. The process will also verify that the installation meets the criteria listed above.

Inspection forms have been developed that will be used during the inspection process. Copies of the inspection forms that will be used are listed on this web site. It is strongly recommended that program participants review these forms. In addition, FSEC and VIEO staff will inspect the systems to make sure that the above listed specification requirements have been met.


The following guidelines must be met before a solar installer is allowed to install systems under the SWAP program.

9.1 License

Contractors must obtain and possess an active U.S. Virgin Islands "General Contractor" or "Installation of Equipment" license to install solar water heating and photovoltaic systems.

9.2 Experience

Installers must demonstrate capabilities to install residential solar water heating systems. Past experience is critical in meeting this requirement. Installing contractors must provide at least four (4) references of previous installations. Please see the Contractor Information Form.

9.3 Place of Business

Installers are required to provide continuous post-installation service to the areas in which they install solar water heating systems. Therefore, installation contractors must be located within the Territories in which the systems will be installed.

9.4 Local Codes and Ordinances

Contractors must comply with all applicable local codes and ordinances.

9.5 Insurance

The Contractor must have a certificate of workmen's compensation insurance.


10.1 Collector

The contractor shall provide a 10-year warranty on the collector. The warranty does not cover defects of any kind resulting from exposure to harmful materials, fire, flood, lightning, hurricane, tornado, hailstorm, windstorm, earthquake or other acts of nature, vandalism, explosions, harmful chemicals, acidic or caustic water, other fluids, fumes or vapors, operation of the collector under excessive flow rates, misuse, abuse, negligence, accident, alteration, falling objects or any other causes beyond the control of the contractor.

10.2 System

The contractor shall provide a full three (3) year warranty on the system. The warranty covered failure of the installed solar system, including any component or assembly where such failure was caused by a defect in materials, manufacture, or installation. Contractors should consider the costs of the three (3) year warranty requirement and appropriately reflect this in the system bid. The warranty also covers damage resulting from over-temperature. This includes the full cost of all parts, labor, shipping and handling necessary to remedy the defect, including, and if necessary, replacement at the site.

In those installations in which the SWH system(s) are retrofitted to the existing conventional electric water heater and the existing water heater failed due to normal circumstances during the three (3) year warranty period, the system warranty excludes the replacement of the water tank since an existing tank was used.

The system warranty does not cover defects of any kind resulting from exposure to harmful materials, fire, flood, lightning, hurricane, tornado, hailstorm, windstorm, earthquake or other acts of nature, vandalism, explosions, harmful chemicals, acidic or caustic water, other fluids, fumes or vapors, operation of the collector under excessive flow rates, misuse, abuse, negligence, accident, alteration, falling objects or any other causes beyond the control of the contractor.

The system warranty is effective at the date of installation.

All warranties shall continue to subsequent owners of the residence upon which the solar system was installed.

The contractor's name, address and phone number must conspicuously appear on all warranties.

The fulfillment of the warranty is the responsibility of the installation contractor.

Contractors shall provide warranty service within three (3) working days from notification by system owner or VIEO representatives. The Contractor will be responsible for making necessary field inspections, repairs, modifications, or replacements, at no charge to the system owner, within three (3) working days of notification of a problem during the warranty period.


The VIEO and FSEC will first qualify the quote for completeness and conformance to the specifications. Staff responsible for the procurement of the solar systems will make the final evaluation and determination.


The proposed time schedule as related to this procurement is as follows:

Action: Date:
Release of RFQ: July 31, 2001
Submission of Quotes: August 31, 2001
Selection: September 15, 2001
Requisition Award: September 30, 2001
Installation Begins: October 31, 2001
Installations completed: November 30, 2001


This document is intended to be used as the instrument to transmit requests for quotes and to define the terms, conditions, and specifications desired by the VIEO to receive quotes for solar systems.

It is the intent of the VIEO to select one or more contractors(s) to supply the services necessary for successful completion of tasks, as defined herein.

All quotes shall include the following:

1. Contractor Information (see Form )

2. Systems Quote (see Form)

3. Florida Solar Energy Center system approval form

4. Collector and System Warranty

5. Copy of U.S. Virgin Islands "Contractors" or "Installation of Equipment" License

6. Certificate of Workmen's Compensation Insurance

7. Written statement of experiences and abilities relative to successfully performing the described work.

8. Written statement which describes the firm's current workload and ability to complete the work in a reasonable time period.


1. The Contractor shall indemnify and hold harmless the VIEO, and their agents and employees from and against claims, damages, losses and expenses including attorneys' fees arising out of or resulting from the performance of the work, furnishing of services, or furnishing of materials, goods, or equipment, as required by the bid documents, including but not limited to claims regarding defects in materials, goods, or equipment, which is caused in whole or in part by any breach of contract, or omission of the contractor, any subcontractor, any one directly or indirectly employed by any of them or any one for those acts any of them may be liable.

2. In any and all claims against the VIEO, or any of their agents or employees by any employee of the contractor, any subcontractor, any one directly or indirectly employed by any of them or any one for those acts any of them may liable, the indemnification obligation under this paragraph shall not be limited in any way by any limitation on the amount or type of damages, compensation, or benefits payable by or for the contractor or any subcontractor under Workers' Compensation Acts, Disability Benefits Acts, or any other Employee Benefit Act.


All received quotes will be evaluated on a case by case and quote by quote basis. The elevation criteria will follow the guidelines listed below.

  • System installation cost quote 40%
  • Past Experience and level of work 30%
  • USVI based installation company 10%
  • Thoroughness of application 10%
  • Previous USVI work 5%
  • Location (vicinity) of company to projects 5%


All proposals must be delivered to the VIEO at the address below no later than 5:00 P.M. on August 31, 2001. Failure to comply with this, or any other paragraph of the Request for Proposals, may be sufficient reason for rejection of the proposal.

Please mark three (3) sets (one original, so identified, and two (2) complete copies) of the proposal envelopes as follows:

Solar Domestic Water Heating
Program Quotes

Please address the mailing envelopes as follows:

Mr. Bevan Smith, Jr.
Project Administrator
U.S. Virgin Island Energy Office
Oscar E. Henry Customs House
200 Strand Street
Fredericksted, St. Croix 00840
(340) 772-2616
Fax: (340) 772-0063

All quotes must be recorded (clocked-in) in the VIEO on or before the time and date indicated on this Request for Quotes document. The responsibility for submitting quotes to the VIEO is solely that of the quotee. The VIEO will not be responsible for delays in mail delivery or delays caused by any other occurrence. LATE QUOTES WILL NOT BE ACCEPTED.


The VIEO reserves the right to incorporate the successful contractor's quote into a requisition for installation services. Failure of a contractor to accept this obligation may result in the cancellation of any award.

The selected contractor will be required to assume responsibility for all services offered in the quote. The VIEO will consider the selected contractor to be the sole point of contact with regard to contractual matters, including payment of any or all charges.

Application Forms and required written statements listed in Section 10.0 above must be completed and submitted in order to be considered in the program.


Non-technical questions regarding the Request for Proposals must be directed through Bevan Smith, Virgin Islands Energy Office, Old Customs House, 208 Strand Street, Frederiksted, Telephone: 340/772-2616, Extension 230, Fax 340/772-0063, or e-mail at

All questions concerning the technical (solar water heating system) specifications of this Request for Quotes must be directed through John Harrison, click here to contact.

All telephone conversations are to be considered unofficial responses and will not be binding. Questions, verifying the Request for Quotes content, if appropriate, will be responded to in writing - either e-mail or standard postage. The written response will be the VIEO/FSEC's official response and will be mailed (e-mail or standard postage) to all individuals that requested the Request for Quotes document.