HTP FP-40SC - Manual (Page 10)

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maintained in accordance with the supplier’s instructions if the air temperature is expected to approach
the specified freeze tolerance limit.”
For open or closed loop systems: In areas with temperatures not falling below -5
o
C / 23
o
F, a differential
solar controller with freeze protection may be used (e.g. requiring pump to circulate if the manifold
temperature approaches freezing). In an open loop system, a freeze valve (which opens to allow water to
dribble out) could also be considered.
For closed loop systems: For areas with temperatures falling below -5
o
C / 23
o
F, a propylene 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 propylene glycol, FDA rated as
GRAS, should be used.
NOTE: HTP DOES NOT WARRANT THE SOLAR COLLECTOR AGAINST FREEZE-RELATED
DAMAGE.
H. 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 four attachment points must be made (2 on the upper
and 2 on the lower track), each with a minimum pull strength of 100 kg / 220 lb. If this cannot be
achieved, additional attachment points must be made to achieve minimum strength levels.
If installing at a raised angle (tilt-up mounts, as seen in Part 5), a minimum of four attachment points must
be made (2 on the upper and 2 on the lower track), each with a minimum pull strength of 150 kg / 330 lbs.
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.
I. SNOW LOAD
In areas prone to heavy snowfall, the solar collectors should ideally be installed at an angle of 50
o
or
greater to help promote snow sliding off the collectors. In addition, it is advisable to raise the lower
collector frame off the roof surface 15 – 20 cm / 6 – 8 inches or higher. Doing this places the collector
above moderate snowfall accumulation and allows drifting snow to more easily slide out from under the
collector, which helps ensure that snow does not cover the collector array.
Please refer to local regulations regarding snow loading precautions.
J. STORAGE TANKS
It is recommended that the lever on the 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
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, in order to expel water safely, the PTRV
have a copper pipe connected and run to an appropriate drainage location. The PTRV and drain outlet
pipe must not be sealed or blocked.