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Guidelines and Precautions
Installing Collector Arrays
It is not recommended to install more than three 16-tube collectors in a series (64 tubes). Larger
installations will require parallel piping for balanced flow through each array. Balancing valves should
be installed on multiple arrays. One roof mounting kit is needed for each single collector module. Each
additional collector will require an expansion kit.
Closed Loop and Drainback
OVSOL collectors can be installed for both closed loop and drainback solar heating applications.
Freeze Tolerance Limits
Freeze tolerance limits are based upon the freeze and burst protection of the antifreeze used in the solar
closed loop, or the mixture of the glycol-to-water ratio. Oventrop NT-40 is a 40% glycol-to-water mix with
freeze protection to -6
o
F and burst protection to -60
o
F. Oventrop NT-50 is a 50% glycol-to-water mix with
freeze protection to -30
o
F and burst protection to -60
o
F. For additional protection, the Regusol 130 EL
control has an antifreeze function (“OCF”) that can be programmed to enable the circulator to protect the
antifreeze from freezing or thickening.
Shedding Snow
In regions of snow accumulation, evacuated tube collector tilt angles above 50° will shed snow from col-
lectors even after severe storms. Therefore, in heavy snow areas, it is critical that collectors be sloped to
at least a 50° tilt angle. If collectors are installed on a flat roof in an area that receives heavy snowfall, the
lower end of the units should be at least 18” above the roof level to minimize chances of snow build-up on
the bottom of the collectors.
Transport of Collector
The collector should be transported to the roof in parts and then assembled together on the rooftop.
Lightning Protection
In areas of high incidence of lightning, one lightning rod should be considered. If there is a ready-made
lightning protection device, please connect it with the collector.
Minimum Inclination Angle of Collector (for Evacuated tube collectors only)
In order to ensure heat pipe delivery, a minimum inclination angle of 25° is necessary for OV SOL-5 collec-
tors. If the tilt angle of the roof is not above 25°, please build necessary roof mounting racks.
Precautions
Temperatures in excess of 390 °F are possible in the condenser (top metal protruding bulb) when exposed
to bright sunlight or diffused insolation. DO NOT TOUCH the condenser. Store the tubes in a safe location,
away from the sun,
during the installation of the roof mounting rack. Tubes are installed as the last step.
Oventrop Corporation will not be liable for burns or personal injury due to the touching of a hot condenser.
Handle the tubes with care to avoid accidental bending of the heat pipe at the condenser which may cause
damage to the heat pipe or the vacuum seal.
The maximum solar loop operating pressure is 87 psi. The pressure relief valve must be set to open below
87 psi. A 75 psi pressure relief valve is suggested. Normal operating pressures for a solar closed loop are
25 to 35 psi.
section one
