STIEBEL ELTRON SOL 25 PLUS - Manual (Page 9)

WWW.STIEBEL-ELTRON-USA.COM SOL 25 PLUS | 9
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IMPORTANT: TO PROTECT THE SYSTEM AGAINST FROST AND
CORROSION, FILL THE SOLAR HEATING SYSTEM ExCLUSIVELY WITH
THE RECOMMENDED PROPYLENE GLYCOL MIxTURE (SECTION 2.1.2). THESE
INSTRUCTIONS ARE APPLICABLE ONLY TO SINGLE HYDRAULIC ASSEMBLIES
OF NO MORE THAN 30 INDIVIDUAL COLLECTORS. LARGER SYSTEMS
REqUIRE INDIVIDUAL APPROVAL. COMMERCIAL SYSTEMS MUST ADHERE
TO LOCAL REGULATIONS.
Pipework Installation
Use copper or stainless steel pipes or corrugated stainless steel
hoses for the supply and return lines. Pipe diameter is dependent
on length of run and expected flow rates. Recommended pipe
diameter for systems of up to 10 collectors is 3/4”. If the pipe run is
longer than 60 feet, a larger pipe diameter may be needed.
All pipe runs to the building interior shall be supplied by the
installer. Vent tiles are recommended for the roof penetrations on
steeply pitched tile roofs; for flat roofs, corrugated sheet roofs, and
roofs with shallow pitch, passing the pipes through an external
wall is recommended to avoid water leaks. Pipe hangers must
provide correct support and pitch and must meet building codes.
Hangers must not compress insulation and should allow for thermal
contraction and expansion of the pipework. Installers must comply
with all Local, State and National Codes.
We recommend trimming pipes with pipe cutters to avoid creating
metal filings. Electrically ground the pipework in accordance with
electrical codes. Connect all pipework to the building’s ground over
the shortest possible distance.
Soldered Pipe
Soldered pipe must be hard-soldered using 95/5 lead-free solder.
Alternative Piping
Piping made with locking ring fittings, press fittings, and corrugated
hoses must be sealed using suitable sealants. Seals must be
resistant to propylene glycol and temperatures up to 356°F.
Rated Volumetric Flow Rate
The rated volumetric flow rate for a collector array (max. 5 collectors)
is 27-80 gallons/hour or 0.45-1.33 GPM. All collector arrays must be
connected in parallel. The flow rate for every additional collector
array is added to the total, so in a system with 3 x 3 collectors, the
flow rate would be 80-240 gallons/hour.
Thermal Insulation
All hot water (and final 5 feet of cold water) piping requires
insulation of at least R-2.6. All exterior piping also requires UV and
moisture protection. Insulation must be resistant to temperatures up
to 356°F.
Use the following recommended temperature and UV-resistant
thermal insulation to insulate the external pipework:
•
Polyiscocyanurate, PVC cover
• Armaflex®
• Mineral wool backed by aluminum mesh foil
• Flexible EPDM hose (e.g. type Aeroflex®)
A rigid aluminum sheath is recommended as protection for the
mineral wool. The EPDM hose can be finished with UV-resistant
paint. Where required, protect the thermal insulation against bird
or rodent attack. Insulate all lines of the solar loop. Apply the
thermal insulation after pressure testing and checking the system for
leaks (see Section 8).
Extremely cold climates that experience nighttime winter
temperatures below -30°F may need thicker-than-standard pipe
insulation to prevent freeze-ups or slushing of the anti-freeze
mixture.
Minimum Insulation Thickness
Normal Diameter of Pipes Min. thickness of insulation layer, based
on thermal conductivity of 0.035 W/(m•K)
Less than 3/4” 3/4”
3/4” to 1-1/4” 1”
1-1/4” to 4” identical to pipe diameter
Greater than 4” 4”
Collector Temperature Sensor Well
The collector sensor well is threaded onto the outlet pipe of the
collector array (i.e., positioned at the hot side). The outlet
can be the upper left or right side of the collector, depending on
how the array is plumbed to the pump station. After installing
the sensor well on the collector, coat the sensor probe with heat-
conducting paste and insert it into the sensor well until it bottoms
out. Secure the lead to the outside of the insulation (to avoid
melting under high temperature operation) and under a protective
cover.
Cover the collector sensor well and the roof outlet with thermal
insulation, which must be tightly sealed and must be temperature-
and UV-resistant. Also protect the thermal insulation against bird
attack. See Figure 2 for details.