HTP FP-40SC - Manual (Page 15)

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I. 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.
J. 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.
K. EXPANSION TANK
Expansion of HTF occurs as it heats. When HTF expands, it has to be controlled, as fluid cannot be
compressed like air. A properly sized and installed expansion tank can accommodate expansion of HTF.
If the expansion tank fails, a properly sized and installed PTRV will activate and protect the system.
Failure to properly control HTF expansion may result in property damage, personal injury, or death.
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. Expanded water is released
via the PTRV, which is mounted on the tank or solar collector loop. To prevent wasteful dumping of water,
it is required to install a potable water expansion tank on open loop systems.
2. CLOSED LOOP SYSTEMS
Closed loop systems should always be installed with a solar expansion tank. Refer to the solar expansion
tank manufacturer’s guidelines regarding correct sizing.
3. DRAIN BACK SYSTEMS
Expansion tanks are not required in drain back system design.
L. LIGHTNING PROTECTION
To avoid lightning related damage or electrical safety issues, it is advisable to earth/ground the frame and
copper circulation loop of the collector.
M. PIPE SIZING AND CONNECTIONS
HTP solar collectors are provided as standard with 1” copper pipe ports. For domestic heating
applications with 1 or 2 collectors, nominal ½” piping is suitable. For applications using 2 - 4 solar
collectors in series, it is advised to use nominal ¾” piping. For 5 – 8 collectors, use 1” pipe. For drain back
systems, use ¾” pipe for 1 – 4 collectors and 1” pipe for 5 – 8 collectors. In connections of banks of
collectors, larger pipe sizes should be used as required for the given application, with consideration given
to flow rates, pressure drops, 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 or stainless steel pipe is the most widely used piping material for solar
applications.