All 2W2 drivers look alike. (Two Wire, 2nd Version) All 2W2 drivers
are Static Impeller Drivers™. SID™
2W2 Drivers Available:
A 3.5-Watt driver, intended for PV domestic hot water, without glycol.
Typical: 80gal tank, 4X10 collector. Use SOLAREX model SA-5 or similar
amorphous panel. Also, instant hot water circulation
A 5-Watt driver, intended for PV domestic hot water and 24 hour instant
hot water circulation. Use 5-Watt crystal PV panel.
A 10-Watt driver used for domestic solar hot water and 24 hour instant
hot water in large homes. Use a 10-Watt crystal PV panel and glycol in the
lower 48 states, where freezing is not deep and hard. Use a 20-Watt PV panel
in the North so that more electricity is available in the morning to clear
the slush out of the feed and return lines.
A 10-Watt driver used with 12-volt battery systems. The speed of this driver
will change with battery condition (voltage). Often used in radiant floor
A 10-Watt driver used with 24-volt battery systems. This driver has a built
in dc-dc converter, causing the pump to be "constant-speed" from 20 to 35
volts. An excellent driver for "off-grid" or "lost-grid" radiant floor zone
circulation. Because it is "constant-speed" a zone will not change
characteristics, as batteries discharge. The built-in 3rd generation
converter exceeds 96% efficiency. By distributing conversion among the zone
circulators, instead of one central converter, system reliability is
increased; a single failure does not stop all zones. Simplicity of wiring is
also improved, as no central converter need be wired. Just fuse each zone
pump branch (at the battery) and wire the battery through the thermostat and
then to the zone pump.