HTP Drain Back, Installation, Start-Up, Maintenance, Parts, Warranty

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lp-585 Rev. 000 Rel. 001 Date 9.10.18
13
I. Applications
Figure 7 - Drain Back Tank without Heat Exchanger and Gas Fired Back Up
FIGURE NOTES:
1. This drawing is meant to demonstrate system piping concept only. The installer is responsible for all equipment and detailing by local codes.
2. Non-potable HTF shall only be used for the solar heat exchanger circuit. Never introduce non-potable HTF to any connection other than
the solar loop.
3. If there is a check valve on the cold water feed line, a thermal expansion tank suitable for potable water must be sized and installed within
this piping system between the check valve and cold water inlet of the solar water heater. The expansion tank should be properly sized for the
volume of stored hot water and maximum tank temperature. Normal solar control settings may be between 120
o
and 160
o
. Do not exceed
160
o
on the solar control setting.
4. A solar rated mixing valve is recommended if the domestic hot water setting is above 120
o
F. A standard mixing valve generally cannot
deliver the temperature protection range at which a solar system operates.
5. A minimum of 12 diameters of straight pipe must be installed upstream of all circulators.
6. Make sure solar storage tank is fully purged of air before power is turned on to the backup heat source.
7. Due to extreme temperatures, circulators with integral flow checks are not to be used in solar systems. If circulator comes equipped
with an integral flow check, remove it.
8. Non-vertical drain back solar system piping should pitch ¼” per foot back to the tank to facilitate draining.
9. No check valves are allowed in the solar loop.
10. Solar pumps must be installed 3’ below the drain back tank.