HTP EFT-399 User Manual
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LP-387 REV. 6.10.14
Figure 11
– Primary/Secondary Boiler Piping – Zone Valves and DHW Priority – Outdoor Reset - NOTES:
1. This drawing is meant to show system piping concept only. Installer is responsible for all equipment and detailing required by local codes.
2. All closely spaced tees shall be within 4 pipe diameters center to center spacing.
3. A minimum of 6 pipe diameters of straight pipe shall be installed upstream and downstream of all closely spaced tees.
4. The minimum
pipe size for connecting a SuperStor indirect water heater is 1”
5. The minimum pipe size for connecting an EFT-55/80/110 - 1
”, EFT-155/199/285 – 1.25”, EFT-399 – 1.5”.
6. Circulators are shown with isolation flanges. The alternative is standard flanges with full port ball valves. Purge valves can be used with circulator
flanges as an alternative.
7. A mixing valve is recommended if the DHW temperature is set above the factory setting of 119
o
F.
8. Piping shown is Primary/S
econdary. System flow (secondary loop) must be greater than the boiler’s primary loop flow.
9. Install a minimum of 12 diameters of straight pipe upstream of all circulators.
10. VERY IMPORTANT
– Minimum flow rates outlined in this manual must be maintained through the heat exchanger to minimize short cycling.