HTP 399M - Manual (Page 41)

41
Figure 23
NOTES:
1. This drawing is meant to demonstrate system piping concept only. Installer is responsible for all equipment and detailing required by local codes.
2. Adjust differential pressure bypass valve to eliminate any flow velocity noise when zone with highest pressure drop operates by itself.
3. The minimum pipe size for connecting an indirect water heater
is 1”.
4. The minimum pipe size for connecting the unit is 1.25” and 2” for the 399.
5. Circulators are shown with isolation flanges. The alternative is standard flanges with full port ball valves. Purge valves can be used with the circulator
flanges as an alternative.
6. The anti-scald mixing valve is recommended if the DHW temperature is set above the factory setting of 119
o F.
7. Install a minimum of 12 diameters of straight pipe upstream of all circulators.
8. A minimum of 6 pipe diameters of straight pipe shall be installed upstream and downstream of all closely spaced tees.
9. All closely spaced tees shall be within 4 pipe diameters center to center spacing.
10. High temperature loads cannot operate simultaneously with low temperature loads.
11. Supply water temperature to high temperature loads is not reset based on outdoor temperature.
12. Domestic water heating is highest priority load, and controlled through priority zone of multi-zone relay center.