Table of Contents
Advertisement
41
Figure 27 – Cascaded System - Zoning with Zone Valves and Indirect Water Heating – Primary / Secondary Shown
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. See Table 16 for minimum CH pipe sizing.
5. 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.
6. Piping shown is Primary/Secondary. System flow (secondary loop) must be greater than the boiler's primary loop flow.
7. Install a minimum of 12 diameters of straight pipe upstream of all circulators.
8. VERY IMPORTANT – Minimum flow rates outlined in this manual must be maintained through the heat exchanger to minimize short
cycling.
9. In a valve-based system, each heating zone has a zone valve which opens when that zone calls for heat. Each zone thermostat is
wired to its corresponding zone valve. Contacts in the zone valves provide a signal to the boiler to operate when there is a call for heat.
10. If Boiler Pump on the return line does not have an internal flow check, install a check valve on the return line to the boiler.
WHL-032 REV. 6.2.16
Advertisement
Table of Contents
