NTI INSTALLATION MANUALS

Part 4 - Water Piping

Cap this tting when not in use

Primary/Secondary Piping Shown - See Note 2

Figure 14 - Boiler with Single Central Heating Circulator

NOTE: In piping applications utilizing a single zone, it is recommended that the installer use ow / check valves with weighted seats at or near the appliance to prevent gravity circulation.

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. Primary / Secondary Loop: 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 of DHW piping should be ¾” diameter and CH piping should be 1” in diameter. 5. Circulators are shown with isolation anges. The alternative is standard anges with full port ball valves. Purge valves can be used with circulator anges as an alternative. 6. Piping shown is Primary/Secondary. 7. Install a minimum of 12 diameters of straight pipe upstream of all circulators. 8. VERY IMPORTANT – Minimum ow rates outlined in this manual (2 gpm) 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. Unit is equipped with built-in primary pump. This pump is sized to ensure proper ow rate through the boiler heat exchanger and related piping. 11. IWH Applications - a mixing valve is recommended if the DHW temperature is set above 119 o F.

NOTICE

The piping will not support the weight of the circulators. Refer to the circulator manufacturer’s instructions to properly support the circulator. Failure to comply with these instructions could result in property damage, severe personal injury, or death. On TRX150 / TRX199 Models Only. If the boiler’s DHW connection is not used, cap the tting as indicated above. A cap is included with the boiler. Further, the electrical connection of the 3-way valve motor MUST BE DISCONNECTED while the boiler is operating in central heating mode. This will lock the valve motor in central heating mode and ensure freeze protection operates properly. Failure to disconnect the valve may disable boiler freeze protection and result in property damage. WARNING CAUTION Figure illustrates the basic plumbing requirements for a TRX150 / TRX199 boiler installation utilizing Primary/Secondary piping when the boiler circulator will not provide adequate Áow for the system. Primary / Secondary is required to provide adequate Áow for the secondary circuits.

26