NTI INSTALLATION MANUALS

Part 4 - Water Piping

For direct (not primary / secondary) piping applications, the expansion vessel must be placed on the return side of the boiler as illustrated. Placement of Áow resticting devices, such as check valves, is prohibited between the boiler return and the expansion vessel. Failure to place the expansion vessel as instructed, may result in the release of the pressure relief valve, property damage, severe personal injury, or death. WARNING

Figure 18 - Combi Boiler without Central Heating Circulator

NOTES: 1.

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.

This drawing is meant to show system piping concept only. Installer is responsible for all equipment and detailing required by local codes. 2. The minimum pipe size of DHW piping should be ¾” diameter and CH piping should be 1” in diameter. 3. 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. 4. Install a minimum of 12 diameters of straight pipe upstream of all circulators. 5. VERY IMPORTANT – Minimum ow rates outlined in this manual (2 gpm) must be maintained through the heat exchanger to minimize short cycling. 6. 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. 7. Unit is equipped with built-in primary pump for the heating loop. This pump is sized to ensure proper ow rate through the boiler heat exchanger and related piping. 8. For direct (not primary / secondary) piping applications, it is required to install the expansion vessel on the return side of the boiler as illustrated.

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. Figure illustrates the basic plumbing requirements for a TRX199C boiler installation without an external Central Heating circulator; the boiler’s internal circulator delivers Áow to the heating system. Application is limited to zone valve (or non-circulator) distribution systems with small Áow requirements (e.g. systems requiring no more than 9 gpm at 9 ft. of head pressure). WARNING NOTICE

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