NTI TRX II Series Installation Start-Up Maintenance page 27

ZONE 1 ZONE 2
TRANSFORMER
JUMPER
ZONE #1 ZONE #2
WARNING
For direct (not primary / secondary) piping
applications, the expansion vessel must
be placed on the return side of the boiler
as illustrated. Placement of flow 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.
NOTICE
Figure illustrates the basic
requirements for a TRX150 / TRX199 boiler
installation without an external Central
Heating circulator; the boiler's internal
circulator delivers flow to the heating system.
Application is limited to zone valve (or non-
circulator) distribution systems with small flow
requirements (e.g. systems requiring no more
than 9 gpm at 9 ft. of head pressure).
CAUTION
On TRX150 / TRX199 Models Only.
If the boiler's DHW connection is not used,
cap it and set CH forced diverter position =
ON (2. 1 0.8 = 1) to lock the 3-way valve in
the central heating position. Access the CH
forced diverter position setting from the Tech
Menu - DHW Menu - Advanced Menu.
Failure to lock the valve in the central heating
position may prevent the boiler from delivering
heat, which could result in property damage.
TRX Series 2 - Installation - Startup - Maintenance Instructions
LINE VOLTAGE JUNCTION BOX
CH PUMP DHW PUMP
N G L N G L
MAKE-UP
WATER
NOTE: In piping applications utilizing a single
zone, it is recommended that the installer
use flow / check valves with weighted seats
at or near the appliance to prevent gravity
circulation.
WARNING
plumbing
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.
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. 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
flanges. The alternative is standard
flanges with full port ball valves.
120VAC INPUT
N G L
M
CAP WHEN
NOT IN USE
Figure 16 - Boiler without Central Heating Circulator
Part 4 - Water Piping
INDIRECT FIRED
WATER HEATER
IMPORTANT:
EXPANSION TANK MUST BE ON THE
RETURN SIDE IN APPLICATIONS
PIPED DIRECT TO ZONES
Purge valves can be used with circulator
flanges as an alternative.
4. Install a minimum of 12 diameters of
straight pipe upstream of all circulators.
5. VERY IMPORTANT – Minimum flow 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 flow rate
through the boiler heat exchanger and
related piping.
8. IWH Applications - a mixing valve is
recommended if the DHW temperature is
set above 119oF.
9. For direct (not primary / secondary)
piping applications, it is required to
install the expansion vessel on the return
side of the boiler as illustrated.
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