Part 4 - Water Piping; General Plumbing Information; Backflow Preventer; Expansion Tank - NTI FTVN085 Installation Start-Up Maintenance

WARNING
Failure to follow the instructions in this section WILL VOID the warranty
and may result in property damage, severe personal injury, or death.
The National Standard Plumbing Code, the National Plumbing Code
of Canada, and the Uniform Plumbing Code limit heat transfer fluid
pressure to less than the minimum working pressure of the potable
water system up to 30 PSI maximum. In addition, the heat transfer
fluid must be water or another non-toxic fluid having a toxicity of
Class 1, as listed in Clinical Toxicology of Commercial Products,
5th Edition. Failure to follow this warning could result in property
damage, severe personal injury, or death.
CAUTION
Do not apply a torch within 12" of the boiler. If sweat connections are
used, sweat tubing to the adapter before fitting adapter to the water
connections on the boiler. Damages due to improper installation
practices ARE NOT covered by warranty.
Galvanized steel fittings must not be used in any system loop with
this space heating or combi boiler. Dielectric unions must not be
used on the DHW loop of a combi boiler. Doing so WILL VOID the
warranty. Use only copper, brass, stainless steel, or black iron (CH
loop ONLY) fittings.
Plumbing of this product should only be done by a qualified, licensed
plumber in accordance with all local plumbing codes. The boiler may
be connected to an indirect water heater to supply domestic hot
water. NTI offers indirect water heaters in a wide range of gallon sizes
in stainless steel construction.
A. General Plumbing Information
CAUTION
The building piping system must meet or exceed the piping
requirements in this manual.
Use two wrenches when tightening water piping at boiler. Use one
wrench to prevent the boiler return or supply line from turning.
Failure to prevent piping connections from turning could cause
damage to boiler components.
The boiler control module uses temperature sensors to provide
both high limit protection and modulating temperature control. The
control module may also provide low water protection by sensing
the water level in the heat exchanger. Some codes/jurisdictions may
require additional external controls.
The water connections must be installed in accordance with all local
and national plumbing codes, or any applicable standard with prevails.
• Pipe material must be suitable to meet local codes and industry
standards.
• The pipe must be cleaned and without blemish before any
connections are made.
• The size of the DHW pipes should be 3/4" diameter, and the CH
pipes should be 1-1/4" diameter.
• Isolation (shut-off valves) should be used on both the CH and DHW
loops to ease future servicing.
• All piping should be insulated.
• If the Combi Boiler is installed with a backflow preventer in the
DHW cold water supply line, means shall be provided to control
thermal expansion. Contact the water supplier or a local plumbing
inspector on how to control this situation.
It is recommended to install a sweat shut-off valve and a union in the
return and supply piping to ease future servicing. If there is a backflow
preventer or any type of a no return valve in the system, install an
additional tee here suitable for an expansion tank.
Part 1 - General Safety Information
NOTE: The addition of a high temperature limiting device is important
if the boiler is to be connected to a domestic hot water system.
B. Backflow Preventer
Use a backflow preventer specifically designed for hydronic boiler
installations. This valve should be installed on the cold water fill supply
line per local codes.
C. Expansion Tank
Expansion Tank and Make-Up Water
1. Ensure that the expansion tank is designed and sized to correctly
handle boiler and system water volume and temperature.
WARNING
Expansion tanks must be sized according to total system volume. This
includes all length of pipe, all fixtures, boilers, etc. Failure to properly
size for system expansion could result in wasted time, money, possible
property damage, serious personal injury, or death.
CAUTION
Undersized expansion tanks cause system water to be lost from the
relief valve, causing make-up water to be added. Eventual boiler
failure can result due to excessive make-up water addition. SUCH
FAILURE IS NOT COVERED BY WARRANTY.
DO NOT install automatic air vents on closed type expansion tank
systems. Air must remain in the system and return to the tank to
provide an air cushion. An automatic air vent would cause air to leave
the system, resulting in improper operation of the expansion tank.
Model
FTVN085, 110, 110C
FTVN150, 150C
FTVN199, 199C
Table 9 - Heat Exchanger Water Volume (To Aid in Expansion Tank Sizing)
2. The expansion tank must be located as shown in Applications, this
manual, or following recognized design methods. See expansion tank
manufacturer's instructions for details.
3. Connect the expansion tank to the air separator only if the air
separator is on the suction side of the circulator. Always install the
system fill connection at the same point as the expansion tank
connection to the system.
4. Most chilled water systems are piped using a closed type expansion
tank.
DIAPHRAGM (OR BLADDER) EXPANSION TANK
Always install an automatic air vent on top of the air separator to
remove residual air from the system.
D. Piping the Boiler
CAUTION
Non-Combi Models should not be operated as a direct potable hot
water heater. Only Combi Models should be used to directly heat
hot water.
Use at least the MINIMUM pipe size for all appliance loop piping.
This is to avoid the possibility of inadequate flow through the
appliance. Using less than the required minimum pipe size and
piping could result in system problems, property damage, and
premature appliance failure. Such problems ARE NOT covered by
product warranty.
NOTE: Observe the minimum 1" clearance around all uninsulated hot
water pipes when openings around pipes are not protected by non-
combustible materials.

Part 4 - Water Piping

Heat Exchanger Volume (Gallons)
1.4
2.0
2.7
21