Hubbell NX800, NX200 User Manual
ELECTRIC HEATER COMPANY
OPERATING AND MAINTENANCE
MANUAL FOR
HUBBELL MODEL NX
COMMERCIAL GAS WATER
HEATING SYSTEM
Edition 2020
Hubbell NX
Model Numbers: NX200 - NX800
Version Date: 2020-10-26
INSTALLATION AND OPERATION INSTRUCTIONS
HUBBELL NX WATER HEATER
TABLE OF CONTENTS
1.0 INTRODUCTION ..................................................................................................................... 3
2.0 SPECIFICATION ...................................................................................................................... 6
3.0 WATER HEATER LOCATION ................................................................................................. 7
4.0 GENERAL VENTING ............................................................................................................... 12
5.0 VENT AND AIR-INTAKE TERMINATION CLEARANCES .............................................. 27
6.0 CONDENSATE DRAIN ............................................................................................................ 30
7.0 INSTALLING GAS PIPING ....................................................................................................... 31
8.0 LIGHTING THE WATER HEATER ................................................................................................ 33
9.0 GAS VALVE AND BURNER SET-UP ......................................................................................... 35
10.0 WATER HEATER PIPING ........................................................................................................ 42
11.0 LEAD LAG INSTRUCTIONS ............................................................................................... 51
12.0 FIELD WIRING ..................................................................................................................... 54
13.0 WIRING SCHEMATICS ........................................................................................................ 60
14.0 INSTALLATION CHECKLIST ............................................................................................ 64
15.0 ANNUAL MAINTENANCE AND INSPECTION ................................................................ 65
16.0 PARTS LIST ........................................................................................................................... 67
17.0 TROUBLESHOOTING ......................................................................................................... 79
HAZARD SYMBOLS AND DEFINITIONS
Danger Sign: Indicates a hazardous situation which, if not avoided, will
result in serious injury or death.
Warning Sign: Indicates a hazardous situation which, if not avoided,
could result in serious injury or death.
Caution Sign plus Safety Alert Symbol: Indicates a hazardous situation
which, if not avoided, could result in minor or moderate injury.
Caution Sign without Safety Alert Symbol: Indicates a hazardous situation which, if not avoided, could result in property damage.
Notice Sign: Indicates a hazardous situation which, if not avoided,
could result in property damage.
This Water Heater must be installed by a licensed and trained Heating
Technician or the Warranty is Void. Failure to properly install this unit
may result in property damage, serious injury to occupants, or possibly
death.
1
Hubbell NX │Installation and Operation Instructions NX Series
Read Before Proceeding
If you do not follow these instructions exactly, a fire or explosion may result causing
property damage, serious injury or death.
FOR YOUR SAFETY, READ BEFORE OPERATING
A) This water heater does not have a pilot. It is equipped with an ignition device which automatically lights the
burner. Do not try to light the burner by hand.
B) BEFORE OPERATING smell all around the water heater area for gas. Be sure to smell next to the floor
because some gas is heavier than air and will settle on the floor.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electric switch.
• Do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
C) Use only your hand to push in or turn the gas control knob. Never use tools. If the knob will not push in or
turn by hand, don’t try to repair it, call a qualified service technician. Force or attempted repair may result in
a fire or explosion.
D) Do not use this water heater if any part has been under water. Immediately call a qualified service
technician to inspect the
water heater and to replace any part of the control system and any gas control
which has been under water.
OPERATING INSTRUCTIONS
1. STOP! Read the safety information above very carefully.
2. Set the thermostat to lowest setting. Turn off all electric power to the water heater.
3. This water heater does not have a pilot. It is equipped with an ignition device which automatically lights the
burner. Do not try to light the burner by hand.
4. Turn the manual gas valve to the OFF position. Remove front access panel.
5. Wait five (5) minutes to clear out any gas. Then smell for gas, including near the floor. If you smell gas, STOP!
Follow “B” in the safety information above. If you don’t smell gas, go to the next step.
6. Turn the manual gas valve ON. Wait an additional five (5) minutes smelling for gas.
7. Replace the front access panel.
8. Set thermostat to highest setting. Turn on all electric power to the water heater.
9. Ignition sequence is automatic. Combustion will occur after a brief fan purge.
10. If ignition does not occur, follow the instructions “To Turn Off Gas To Water heater” and call your service
technician or gas supplier.
TO TURN OFF GAS TO THE WATER HEATER
1. STOP! Read the safety information above very carefully.
2. Turn off all electric power to the water heater
3. Turn the manual gas valve to the OFF position
Crystalline Silica - Certain components confined in the combustion chamber may
contain this poteal carcinogen. Improper installation, adjustment, alteration, service or main-
tenance can cause property damage, serious injury (exposure to hazardous materials) or death. Refer to Section
15.0 for information on handling instructions and recommended personal protective equipment. Installation and
must be performed by a qualified installer, service agency or the gas supplier (who must read and follow the
instructions before installing, servicing, or removing this water heater. This water heater contains materials
been identified as carcinogenic, or possibly carcinogenic, to humans).
Void Warranty - This Water heater must have water flowing through it whenever the
burner is on or it will damage the unit and void the warranty. Failure to follow these
instructions may result in serious injury or death.
2
service
supplied
that have
Installation and Operation Instructions │Hubbell NXNX Series
1.0 INTRODUCTION
General Installation Requirements
The installation of your Hubbell NX water heater must conform to the requirements of this manual, your local
authority, and the National Fuel Gas Code ANSI Z223.1 and or CAN/CGA B149 Installation Codes. Where
required by the Authority, the installation must conform to the standard for Controls and Safety Devices for
Automatically Fired Water heaters ANSI/ASME CSD-1.
This document pertains to the correct installation and operation of Hubbell water heater models NX200, NX300,
NX400, NX500, NX600, NX700 and NX800. The instructions detailed in this document supersede any and all previous
instructions provided by Hubbell, written or otherwise. Each unit is provided with the following:
1. Installation and Operating Instructions,
2. Appendix A – Controller and Touchscreen Display Instructions,
3. Hubbell User’s Manual, and
4. Natural Gas to LP Conversion Kit*
Models NX600-NX800 are not approved for operation with Propane (LP Gas). Operating these
models with Propane will result in property damage, serious injury or death.
Read and understand this entire document prior to proceeding with the installation of the
Hubbell NX. Failure to follow the instructions outlined in this document will result in property
damage, serious injury or death.
User Responsibilities
This water heater must be installed and serviced by a qualified installer or service technician. This water heater
must be serviced and inspected annually. Demanding applications or extreme conditions may require more frequent
service and inspection. As the User/Owner of this equipment, you are responsible for ensuring the maintenance
is performed at the required intervals (see Section 15 – Annual Maintenance and Inspection).
Failure to have the water heater properly serviced and inspected on a regular basis by a qualified
service technician may result in property damage, serious injury or death.
Failure to keep the Vent and Combustion Air-inlet clear of ice, snow, and other debris may result in
property damage, serious injury, or death.
Installer Responsibilities
A qualified installer is a licensed person who has appropriate training and a working knowledge of the applicable
codes, regulations, tools, equipment and methods necessary to install a water heater. The Installer assumes all responsibility for a safe installation and that it meets the requirements of the water heater instruction manuals, as well as National and local installation codes. It is also the installer’s responsibility to inform the User/Owner of their obligation with
respect to the description under “User Responsibilities”. Failure to follow this warning could result in fire, serious
injury, or death.
Failure to use the appropriate Natural to LP Conversion Kit and Orifice when operating
the Hubbell NX with Propane will result in extremely dangerous burner operation leading
to property damage, serious injury or death. Refer to section titled
ATTENTION: LIQUEFIED PETROLEUM (LP) PROPANE for applicable conversion
kit and LP orifice numbers.
3
Hubbell NX │Installation and Operation Instructions NX Series
Water heater Vent / Air-Inlet Piping
The Hubbell NX is certified as a “Category IV” water heater, and requires a “Special Venting System” designed for pressurized venting. The exhaust gases must be piped directly
to the outdoors using the vent materials and rules outlined in these instructions. Failure to
follow these instructions will result in serious injury or death.
4
Installation and Operation Instructions │Hubbell NXNX Series
IN THE STATE OF MASSACHUSETTS ONLY
(a) For all horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or
in part for residential purposes, including those owned and operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited
to decks and porches, the following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS At the time of installation of the side wall
horizontal vented gas fueled equipment, the installing plumber or gas fitter shall observe that a hard wired
carbon monoxide detector with an alarm and battery back-up is installed on the floor level where the gas
equipment is to be installed and on each additional level of the dwelling, building or structure served by the equipment. It shall be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors. a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard wired carbon monoxide detector
with alarm and battery back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision cannot be met at the time of completion of
installation, the owner shall have a period of 30 days to comply with the above requirements; provided, however, that during said 30 day period a battery operated carbon monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS Each carbon monoxide detector as required in accordance
with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE A metal or plastic identification plate shall be permanently mounted to the exterior of the building
at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the
horizontally vented gas fueled heating water heater or equipment. The sign shall read, in print size no less than onehalf (1/2) inch in size,
(plate included with water heater).
“
GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS
4. INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall
not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and
signage installed in accordance with the provisions of 248 CMR 5.08(2)(a)1 through 4.
”
(b) EXEMPTIONS
: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most current
edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate
from the dwelling, building or structure used in whole or in part for residential purposes.
(c) MANUFACTURER REQUIREMENTS – GAS EQUIPMENT VENTING SYSTEM PROVIDED:
manufacturer of Product Approved side wall horizontally vented gas equipment provides a venting system design or
venting system components with the equipment, the instructions provided by the manufacturer for installation of the
equipment and the venting system shall include:
1. Detailed instructions for installation of the venting system design or the venting system components; and
2. A complete parts list for the venting system design or venting system.
(d) MANUFACTURER REQUIREMENTS – GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED:
When the manufacturer of a Product Approved side wall horizontally vented gas fueled equipment does not provide the
parts for venting the flue gases, but identifies “special venting systems”, the following requirements shall be satisfied by
the manufacturer:
1. The referenced “special venting system” instructions shall be included with the water heater or equipment
installation instructions; and
2. The “special venting system” shall be Product Approved by the Board, and the instructions for that system shall
include a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product Approved side wall horizontally vented gas fueled equipment,
all venting instructions, all parts list for venting instructions, and/or all venting design instructions shall remain with the
water heater or equipment at the completion of the installation.
When the
5
(
(
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2.0 SPECIFICATION
Table 2-1 General Specification
NX200
Installation and Operation Instructions │Hubbell NXNX Series
NX700
NX300
NX400
NX500
NX600
NX800
Gas Connection
1∕2"(Female)
3∕4"(Female)
1" (Male)
(inches, NPT)
Water Connections
1" (Female)
1-1/4" (Female)
2" (Female)
inches, NPT)
Exhaust Vent
3
4
Connection (inches)
Air-inlet connection
3
4
inches)
Cabinet Height
29.5
36
43
37
inches)
Cabinet Width
17
(inches)
Cabinet Depth
18.5
21.5
24
32.5
47.5
(inches)
Approximate Weight
125
180
225
320
380
with Water (lbs)
Water Content
1.2
2.1
2.4
3.3
4
(gallons)
Electrical Rating
Table 2-2(a) Water Heater Performance Specification
Description
CSA Input
Modulation (MBH)
Recovery Rating at
100⁰F Rise (GPH)
Thermal Efficiency
2
(%)
Notes:
NX200
NX300
25 - 199
1
1,2
229
55 - 275
317
120V / 1 Phase / 60 Hz / 12A
NX400
75 - 399
460
NX500
100 - 500
576
96
NX600
120 - 600
691
NX700
160 - 700
806
1. Listed Input and Output ratings are at minimum vent lengths at Sea Level. Numbers will be lower with longer venting and/or
altitudes greater than 2000 feet.
2. Based on standard test procedures prescribed by the U.S. Department of Energy. Ratings have been confirmed by AHRI.
6
63.5
475
5.2
NX800
160 - 800
922
High Altitude Operation
The Hubbell NX is designed to operate at its maximum listed capacity in installations less than or equal to 2000 ft
above Sea Level. Since the density of air decreases as elevation increases, maximum specified capacity should be
de-rated for elevations above 2000 ft in accordance with Table 2-3.
Table 2-3 De-rate % for High Altitudes
Elevations
In Canada
In USA
Notes:
1
Canada: Altitudes between 2000-4500 ft [610-1372 m], de-rate by 10%. Consult local authorities for de-rating capacities for
altitudes above 4500 ft [1372 m].
2
USA: De-rate capacity by 4% for every 1000 ft [305 m], if altitude is over 2000 ft [610 m].
1
2
2000 ft [610 m]
de-rate by 10%
-
3000 ft [914 m] 4000 ft [1219 m] 4500 ft [1372 m] 5000 ft [1524 m]
de-rate by 10%
de-rate by 12%
de-rate by 10%
de-rate by 16%
de-rate by 10% de-ra te % m ay vary
de-rate by 18%
de-rate by 20%
Combustion – At elevations above 2000 feet, the combustion of the water heater must be
checked with a calibrated combustion analyzer to ensure safe and reliable operation.
It is the Installers responsibility to check the combustion and to adjust the combustion
in accordance to Section 9.0. Failure to follow these instructions may result in property
damage, serious injury, or death.
6
Hubbell NX │Installation and Operation Instructions
3.0 WATER HEATER LOCATION
NX Series
In all cases, the Hubbell NX must be installed indoors in a dry location where the ambient temperature must be
maintained above freezing and below 100F [38C]. Gas components must be protected from dripping, spraying
water, or rain during operation and servicing. Consider the proximity of system piping, gas and electrical supply,
condensate disposal drain, and proximity to vent termination when determining the best water heater location.
Water or flood damaged components must be replaced immediately with new factory
approved components as failure to do so may result in fire, serious injury, or death.
Floor Mounting
The Hubbell NX can be mounted directly on combustible flooring, with the exception of carpeting. Installing the
water heater on carpeting is not permissible. Ensure the water heater is mounted above any anticipated flood level.
Models NX200-NX400 come equipped with stationary, low profile legs. Models NX500-NX800 include factory
supplied/field installed leveling legs. Once the unit is removed from the pallet, thread the leveling legs into the
allocated threaded inserts in the bottom of the unit.
Water heater Area Ventilation Air Openings
Direct Vent – If water heater area clearances are less than the recommended clearances specified in Table 3-1, the
water heater area must be ventilated. (Exception: if the water heater area/room has a volume of 150 ft3or
greater, ventiation of the water heater room is not required). Each ventiation air opening must meet the
minimum requirements of 1 in2per 1000 Btu/hr, but not less than 100 in2. The lower ventilation opening must
be located within 6" of the floor while the upper opening must be located 6" from the top of the space.
If the “Water heater Area” does not meet the recommended clearances listed in Table 3-1, and
if the water heater area has a volume less than 150 ft3, it is considered a Closet or Alcove.
PVC vent pipe and fittings shall not be used within the closet or alcove; only approved CPVC,
Polypropylene or Stainless Steel vent pipe and fittings can be used. See Table 4-3 for a list
of approved materials.
Indoor Combustion Air – When using Indoor Combustion Air in lieu of Direct Vent air-inlet piping (an option
for models NX500-NX800), provisions for combustion and ventiation air, in accordance with section “Air for
Combustion and Ventilation,” of the National Fuel Gas Code, ANSI Z223.1/NFPA 54 (U.S.), or Clause
8.2, 8.3 or 8.4 of Natural Gas and Propane Installation Code, CAN/CSA B149.1 (Canada), or applicable
provisions of the local building codes, must be adhered to.
Closet Installations
For closet installations, it is necessary to provide two ventilation air openings as shown in Figure 3-1(a), (b) and
(c), each providing a minimum area equal to 1 in2per 1000 Btu/hr, but not less than 100 in2and within 6" of the top
and bottom of the closet door. See Table 3-1for minimum recommended clearances.
Alcove Installations
Alcove installations have the same minimum clearances as closet installations, except the front must be
completely open to the room at a distance no greater than 18" [457 mm] from the front of the water heater and the
room is at least three (3) times the size of the alcove. Provided these conditions are met, the water heater requires no
extra ventilation air openings to the space. See Table 3-1for minimum recommended clearances.
Wall Mounting Installations (Optional)
NX200-NX400 models are shipped with wall mounting brackets to provide installers with the option of wall
mounting the water heater. NX500-NX800 models are not available as a wall mountable unit. Refer to Figures
3-3(a) and 3-3(b) for instructions and illustrations on wall mounting applicable models.
7
NX Series
Installation and Operation Instructions │
Hubbell NX
Closet/alcove installations in US and Canada require approved
CPVC
vent and air-inlet
pipe, fittings, cements and primers (Table 4-3).
8
Hubbell NX
│Installation and Operation Instructions
NX Series
Table 3-1 Minimum Clearances for Installation and Service
Model No.
Clearances
Front
NX200
NX300 & NX400
NX500-NX800
3
Minimum
Recommended
Minimum
Recommended
Minimum
Recommended
36
36
36
36
36
36
0
0
0
0
14
18
Flue Pipe
4
4
4
4
1
1
1
1
1
1
Dimensions - inches
Top
12
24
12
24
12
24
Left Side Right Side Rear
12
24
12
24
24
30
12
12
24
4
4
4
9
0
Installation and Operation Instructions │Hubbell NXNX Series
Notes:
1. 6"
if surface is removable allowing 36" clearance (i.e. closet installation). See Ventilation Air Opening dimensions in Figure
3-1.
2.
Clearances can be as low as 12" if the right side has a clearance of 24"
3.
For models NX500-NX800, ensure rear of unit is accessible for wiring and flue gas testing.
4. Code requires all wall mounted instantaneous water heaters to be installed with suitable wall protection extending the full
length and width of the water heater. Check with local authorities regarding acceptable protection materials.
1
r
Hubbell NX
│Installation and Operation Instructions NX Series
1. Remove the uppe
back of the water heater.
2.
Secure the upper wall mount bracket to a solid
wall using field supplied lag screws (anchors
when mounting on a concrete wall) that are
adequate to support the weight of the water
heater. Ensure the bracket is mounted in the
level position. Refer to Table 2-1
Specifications for water heater weight.
3.
Mount the water heater to the bracket by
aligning the slots in the back of the water
heater with the hooks protruding from the wall
bracket. The top of the slots must rest at the
bottom of the groove in the hooks of the wall
mount bracket.
4.
Pull the bottom of the unit away from the wall to
allow the installation of the lower wall mount
bracket (included with water heater). The
bracket will snap into place using the slots
provided in the bottom of the unit (ensure the
snaps lock into place, once installed the bracket
should not be easily removed).
wall mount bracket from the
Failure to follow instructions may
result in fire, serious injury, or death.
1
This unit requires two people to lift it
or damage and injury may result.
3
2
4
Code requires all wall mounted instantaneous water heaters to be installed with suitable
wall protection extending the full length and width of the water heater. Check with local
authorities regarding acceptable protection materials.
10
NX Series
1.
While leaving the upper bracket intact (A),
remove the wall mount bracket attached to the
bottom-back of the water heater (B). Save
the mounting hardware for Step 4.
2.
Secure the wall mount bracket, removed from
the bottom of the water heater in Step 1,
to a solid wall using field supplied lag
screws (anchors when mounting to a concrete wall) that are adequate to support the
weight of the water heater (refer to Table 2-1
Specifications). Ensure the wall mount bracket
is mounted level and flush to the wall with
mounting holes on the bottom, flange pointed
upward and angled away from the wall.
3.
Mount the water heater to the wall by aligning the upper bracket (A) with the wall mount
bracket (B). Slide the upper bracket down
over the wall mount bracket until it hooks.
Once the water heater is resting securely on the
upper bracket, secure the bottom bracket
to the underside of the water heater using
the mounting hardware removed in Step 1;
then, anchor the bottom bracket to the wall as
shown.
Installation and Operation Instructions │
1
Failure to follow instructions may
result in fire, serious injury, or death.
This unit requires two people to lift it or
damage and injury may result.
Hubbell NX
3
2
4
Code requires all wall mounted instantaneous water heaters to be installed with suitable
wall protection extending the full length and width of the water heater. Check with local
authorities regarding acceptable protection materials.
11
Hubbell NX │Installation and Operation Instructions NX Series
4.0 GENERAL VENTING
The Hubbell NX is certified as a “Category IV” water heater requiring a “Special Venting System” designed for pressurized venting. The Exhaust Vent must be piped to the outdoors, using the vent materials and rules outlined in this
section. Under no conditions may this unit vent gases into a masonry chimney, unless it is vacant, and utilizes the
approved venting material and rules described in this section.
Vent and Air-inlet are to be piped separately. The Hubbell NX cannot share a common vent or
air-inlet with multiple appliances. Failure to comply will result in serious injury or
death.
Removing an Existing Water heater from Common Venting System
Do not install the Hubbell NX into a common venting system with any other appliances. Failure
to comply with this warning will cause flue gas spillage and leech carbon monoxide
emissions into the surrounding air resulting in serious injury or death.
When an existing water heater is removed from a common venting system, the common
venting system is likely to be too large for proper venting of the remaining appliances connected
to it.
12
NX Series
Direct Vent Installation
Installation and Operation Instructions │
(Mandatory for models NX200-NX400)
Hubbell NX
When installed as a Direct Vent water heater the combustion air-inlet must also be piped directly to the outdoors using
the methods described in this section and in accordance with the National Fuel Gas Code, ANSI Z223.1 (U.S.) or
CSA B149.1 (Canada) and local requirements.
Indoor Combustion Air
(Optional for models NX500-NX800)
When the installation uses Indoor Combustion Air (i.e. piping is not directly connecting the water heater air-inlet
fitting to the outdoors), provisions for combustion and ventilation air, in accordance with section “Air for
Combustion and Ventilation,” of the
Natural Gas and Propane Installation C ode, CAN/CS A B149.1
8.4 of
National Fuel Gas Code, ANSI Z223.1/NFPA 54
(Canada), or applicable provisions of the local
(U.S.), or Clause 8.2, 8.3 or
building codes, must be adhered to.
The water heater shall be located so as not to interfere with proper circulation of
combustion, ventilation, and dilution air.
Make up air requirements for the operation of exhaust fans, kitchen ventilation systems,
clothes dryers, and fireplaces shall be considered in determining the adequacy of a space to
provide combustion air requirements. Failure to ensure adequate make up air to all
appliances may result in personal injury or death.
Controller RPM Adjustments
– To avoid the potential water heater lockouts due to wind and
static pressure differences, the Lightoff and Minimum Modulation RPM Rates must be adjusted
as per Figures 4-11 and 4-21 in Appendix A when using indoor combustion air.
Air Filter Kit (P/N HUB-84093) –
When using indoor combustion air (non-Direct Vent), it is highly recommended to
use the optional Air Filter Kit (P/N HUB- 84093) to limit the amount of dust that enters the combustion system.
The Air Filter Kit (P/N HUB- 84093) can be installed on water heater models NX500-NX800, as illustrated in
Figure 4-1 (comprehensive installation instructions are provided with the Filter Kit).
Venting Limitation
maximum equivalent exhaust vent length is limited to 30 ft. with 4" piping, or 90 ft.
"
with 6
piping; see warning below Table 4-5.
Figure 4-1 Installation of Optional Air Filter Kit (P/N HUB-84093)
– When using the Air Filter Kit on models NX500 & NX600, the
air-inlet adapter; keep screws from
installation of filter kit
2.Secure filter kit using factory
screws removed in step 1. Reuse the
factory gasket.
3.Secure the filter in place
with the brackets and knurled screws
provided in the filter kit.
13
Hubbell NX │Installation and Operation Instructions NX Series
Combustion Air-inlet Contamination
Be careful not to locate the Air-inlet termination in an area where contaminants can be drawn in and used for
combustion. Combustion air containing dust, debris or air-borne contaminants will drastically increase the required
maintenance and may cause a corrosive reaction in the Heat Exchanger which could result in premature failure, fire,
serious injury, or death. See Table 4-1 for a list of areas to avoid when terminating air-intake piping:
Table 4-1 Corrosive Products and Contaminant Sources
Products to Avoid
Antistatic fabric softeners, bleaches, detergents, cleaners
Perchloroethylene (PCE), hydrocarbon based cleaners
Chemical fertilizer, herbicides/pesticides, dust, methane gas
Paint or varnish removers, cements or glues, sawdust
Water chlorination chemicals (chloride, fluoride)
Solvents, cutting oils, fiberglass, cleaning solvents
Refrigerant charge with CFC or HCFC
Permanent wave solutions
Fixer, hydrochloric acid (muriatic acid), bromide, iodine
Cement powder, crack fill dust, cellulose, fiber based insulation
Contaminated Sources to Avoid
Laundry facilities
Dry cleaning facilities
Farms or areas with livestock and manure
Wood working or furniture refinishing shops
Swimming pools, hot tubs
Auto body or metal working shops
Refrigerant repair shops
Beauty shops
Photo labs, chemical / plastics processing plants
Concrete plant or construction site
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any
other appliance. Failure to follow instructions may result in serious injury or death.
It is BEST PRACTICE to pipe the combustion air-inlet directly to the outdoors (Direct Vent
installation) to avoid contamination often contained in indoor air.
Flammable Solvents and Plastic Piping
Due to the extremely flammable characteristics of most glues, cements, solvents and primers used in the process of
joining plastic vent and air-inlet pipe, explosive solvent vapors must be evacuated from the vent and air-intake prior to
start-up. Avoid using excess cement or primer that may lead to pooling inside the pipe assembly. Freshly assembled
piping assembly should be allowed to cure for a minimum of 8 hours before applying power to the gas fired
appliance. Refer to Mandatory Pre-commissioning Procedure for Plastic Venting in this section.
Flammable Cements and Primers–It is the installers’responsibility to familiarize themselves
with the hazards associated with explosive solvents and to take all precautions to reduce these
risks. Failure to follow these instructions can cause explosions, property damage, injury or
death.
Mandatory Pre-commissioning Procedure for Plastic Venting (PVC or CPVC)
Do not apply power to the water heater prior to Step 4 in the Mandatory Pre-commissioning
Procedure for Plastic Venting.
Spark Igniter Cable - Maintain a minimum 2" separation between spark igniter circuit and
conductors. Failure to follow instructions may result in component failure, injury or death.
1) Working with the power turned off to the water heater, completely install the vent and air-inlet system, securely
cementing joints together. If possible, allow primers/cements to cure for 8 hours before firing the burner. If curing
time is less than 8 hours, proceed with Steps 2 through 6.
2) Maintain the water heater gas supply shut-off valve in the off position.
3) Disconnect electrical leads to the Hot Surface or Spark Igniter. Ensure the cables are placed in a fashion where
they will not arc to ground or other conductor. Refer to warning regarding Spark Igniter Cable.
4) Turn power on to the water heater and apply a heat demand.
5) Allow for 3 complete trials for ignition, consisting of pre and post purge of the combustion blower, until an
ignition lockout occurs. Repeat the process two more times (i.e. 9 complete ignition sequences in total).
6) Turn power off and reconnect the electrical leads to the Igniter.
14
Hubbell NX │Installation and Operation Instructions NX Series
Near Water Heater Vent/Air Piping
Each Hubbell NX is equipped with a short piece of approved CPVC vent pipe (see Table 4-2 CPVC Vent Pipe Transition Piece). Insert one end into the water heater flue outlet adapter and cement the other to field venting (see Table
4-4 for approved venting material). The CPVC vent pipe should extend fully into the water heater flue outlet adapter
(see Table 4-2). Ensure that the venting system does not apply a load or strain on the water heater flue outlet adapter.
The manufacturer recommends using two elbows to create a “swing joint” to reduce potential strain on vent piping
and cemented joints; see Figures 4-2 through 4-5.
Gasket Seating - Improper seating can cause leakage and eventual failure of the sealing
gasket. Failure to follow these instructions may result in serious injury or death.
PVC Exhaust Venting – DO NOT insert PVC pipe directly into the water heater exhaust
adapter, as it can deform from the clamping force of the gear clamp. Failure to follow these
instructions may result in gasket failure and/or the dislodging of the exhaust pipe
water heater adapter, resulting in property damage, serious injury or death.
Table 4-2 CPVC Vent Pipe Transition Piece
Model No.
CPVC Vent Pipe Size CPVC Transition Vent Pipe Length
NX200
NX300-NX600
NX700 & NX800
Polypropylene or Stainless Steel Venting – When using Polypropylene or Stainless Steel
piping, the appropriate water heater adapters must be used to transition the water heater vent
connections to accept the respective Polypropylene or Stainless Steel venting. See Table
4-3 for a list of approved adapters. Failure to use the correct adapter will result in flue gas
leakage resulting in property damage, serious injury or death.
Table 4-3 Water heater Adapters for Polypropylene and Stainless Steel Venting
Model No.
NX200
NX300-NX600
NX700 & NX800
Notes: 1 Listed water heater adapters are only approved for use with the respective venting brand; i.e. a PolyPro water heater
adapter shall not be used with InnoFlue venting.
2
PolyPro and FasNSeal water heater adapters are available from DuraVent (1-800-835-4429 or www.duravent.com); Inno-
Flue water heater adapters are available from Centrotherm Eco Systems (1-877-434-3432 or www.centrotherm.us.com).
Vent Material
Polypropylene
Stainless Steel
Polypropylene
Stainless Steel
Polypropylene
Stainless Steel
Exhaust venting must be supported to reduce strain on piping joints. Failure to follow
these instructions may result in result in damage, serious injury or death.
(used when venting with PVC)
3"
4"
6"
Minimum 5"[127 mm]
Minimum 4" [100 mm]
Minimum 6" [152 mm]
Centrotherm - InnoFlue
Centrotherm - InnoFlue
Centrotherm - InnoFlue
Venting Brand
DuraVent – PolyPro
DuraVent – FasNSeal
DuraVent – PolyPro
DuraVent – FasNSeal
DuraVent – PolyPro
DuraVent – FasNSeal
Full Insertion Depth
2-7/8" [73 mm]
1-7/8" [48 mm]
2-1/2" [63 mm]
Adapter Part No.
300150
ISANY0303
300715
300151
ISAA0404
303631
810004281
ISAA0606
810005231
from the
1,2
In Canada, the first 3 ft (915 mm) of vent piping must be readily accessible for inspection.
15
NX Series
Installation and Operation Instructions │Hubbell NX
Figure4-
2(a) Near Water Heater Venting (CPVC)
Air Inlet
3" Pipe *
Coupling
3" Removable
(field supplied)
Figure 4-3(a) Near Water Heater Venting (CPVC)
Models NX300 & NX400
Exhaust Vent
4"/6" CPVC
0o elbow typical, or tee and
rain cap option for easy cleanouts
Model NX200
Exhaust Vent
3" CPVC
Flue Outlet
Stainless Steel Adapter
(factory supplied)
Swing Joint
to attain slope in
horizontal runs
Flue Outlet
Stainless Steel Adapter
(factory supplied)
Coupling
4"Removable
(factory supplied)
Swing Joint
to attain slope in
horizontal runs
Air-Inlet
4" Pipe *
Figure 4-2(b) Near Water Heater Venting (PVC)
Air Inlet
3" Pipe *
Coupling
3" Removable
(field supplied)
Figure 4-3(b) Near Water Heater Venting (PVC)
Mandatory Vent Pipe
Transition Piece
See Table 4-2. horizontal runs
Exhaust Vent
4"/6"PVC (check local
codes and Table 4-3)
Transition Piece
4" CPVC, minimum
4" long (factory supplied)
90o elbow typical, or tee and
drain cap option for easy cleanouts
Model NX200
Models NX300 & NX400
Swing Joint
to attain slope in
horizontal runs
Exhaust Vent
(check local codes and Ta
4-3)
Coupling
Transition Piece
3" CPVC, minimum 5" l
(factory supplied)
Flue Outlet
Stainless Steel
Adapter (factory
supplied)
Mandatory Vent Pipe
Transition Piece
See Table 4-2.
- 3" PVC,
3" PVC
Swing Joint
to attain slope in
Coupling
4"/6"x4" PVC
Flue Outlet
Stainless Steel Adapter
(factory supplied)
Coupling
4" Removable
(factory supplied)
Air-Inlet
4" Pipe *
ble
ong
* Air-Inlet- check with applicable local codes for acceptable pipe material
16
Air-
Air-
Hubbell NX │Installation and Operation Instructions NX Series
Figure 4-4(a) NearWaterHeater Venting(CPVC/PVC)
Swing Joint
to attain slope in
horizontal runs
Exhaust Vent
4" CPVC
OR
Exhaust Vent
4" PVC (check
local codes
and Table 4-3)
Flue Outlet 4"
stainless steel
(factory supplied)
Transition
4" CPVC
Mandatory Vent Pipe
Transition Piece
4" CPVC (factory supplied).
See Table 4-2.
Figure 4-5(a) Near Water Heater Venting (CPVC)
Models NX700 & NX800
Models NX500 & NX600
InletAdapter
4” stainless steel
(factory supplied
Air-Inlet
4" Pipe *
)
90o elbow typical, or tee
and drain cap option for
easy cleanouts
Figure 4-5(b) Near Water Heater Venting (PVC)
Models NX700 & NX800
Exhaust Vent
6" CPVC
Flue Outlet
6" stainless
steel elbow
(factory supplied)
90o elbow typical, or tee
and drain cap option for
easy cleanouts
Swing Joint to
attain slope in
horizontal runs
Air-Inlet
Air-Inlet Adapter
4" stainless steel
(factory supplied
4" Pipe *
Mand atory Vent Pi pe Transition Piece
6" CPVC (factory supplied). See Table 4-2.
Swing Joint
to attain slope in
horizontal runs
Exhaust Vent
6" PVC
(check local
codes and
)
Table 4-3)
Coupling 6"
PVC, length 4"
Transition
6" CPVC
Flue Outlet 6"
stainless steel
elbow (factory
supplied)
90o elbow typical, or tee
and drain cap option for
Air-Inlet
4” stainless steel
(factory supplied
4/6" Pipe *
Inlet Adapter
)
*Air-Inlet - check with applicable local codes for acceptable pipe material.
17
NX Series
Installation and Operation Instructions │Hubbell NX
Vent/Air-inlet Pipe Material
Table 4-4 Acceptable Vent and Air-inlet Pipe Material
Items
1
Materials
2, 3
United States
Vent Piping
and Fittings
Pipe Cement
Primers
Notes:
1
2
3
4
Refer to Table 4-5 for Allowable Vent and Air-inlet Pipe Sizes and Lengths.
PVC venting (exhaust and air-intake) is not permitted within the Closet/alcove of a Closet/alcove installation.
The Air-Intake does not require high temperature pipe material. Check applicable local codes for acceptable materials.
ULC S636 PVC is approved for flue gas temperatures up to 149oF (65oC) and must only be used for low temperature
PVC - DWV
PVC Schedule 40
CPVC Schedule 40 ANSI/ASTM F441
AL29-4C
Polypropylene (PP) -
PVC
CPVC
PVC / CPVC
ANSI/ASTM D2265
ANSI/ASTM D1785
UL-1738
ANSI/ASTMD2564
ANSI/ASTMF493
ANSI/ASTM F656
applications. High temperature applications requiring water heater supply water temperatures greater than 140oF
(60oC) must use ULC S636 CPVC, PP or AL29-4C.
Installation Standards
All venting material in
ULC S636 approved.
See Note 4 below for
appropriate temperature
Canada
4
Canada must be
applications.
All Vent and Air-inlet materials installed on gas fired
appliances in CAN/US must
meet the Standards listed
in Table 4-4. Failure to
comply could result in fire,
serious injury or death.
The use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenolsulfone) in the exhaust venting system is prohibited. Failure to follow these instructions
may result in property damage, personal injury or death.
Covering non-metallic vent pipe and fittings with thermal insulation is prohibited. Failure
to follow these instructions may result in property damage, personal injury or death.
18
Hubbell NX │Installation and Operation Instructions NX Series
Vent and Air-inlet Pipe Length Determination
Use Table 4-5 to determine the maximum pipe length that can be used. The table calculates sweep, 90º elbows, and
45º elbows at 5 equivalent feet each. Note: model NX200 has limitations when operating with Propane Gas (LP).
Example: An NX200 can be installed with 105 equivalent feet of air-inlet piping and 105 equivalent feet of exhaust
vent piping when operating with Natural Gas. When operating with Propane Gas (LP), the maximum length of
each the exhaust vent and air-inlet pipe is limited to 50 equivalent feet (3" diameter pipe).
The length of one vent pipe (air-inlet or exhaust) may not exceed the length of the other vent
pipe by more than 20 equivalent feet.
Table 4-5 Allowable Vent and Air-Intake Pipe Size and Lengths
Model
Pipe Size
3"
Gas
LP
Length
ft.
50
Number of Elbows (90’s or 45’s) and Equivalent Feet
1 2 3 4 5
45
40 35
30 25 20 15
6
7
NG
NX200
NX300&
NX400
NX500
NX600
3"
4"
4" or 6"
4" or 6
4"or 6
3
"
3
"
NG &
LP
NG &
LP
NG & LP
2
NG
105
100 95 90
105
100 95 90
100
95
90 85
100
95
90 85
100
95
90 85
85 80 75 70 65
85 80 75 70 65
80 75
80 75 70 65
80 75 70 65
70 65
8 9
10
60 55
60 55
60 55
60
60
5
NX700 &
NX800
Notes:
1
Only 6" exhaust vent is permissible for models NX700-800. Air-inlet pipe can be 4" or 6" (6" is highly recommended).
2
Models NX600-NX800 operate with Natural Gas only.
3
Models NX500 & NX600 are limited to 30 ft. of 4" or 90 ft. of 6" exhaust venting when using the Air Filter Kit
(P/N HUB-84093).
1
6
"
NG
2
100
95
90 85
80 75 70 65
Air Filter Kit venting restrictions - Models NX500 & NX600 are limited to 30 equiva-
lent feet of 4" (or 90 equivalent feet of 6") exhaust vent when using the optional Air Filter
Kit. When transitioning from 4" to 6", the 4” venting used must be counted 3 times to
convert to an equivalent length in 6".
Example: An application uses one 90º elbow and 5 feet of 4" venting before converting to 6"; therefore, the 4"
venting has an equivalent length of 30’ [(5'+5') x 3] of 6" venting; thus allowing an additional 60' equivalent of
6"venting (Note: Example is only true with NX500-600 models using the optional Indoor Combustion Air Kit).
60 55
19
NX Series
Installation and Operation Instructions │Hubbell NX
Termination Options – Direct Vent Installation
The venting system of the Hubbell NX may be terminated using field supplied piping to construct a “Two-Pipe”
termination, see Figures 4-6(b), 4-7(a), 4-7(b) and 4-8(a); alternatively the venting may be terminated using a factory
kit selected from Table 4-6.
Kits certified with the Hubbell NX are listed in Table 4-6 and available from IPEX, DuraVent, Centrotherm, and/
or Hubbell. For more information on System 636 Vent Kits or wholesaler locations contact IPEX directly USA:
1-800-463-9572 or www.IPEXamerica.com
│ CAN: 1-866-473-9462 or www.ipexinc.com. For more information
on PolyPro Vent Kits or wholesaler locations contact DuraVent directly 1-800-835-4429 or www.duravent.com. For
more information on InnoFlue Vent Kits or wholesaler locations contact Centrotherm directly at 1-877-434-3432 or
www.centrotherm.us.com.
Table 4-6 Optional Vent Termination Kits
Vent
Description
IPEX Low Profile
(Flush Mount)
7
IPEX Concentric
(Wall/Roof)
5,6,7,8
Size
3"
4"
3"
4"
DuraVent - Poly Pro
Concentric (Wall)
DuraVent - Poly Pro
Concentric (Roof)
Centrotherm – InnoFlue
(Flush Mount)
Centrotherm – InnoFlue
Concentric (Wall)
Centrotherm – InnoFlue
Concentric (Roof)
9
9
3"
4"
3"
4"
3"
3"
4"
3"
4"
Models NX300-NX800 are not approved for use with any of the 3" vent termination
kits; only 4" vent termination kits, listed in Table 4-6, are acceptable.
Supplier P/N
196985 (Hubbell P/N 84357)
196986 (Hubbell P/N 84358)
196116 (Hubbell P/N 82666)
196021 (Hubbell P/N 84355)
3PPS-HK
4PPS-HK
3PPS-VK
4PPS-VK
ISLPT0303
ICWS3513 & ICTC0335
ICWS4639 & ICTC0446
ICRT3539 & ICTC0335
ICRT4679 & ICTC0446
Figure
4-9(b), 4-10(b)
4-9(d)
4-10(c)
4-9(d)
4-10(c)
4-9
4-9
Vent Material
Compatibility
PVC/CPVC
7
PVC/CPVC
PVC/CPVC/PP
PVC/CPVC/PP
PVC/CPVC/PP
7
Vent Option
✘
✔ ✔
✘
✔
✘
PVC/CPVC/PP
PVC/CPVC/PP
✘
✔
Wall
✔
✔
✘
✔
✔
✘
PVC In Canada - Authorities in some jurisdictions may not allow the use of any PVC
venting materials with condensing water heaters; check with the local safety inspector to
verify compliance prior to installing a PVC Concentric Vent Kit with a Hubbell NX.
20
Hubbell NX │Installation and Operation Instructions NX Series
Sidewall Termination - Due to potential moisture loading (build-up) along the exterior
wall, sidewall venting may not be the preferred venting option. Refer to Figures 4-8 and
Sidewall Termination Examples – Direct Vent Installation
Figure
4-6(a) Concentric Sidewall Termination
4-10 for roof top venting options.
(NX200 Illustrated)
Figure 4-6(b) Two-Pipe Sidewall Termination
(NX200Illustrated)
Figure 4-7(a) Two-Pipe Sidewall Termination
(NX800 Illustrated)
Figure 4-7(b) Two-Pipe Sidewall Termination
(NX400 Illustrated)
21
NX Series
Installation and Operation Instructions │Hubbell NX
Extra precaution must be taken to adequately support the weight of the Vent/Air-inlet
piping in applications using roof-top terminations. Failure to follow these instructions
may result in venting or water heater component failure resulting in flue gas spillage
leading to property damage, serious injury or death.
Roof Termination Examples – Direct Vent Installation
Figure 4-8(a) Two-Pipe Roof Termination
(NX200 Illustrated)
Figure 4-8(b) Concentric Roof Termination
(NX200 Illustrated)
22
V
Air-
V
V
V
V
Hubbell NX
│Installation and Operation Instructions NX Series
Sidewall Termination Details – Direct Vent Installation
Horizontal 4-12" or
greater than 36"
ertical
Min. 18"
ent Screen
Min. 12" above
grade or snow
level
ent pipe piece to
retain vent screen
Min. 12"
above grade
or snow
inletaround
perimeter (1-2" from
wall)
Exhaust through
center
ent Screen
ent pipe piece to
retain vent screen
Air-inlet around
Min. 12" above
grade or snow
level
Min. 12" above
grade or snow
level
Air-inlet bottom
Exhaust center
23
NX Series
Installation and Operation Instructions │Hubbell NX
Roof Termination Details – Direct Vent Installation
Two-Pipe Termination (Roof)
Figure 4-10(a)
Exhaust
Vent Screen
Vent pipe piece to
retain vent screen
Air-inlet
Min. 12" above
grade or snow
level
Flashing
Vertical
Min. 18"
Horizontal
4-12" or greater
than 36"
Figure 4-10(b)
IPEX Concentric Termination (Roof)
Refer to documentation included with termination kit for co
plete installation instructions.
Exhaust center
Vent pipe piece to
retain vent screen
Vent Screen
Air-inlet around
perimeter
Min. 12" above
grade or snow
level
Flashing
m-
Figure 4-10(c)
PolyPro / InnoFlue Termination (Roof)
Refer to documentation included with termination kit for
complete installation instructions.
Min. 12"
above grade or
snow level
Air-inlet
Flashing
Exhaust
Figure 4-10(d)
Exhaust only Termination (Roof)
Figure illustrates two options for exhaust termination only;
neither vent pipe illustrated is for combustion air-inlet.
Vent pipe piece to
retain vent screen
Vent Screen
Exhaust
Option 1
Min. 12" above
grade or snow
Exhaust
Option 2
level
Flashing
24
Hubbell NX │Installation and Operation Instructions NX Series
Venting Rules and Guidelines
1. Prevailing Winds: Ensure the vent is located where it will not be exposed to normal prevailing winds.
2. Combustion Air-inlet Contamination: Air for combustion must be drawn from an area free of dust and
contaminants. Combustion air containing chemicals such as chloride, fluoride, bromine or iodine or dust and
debris will cause corrosion damage of the heat exchanger voiding your Hubbell warranty. Refer to Table 4-1 for
a list of corrosive products and contaminants sources to avoid.
3. Vertical Separation: The exhaust must be a minimum of 18 in. above the air inlet, and the air inlet must always
be a minimum of 12 in. plus snow allowance above any surface that will support snow. (Two feet plus snow
allowance is highly recommended). Consult your weather office for the maximum typical snowfall for
your region.
4. Horizontal Separation: The horizontal distance between the inlet and exhaust must be a minimum of 4" center to
center.
5. Wall Flashing: Under normal operating conditions this water heater will produce a plume of white gases, and
should be taken into consideration when selecting an adequate location. A 36 in. diameter stainless,
plastic, or vinyl shield can be used to flash the exterior of the building.
6. Flue Gas Hazard: Position the vent termination where vapors cannot make accidental contact with people and
pets or damage nearby shrubs and plants.
7. Elbow Extensions: Elbows on outside of wall must be no more than 1∕2 in. away from the wall.
8. Vent Sloping: All indoor exhaust piping must be on a slope back to the water heater a minimum of 1∕4 in.
per linear foot of vent. For applications where excessive condensation is possible 1∕2 in. per linear foot is
recommended.
9. Vent Supports: Where required Vent and Air-inlet piping shall be secured to the wall for more rigidity.
All interior vent pipe shall be supported a minimum of every 36 in..
10. Roof Exhaust: In all roof applications the discharge must point away from the pitch of the roof.
11. Roof Flashing: Install adequate flashing where the pipe enters the roof, to prevent water leakage.
12. Rain Cap: Install and seal a rain cap over existing chimney openings, in vacant chimney applications.
13. Venting Below Grade: For installations that exit the wall below grade refer to Figure 4-11.
14. Vent Screens: Install factory supplied vent screens on the outside of the last elbow for both the inlet and exhaust
vent terminal elbows. Install the screen into the female opening of the elbow, and then cut a small
piece of pipe to sandwich the screen into the elbow. NOTE: ensure the small piece of pipe cut, does not extend
past the end of the elbow. Two screens are provided in the package. See Figures 4-9 and 4-10.
15. Condensate Hazard: Do not locate vent over public walkways, driveways or parking lots. Condensate
could drip and freeze resulting in a slip hazard or damage to vehicles and machinery.
16. Warning Plate: For Sidewall Venting, install the warning plate “Gas Vent Directly Below”, directly above
(within 4 ft. vertically) the location of the air-inlet pipe, so it is visible from at least 8 ft away.
See Figure 4-9.
17. Wall Thickness: Direct vent terminations are designed to work with any standard wall thickness.
Installation guidelines for min/max wall thickness are as follows: Min. = 1 in., Max. = 60 in..
18. Venting Options: Due to potential moisture loading (build-up) along the exterior wall, sidewall venting
may not be the preferred venting option. Refer to Figures 4-8 and 4-10 for roof top venting options.
The vent for this water heater shall not terminate over public walkways; or near soffit vents or
crawl space vents or other area where condensate of vapor could create a nuisance or
hazard or cause property damage; or where condensate or vapor could cause damage or could
be detrimental to the operation of regulators, relief valves, or other equipment.
25
r
Hubbell NX │Installation and Operation Instructions NX Series
For installations that exit the wall below grade:
1.
Excavate site to a point below where the pipes
are
to exit as shown.
2.
Ensure the wall is fully sealed where the pipes
penetrate.
The Vent/Air-inlet piping MUST be secured to
3. the
side of the building above grade, as shown, to
provide rigidity.
4.
Optional mounting bracket P/N. HUB-82075 for
securing the exhaust pipes (only applicable for 3
in. PVC/CPVC venting).
Ensure that the Vent/Air-inlet clearances are
5.
maintained, see Section 5.0 fo
details.
Vent piping outside the building is permitted under the
following conditions:
1. The maximum length outside the building is 20 ft.
Note that outdoor length must be included in the
overall vent length calculation.
2. All normal termination clearances are maintained.
3. The pipe is supported every 24 in..
4. The exhaust and inlet are sloped back to the water
heater 1∕2 in. elevation for every linear foot.
Wall Brackets
Gas Vent Directly Below
Keep Free of Obstructions
Supports every
24 in.
Exhaust
Vent
Air-Inlet
Maximum of 20 ft. is
permitted for piping
outside a building.
12 in. plus snow
allowance above grade
Figure 4-13 Existing Chimney Chase Way
It is permissible to use an existing chimney as a chase
way to run the Vent/Air-inlet piping as long as:
1. The chimney is not being used by any other water
heater.
2. Flue gases do not enter the vacant chimney.
3. Only Hubbell NX certified venting materials are
used, see Table 4-4.
4. Vent lengths are within the maximums specified.
5. The top of the chimney is capped and the Vent/
Air-inlet pipes are flashed to prevent leakage
into the vacant chimney.
Chimney
Cap
Existing
Chimney
(used as a
chase way)
Under no circumstances may an existing chimney or chase-way be used to vent or
26
Exhaust Vent
Air-Inlet
Exhaust Vent Min.
18 in. above air-inlet
Min. 12 in. above roof
Air-Inlet
and snow level
Hubbell NX │Installation and Operation Instructions NX Series
provide combustion intake air to a Hubbell NX. Failure to follow these instructions will
result in fire, property damage, serious injury or death.
27
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