DuraVent FasNSeal 8090 User Manual

Installation Instructions

FNS 80/90

Combined Category I and
IV venting for Gas-Burning
Appliances

For the most up-to-date installation instructions, see www.duravent.com

CONTENTS

LISTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 3

NOTES / A PPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

CLEARANCES TABLE 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 3

PRIOR TO INSTALLATION. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .3

INSTALLATION OF LINER. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .5

MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

WARRANTY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

®

A MAJOR CAUSE OF VENT RELATED FIRES IS FAILURE

TO MAINTAIN REQUIRED CLEARANCES (AIR SPACES)
TO COMBUSTIBLE MATERIALS. IT IS OF THE UTMOST

IMPORTANCE THAT DURAVENT PRODUCTS BE INSTALLED

ONLY IN ACCORDANCE WITH THESE INSTRUCTIONS.

WARNING

CARBON MONOXIDE POISONING
HAZARD. Failure to follow the steps
outlined below for each appliance
connected to the venting system being
placed into operation could result in
carbon monoxide poisoning or death.

• Examine all components for possible

shipping damage prior to installation;

• Read all instructions before beginning

the installation and follow these
instructions exactly as written.

• Proper joint assembly is essential for a

safe installation. Check the integrity of
ALL joints upon completion of assembly

• This venting system must be free to

expand and contract under normal
operation.

• Assure unrestricted vent movement

where required through walls, ceilings
and roof penetrations.

• This venting system must be supported

in accordance with these instructions.

• Do not mix pipe, ttings, or joining

methods from dierent vent system
manufacturers. Do not use adhesives
of any kind with this venting system.
Acceptance of the installed system is
dependant on full compliance with
these installation instructions.

WARNING

Risk of carbon monoxide poisoning
or re due to joint separation or pipe
breakage.

Keep these instructions for future
reference.

Dear Customer, Installer, or End User:

We welcome any comments regarding
matters pertaining to our DuraVent products.
We welcome any ideas, input or complaints
to help improve our product oering.

If you are searching for tech support or
product information, please phone us at
800-835-4429.
Or email us at:
[e-mail]

LISTED

MH6357

LISTING

M&G DuraVent's FNS 80/90 Combination
Cat I and Cat IV gas vent system is designed
and UL listed for use with approved M&G
Duravent / Security Chimneys special gas
vent components only! Listed to applicable
portions of ULC S636/UL1738, UL1777, and
UL441.

GENERAL INSTALLATION NOTES
Read these instructions before beginning.

You must follow these installation
instructions when installing the FNS 80/90
system. This is a supplemental instruction to
other DuraVent listed instructions that are
used during this installation.

APPLICATION

The FNS 80/90 system is a tested and listed
exhaust vent for the replacement of one
Category I gas red appliance with a high
eciency appliance in an existing Type B
common vent system. In a typical common

IMPORTANT

The vent system must be installed in
accordance with local code requirements
and appropriate National Codes: In the
US: NFPA 54 / ANSI Z223.1 National Fuel
Gas Code or the International Fuel Gas
Code.

vent Type B setup (Fig.1), two Category I
(Cat I) appliances vent into one common
vent that conveys ue products outside the
building. In many appliance retrots, one
Cat I appliance is removed, and replaced
with a higher eciency (typically a Cat
IV) condensing appliance. The new Cat IV
appliance is NOT permitted to be vented with
B Vent, but requires a vent system engineered
for a dierent exhaust requirement.
Condensing appliances have much lower
exhaust temperatures, which create
signicant amounts of acidic condensate.
Using the FNS 80/90 solution, a special
stainless steel Cat IV liner is installed within
the existing Cat I vent. This ex handles the
Cat IV ue products, while the remaining
Cat I appliance uses the annular space
around the liner to exhaust ue products
to the outside via natural draft (Fig.2). A
patent pending termination is engineered
to provide separate exhaust exit paths for
each appliances's exhaust system (Fig.2). The
combination of these systems helps both
operate more eectively.

PRIOR TO INSTALLATION: RELINING
COMMON VENTED B VENT SYSTEMS

When relining common vented B-Vent (or

WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow these installation

instructions could result in personal

injury or death

Table 1

Clearance to Combustibles

Type B Gas Vent Unchanged Unchanged

VENT PIPE ORIENTATION

Vertical Horizontal

3

TYPICAL

COMMON

VENTED

CATEGORY I

INSTALLATION

Figure 1

CAT I EXHAUST
PATH

CAT IV EXHAUST
PATH

Figure 2

other approved factory built vent), special
care must be taken. Prior to reline work
being started:

BIRDSCREEN

FNS FLEX

COLLAR

TERMINATION

CAP

CAP MOUNT

STRAPS /

HARDWARE

FNS FLEX

B VENT

PRE-EXISTING

CAT IV

FIRESTOP /

HARDWARE

POLYPRO

TO FNS FLEX

ADAPTER

CATEGORY

IV EXHAUST

ENTRY

FIG.5

CAT I
EXHAUST
ENTRY

Ensure the new proposed vent system

Figure 3

is appropriate for the two appliances in
question. For the Category IV appliance,
reference the OEM Appliance manual for
information on min/max vent run and vent
diameter requirements. OEM guidance

should include maximum number of elbows
and related pressure-drops. The total vent
length from the appliance to the termination
should not be greater than the maximum

Table 2 - Equivalent Length Chart

2" Equivalent Length 3" Equivalent Length 4" Equivalent Length 5" Equivalent Length

1-ft Rigid Pipe 1-ft 1-ft 1-ft 1-ft

1-ft SS FNS (or
Secure Seal)Flex

1-ft Flex Pipe

45 Elbow 3-ft 3-ft 5-ft 6-ft

90 Elbow 5-ft 7-ft 12-ft 14-ft

Tee 9-ft 12-ft 19-ft 21-ft

Same as rigid pipe (or

elbows)

0.4-ft

(updsized one diameter)

Same as rigid pipe (or

elbows)

0.6-ft

(updsized one diameter)

Same as rigid pipe (or

elbows)

0.6-ft

(updsized one diameter)

Same as rigid pipe (or

elbows)

N/A

4

Equivalent Vent Length (EVL) specied by the
appliance manufacturer. If specic guidance
is not oered by the appliance manufacturer
regarding EVL for vent components, the
general guidelines in Table 2 may be used for
PolyPro, FNS, FNS W2 and Security Chimney
Secure Seal product.

For sizing of the remaining Cat I appliance
into the B Vent, reference Table 3. This Table
shows B Vent diameter, inner Cat IV liner
diameter, and the resulting annular space in
terms of an "Equivalent" diameter. This data
takes into account ow restriction on the Cat
I ue introduced from the inner ex and has
been experimentally conrmed. Ensure this
"equivalent" diameter is appropriate for your
remaining Cat I appliance via use of Type B
Gas Vent sizing tables / NFPA54 (Chapter 13).
Treat the connector from the Cat I appliance
and the common vent as a single appliance
vent with the height, length, osets, etc
and verify that the tables conrm adequate
capacity of this annular space before
proceeding.

After conrming the combination vent
system is appropriate for your installation,
inspect the physical condition of existing
B Vent. The B vent must be inspected for
evidence of damage, internal ue blockage,
appropriateness of components including
restops, supports, etc. The inspection must
also ensure the original installation meets
current codes for termination location,
height, etc. Clean and repair as needed to
bring the vent system into compliance.

4a

4b 4c

Figure 4

INSTALLATION OF LINER WITHIN B VENT

Reference Fig.3 for the components required.
Inspect the area where the Cat I exhausts
come together- typically a "Tee" or "Wye". It is
critical that when the Cat IV liner is installed,
it maintain a slope of at least 45° downward
towards the appliance (Fig.4) throughout
the vent run- This is to ensure proper ow of
condensate back to the appliance / drain. If
the inlet end of the existing (common) B vent
is a tee, either the ex for the Cat IV appliance
vent must route through the bottom end of
the tee (Fig.4a) or the tee should be replaced
with a "wye" (Fig.4b), so the ex can route
through the inclined snout of the wye (to
maintain proper slope). Do not install per
Fig.4c!

Table 3 - Annular Space- Effective Remaining B Vent Diameter

2" Cat IV Liner Dia 3" Cat IV Liner Dia 4" Cat IV Liner Dia 5" Cat IV Liner Dia

5" B Vent 4" 3" N/A N/A

6" B Vent 5" 4" 4" N/A

7" B Vent 6" 5" 5" 4"

8" B Vent 6" 6" 6" 5"

5

APPLY SEALANT

BIRD-SCREEN

SLIDE FLEX
UP TO
SEAL

Figure 5a- 2" Flex

APPLY SEALANT

APPROX 3/4"

FROM TOP

BIRD-SCREEN

Figure 5b- 3"-5" Flex

If the lower tee or wye needs to be replaced,
determine the existing brand of B Vent. If
the B Vent is DuraVent, the appropriate Tee
or Wye can be purchased and connected as
is. If the B Vent is not DuraVent, purchase a
"Female Adapter" which allows connection to
non-DuraVent B Vent, and the DuraVent tee
or wye desired.

1. Remove the Cat I appliance being
replaced, the associated B Vent pipe, and
existing termination cap.

2. Measure vent run, cut ex to length,
ensure 1 ft of excess ex. Remove burrs from
ex for ease of install.

4. Connect ex to termination cap:
4a. If installing 2" Flex: Flip the
termination cap upside down and apply
a generous amount of high temperature
non-hardening silicone around the outer
ange edge of the FNS Flex Collar (Fig.5a).
Once applied, ip the termination cap back
upright and carefully lower cap onto ex
so that the silicone ange is seated inside
the 2” ex. Tighten hose clamp to secure
the ex to the termination cap.

4b. If installing 3”-5” ex: Run the ex
through the termination cap until ex is
¾” from exit at the top of the cap. Tighten
the hose clamp to secure the ex into
position. Apply a generous bead of high
temperature non-hardening silicone
(Fig.5b) to seal ex to the inner diameter
of the termination cap.

5. Lower cap to B-Vent and ax with

hardware / mount straps to the vent pipe.
Strap can be trimmed if desired.

6. Compress / Install Bird Screen Ring into

Flex collar groove. (Fig.5a/b)

3"-5"

APPLY
SEALANT

TOP (CAP) side of install:

3. Route ex through B Vent, leave 8" excess
at top. Ensure ex does not go beyond 45
degree anywhere along the vent run for
proper condensate handling. Ensure ex is
installed so the arrow goes in direction of
exhaust ow

POLYPRO
/ FLEX
ADAPTER

FIRESTOP

Figure 6- Appliance Side

Connection

6

IMPORTANT

When installing FasNSeal Flex, the
direction of exhaust ow is away
from the appliance. There is an arrow
printed on each section of liner and
components that will point in the
direction of the exhaust gas. You can
conrm the liner is installed correctly
by running your ngernails up the
inside wall of the liner. If the direction
is correct your nails will catch at the
seams of the inner wall. If it is incorrect

your nails will slide smoothly across

the inner surface.

LOWER (Appliance) side of install (Fig.6)

1. Flex should stick outside B Vent minimum
3”, maximum 5” (trim if needed).

2. Apply generous amount of silicone to ex
and PolyPro / Flex adapter (or other approved
DuraVent or Security Chimneys product).
Insert ex into adapter and tighten hose
clamp.

3. Install restop onto adapter, fasten to
B-Vent using supplied hardware.

4. Continue vent run to the appliance per the
appropriate instruction.

MAINTENANCE

Have your venting system checked annually.
This can be done by the same technician
who inspects & services the appliance.
Recommended areas to inspect are as
follows:

- Check areas of the Venting System which
are exposed to the elements for wear or
damage. If damage is found, the components
should be replaced immediately.

- Where possible, look into the Termination
Cap to verify no foreign material is there to
block the vent. Remove any foreign material
found.

- Where practical, inspect joints to verify

Figure 7- Disassembly of Cap

that no Pipe Sections or Fittings have been
disturbed, and consequently loosened. Also
check mechanical supports such as Wall
Straps, support plates, etc for rigidity.

Should the termination need to be removed,
loosen ex hose clamp and unfasten from
B-Vent. If internal access is needed, the four
screws holding the termination top to the
termination base may be removed and the
termination top will lift o (Fig.7).

7

M&G DURAVENT LIMITED LIFETIME WARRANTY

M&G DuraVent, Inc. (“DuraVent”) provides this limited lifetime warranty for all of its products with the exception of Ventinox® (lifetime), and
PolyPro® (ten years). Subject to the limitations set forth below, DuraVent warrants that its products will be free from defects in material or
manufacturing, if properly installed, maintained and used. DuraVent products are fully warranted if installed only by a professional installer.
This Warranty is transferable from the original homeowner to the buyer of the home. This warranty does not cover normal wear and tear,
smoke damage or damage caused by chimney res, acts of God, or any product that was: (1) purchased other than from an authorized
DuraVent dealer, retailer or distributor; (2) modied or altered; (3) improperly serviced, inspected or cleaned; or (4) subject to negligence or
any use not in accordance with the installation instructions included with the product as determined by DuraVent. Installation instructions are
available online at www.duravent.com under Support/Literature and through our Customer Service Department 800-835-4429 or

[e-mail]. This limited lifetime warranty applies only to parts manufactured by DuraVent.

DuraVent provides the following warranties for its products: One Hundred Percent (100%) MSRP 15 years from the date of purchase, and Fifty
Percent (50%) thereafter, except for the following limitations on: all Termination Caps and DuraBlack® are warranted at One Hundred Percent
(100%) for ve years.

All warranty obligations of DuraVent shall be limited to repair or replacement of the defective product pursuant to the terms and conditions
applicable to each product line. These remedies shall constitute DuraVent’s sole obligation and sole remedy under this warranty. This warranty
provides no cash surrender value. The terms and conditions of this warranty may not be modied, altered or waived by any action, inaction or
representation, whether oral or in writing, except upon the express, written authority of an executive ocer of DuraVent.

Corn, bio-fuels, driftwood or other wood containing salt, preservative-treated lumber, plastic and household trash or garbage, or wood pellets
containing such materials must not be burned in the appliance or replace. In case of a chimney re, the chimney must be inspected and
approved by a certied Chimney Sweep before reuse. After each annual inspection, maintenance, and cleaning, the certied Chimney Sweep
must ll out and date the appropriate section of the warranty card provided with the chimney liner.

LIMITATIONS ON INTERNET SALES: Notwithstanding any other terms or conditions of this Limited Lifetime Warranty, DuraVent provides no
warranty for the following specic products if such products are not installed by a qualied professional installer: DuraTech®, DuraPlus HTC®,
DuraChimney® II, PelletVent Pro®, DirectVent Pro®, FasNSeal®, FasNSeal® W2, FasNSeal® Flex, and PolyPro®, and M&G DuraVent’s relining
products including DuraLiner®, DuraFlex® (SW, Pro, 316, 304), and Ventinox®. For purposes of this warranty, a trained professional installer is
dened as one of the following: licensed contractors with prior chimney installation experience, CSIA Certied Chimney Sweeps, NFI Certied
Specialists, or WETT Certied Professionals.

DuraVent must be notied and given the opportunity to inspect defective product prior to replacement under the terms of this limited lifetime
warranty. All warranty claims must be submitted with proof of purchase. Labor and installation costs are not covered under this warranty. To
obtain warranty service contact: DuraVent Warranty Service, 877 Cotting Ct., Vacaville CA 95688, or call 800-835-4429.

WHERE LAWFUL, DURAVENT DISCLAIMS ALL OTHER WARRANTIES, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL DURAVENT BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL,
PUNITIVE OR SPECIAL DAMAGES OR DIRECT OR INDIRECT LOSS OF ANY KIND, INCLUDING BUT NOT LIMITED TO PROPERTY DAMAGE AND
PERSONAL INJURY. DURAVENT’S ENTIRE LIABILITY IS LIMITED TO THE PURCHASE PRICE OF THIS PRODUCT. SOME STATES DO NOT ALLOW
LIMITATIONS ON IMPLIED WARRANTIES, OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE
LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO
HAVE OTHER RIGHTS THAT VARY FROM STATE TO STATE.

For the most up-to-date installation instructions, see

www. duravent.com

REV 3.22.2012

Manufactured in Vacaville CA and Albany NY

Customer Service Support 800-835-4429 707-446-4740 FAX www.duravent.com

PolyPro® and GreenVent® are registered trademarks of M&G DuraVent, Inc.
All rights reserved, ©2012 M&G DuraVent is a member of M&G Group.

820014370- L273C 11/2014