Riva PLUS COMBI Installation instructions

Riva
BOILER INSTALLATION, OPERATION
INSTRUCTIONS
Riva
PLUS COMBI
WALL HUNG GAS BOILER FOR
CENTRAL HEATING SUPPLY
Please Read Instructions Carefully
Save for Future Reference
— Do not store or use gasoline or other flammable vapors and liquids
in the vicinity of this or any other appliance.
— 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. Fol-
low the gas supplier’s instructions.
• If you can not reach your gas supplier call the fire department.
— Installation and service must be performed by a qualified installer,
service agency or the gas supplier.
WARNING: If the information in this manual is not followed
exactly, a fire or explosion may result causing property dam-
age, personal injury or loss of life.
Quincy Hydronic Technology, Inc.
3560 Lafayette Road
Bldg. 2, Unit A
Portsmouth, NH 03801
Phone: [phone]
Fax: [phone]

2 RIVA PLUS COMBI MANUAL
Dear Customer:
Thank you for buying a Biasi Riva Plus Combi.
The Riva Plus Combi is a high efficiency condensing, wall mounted gas boiler which provides
central heat supply water.
We realize that it is not possible to answer all questions about the Riva Plus Combi system in
this manual. Reading this installation manual does not make the reader an expert in all aspects
of installation and operation, and does not replace the need for a qualified, licensed heating
contractor. We urge you to contact your installing contractor or distributor if you are in question
about any aspect of your boiler’s performance. Our main concern is that you are satisfied with
your boiler and its performance. We require that your contractor complete efficiency tests using
instruments.
The external controls and accessories listed in this manual (excluding those supplied inside
the boiler) are intended to serve as guidelines rather than specific recommendations. We re-
alize that other makes and models of such devices are available and can be used as suc-
cessfully as those we specify. The installing contractor is the best judge of a system’s specific
requirements, as well as the local availability of certain makes and models of controls and
accessories. The preceding does not apply, however, to the equipment that comes with every
boiler, such as the overheat control and pressure relief valves. The installation of the spe-
cific devices supplied with every boiler is absolutely necessary to the safe operation of
the boiler and protection of the heating system.
All BIASI wall hung boilers are built in accordance with the ASME boiler and pressure vessel
code, and bear the “H” stamp. The Entire range of applications for the Riva Plus Combi has
been tested to standard CSA 4.9 and is CSA compliant.
This Riva Plus Combi has a 2 year warranty, a copy of which is provided with the boiler. Please
be sure to return the warranty registration card as the warranty will be void without your boiler’s
serial numbers (located on the ratings label affixed to the boiler), date of installation and the
name of your installer being on record in our files.
Thank you for purchasing our Riva Plus Combi. If you have questions or comments, please
don’t hesitate to contact us immediately. Our goal is 100% customer satisfaction.
QHT inc.

RIVA PLUS COMBI MANUAL 3
Table of Contents
Section Title Section Number Page Number
Warnings - 5-6
Important Information - 7
General Information 1 8
Technical Information (M135.30CM) 2 8-9
Parts List 3 10
Internal Piping and Parts List 4 11
Electric Diagrams 5 12
Sequence of operation 5.1 13
Installation Location 6 14
Exhaust Pipe Location 7 15
Mounting Bracket 8 16
Venting 9 17-24
Restrictor Sizing 9.1 19
Fitting the Flue System 9.2 19
Choice of Flue 9.3 20-23
Pipe Connections 10 24
Gas Pipe Connections 11 25
Electrical Connections/Wiring 12 26-27
Power Connection 12.1 26
Connection to the Electricity Supply 12.2 26
Room Thermostat Connection 12.3 27
Relay Panel Control Connection 12.4 27
Zone Valve Microswitch Connection 12.5 28
Finishing 12.6 28
Circulator Sizing 13 29
Circ. Cap. as a Function of Flow Rate 13.1 29
Expansion Vessel 13.2 29
Piping 14 30-33

4 RIVA PLUS COMBI MANUAL
Table of Contents
Section Title Section Number Page Number
Primary-Secondary with Zone Valves 14.2 32
Manifold Piping with Zone Valves or Circ. 14.3 33
Commissioning 15 34-40
Initial Filling of the System 15.1 34
Lightning the Boiler 15.2 34
Checking the Gas Pres. at the Burner 15.3 35
Adjustment of the Gas Pressure 15.4 36
Checking the Ignition Device 15.5 36
Checking the Burner Ignition 15.6 37
Adjustment of the Useful c.h. Output 15.7 37
Labels Placement 15.8 37
Checking the Flue System and Comb. 15.9 38
Instructing the User 15.10 39
Gas Conversion 16 40
Annual Maintenance 17 41-43
Warnings 17.1 41
Dismantelling the External Panels 17.2 41
Emptying the C.h. System 17.3 41
Emptying the D.h.w.circuit 17.4 42
Cleanig the Burner. 17.5 42
Checking the combustion fan 17.6 42
Checking the Flue 17.7 42
Checking the press. in the exp.vassel 17.8 43
Visual Inspection of Appliance 17.9 43
Gas Pressures and Soundness 17.10 43
Cleanig the primary heat exchanger 17.11 43
Cleanig the domestic hot water exchanger 17.12 43
Condensate trap 17.13 43
Vent Part Spares 18 44-46
Installer Notes 19 47

RIVA PLUS COMBI MANUAL 5
WARNING
Boiler is certified as an indoor appliance. Do not install boiler outdoors or locate where it will
be exposed to freezing temperatures.
— Do not store or use gasoline or other flammable vapors and liquids in the
vicinity of this or any other appliance.
— 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 build-
ing.
• Immediately call your gas supplier from a neighbor’s phone. Follow the
gas supplier’s instructions.
• If you can not reach your gas supplier call the fire department.
— Installation and service must be performed by a qualified installer, ser-
vice agency or the gas supplier.
WARNING: If the information in this manual is not followed
exactly, a fire or explosion may result causing property dam-
age, personal injury or loss of life.
DANGER
Caution: Do not store or use flammable materials, chemicals or flammable liquids,
especially gasoline, in the vicinity of this heating appliance.
Caution: Should overheating occur or the gas supply fail to shut off, do not turn
off or disconnect the electrical supply to the pump. Instead, shut off the gas
supply at a location external to the appliance.
Caution: Do not use this boiler if any part has been under water. Immediately
call a qualified service technician to inspect the boiler and to replace any part of
the control system and any gas control which has been under water.

6 RIVA PLUS COMBI MANUAL
WARNING
Any appliance that burns natural gas, propane gas, fuel oil, wood or coal is capable of pro-
ducing carbon monoxide (CO). Carbon Monoxide (CO) is a gas which is odorless, colorless
and tasteless but is very toxic. CO is lighter than air and thus may travel throughout the
building.
BRIEF EXPOSURE TO HIGH CONCENTRATIONS OF CO, OR
PROLONGED EXPOSURE TO LESSER AMOUNTS OF CO MAY
RESULT IN CARBON MONOXIDE POISONING. EXPOSURE CAN BE
FATAL AND EXPOSURE TO HIGH CONCENTRATIONS MAY RESULT
IN THE SUDDEN ONSET OF SYMPTOMS INCLUDING
UNCONSCIOUSNESS.
Symptoms of CO poisoning include the following:
dizziness vision problems shortness of breath
headache loss of muscle control unclear thinking
nausea weakness unconsciousness
The symptoms of CO poisoning are often confused with those of influenza, and the highest
incidence of poisoning occurs at the onset of cold weather or during flu season.
A victim may not experience any symptoms, only one symptom, or a few symptoms.
Suspect the presence of carbon monoxide if symptoms tend to disappear when you
leave your home.
The following signs may indicate the presence of carbon monoxide:
• Hot gasses from appliance, venting system pipes or chimney, escaping into the living
space.
• Flames coming out around the appliance.
• Yellow colored flames in the appliance.
• Stale or smelly air.
• The presence of soot or carbon in or around the appliance.
• Very high unexplained humidity inside the building.
If any of the symptoms of CO occur, or if any of the signs of carbon monoxide are
present, VACATE THE PREMISES IMMEDIATELY AND CONTACT A QUALIFIED
HEATING SERVICE COMPANY OR THE GAS COMPANY OR THE FIRE
DEPARTMENT.
ONLY QUALIFIED, LICENSED SERVICE CONTRACTORS SHOULD PERFORM
WORK ON YOUR BIASI RIVA COMBI BOILER.

RIVA PLUS COMBI MANUAL 7
IMPORTANT INFORMATION
Please read this page carefully.
• ALL BOILERS MUST BE INSTALLED IN ACCORDANCE WITH NATIONAL,
STATE AND LOCAL PLUMBING, HEATING AND ELECTRICAL CODES
AND ORDINANCES, AS WELL AS THE REGULATIONS OF THE SERVING
ELECTRICAL, WATER AND GAS UTILITIES.
• All systems should be designed by competent contractors, and only persons
knowledgeable in the layout and installation of heating systems should attempt
the installation of any boiler. It is the responsibility of the installing contractor
to see that all controls are correctly installed and operating properly when the
installation is completed.
• This boiler is intended for use, only with propane or natural gas. All flammable
liquids (especially gasoline), chemicals, rags, paper, wood scraps, debris, etc.,
should be kept away from the boiler at all times. Keep the boiler area clean and
free of all fire hazards.
• Please read the literature and warranties supplied by the manufacturers of the
various accessory equipment. This equipment is warranted by the respective
manufacturers, not by Quincy Hydronic Technologies, Inc. Each piece of
equipment must be installed and used according to the recommendations of
the manufacturer.
Codes and Regulations:
Installation of the boiler and related equipment must conform to national, state and
local regulating agencies and codes applicable to the installation of the equipment. In
the absence of local requirements, the following codes apply:
A. ANSI/NFPA - #70 National Electric Code
B. ANSI/NFPA - #211 Chimneys and Vents
C. ANSI/NFPA - #Z223.1 National Fuel Gas Code
C. ANSI/NFPA - Domestic Gas Conversion Burner
D. CAN/CGA - B149 Installation Codes
E. ANSI/ASME - CSD-1
The above codes are available from:
National Fire Protection Association (NFPA) CSA International
Battery March Park 8501 E. Pleasant Valley Road
Quincy, Massachusetts, 02269 Cleveland, OH 44134-5575
http://www.nfpa.org http://www.csa-international.org

8 RIVA PLUS COMBI MANUAL
1. General Information
2. Technical Information (M135.30CM)
The Riva Plus Combi is a high efficiency condensing, wall mounted gas boiler which provides
central heat. The boiler features a gas valve which modulates the energy input from 49,476
BTU/h to 116,008 BTU/h. The boiler is shipped fully assembled with the components listed on
page 11. All units are pressure and combustion tested at the factory prior to shipping.
Key Features:
• Wall mountable - saving valuable floor
space.
• Several flue options available
• Electronic spark ignition
• Safety flow switch - positioned on the
main circuit, which monitors the flow and
protects the main heat exchanger from
thermal shock should there be a lack of
water in the system.
• Frost protection - contains an integral frost
protection system to prevent frost dam-
age which can occur in areas susceptible
to very cold weather conditions.
• Boiler operation recognition system -
should the boiler not be used for longer
than 24 hours, it then performs a con-
trolled system test to ensuring the motor-
ized components within the boiler do not
become inoperable due to lack of use.
• Gas valve modulation - the gas input
modulates based off central heating tem-
perature to within ± 2 ºF
• Diagnostic information system equipped
with three LED diagnostic lights for quick
error assessment.
GENERAL
Height in 31.6
Width in 15.7
Depth in 13.8
Weight lb 109.5
ELECTRICAL
Voltage V 120
Frequency Hz 60
Current A 1.6
Power consumption W 180
INJECTORS No. Size
Natural 14 130
Propane 14 89
CENTRAL HEATING
Maximum working temp. °F 185
Temp. Regulation range* °F 100-176
Maximum pressure psi 30.0
Minimum pressure psi 4.35
Max head loss (at 4.4 GPM) ft 8.25
*At the minimum useful output

RIVA PLUS COMBI MANUAL 9
2. Technical Information Cont.
ENERGY CAPACITY
Nominal heat input
(0/2000ft) MBH 116.0
Nominal heat input
(2000/4500ft) MBH 110.2
Minimum heat input MBH 49.5
Maximum useful output
(0/2000ft) MBH 102.0
Maximum useful output
(2000/4500ft) MBH 97.2
Minimum useful output MBH 41.6
GAS SUPPLY PRESSURE
Gas Normal Min Max
Natural inwc 7.0 3.5 10.5
Propane inwc 11.0 8.0 13.0
GAS PRESSURE AT BURNER
Gas Min Max Ignition
Natural inwc 1.0 4.8 2.4
Propane inwc 2.0 10.3 5.2
FLUE DESIGN
Minimum Venturi pressure inwc 0.64
Flue pipe diameter
Coaxial in 2.25/4
3.25/5
Twin split pipes in 3.25/3.25
Nominal heat flow rate
(0/2000ft) MBH 116.0
Nominal heat flow rate
(2000/4500ft) MBH 110.2
Min Exhaust temperature °F 140
Max Exhaust temperature °F 180
GAS FLOW RATE
Gas Min Max
Natural ft³/h 48.7 115.1
Propane lb/h 2.2 5.2
CLEARANCE TO COMBUSTIBLES
Front in 18
Back in 0
Top in 8
Sides in 2
Bottom in 8
Flue pipe enclosed in 2
Flue pipe free air in 0
Hot water pipes in 1”
FLUE GAS FIGURES
Gas Min Max
CO22.5% 6.3%
O216.5% 9.7%
DOMESTIC HOT WATER
Maximum temperature °F 131
Minimum temperature °F 95
Maximum pressure psi 145
Minimum pressure psi 4.35
D.h.w. ΔT 45 F (25 C) gpm 4.5
D.h.w. ΔT 54 F (30 C) gpm 3.8
D.h.w. ΔT 63 F (35 C) gpm 3.2
D.h.w. ΔT 72 F (40 C gpm 2.8

10 RIVA PLUS COMBI MANUAL
3. Parts List
Primary Components:
1 Pump
2. Pump vent plug
3. Automatic air purger valve
4. Modulation gas valve
5. Flame-detecting electrode
6. Ignition electrodes
7. Burner
8. Combustion chamber
9. Primary heat exchanger
10. Fan
11. Air pressure switch
12. Air switch pres. Test points
13. Safety thermostat
14. Modulation operator
15. Gas valve outlet pres. Test point
16. Gas valve inlet pres. Test point
17. Central heating expansion vessel
18. Central heating temp. Probe NTC
19. Central heating pressure relief valve
20. Primary circuit flow switch
21. Main circuit drain cock
22. By-pass valve
23. Three-way diverter valve
24. Venturi device
25. Flue outlet pipe
26. Air Intake Pipe
27. Control panel
28. Safety thermostat probe
29. Pressure reducing automatic fill valve
30. Backflow preventer
31. Gas supply line cock
32. Water supply inlet cock
33. Condensate trap
34. Condensing heat exchanger
35. Flue termostat
36. D.h.w heat exchanger
37. D.h.w flow switch
38. Domestic water circuit filter
39. D.h.w flow limiter
40. Domestic hot water temp.probe NTC
41. Domestic cold water inlet valve
42. D.h.w. outlet pipe

RIVA PLUS COMBI MANUAL 11
4. Internal Piping & Parts List
Note: Pressure Relief Valve (#19) should be piped to a drain or to the floor as lose as pos-
sible to a drain.

12 RIVA PLUS COMBI MANUAL
5. Electric Diagrams

RIVA PLUS COMBI MANUAL 13
Is
primary circuit temp higher
than selected temp
Request for heat from
thermostat
Circulator off
Ignition device off
Starts the circulator
Supplies the ignition device
YES
NO YES
NO
Is the boiler in lockout?
Air pressure switch open?
Fan starts
Air pressure switch closed?
Begin wait period
Presence of flame?
Air pressure switch closed?
Starts ignitors
Opens gas valve
Begins ignition timing
Flame presence?
Closes gas valve
Stops fan
Interrupts ignitor
Boiler lockout
End of ignition period?
Interrupt igniter
Gas valve open
Reset push – button
pressed
Flame presence?
Safety thermostat
Opens the circuit?
Flame presence?
Close gas valve
NO
YES
YESNO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
5. Electric Diagrams Cont.
5.1 Sequence of Operation

14 RIVA PLUS COMBI MANUAL
6. Installation Location
The installation location chosen must:
• Comply with all clearances listed below.
• Provide suitable location for the exhaust and intake venting.
• Not be installed in an unheated space.
• Comply with all local codes and standards.
Note: Dimensions shown are minimums. Greater clearances will simplify installation
and service.
Figure 6.1
WARNING: Do not install the boiler on carpeting
If the boiler is to be installed in an enclosed room with no fresh air intake, the room must have
proper vent louvers installed. There should be two louvers, place each within 12” of the ceiling
and floor respectively. Each vent will have a free area of 54 square inches.
8. 0 i n
27.7 in
12.8 in
3. 0 i n
18.0
2. 0 i n
15.8 in
10.0 in
2.0 i n CLOSE T INST
A
LL
A
TI ON
MI N I MU M P ER M
A
N
A
NT
CLE
A
R
A
NCE
FRONTV ISWEIDEVIEWCLOSET
INST
A
LL
A
TI ON
CLOSE T IN ST
A
LL
A
TI ON
SERVICECLE
A
R
A
NCE
Figure 6.2
When choosing an installation location insure the exhaust and intake pipes comply with NFPA
54. The drawing on the next page illustrates the restrictions on exhaust locations.
Note: For boilers in an enclosed space
it is recommended to install a CO
detector in the boiler room.

RIVA PLUS COMBI MANUAL 15
7. Exhaust Pipe Location
CAUTION
EXTERNAL VENT SURFACES ARE HOT.
IT IS RESPONSABILITY OF THE HOMEOWNER TO KEEP THE VENT
TERMINAL CLEAR OF SNOW AND ICE
NOTE: USE ONLY LISTED COMPONENTS SUPPLIED WITH THE BOILER.
SURFACE DISCOLORATION OF THE BUILDING MAY OCCUR DUE TO
IMPROPER INSTALLATION. QHT WILL NOT ACCEPT RESPONSIBILITY OR
LIABILITY FOR SUCH DISCOLORATION.
C - 12 in. minimum 12 in. minimum 3 ft. minimum
12 in. minimum 12 in. minimum
The Exhaust Hood must be installed on the leeward side of house and conform to the
following guidelines:
1. The Vent hood shall not be less than 3 feet above any forced air inlet to the house.
2. The Vent hood shall not be less than 1 feet below, 1 feet horizontally, or 1 foot above any
door, window or gravity inlet into any building.
3. The Vent hood shall not be less than 2 feet from an adjacent building.
4.
The Vent hood shall be not less than 7 feet above grade when located adjacent to public walkway.
5. The Vent hood shall be located so that flue gasses are not directed to jeopardize people,
overheat combustible structures, materials or enter buildings.
6. Minimum of 4 feet horizontal clearance from electric meters, gas meters, regulators and relief
equipment.
7. All joints in system are to be sealed to prevent leakage of products of combustion in
the building.
8. Avoid installing exhaust hood on the North, West, or the side of the house receiving the
prevailing winds.
9.
The vent should not be situated so that the flue gases are directed towards brickwork,siding, or other
construction , in such a manner that may cause damage from heat or condensate from the flue gases

16 RIVA PLUS COMBI MANUAL
8. Mounting Bracket
After a suitable installation location is chosen, verify that the mounting wall is properly braced
and strong enough to support the 110 pound weight of the unit when filled with water.
NOTE: The boiler shall be installed such that the gas ignition system components are
protected from water and liquids in general (dripping,spraying, rain, etc) during
the appliance operation and service.
Use the paper template provided with the boiler to determine the location of the mounting
bracket. Securely mount the bracket to the wall using appropriate hardware for the particular
wall construction.
Mounting Steps:
1. Tape the paper template to the wall in the chosen location. Be sure to level the
template.
2. Pre-drill two holes in the center of the “oval” slots on the mounting bracket, sized for
the hardware being used.
3. Mount the bracket to the wall. Be sure to level the bracket by adjusting the screw in
the vertical slot.
4. Pre-drill the remaining hole in the mounting bracket and secure the final screw.
5. Mark and drill the exhaust/intake pipe holes through the house. If you are using a
coaxial pipe system, drill the hole marked A (ø 4”) in the drawing below and on the
paper template. If you are using a separate pipe system drill holes marked B and C (ø
3.25”) shown below as well as on the paper template.
6. Remove paper template and hang boiler on bracket.
Figure 8.1

RIVA PLUS COMBI MANUAL 17
9. Venting
The Riva Plus Combi is a mechanical draft, side wall vented boiler. There are two side wall
flue options available – separate and coaxial. The coaxial option has one configuration shown
on the next page. The separate option has two possible configurations shown on the follow-
ing pages. There is also a vertical roof venting option. Regardless of what vent kit is installed,
they should all conform to the Provisions for combustion and ventilation air in accordance
with section 5.3, Air for Combustion and Ventilation, of the National Fuel Gas Code,
ANSI Z223.1, or Sections 7.2, 7.3 or 7.4 of CAN/CGA B149, Installation Codes, or appli-
cable provisions of the local building codes.
If the Biasi Riva Plus Combi replaces a boiler that was attached to a common vent system, the
common venting system is likely to be too large for proper venting of the appliances remaining
connected to it. To ensure the remaining appliances will function properly, the test procedure
below should be followed:
At the time of removal of an existing boiler, the following steps shall be followed with each
appliance remaining connected to the common venting system placed in operation, while the
other appliances remaining connected to the common venting system are not in operation.
(a) Seal any unused openings in the common venting system.
(b) Visually inspect the venting system for proper size and horizontal pitch and determine
there is no blockage or restriction, leakage, corrosion and other deficiencies which could
cause an unsafe condition.
(c) Insofar as is practical, close all building doors and windows and all doors between the
space in which the appliances remaining connected to the common venting system are
located and other spaces of the building. Turn on clothes dryers and any appliance not
connected to the common venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate
a summer exhaust fan. Close fireplace dampers.
(d) Place in operation the appliance being inspected. Follow the lighting instructions. Adjust
thermostat so appliance will operate continuously.
(e) Test for spillage at the draft hood relief opening after 5 minutes of main burner operation.
Use the flame of a match or candle, or smoke from a cigarette, cigar or pipe.
(f) After it has been determined that each appliance remaining connected to the common
venting system properly vents when tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas-burning appliance to their previous
condition of use.” (g) Any improper operation of the common venting system should be
corrected so the installation conforms with the National Fuel Gas Code, ANSI Z223.1
and/or CAN/CGA B149, Installation Codes. When resizing any portion of the common
venting system, the common venting system should be resized to approach the mini-
mum size as determined using the appropriate tables in Part 11 of the National Fuel Gas
Code, ANSI Z223.1 and/or CAN/CGA B149, Installation Codes.

18 RIVA PLUS COMBI MANUAL
The Commonwealth of Massachusetts requires compliance with regulation 248 CMR 4.00
and 5.00 for installation of through – the – wall vented gas appliances as follows:
(a) For direct-vent appliances, mechanical-vent heating appliances or domestic hot water equipment,
where the bottom of the vent terminal and the air intake is installed below four feet above grade the
following requirements must be satisfied:
1. If there is not one already present, on each floor level where there are bedroom(s), a carbon
monoxide detector and alarm shall be placed in the living area outside the bedroom(s). The carbon
monoxide detector shall comply with NFPA 720 (2005 Edition).
2. A carbon monoxide detector shall be located in the room that houses the appliance or equipment
andshall:
a. Be powered by the same electrical circuit as the appliance or equipment such that only one
service switch services both the appliance and the carbon monoxide detector;
b. Have battery back-up power;
c. Meet ANSI/UL 2034 Standards and comply with NFPA 720 (2005 Edition);and
d. Have been approved and listed by a Nationally Recognized Testing Laboratory as recognized
under 527 CMR.
3. A Product-approved vent terminal must be used, and if applicable, a Product-approved air intake
must be used. Installation shall be in strict compliance with the manufacturer’s instructions. A copy
of the installation instructions shall remain with the appliance or equipment at the completion of the
installation.
4. A metal or plastic identification plate shall be mounted at the exterior of the building, four feet
directly above the location of vent terminal. The plate shall be of sufficient size to be easily read from
a distance of eight feet away, and read “Gas Vent Directly Below”.
(b) For direct-vent appliances, mechanical-vent heating appliances or domestic hot water equipment
where the bottom of the vent terminal and the air intake is installed above four feet above grade the
following requirements must be satisfied:
1. If there is not one already present, on each floor level where there are bedroom(s), a carbon
monoxide detector and alarm shall be placed in the living area outside the bedroom(s). The
carbon monoxide detector shall comply with NFPA 720 (2005 Edition).
2. A carbon monoxide detector shall:
a. Be located in the room that houses the appliance or equipment;
b. Be either hard-wired or battery powered or both; and
c. Shall comply with NFPA 720 (2005 Edition).
3. A Product-approved vent terminal must be used, and if applicable, a Product-approved
air intake must be used. Installation shall be in strict compliance with the manufacturer’s
instructions. A copy of the installation instructions shall remain with the appliance or
equipment at the completion of the installation.
9. Venting Requirements for the State
of Massachussetts

RIVA PLUS COMBI MANUAL 19
9. Venting Cont.
The Riva is a mechanical draft, side wall vented boiler. There are two flue options
available - separate and coaxial. The coaxial option has one configuration shown
on the next page. The separate option has two possible configurations shown on
the following pages.
9.1 Restrictor Sizing:
Each exhaust option is shipped standard with 3 feet of exhaust pipe, 3 feet of in-
take air pipe. There is also a restrictor kit in which there are some restrictors that
must be placed in exhauset breech of fan on the top of the boiler (Fig. 9.1) accor-
ding to the flue confuguration used.
If additional flue piping is needed for a particular application, it can be ordered
separately in 3 foot increments. Dependin on th efinal flue pipe lenght, an alter-
native restrictor may be required. Refer to the tables 9.1 for proper restrictor ring
sizing.
Separate 3.25/3.25 Restrictor Size
From 3.30 to 49.2 ft (in+out) 45
From 49.2 to 99 ft (in+out) No restrictor
Coaxial 2.5/4.0 Restrictor Size
From 0 to 2.9 ft 82
From 2.9 to 9 ft No restrictor
Table 9.1
9.2 Fitting the flue system:
In general, it has to be taken in consideration that the horizontal section of the
flue pipe must have a slope not less than .3 inches per foot towards the boiler.
In the standard horzontal flue kit the flue pipe is angled with in the air duct
therefore the air duct must be horizontally installed. If one or more exstensions
have to be used they must be adequately supported so that there is no sag in the
flue pipe and a minimum fall of .3 inches per foot toward the boiler is ensured.

20 RIVA PLUS COMBI MANUAL
9. Venting Cont.
9.3 Choice of flue:
The following flue kits are available for connecting to the boiler:
A Standard coaxial horizontal flue kit (Exhaust & intake outside)
Figure 9.3 (Coaxial 2.4/4.0 inches – nominal lenght 3.3 ft)
It can be fitted to allow discharge to the rear or either side of the boiler via the flanged boiler
adapter elbow. Minimum lenght required is 2.9 ft. Maximum equivalent lenght of 8.8 ft can be
achieved utilising extensions. This flue system can only be used to discharge horizontally, it is
not designed to enable termination in the vertical plane.
Installation:
• Drill hole A (on the wall template) through the outside wall that is less than 18”thick.
• Cut the pipe as necessary so that a no more than 6” protrudes from the house.
• Slide the intake and exhaust pipes through the hole.
• Slide one rubber wall trim piece on the pipe from inside and one from outside.
• Connect exhaust (inner) pipe to concentric elbow.
• Connect intake (outer) pipe to concentric elbow.
• Secure elbow to boiler using gasket and four screws provided.
• Secure end cap on the intake pipe outside the house.