Laars PNCH, PNCV Installation Manual

Installation and Operation Instructions Document 1176B

Installation and Operation
Instructions for

™

Pennant

Hydronic Boiler
Model PNCH

Water Heater
Model PNCV

U.S. Reg. 2,765,423

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualified in hot water boiler installation and maintenance. Improper installation and/or operation could
create carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.
Improper installation and/or operation will void the warranty. For indoor installations, as an additional
measure of safety, Laars strongly recommends installation of suitable Carbon Monoxide detectors in the
vicinity of this appliance and in any adjacent occupied spaces.

If the information in this manual is not

WARNING

followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.

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 electrical switch; do not
use any phone in your building.

• Immediately call your gas supplier from a
nearby phone. Follow the gas supplier's
instructions.

• If you cannot reach your gas supplier, call
the fire department.

Installation and service must be performed by
a qualified installer, service agency, or gas
supplier.

Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion ou
pour éviter tout dommage matériel, toute
blessure ou la mort.

Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides inflammables dans
le voisinage de cet appareil ou de tout autre
appareil.

QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:

• Ne pas tenter d’allumer d’appareils.

• Ne touchez à aucun interrupteur. Ne pas vous
servir des téléphones dansle bâtiment où vous
vous trouvez.

• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
du fournisseur.

• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.

L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien qualifié ou
par le fournisseur de gaz.

AVERTISSEMENT

H2214400B

Page 2

LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1. General Information

1.1 Introduction ....................................................... 3

1.2 Model Identification ........................................... 3

1.3 Warranty ........................................................... 4

1.4 Dimensions ....................................................... 4

1.5 Locating the Appliance ..................................... 4

1.6 Locating Pump-Mounted Water Heater

with Respect to Storage Tank(s) ...................... 6

1.7 Locating Pump-Mounted Boiler with

Respect to Return/Supply Header .................... 6

1.8 Locating Appliance for Correct Horizontal Vent/

Ducted Air Distance From Outside Wall ........... 6

SECTION 2. Venting and Combustion Air

2.1 Combustion Air ................................................. 6

2.1.1 Combustion Air From Room ............................. 6

2.1.2 Intake Combustion Air ...................................... 7

2.2 Venting ............................................................. 8

2.2.1 Vent Categories ................................................ 8

2.2.2 Category I Vent ................................................. 8

2.2.3 Common Venting Systems ............................... 8

2.2.4 Category III Vent ............................................... 8

2.3 Locating Vent & Combustion Air Terminals .... 10

2.3.1 Side Wall Vent Terminal ................................. 10

2.3.2 Side Wall Combustion Air Terminal ................ 10

2.3.3 Vertical Vent Terminal .................................... 10

2.3.4 Vertical Combustion Air Terminal ................... 10

2.4 Common Vent Test – Boilers .......................... 10

2.5 Vent Terminals for Outdoor Units ................... 11

SECTION 3. Gas Supply and Piping

3.1 Gas Supply and Piping ................................... 11

SECTION 4A.
Water Connections – Pennant Boiler

4A.1 Heating System Piping:

Hot Supply Connections – Boiler .................... 12

4A.2 Cold Water Make-Up – Boiler ......................... 13

4A.3 Water Flow Requirements – Boiler ................. 13

4A.4 Freeze Protection – Boiler .............................. 13

SECTION 4B. Water Connections –
Pennant Water Heater

4B.1 Water System Piping – Water Heater ............. 14

4B.2 Hot Water Supply Piping – Water Heater ....... 14

4B.3 Water Flow Requirements – Water Heater ..... 14

4B.4 Combined Water Heating (potable)

and Space Heating – Water Heater ................ 14

4B.5 Freeze Protection – Water Heater .................. 15

SECTION 5. Electrical Connections

5.1 Main Power ..................................................... 24

5.2 Temperature Control ...................................... 24

5.2.1 Temperature Control Description.................... 24

5.3 External Staging Control Wiring ...................... 24

SECTION 6. Operating Instructions

6.1 Sequence of Operation ................................... 25

6.2 Filling the Boiler System ................................. 26

6.3 Programming the Temperature Control .......... 27

6.3.1 System Piping ................................................. 27

6.3.2 Choosing the Mode ........................................ 27

6.3.3 Programming .................................................. 28

6.3.4 Choosing the Mode for your Application ......... 30

6.4 Advanced Topics ............................................ 31

6.4.1 Differential: ..................................................... 32

6.4.2 Staging Mode ................................................. 32

6.4.3 Boiler Minimum (BOIL MIN) ............................ 33

6.4.4 Boiler Maximum (BOIL MAX) .......................... 33

6.4.5 Boiler Target Temperature.............................. 33

6.4.6 Pump Operation ............................................. 33

6.4.7 Setpoint Operation .......................................... 33

6.4.8 Dedicated Domestic Hot Water ...................... 34

6.4.9 Outdoor Reset Operation................................ 34

6.4.10 External Boiler Operation ............................. 35

6.4.11 Limit Controls ............................................... 36

6.4.12 Advanced Programming Mode ..................... 36

6.5 Operating the Burner and Set Up ................... 36

6.5.1 Set Up for 0 to 2500 Feet Altitude................... 36

6.5.2 High Altitude Adjustment and Set Up.............. 37

6.6 Shutting Down the Pennant ............................ 37

6.5 To Restart the Pennant................................... 37

SECTION 7. Maintenance

7.1 System Maintenance ...................................... 37

7.2 Appliance Maintenance and

Component Description .................................. 38

7.2.1 Burners ........................................................... 38

7.2.2 Filter................................................................ 38

7.2.3 Gas Valves ..................................................... 38

7.2.4 Manual Reset High Limit Control .................... 38

7.2.5 Automatic Reset High Limit Control ................ 38

7.2.6 Temperature Control ...................................... 39

7.2.7 Ignition Controls .............................................. 39

7.2.8 Ignitors ............................................................ 39

7.2.9 Ignition Sensors .............................................. 39

7.2.10 Transformer .................................................. 39

7.2.11 Blowers ........................................................ 39

7.2.12 Flow Switch .................................................. 39

7.2.13 Heat Exchanger Coil .................................... 39

SECTION 8. Trouble Shooting

8.1 Resolving Lockouts ........................................ 40

8.2 Delayed Ignition – Possible Causes ............... 40

8.3 Short Cycling – Boiler ..................................... 40

8.4 Short Cycling – Water Heater ......................... 41

8.5 High Gas Consumption .................................. 42

8.6 Troubleshooting the Temperature Control ...... 42

8.7 Troubleshooting Pennant Controls ................. 42

SECTION 9. Replacement Parts

9.1 General Information ........................................ 43

9.2 Parts List ......................................................... 43

Pennant

Page 3

SECTION 1.
General Information

USING THIS MANUAL – Because the
Pennant Boilers and Pennant Water Heaters are
identical appliances, with the exception of
materials of manufacture, labels and ultimate use
application, this manual provides information for
the proper installation, operation and maintenance
of both products. Where differences exist between
the application of the appliances and their
operation, the sections pertinent to only one
appliance or the other will be so identified.

In the Commonwealth of Massachusetts, this
appliance must be installed by a licensed plumber or
gas fitter.

WARNING

The Pennant hydronic, boiler or water heater must
be installed in accordance with the procedures
detailed in this manual, or the Laars Heating
Systems warranty may be voided. The installation
must conform to the requirements of the local
jurisdiction having authority, and, in the United
States, to the latest edition of the National Fuel Gas
Code, ANSI Z223.1/NFPA54. In Canada, the
installation must conform to the latest edition of the
Natural Gas and Propane Installation Code, CSA
B149.1 and/or local codes. Where required by the
authority having jurisdiction, the installation of
Pennant appliances must conform to the Standard
for Controls and Safety Devices for Automatically
Fired Boilers, ANSI/ASME CSD-1. Any
modifications to the boiler, its gas controls, or wiring
may void the warranty. If field conditions require
modifications, consult the factory representative
before initiating such modifications.

1.1 Introduction

This manual provides information necessary for
the installation, operation, and maintenance of Laars
Heating Systems Pennant copper tube appliances.
Read it carefully before installation.

All application and installation procedures
should be reviewed completely before proceeding with
the installation. Consult the Laars Heating Systems
factory, or local factory representative, with any issues
or questions regarding this equipment. Experience has
shown that most operating issues are caused by
improper installation.

The Pennant appliance is protected against over
pressurization. A pressure relief valve is fitted to all
appliances. It is installed on the outlet header, at the
water outlet of the appliance.

IMPORTANT: The inlet gas pressure to the appliance
must not exceed 13" W.C. (3.2kPa).

All installations must be made in accordance with:

1) In the U.S., the " National Fuel Gas
Code"ANSI Z223.1/NFPA54, Latest Edition and all
applicable local codes as required by the Authorities
Having Jurisdiction (AHJ), or

2) In Canada, the "Natural Gas and Propane
Installation Code", CSA B149.1, latest edition and all
applicable local codes as required by the AHJ.

All electrical wiring is to be done in accordance with:

1). In the U.S., the "National Electrical Code"
(NEC), ANSI/NFPA 70, latest Edition and all
applicable local codes as required by the AHJ, or

2). In Canada, the “Canadian Electrical Code ­Part 1”, CSA STD. C22.1 and all applicable local
codes as required by the AHJ.

This appliance must be electrically grounded in
accordance with the applicable codes and standards
referenced above.

1.2 Model Identification

Consult the rating plate on the unit. The
following information describes the model number
structure.

12 3 4 5678 9 10 11 12 13 14 15 16

PN C A C 2

SERIES

PN C

USAGE

H

V

SIZE

0 500

0 750

1 000

1 250

1 500

1 750

2 000

FUEL

N

P

ALTITUDE

A

LOCATION

C

FIRING

MODE

K (500/750)

N (1000)

L (1250-2000)

REVISION

2

HEAT

EXCHANGER

B

C

K

N

P

S

OPTIONS

CODE

X

J

L

PUMP

OPTIONS

X

H

N

S

Page 4

Model Character Designation

1-3 Model Series Designation

P N C = Pennant

4 Usage

H = Hydronic
V = Volume Water

5-8 Size

0 5 0 0 = 500,000 BTU/h input
0 7 5 0 = 750,000 BTU/h input
1 0 0 0 = 999,000 BTU/h input
1 2 5 0 = 1,250,000 BTU/h input
1 5 0 0 = 1,500,000 BTU/h input
1 7 5 0 = 1,750,000 BTU/h input
2 0 0 0 = 1,999,000 BTU/h input

9 Fuel

N = Natural Gas
P = Propane

10 Altitude

A = 0-10,000 feet

11 Location

C = Indoor and Outdoor

12 Firing Mode

K = Two-stage (models 500 & 750)
N = Three-stage (model 1000)
L = Four-stage (models 1250 - 2000)

13 Revision

2 = Second version

14 Heat Exchanger

B = Glass-lined CI / copper / brz trim (std. PNCV)
C = Glass-lined cast iron / copper (standard PNCH)
K = Bronze / copper
N = Glass-lined cast iron / cu-nickel
P = Glass-lined cast iron / cu-nickel / brz trim
S = Bronze / cu-nickel

15 Option Code

X = Standard unit
J = CSD-1, FM, IRI, IL
L = MN and LDS (Indoor units only)

16 Pump Options

X = No Pump
H = Pump mounted, hard water pump
N = Pump mounted, normal pump
S = Pump mounted, soft water pump

LAARS Heating Systems

warranty coverage.

Some accessory items are shipped in separate
packages. Verify receipt of all packages listed on the
packing slip. Inspect everything for damage
immediately upon delivery, and advise the carrier of
any shortages or damage. Any such claims should be
filed with the carrier. The carrier, not the shipper, is
responsible for shortages and damage to the shipment
whether visible or concealed.

1.4 Dimensions

See Figure 1.

1.5 Locating the Appliance

The appliance should be located to provide
clearances on all sides for maintenance and inspection.
It should not be located in an area where leakage of
any connections will result in damage to the area
adjacent to the appliance or to lower floors of the
structure.

When such a location is not available, it is
recommended that a suitable drain pan, adequately
drained, be installed under the appliance.

The appliance is design certified by CSA­International for installation on combustible flooring;
in basements; in closets, utility rooms or alcoves.

Pennant Boilers or Water Heaters must never be
installed on carpeting. The location for the appliance

should be chosen with regard to the vent pipe lengths
and external plumbing. The unit shall be installed such
that the gas ignition system components are protected
from water (dripping, spraying, rain, etc.) during
operation and service (circulator replacement, control
replacement, etc.). When vented vertically, the
Pennant must be located as close as practical to a
chimney or outside wall. If the vent terminal and/or
combustion air terminal terminate through a wall, and
there is potential for snow accumulation in the local
area, both terminals should be installed at an
appropriate level above grade.

The dimensions and requirements that are shown
in Table 2 should be met when choosing the locations
for the appliance.

1.3 Warranty

Laars Heating Systems’ Pennant appliances are
covered by a limited warranty. The owner should fill
out the warranty registration card and return it to Laars
Heating Systems.

All warranty claims must be made to an
authorized Laars Heating Systems representative or
directly to the factory. Claims must include the serial
number and model (this information can be found on
the rating plate), installation date, and name of the
installer. Shipping costs are not included in the

Pennant

Page 5

Shipping Weight

Size lbs. kg
500 425 193
750 505 229
1000 615 279
1250 675 306
1500 760 345
1750 825 375
2000 955 434

*Add 55 lbs. (25kg) for pump­mounted units.

Size in cm in cm in cm in cm in cm in cm in cm in cm W V Pipe

A B C D E F G H Conn. Conn. Vent

500 33½ 85 15¾ 40 5¾ 15 29¾ 76 32¾ 83 7¾ 20 8¾ 22 46 11 7 6 15 6 15 6 15

750 45½ 116 21¾ 55 5¾ 15 29¾ 76 32¾ 83 7¾ 20 8¾ 22 58 147 6 15 8 20 6 15
1000 57½ 146 28¾ 73 5¾ 15 29¾ 76 32¾ 83 7¾ 20 7 18 70 178 8 20 10 25 8 20
1250 68 172 34 86 101/826 30¾ 78 29½ 75 8¾ 22 8¾ 22 80 203 8 20 12 30 8 20
1500 78½ 199 39¾ 101 101/826 30¾ 78 29½ 75 8¾ 22 8¾ 22 91 231 8 20 12 30 8 20
1750 89 226 44½ 113 101/826 30¾ 78 29½ 75 8¾ 22 8¾ 22 101 256 8 20 14 36 8 20
2000 99½ 253 49¾ 126 101/826 30¾ 78 29½ 75 8¾ 22 8¾ 22 11 2 284 12 30 14 36 12 30

*Air and vent connections may be on top or back of the Pennant, and are field convertible. Dimensions in inches cm.

Air Vent Horiz.

Figure 1. Dimensional Data.

Page 6

LAARS Heating Systems

Heater Vent Collar Vent Pipe & Pipe Max. Pipe Max. No. Side Wall Side Wall

Size Size Diameter Diameter Length of Elbows Vent Combustion

in. cm in. cm in cm ft. m Part Number Part Number
500 6 15 6 15 6 15 50 15 3 CA001401 20260701
750 8 20 6 15 6 15 50 15 3 CA001401 20260701

1000 10 25 8 20 8 20 50 15 3 CA001402 20260703
1250 12 30 8 20 8 20 50 15 3 CA001403 20260703
1500 12 30 8 20 8 20 50 15 3 CA001403 20260703
1750 14 36 8 20 8 20 50 15 3 CA001403 20260703
2000 14 36 12 30 12 30 50 15 3 CA001404 20260706

Horizontal Air Collar

Terminal Air Terminal

Table 1. Horizontal Vent / Combustion Air Parameters.

1.8 Locating Appliance for Correct

Required Recommended

Appliance Clearance From Service Access

Surface Combustible Material Clearance

inches cm inches cm

Left Side 1 2.5 24 61

Right Side 1 2.5 24 61

Top 1 2.5 12 30

Back 1 2.5 **12** 30**

Front 1 2.5 36 91

Vertical

(Category 1) 6* 15.2*

Vent

Horizontal per UL1738 venting

(Category 3) system supplier’s

Vent instructions

*1" (2.5cm) when b-vent is used.
**When vent and/or combustion air connects to the back,
recommended clearance is 36" (91cm).

Table 2. Clearances.

Horizontal Vent/Ducted Air Distance
From Outside Wall

The forced draft combustion air blower/blowers
in the appliance has/have sufficient power to pull air
and vent properly when the following guidelines for
horizontal air and vent are followed (see Table 1).

NOTE: On models 750-2000, the vent collar size is
larger than the size of the vent pipe that can be used.
Vent collar size and horizontal pipe diameters can be
found in Table 1. The larger vent collar size is to
accommodate Category I (vertical) vent systems.

NOTE: When located on the same wall, the Pennant
combustion air intake terminal must be installed a
minimum of 12" (30cm) below the exhaust vent
terminal and separated by a minimum of 36 inches
(91cm) horizontally.

The air intake terminal must be installed high
enough to avoid blockage from snow, leaves and other
debris.

1.6 Locating Pump-Mounted Water Heater
with Respect to Storage Tank(s)

For best results, a pump-mounted Pennant water

heater should be located within 15 feet (4.6m) of the
storage tank(s). The pump is sized for 30 feet (9.1m)
of piping.

If the appliance must be installed with longer

piping runs, then larger diameter pipe or tubing shall
be used. Consult the factory for assistance.

1.7 Locating Pump-Mounted Boiler with
Respect to Return/Supply Header

For the best results, a pump-mounted Pennant

Boiler should be located within 15 feet (4.6m) of the
supply and return headers. The pump is sized for 30
feet (9.1m) of piping.

If the appliance must be installed with longer

piping runs, then larger diameter tubing shall be used.
Consult the factory for assistance.

SECTION 2.
Venting and Combustion Air

2.1 Combustion Air

Pennant boilers and water heaters must have
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 CSA B149.1,
Installation Codes, or applicable provisions of the
local building codes.

A Pennant appliance may receive combustion air
from the space in which it is installed, or it can be
ducted directly to the unit from the outside.
Ventilation air must be provided in either case.

2.1.1 Combustion Air From Room

In the United States, the most common
requirements specify that the space shall communicate
with the outdoors in accordance with method 1 or 2,
which follow. Where ducts are used, they shall be of
the same cross-sectional area as the free area of the
openings to which they connect.

Pennant

Page 7

Method 1: Two permanent openings, one

commencing within 12 inches (30 cm) of the top and
one commencing within 12 inches (30 cm) of the
bottom, of the enclosure shall be provided. The
openings shall communicate directly, or by ducts, with
the outdoors or spaces that freely communicate with
the outdoors. When directly communicating with the
outdoors, or when communicating to the outdoors
through vertical ducts, each opening shall have a
minimum free area of 1 square inch per 4000 Btu/hr
(5.5 square cm/kW) of total input rating of all
equipment in the enclosure. When communicating to
the outdoors through horizontal ducts, each opening
shall have a minimum free area of not less than
1 square inch per 2000 Btu/hr (11 square cm/kW) of
total input rating of all equipment in the enclosure.
Table 3 shows data for this sizing method, for each
Pennant model.

Method 2: One permanent opening,

commencing within 12 inches (30 cm) of the top of
the enclosure, shall be permitted. The opening shall
directly communicate with the outdoors or shall
communicate through a vertical or horizontal duct to
the outdoors or spaces that directly communicate with
the outdoors and shall have a minimum free area of
1 square inch per 3000 Btu/hr (7 square cm/kW) of the
total input rating of all equipment located in the
enclosure. This opening must not be less than the sum
of the areas of all vent connectors in the confined
space.

Other methods of introducing combustion and
ventilation air are acceptable, providing they conform
to the requirements in the applicable codes listed
above.

In Canada, consult local building and safety
codes or, in absence of such requirements, follow CSA
B149.1.

2.1.2 Intake Combustion Air

The combustion air can be taken through the
wall, or through the roof. When taken from the wall, it
must be taken from out-of-doors by means of the
Laars horizontal wall terminal (see Table 1). When
taken from the roof, a field-supplied rain cap or an
elbow arrangement must be used to prevent entry of
rain water (see Figure 2).

Use single-wall galvanized pipe, per Table 4,
for the combustion air intake (see Table 1 for
appropriate size). Route the intake to the heater as
directly as possible. Seal all joints with tape. Provide
adequate hangers. The unit must not support the
weight of the combustion air intake pipe. Maximum
linear pipe length allowed is 50 feet (15.2m). Three
elbows have been calculated into the 50-foot (15.2m)
linear run. Subtract 10 allowable linear feet (3.0m) for
every additional elbow used (see Table 1). When
fewer than 3 elbows are used, the maximum linear
pipe length allowed is still 50 feet (15.2m).

Term Description

Pipe

Joint

Sealing

Table 4. Required Combustion Air Piping Material.

Single-wall galvanized steel pipe, 24 gauge
minimum (either insulated or non-insulated)

Permanent duct tape or aluminum tape

The connection for the intake air pipe is on the
filter box. The Pennant appliances may have venting
and combustion air ducting attached to the top or the
back. They are shipped with the connections at the
top. For attaching either or both pipes to the back, the
mounting flanges are reversible by removing the
mounting screws and orienting the flanges in the

Boiler Each Opening*
Model Square inches Square cm

500 125 807

750 188 1213
1000 250 1613
1250 313 2020
1500 375 2420
1750 438 2826
2000 500 3226

*Net Free Area in Square Inches / Square cm
Area indicated is for one of two openings; one at floor level and
one at the ceiling, so the total net free area could be double the
figures indicated.

This chart is for use when communicating directly with the
outdoors. For special conditions and alternate methods, refer to
the latest edition of ANSI Z223.1.

Note: Check with louver manufacturers for net free area of
louvers. Correct for screen resistance to the net free area if a
screen is installed. Check all local codes applicable to
combustion air.

Table 3. Combustion Air Openings.

Figure 2. Combustion Air and Vent Through Roof.

Page 8

LAARS Heating Systems

desired position. Replace the screws after positioning
flanges. Run a bead of silicone around the collar and
slide the pipe over the collar. Secure with sheet metal
screws.

In addition to air needed for combustion, air shall
also be supplied for ventilation, including all air
required for comfort and proper working conditions
for personnel. The Pennant loses less than 1 percent of
its input rating to the room, but other heat sources may
be present.

2.2 Venting

2.2.1 Vent Categories

Depending upon desired Pennant venting, it may
be considered a Category I or a Category III
appliance. In general, a vertical vent system will be a
Category I system. However, in rare instances, a
Pennant’s vertical vent system may be considered
Category III. In the U.S., the National Fuel Gas Code
(ANSI Z223.1-Latest Edition), or in Canada the CSA
B149.1 (latest edition), defines a Category I vent
system, and includes rules and tables to size these vent
systems. If the Pennant’s vertical vent system does not
satisfy the criteria for Category I venting, it must be
vented as a Category III system.

All Pennant vent systems which discharge
horizontally (without the use of a power venter) are
considered Category III vent systems.

2.2.2 Category I Vent

When vented as a category I appliance, the vent
system must conform to the National Fuel Gas Code
(ANSI Z223.1-Latest Edition) in the U.S., or in
Canada, to CSA B149.1 (latest edition). The vent
system must be sized and installed for a Category I
Fan-Assisted Appliance.

If chimney height is greater than 25 feet, or if
multiple units are vented into the same vertical vent, a
barometric damper must be installed on each
appliance, such that the flue draft does not exceed
(negative) 0.1" w.c.

If using a power venter for any type of Category
I venting, the draft should be set between (negative)

0.01 and 0.10" w.c.

2.2.3 Common Venting Systems

Pennant units are Category I fan-assisted when
vented vertically and adhering to all applicable codes.
Pennant units are not allowed to be vented into a
common horizontal vent system, unless a properly
sized vent fan is used, and the common vent system is
properly designed by the vent fan manufacturer or a
qualified engineer. When common venting Pennant
fan-assisted unit with other appliances through one
shared vertical duct called a “common vent”, special
care must be taken by the installer to ensure safe
operation. In the event that the common vent is
blocked, it is possible, especially for fan-assisted

devices, to vent backwards through non-operating
appliances sharing the vent, allowing combustion
products to infiltrate occupied spaces. If the

appliances are allowed to operate in this condition,
serious injury or death may occur.

WARNING

Operation of appliances with a blocked common
vent may lead to serious injury or death. Safety
devices must be implemented to prevent blocked
common vent operation. If safe operation of all
appliances connected to a common vent cannot be
assured, including prevention of spillage of flue
gasses into living spaces, common venting should
not be applied, and appliances should each be
vented separately.

It is for this reason that, in addition to following
proper vent sizing, construction and safety
requirements from the National Fuel Gas Code, ANSI
Z223.1 or in Canada, from CSA B149.1 as well as all
applicable local codes, it is required that installers
provide some means to prevent operation with a
blocked common vent. It is suggested that a blocked
vent safety system be employed such that if the switch
from one appliance trips due to excessive stack spill or
backpressure indicating a blocked vent condition, that
all appliances attached to the vent be locked out and
prevented from operating. Note that the Pennant is
equipped with a blocked vent safety (pressure) switch,
as shipped. However, this safety switch has only been
designed and tested to be effective in installations
where the Pennant is vented separately and NOT
common vented with other appliances. As an
additional precaution, it is recommended that a Carbon
Monoxide (CO) alarm be installed in all enclosed
spaces containing combustion appliances. If assistance
is required in determining how a blocked vent safety
system should be connected to a LAARS product,
please call Applications Engineering at the Rochester
phone number listed on back cover of this manual.

Refer to the installation and operating
instructions on all appliances to be common vented for
instructions, warnings, restrictions and safety
requirements. If safe operation of all appliances
connected to a common vent cannot be assured,
including prevention of spillage of flue gasses into
living spaces, common venting should not be applied,
and appliances should each be vented separately.

2.2.4 Category III Vent

When the Pennant is vented with horizontal
discharge, it must be installed per this installation
manual and the venting system manufacturer’s
installation instructions. The vent system must be
sealed stainless steel, per Table 5.

Route the vent pipe to the heater as directly as
possible. Seal all joints and provide adequate hangers

Pennant

U.S. Installations (see note 1) Canadian Installations (see note 2)

A= Clearance above grade, veranda, porch, 12 inches (30 cm) 12 inches (30 cm)

deck, or balcony

B= Clearance to window or door that may be 4 feet (1.2 m) below or to side of opening; 36 inches (91 cm)

opened 1 foot (30 cm) above opening

C= Clearance to permanently closed window See note 4 See note 5

D= Vertical clearance to ventilated soffit located

above the terminal within a horizontal See note 4 See note 5
distance of 2 feet (61cm) from the center
line of the terminal

E= Clearance to unventilated soffit See note 4 See note 5

F= Clearance to outside corner See note 4 See note 5

G= Clearance to inside corner See note 4 See note 5

H= Clearance to each side of center line 3 feet (91 cm) within a height 15 feet above

extended above meter/regulator assembly See note 4 the meter/regulator assembly

I= Clearance to service regulator vent outlet See note 4 3 feet (91 cm)

J= Clearance to nonmechanical air supply inlet

to building or the combustion air inlet to 4 feet (1.2 m) below or to side of opening; 36 inches (91 cm)
any other appliance 1 foot (30 cm) above opening

K= Clearance to a mechanical air supply inlet 3 feet (91 cm) above if within 10 feet (3 m) 6 feet (1.83 m)

horizontally

Vent termination not allowed in this location

Vent termination not allowed in this location for category IV appliances. A vent shall not

L= Clearance above paved sidewalk or paved for category IV appliances. For Category III terminate directly above a sidewalk or paved

driveway located on public property appliances, vent must terminate at least 7 driveway that is located between two single

feet (2.13m) above the sidewalk or driveway. family dwellings and serves both dwellings.

For Category III appliances that do not violate
the previous condition, vent must terminate
at least 7 feet (2.13m) above the sidewalk or
driveway.

M= Clearance under veranda, porch, deck, See note 4 12 inches (30 cm) (see note 3)

or balcony

Notes:

1. In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code.

2. In accordance with the current CSA-B149.1 Installation Codes.

3. Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.

4. For clearances not specified in ANSI Z223.1 / NFPA 54, clearance is in accordance with local installation codes and the requirements of
the gas supplier.

5. For clearances not specified in CSA-B149.1, clearance is in accordance with local installation codes and the requirements of the gas
supplier.

Page 9

Figure 3. Combustion Air and Vent Through Side Wall.

Page 10

LAARS Heating Systems

as required in the venting system manufacturer’s
Installation Instructions. Horizontal portions of the
venting system must be supported to prevent sagging
and may not have any low sections that could trap
condensate. The unit must not support the weight of
the vent pipe. Horizontal runs must slope downwards
not less than ¼ inch per foot (2 cm/m) from the unit to
the vent terminal. Reference Table 1 for the size of the
Category III vent system. Up to three elbows can be
used with 50 linear feet (15.2m) of pipe. Subtract 10
allowable linear feet (3.0m) for every additional elbow
used.

Term Description

Pipe Must comply with UL Standard 1738

such as Type 29-4C Stainless Steel

(either insulated or non-insulated).

Joint Follow vent manufacturer’s instructions

Sealing

Table 5. Required Horizontal Venting Material.

WARNING

The outdoor vent terminal gets hot. Unit must be
installed in such a way as to reduce the risk of
burns from contact with the vent terminal.

2.3 Locating Vent & Combustion Air
Terminals

2.3.1 Side Wall Vent Terminal

The appropriate Laars side wall vent hood must

be used, and is listed in the installation and operation
manual. The terminal provides a means of installing
the vent piping through the building wall, and must be
located in accordance with ANSI Z223.1/NFPA 54
and applicable local codes. In Canada, the installation
must be in accordance with CSA B149.1 or .2 and
local applicable codes. Consider the following when
installing the terminal:

1. Figure 3 shows the requirements for mechanical
vent terminal clearances for the U.S. and Canada.

2. Vent terminals for condensing appliances or
appliances with condensing vents are not
permitted to terminate above a public walkway,
or over an area where condensate or vapor could
create a nuisance or hazard.

3. Locate the vent terminal so that vent gases
cannot be drawn into air conditioning system
inlets.

4. Locate the vent terminal so that vent gases
cannot enter the building through doors,
windows, gravity inlets or other openings.
Whenever possible, locations under windows or
near doors should be avoided.

5. Locate the vent terminal so that it cannot be
blocked by snow. The installer may determine
that a vent terminal must be higher than the
minimum shown in codes, depending upon local
conditions.

6. Locate the terminal so the vent exhaust does not
settle on building surfaces or other nearby
objects. Vent products may damage such
surfaces or objects.

7. If the boiler or water heater uses ducted
combustion air from an intake terminal located
on the same wall, locate the vent terminal at least
3 feet (0.9m) horizontally from the combustion
air terminal, and locate the vent terminal at least
1 foot (0.3m) above the combustion air terminal.

2.3.2 Side Wall Combustion Air Terminal

The Laars side wall combustion air terminal

(listed in Table 1) must be used when the unit takes its
combustion air through a duct from a side wall.
Consider the following when installing the terminal:

1. Do not locate the air inlet terminal near a source
of corrosive chemical fumes (e.g., cleaning fluid,
chlorinated compounds, etc.)

2. Locate the terminal so that it will not be subject
to damage by accident or vandalism.

3. Locate the combustion air terminal so that it
cannot be blocked by snow. The National Fuel
Gas Code requires that it be at least 12 inches
(30 cm) above grade, but the installer may
determine it should be higher, depending upon
local conditions.

4. If the Pennant is side-wall vented to the same
wall, locate the vent terminal at least 3 feet
(0.9m) horizontally from the combustion air
terminal, and locate the vent terminal at least 1
foot (0.3m) above the combustion air terminal
(see Figure 3).

2.3.3 Vertical Vent Terminal

When the unit is vented through the roof, the

vent must extend at least 3 feet (0.9m) above the point
at which it penetrates the roof. It must extend at least 2
feet (0.6m) higher than any portion of a building
within a horizontal distance of 10 feet (3.0m), and
high enough above the roof line to prevent blockage
from snow. When the combustion air is taken from the
roof, the combustion air must terminate at least 12"
(30cm) below the vent terminal (see Figure 2).

2.3.4 Vertical Combustion Air Terminal

When combustion air is taken from the roof, a

field-supplied rain cap or an elbow arrangement must
be used to prevent entry of rain water (see Figure 2).
The opening on the end of the terminal must be at
least 12" (30cm) above the point at which it penetrates
the roof, and high enough above the roof line to
prevent blockage from snow. When the vent
terminates on the roof, the combustion air must
terminate at least 12" (30cm) below the vent terminal.

Pennant

Page 11

2.4 Common Vent Test — Boilers

When an existing boiler is removed from a
common venting system, the common venting system
is likely to be too large for proper venting of the
appliances remaining connected to it.

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.

1. Seal any unused openings in the common

venting system.

2. 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.

3. Insofar as it 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.

4. Place in operation the appliance being inspected.

Follow the lighting instructions. Adjust

thermostat so appliance will operate

continuously.

5. 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.

6. 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 conditions of use.

7. Any improper operation of the common venting

system should be corrected so that the

installation conforms to the National Fuel Gas

Code, ANSI Z223.1/NFPA 54 and/or CSA

B149.1, Installation Codes. When resizing any

portion of the common venting system, the

common venting system should be resized to

approach the minimum size as determined using

the appropriate tables in Part II of the National

Fuel Gas Code, ANSI Z223.1/NFPA 54 and/or

CSA B149.1, Installation Codes.

2.5 Vent Terminals for Outdoor Units

For outdoor applications, the vent and
combustion air openings must be covered with proper
terminals to prevent rain, snow and other objects from

falling into the Pennant.

If local codes allow, outdoor installations may
use 1' of appropriately sized galvanized single wall or
B-Vent and a rain cap for exhaust vent termination in
the default configuration (venting out of the top). An
appropriately sized galvanized 90° ell, positioned with
the opening facing down, may be used on the
combustion air inlet in the default configuration on the
back of the unit. Note that some local codes may
require a higher vertical vent height, extending above
any perimeter fencing, etc. In installations where the
appearance of the vent is objectionable, the low profile
vent terminals in Table 6 may be used.

Part numbers for the low profile terminals to
cover the vent and combustion air openings are shown
in Table 6.

Outdoor Vent Outdoor

Model (Size) Terminal Combustion

Air Terminal

500 20254701 D2007900

750 20254703 D2007900

1000 20254705 D2008000

1250 D2007700 D2008000

1500 D2007700 D2008000

1750 D2007800 D2008000

2000 D2007800 D2008200

Table 6. Vent Terminals for Outdoor Units.

SECTION 3.
Gas Supply and Piping

3.1 Gas Supply and Piping

Gas piping should be supported by suitable
hangers or floor stands, not by the appliance.

The Pennant’s gas train allows the user to pipe
the gas from either the right side or the left side of the
unit. As shipped, the right side of the gas train is
capped off, and there is a manual valve on the left
side. If desired, the manual valve on the left side of the
gas train may be moved to the right side, and the cap
on the right side may be moved to the left.

Review the following instructions before
proceeding with the installation.

1. Verify that the appliance is fitted for the proper

type of gas by checking the rating plate. Pennant

appliances are equipped to operate at elevations

up to 10000 feet (3050m). Pennant appliances

may be adjusted to operate properly at altitudes

above 2500 feet (see Section 6.5.2) and the input

will be reduced if the heating value of the gas

supply is below sea level values.

2. The maximum inlet gas pressure must not exceed

13" W.C (3.2kPa). The minimum inlet gas

pressure is 5" W.C. (1.2kPa).

Page 12

LAARS Heating Systems

Distance from Gas Meter

or Last Stage Regulator

Model and

Gas Type 0-100' 0-31m 100-200' 31-61m 200-300' 61-91m

500 natural 1-1/2" 3.8cm 2" 5.1cm 2" 5.1cm
500 propane 1" 2.5cm 1-1/2" 3.8cm 1-1/2" 3.8cm

750 natural 2" 5.1cm 2" 5.1cm 2-1/2" 6.4cm
750 propane 1-1/2" 3.8cm 1-1/2" 3.8cm 2" 5.1cm

1000 natural 2" 5.1cm 2-1/2" 6.4cm 3" 7.6cm
1000 propane 1-1/2" 3.8cm 2" 5.1cm 2-1/2" 6.4cm
1250 natural 2-1/2" 6.4cm 2-1/2" 6.4cm 3" 7.6cm
1250 propane 2" 5.1cm 2" 5.1cm 2-1/2" 6.4cm

1500 natural 2-1/2" 6.4cm 3" 7.6cm 3" 7.6cm
1500 propane 2" 5.1cm 2-1/2" 6.4cm 2-1/2" 6.4cm
1750 natural 2-1/2" 6.4cm 3" 7.6cm 3" 7.6cm
1750 propane 2" 5.1cm 2-1/2" 6.4cm 2-1/2" 6.4cm

2000 natural 3" 7.6cm 3" 7.6cm 3-1/2" 8.9cm
2000 propane 2-1/2" 6.4cm 2-1/2" 6.4cm 3" 7.6cm

Notes:

1.These figures are based on 1/2" (0.12kPa) water column pressure drop.

2.Check supply pressure and local code requirements before proceeding with work.

3.Pipe fittings must be considered when determining gas pipe sizing.

Table 7. Gas Piping Size.

3. Refer to Table 7, size supply.

4. Run gas supply line in accordance with all
applicable codes.

5. Locate and install manual shutoff valves in
accordance with state and local requirements.

6. A sediment trap must be provided upstream of
the gas controls.

7. All threaded joints should be coated with piping
compound resistant to action of liquefied
petroleum gas.

8. The appliance and its individual shutoff valve
must be disconnected from the gas supply piping
during any pressure testing of that system at test
pressures in excess of 1/2 PSIG (3.45kpa).

9. The unit must be isolated from the gas supply
system by closing its individual manual shutoff
valve during any pressure testing of the gas
supply piping system at test pressures equal to or
less than 1/2 PSIG (3.45kpa).

10. The appliance and its gas connection must be
leak tested before placing it in operation.

11. Purge all air from gas lines.

Warning

Do not use open flame to check for leaks. An open
flame could lead to explosion, which could result in
property damage, serious injury or death.

NOTE: The Pennant appliance and all other gas
appliances sharing the gas supply line must be firing
at maximum capacity to properly measure the inlet
supply pressure. The pressure can be measured at
the supply pressure port on the gas valve. Low gas

pressure could be an indication of an undersized gas
meter, undersized gas supply lines and/or an
obstructed gas supply line.

SECTION 4A.
Water Connections —
Pennant Boiler

4A.1 Heating System Piping:

Hot Supply Connections — Boiler

NOTE: This appliance must be installed in a closed

pressure system with a minimum of 12 psi (82.7kPa)
static pressure at the boiler.

Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with
this appliance. Due to expansion and contraction of
copper pipe, consideration should be given to the type
of hangers used. Rigid hangers may transmit noise
through the system resulting from the piping sliding in
the hangers. It is recommended that padding be used
when rigid hangers are installed. Maintain 1"
clearance to combustibles for hot water pipes.

Pipe the discharge of the relief valve (full size) to
a drain or in a manner to prevent injury in the event of
pressure relief. Install an air purger, an air vent, a
diaphragm-type expansion tank, and a hydronic flow
check in the system supply loop. Minimum fill
pressure must be 12psig (82.7kPa). Install shutoff
valves where required by code.

Pennant

Page 13

Model 20°F 25°F 30°F 35°F
(Size) flow H/L flow H/L flow H/L flow H/L

gpm feet gpm feet gpm feet gpm feet
500 43 1.7 34 1.1 28 0.9 24 0.7
750 64 3.3 51 2.3 43 1.7 36 1.2

1000 85 5.0 68 3.6 57 3.1 49 2.2
1250 106 8.1 85 6.1 71 4.7 61 3.4
1500 128 10.0 102 7.2 85 5.5 73 4.2
1750 N/R N/R 119 10.5 99 8.4 85 5.8
2000 N/R N/R 136 12.5 113 10.4 97 8.3

Metric Equivalent

Model 11°C 14°C 17°C 19°C
(Size) flow H/L flow H/L flow H/L flow H/L

lpm m lpm m lpm m lpm m
500 161 0.5 129 0.3 107 0.3 92 0.2
750 241 1.0 193 0.7 161 0.5 138 0.4

1000 321 1.5 257 1.1 214 0.9 184 0.7
1250 401 2.5 322 1.9 269 1.4 231 1.0
1500 483 3.0 386 2.2 322 1.7 276 1.3
1750 N/R N/R 451 3.2 375 2.6 322 1.8
2000 N/R N/R 515 3.8 429 3.2 368 2.5

Notes: gpm = gallons per minute, lpm = liters per minute,
H/L = headloss, ft = headloss in feet,
m = headloss in meters.
Maximum temperature rise is 35°F (19°C), as shown.
Headloss is for boiler’s heat exchanger only.
N/R = not recommended.

Table 8. Water Flow Requirements - PNCH.

Suggested piping diagrams are shown in Figures
4, 5, 6, 7 and 8. These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.

Note the recommended location of the
temperature sensor on the diagrams; you must provide
a location for the additional sensor shipped with the
Pennant. This sensor may be strapped onto pipe from
1" to 4" diameter, or inserted into an immersion well.

4A.2 Cold Water Make-Up — Boiler

1. Connect the cold water supply to the inlet

connection of an automatic fill valve.

2. Install a suitable back flow preventer between

the automatic fill valve and the cold water

supply.

3. Install shut off valves where required.

NOTE: The boiler, when used in connection with a
refrigeration system, must be installed so the chilled
medium is piped in parallel with the boiler with
appropriate valves to prevent the chilled medium from
entering the boiler.

The boiler piping system of a hot water heating
boiler connected to heating coils located in air
handling appliances where they may be exposed to
refrigerated air circulation must be equipped with flow
control valves or other automatic means to prevent

gravity circulation of the boiler water during the
cooling cycle.

A boiler installed above radiation level, or as
required by the authority having jurisdiction, must be
provided with a low water cutoff device either as a
part of the boiler or at the time of boiler installation.

4A.3 Water Flow Requirements — Boiler

A hydronic heating (closed loop) application re­circulates the same fluid in the piping system. As a
result, no new minerals or oxygen is introduced into
the system. To ensure a proper operating temperature
leading to long boiler life, a flow rate has been
established based on the fluid temperature rise for this
specific size boiler.

Pump-mounted boilers can be ordered for use in
primary secondary piping systems. The pumps used
are sized for the headloss through the heater, plus 30
feet (9.1m) of full-sized piping (same size as boiler
outlet) and a normal number of fittings.

Table 8 specifies water flow rates for boilers,
which will enable the user to size a pump. The
headloss shown is for the heater only, and the user will
need to add the headloss of the system piping to
properly size the pump.

The minimum inlet water temperature for the
Pennant is 120°F (49°C) to avoid condensing on the
copper coils.

4A.4 Freeze Protection — Boiler

Boiler installations are not recommended in areas
where the danger of freezing exists unless proper
precautions are made for freeze protection. A non
toxic, heating system, anti-freeze may be added to the
hydronic system provided that the concentration does
not exceed 50% and the anti freeze contains an anti
foamant. When a 50/50 mixture is used, increase the
water flow requirements by 15%, and increase the
headloss requirements by 20%.

Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a boiler from firing. Any time a
boiler is subjected to freezing conditions, and the
boiler is not able to fire, and/or the water is not able to
circulate, there is a risk of freezing in the boiler or in
the pipes in the system. When water freezes, it
expands. This can result in bursting of pipes in the
system, or damage to the boiler, which could result in
leaking or flooding conditions.

IMPORTANT NOTES: Different glycol products may
provide varying degrees of protection. Glycol products
must be maintained properly in a heating system, or
they may become ineffective. Consult the glycol
specifications, or the glycol manufacturer, for
information about specific products, maintenance of
solutions, and set up according to your particular
conditions.

Page 14

LAARS Heating Systems

SECTION 4B.
Water Connections —
Pennant Water Heater

4B.1 Water System Piping —

Water Heater

Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with
this appliance. Due to expansion and contraction of
copper pipe, consideration should be given to the type
of hangers used. Rigid hangers may transmit noise
through the system resulting from the piping sliding in
the hangers. It is recommended that padding be used
when rigid hangers are installed.

The Pennant can be used with several different
types of readily available storage tanks. A pump draws
water from the storage tank and pumps the water
through the heater and back into the tank. Pump­mounted units have a circulating pump built into the
water heater. The pumps used are sized for the
headloss through the heater, plus 30 feet (9.1m) of
full-sized piping (same size as boiler outlet) and a
normal number of fittings. Pumps used on pump­mounted unit are sized for soft/normal or hard water,
so make sure a pump-mounted unit matches the water
quality of the installation.

Pipe the outlet from the heater’s relief valve such
that any discharge from the relief valve will be
conducted to a suitable place for disposal when relief
occurs. Do not reduce line size or install any valves in
this line. The line must be installed to allow complete
drainage of both the valve and the line.

Suggested piping diagrams are shown in Figures
9, 10, 11 and 12. These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.

Note the recommended location of the
temperature sensor on the diagrams. The Pennant is
shipped with an additional sensor that can be used for
more full-featured domestic water heating control. To
get these features, you must provide a location for the
additional sensor. It can be strapped to a pipe from 1"
to 4" diameter, or inserted into a tank immersion well.

The minimum inlet water temperature for the
Pennant is 120°F (49°C) to avoid condensing on the
copper coils.

4B.2 Hot Water Supply Piping —

Water Heater

Follow the tank manufacturer’s guidelines for
completion of the hot water system connections.

NOTE: A listed temperature and pressure relief
valve listed as complying with the Standard for
Relief Valves and Automatic Gas Shutoff Devices
for Hot Water Supply Systems (ANSI Z21.22 / CSA

4.4) of suitable discharge capacity must be
installed in the separate storage tank system.

If the Pennant water heater is installed in a
closed water supply system, such as one having a
backflow preventer in the cold water supply line, the
relief valve may discharge periodically, due to thermal
expansion. Means (such as a properly-sized expansion
tank) shall be provided to control thermal expansion.
Contact the water supplier or local plumbing inspector
on how to control this situation.

4B.3 Water Flow Requirements —

Water Heater

In a water heating application (an open system),
new water is constantly being introduced. With the
new water comes a fresh supply of minerals that can
be deposited on the unit’s heat exchanger. This is
commonly known as scaling. The amount of minerals
will depend upon the hardness of the water. Water can
also be aggressive, and can erode metals, including
copper, if the water is moved too quickly. The water
flow requirements for the Pennant water heater are
based upon the hardness of the water. The water flow
is kept high enough to prevent scaling, but low enough
to prevent tube erosion. For extremely soft or hard
water, cupro-nickel tubes are available. Contact a
Laars Representative if you have questions or
concerns about water quality.

Pump-mounted water heaters can be ordered
with standard pumps for soft or normal water or with
pumps for hard water. The pumps used are sized for
the headloss through the heater, plus 30 feet (9.1m) of
full-sized piping (same size as heater outlet) and a
normal number of fittings.

Table 9 specifies water flow rates for water
heaters, which will enable the user to size a pump. The
headloss shown is for the heater only, and the user will
need to add the headloss of the piping system to
properly size the pump.

4B.4 Combined Water Heating (potable)

and Space Heating — Water Heater

NOTE: These systems are not allowed in the

Commonwealth of Massachusetts.

Piping and components connected to this water
heater for the space heating application shall be
suitable for use with potable water.

Toxic chemicals, such as used for boiler
treatment, shall not be introduced into the potable
water used for space heating.

This water heater when used to supply potable
water shall not be connected to any heating system or
component(s) previously used with a non-potable
water heating appliance.

When the system requires water for heating at
temperatures higher than required for other uses,

Pennant

SYSTEM
RETURN

Page 15

COLD WATER

MAKE-UP

C

C

PUMP LOCATION FOR
NON-PUMP-MOUNTED UNITS

CAUTION: THIS DRAWING SHOWS SUGGESTED
PIPING CONFIGURATION AND VALVING, CHECK
WITH LOCAL CODES AND ORDINANCES FOR
ADDITIONAL REQUIREMENTS.

LEGEND

THERMOMETER

TEMPERATURE
SENSOR

GLOBE VALVE

CHECK VALVE

PRESSURE REDUCING VALVE
W/ FAST FILL BYPASS

PURGE

VALV E

EXPANSION TANK
WITH AIR SCOOP AND

AUTO AIR VENT

3- WAY VALV E

VALV E

PUMP

PUMP LOCATION FOR PUMP-MOUNTED UNITS

PRIMARY/SECONDARY MANDITORY FOR ALL
VARIABLE FLOW SYSTEMS

INSTALLAIR VENTS AT HIGH POINTS IN SYSTEM
PIPING & SIZING OF EXPANSION TANK

PER TANK MANUFACTURER'S INSTRUCTIONS
DIMENSION "C" (COMMON PIPING) TO BE FOUR

PIPE DIAMETERS, MAX. (NO ELBOWS OR VALVES)
BOILER CIRCUIT PIPING MUST BE EQUAL

TO BOILER WATER CONNECTION SIZE
BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS
PUT BOILER CONTROL SENSOR IN THE SYSTEM

SUPPLY WHEN USING THIS PIPING STYLE.
MINIMUM BOILER INLET WATER TEMPERATURE

MUST BE AT LEAST 120°F.

SYSTEM PUMP

SYSTEM
SUPPLY

Figure 4. Hydronic Piping — Multiple Boilers, Primary Secondary System.

an anti-scald mixing or tempering valve shall be
installed to temper the water for those uses in
order to reduce scald hazard potential.

4B.5 Freeze Protection – Water Heater

Although Pennant water heaters are design­certified for outdoor installations, such installations
are not recommended in areas subject to freezing
temperatures, unless proper precautions are taken.

etc., may prevent a heater from firing. Any time a

heater is subjected to freezing conditions, and the
heater is not able to fire, and/or the water is not
able to circulate, there is a risk of freezing in the
heater or in the pipes in the system. When water

freezes, it expands. This can result in bursting of pipes
in the system, or damage to the heater, which could
result in leaking or flooding conditions.

Contact the local factory representative or Laars

for additional information.

Power outage, interruption of gas supply, failure
of system components, activation of safety devices,

Page 16

LAARS Heating Systems

COLD WATER

MAKE-UP

SYSTEM
RETURN

PUMP LOCATION FOR
NON-PUMP-MOUNTED UNITS

CAUTION: THIS DRAWING SHOWS SUGGESTED
PIPING CONFIGURATION AND VALVING, CHECK
WITH LOCAL CODES AND ORDINANCES FOR
ADDITIONAL REQUIREMENTS.

LEGEND

THERMOMETER

TEMPERATURE
SENSOR

GLOBE VALVE

CHECK VALVE

PRESSURE REDUCING VALVE
W/ FAST FILL BYPASS

PURGE

VALV E

EXPANSION TANK
WITH AIR SCOOP AND
AUTO AIR VENT

3-WAY VALVE

VALV E

PUMP

C

B

A

T1

PUMP LOCATION FOR PUMP-MOUNTED UNITS

PRIMARY/SECONDARY MANDITORY FOR ALL
VARIABLE FLOW SYSTEMS
INSTALLAIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK
PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION "C" (COMMON PIPING) TO BE FOUR
PIPE DIAMETERS, MAX. (NO ELBOWS OR VALVES)

BOILER CIRCUIT PIPING MUST BE EQUAL
TO BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

PUT BOILER CONTROL SENSOR IN THE SYSTEM
SUPPLY WHEN USING THIS PIPING STYLE.

MINIMUM BOILER INLET WATER TEMPERATURE
MUST BE AT LEAST 120°F.

C

B

A

T1

SYSTEM

SYSTEM PUMP

ADJUSTMENT PROCEDURE TO MAINTAIN
120°F INLET TEMP:

1. Turn on boiler and open valves A & B.

2. After steady-state operation, if T1 is less than
slowly close valve B until T1 climbs to

120°F,
120°F.

3. If T1 is greater than 120°F, slowly close

4. Check after system operating temperature

until T1 drops to 120°F.

valve A

has stabilized. Make final adjustments.

SUPPLY

Figure 5. Hydronic Piping — Multiple Boilers, Low Temperature System.

Pennant

PRIMARY/SECONDARY MANDITORY FOR ALL
VARIABLE FLOW SYSTEMS

INSTALLAIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK
PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION "C" (COMMON PIPING) TO BE FOUR
PIPE DIAMETERS, MAX. (NO ELBOWS OR VALVES)

BOILER CIRCUIT PIPING MUST BE EQUAL
TO BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

PUT BOILER CONTROL SENSOR IN THE SYSTEM

PUMP LOCATION FOR PUMP-MOUNTED UNITS

SYSTEM PUMP

MAKE-UP

COLD WATER

PUMP LOCATION FOR
NON-PUMP-MOUNTED UNITS

SUPPLY WHEN USING THIS PIPING STYLE.

MINIMUM BOILER INLET WATER TEMPERATURE
MUST BE AT LEAST 120°F.

C

C

C

C

180°F

180°F

150°F

130°F

NOTES:

1. BOILER LOOP IN EXAMPLE IS MAINTAINED AT 180°F.

2. ZONE THERMOSTATS CAN BE INTERLOCKED WITH BOILER,
SO THAT BOILER FIRES UPON CALL FOR HEAT FROM ANY
ZONE.

3. ZONE PIPING AND INTERLOCK WIRING TO BE DESIGNED
BY SYSTEM ENGINEER.

LEGEND

CHECK VALVE

THERMOMETER

TEMPERATURE
SENSOR

GLOBE VALVE

EXPANSION TANK
WITH AIR SCOOP AND
AUTO AIR VENT

3- WAY VA LVE

VALV E

CAUTION: THIS DRAWING SHOWS SUGGESTED
PIPING CONFIGURATION AND VALVING, CHECK
WITH LOCAL CODES AND ORDINANCES FOR
ADDITIONAL REQUIREMENTS.

PRESSURE REDUCING VALVE
W/ FAST FILL BYPASS

PURGE

VALV E

PUMP

Page 17

Figure 6. Hydronic Piping — One Boiler, Multi-Temperature System.

Page 18

SYSTEM
RETURN

PUMP LOCATION FOR
NON-PUMP-MOUNTED UNITS

LAARS Heating Systems

COLD WATER

MAKE-UP

C

SYSTEM PUMP

SYSTEM
SUPPLY

PUMP LOCATION FOR PUMP-MOUNTED UNITS

CAUTION: THIS DRAWING SHOWS SUGGESTED
PIPING CONFIGURATION AND VALVING, CHECK
WITH LOCAL CODES AND ORDINANCES FOR
ADDITIONAL REQUIREMENTS.

LEGEND

THERMOMETER

TEMPERATURE
SENSOR

GLOBE VALVE

CHECK VALVE

PRESSURE REDUCING VALVE
W/ FAST FILL BYPASS

PURGE

VALV E

EXPANSION TANK
WITH AIR SCOOP AND
AUTO AIR VENT

3- WAY VA LVE

VALV E

PUMP

PRIMARY/SECONDARY MANDITORY FOR ALL
VARIABLE FLOW SYSTEMS

INSTALLAIR VENTS AT HIGH POINTS IN SYSTEM

PIPING & SIZING OF EXPANSION TANK
PER TANK MANUFACTURER'S INSTRUCTIONS

DIMENSION "C" (COMMON PIPING) TO BE FOUR
PIPE DIAMETERS, MAX. (NO ELBOWS OR VALVES)

BOILER CIRCUIT PIPING MUST BE EQUAL
TO BOILER WATER CONNECTION SIZE

BOILER CIRC. PUMP SIZED FOR FLOW THROUGH BOILER

DOTTED DEVICES INDICATE ALTERNATE LOCATIONS

PUT BOILER CONTROL SENSOR IN THE SYSTEM
SUPPLY WHEN USING THIS PIPING STYLE.

MINIMUM BOILER INLET WATER TEMPERATURE
MUST BE AT LEAST 120°F.

Figure 7. Hydronic Piping - Primary-Secondary, Reverse-Return.