LAARS Mighty Therm HH-PH Installation Manual
Installation, Operation and Maintenance Instructions Document 1064E
Installation,
Operation and
Maintenance
Instructions for
Mighty Therm
Hydronic Boilers
Model HH-PH
Sizes 175-400
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.
WARNING
If the information in this manual is not 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.
H0147400E
A subsidiary of BRADFORD WHITE Corporation
Page 2
LAARS HEATING SYSTEMS
TABLE OF CONTENTS
SECTION 1.
General Information
1A. Introduction ................................................... 3
1B. Warranty ....................................................... 3
1C. Technical Assistance.................................... 3
SECTION 2.
Installation Instructions
2A. General Information ...................................... 4
2B. Field Assembly ............................................. 4
2C. Site Location................................................. 5
2C-1. Installation Information ................................. 5
2C-2. Outdoor Installation (U.S. Only) .................... 6
2C-3. Flooring - Typical Installation ........................ 6
2D. Combustion and Ventilation
Air Supply ..................................................... 7
2D-1. Outdoor Air Supply ....................................... 7
2D-2. Indoor Air Supply .......................................... 7
2D-3. Exhaust Fans or Vents ................................. 7
2E. Venting of Combustion Products .................. 7
2E-1. General Information ...................................... 7
2E-2. Replacement of Existing Boiler ..................... 8
2F. Water Flow System ...................................... 8
2F-1. Reversible Water Connections ..................... 8
2F-2. Freeze Protection ....................................... 11
2F-3. Pump Requirements ................................... 11
2F-4. Variable Water Flow Systems .................... 13
2F-5. System Pressure Requirements ................. 13
2F-6. Chilled Water Systems ............................... 15
2F-7. System to Boiler Piping .............................. 15
2F-8. Filling the System ....................................... 15
SF-9. Minimum Boiler Temperature ..................... 15
2G. Gas Supply and Piping ............................... 16
2G-1. General Instructions ................................... 16
2G-2. Special Precautions for Propane Gas ........ 16
2H. Electrical Wiring .......................................... 19
SECTION 3.
Operating Instructions
3A. Setting the Temperature Controls .............. 19
3B. Start-Up Procedure .................................... 20
3C. Adjustment for Minimum Input Rate
(Models with Modulating Gas Valve) .......... 20
3D. Hi-Limit Switch Checkout ........................... 20
3E. Shut-Down Procedure ................................ 21
SECTION 4.
Service Instructions
4A. Regular Inspection ..................................... 21
4B. Replacement of Gas Controls .................... 21
SECTION 5.
Parts List for HH and PH Boilers
5A. General Information .................................... 22
5B. Parts List .................................................... 22
Mighty Therm HH-PH Hydronic Boilers
Page 3
SECTION 1.
General Information
1A. Introduction
This manual provides installation and operation
instructions for the Model HH and PH Hydronic
Boilers, Sizes 175 through 400. Review all application
and installation procedures completely before
proceeding with the installation. Experience has
shown that most operating problems are caused by
improper installation.
The HH-PH boilers are offered in a basic
configuration (see Figure 1). On PH boilers the pump
is factory installed. On HH boilers the pump is field
installed.
1B. Warranty
The HH-PH boilers are sold with a limited
factory warranty.
Make all warranty claims to an authorized Laars
representative or directly to the factory. Claims must
TOP VIEW
include the boiler 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 warranty coverage.
Some accessory items are shipped in separate
packages. Inspect everything for damage immediately
upon delivery, and advise the transporter of any
shortages or damage. Any such claims should be filed
with the transporter. The transporter will not accept a
claim from the shipper, Laars.
The warranty does not cover damage caused by
improper installation, operation, or field modification.
1C. Technical Assistance
Consult Laars or your local company
representative with any questions or problems
involving the specification, installation and operation
of Laars equipment. An experienced technical support
staff is ready to assist in assuring the proper
performance and application of Laars products.
V
OPTIONAL
VENT CAP FOR
OUTDOOR USE
CC
DRAFTHOOD
DRAFTHOOD MUST
BE INSTALLED IN
THE FIELD
SIDE VIEW
30-3/16 in. (767mm)
INLET
5-1/2 in.
(140mm)
26-1/2 in.
(673mm)
HEADER
LOCATION
OUTLET
40-9/16 in. (1030mm)
8-1/2 in.
(216mm)
A
INLET OUTLET
B
Gas Connection C* C
Size Water C (Indoor (Indoor V
Connect. U.S. Only w/ Vent w/o Vent Vent
Nat. Propane Size A B (Outdoor) Damper) Damper) Dia.
Size in. mm in. mm in. mm in. mm in. mm in. mm in. mm in. mm in. mm
1
175 ¾ 19 ½ 13 1½ 38 18 457 26½ 673 14
250 ¾ 19 ½ 13 1½ 38 22½ 572 31 787 18
325 ¾ 19 ½ 13 1½ 38 26¾ 679 35¾ 908 19
400 ¾ 19 ½ 13 1½ 38 31¾ 806 40¼ 1022 22
/16357 28½ 724 23½ 597 6 152
1
/16473 30½ 775 24¾ 629 7 178
3
/16488 —— 257/8657 8 203
5
/8575 —— 267/8683 9 229
*Vent damper only required on indoor installations, sizes 175 and 250.
Note: Dimensions may vary.
Figure 1. General Configuration.
Page 4
SECTION 2.
Installation Instructions
2A. General Information
LAARS HEATING SYSTEMS
Follow local regulations with respect to installation
WARNING
of carbon monoxide (CO) detectors and
manufacturer's maintenance schedule of the boiler.
Install the HH-PH boilers in accordance with the
procedures in this manual (or the Laars warranty may
be voided), local codes and ordinances. In the absence
of such codes, install the boilers in accordance with
the latest edition of the National Fuel Gas Code, ANSI
Z223.1. In Canada, the installation must be in
accordance with CAN1-B149.1 or .2 and local codes.
The authority having jurisdiction may require the
installation conform to the Standard for Controls and
Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1. Any changes to the boiler, gas
controls, gas orifices, wiring or draft hood may void
the warranty. If field conditions require change,
consult the factory.
All gas-fired products require correct installation
to assure safe operation. The requirements for boilers
include the following:
1. Field assembly of draft hood and vent cap
(if required – see Section 2B)
2. Appropriate site location (clearances) and
flooring
3. Sufficient combustion and ventilation air
4. Adequate venting of combustion products
5. Adequate water flow
6. Properly sized gas meter and piping
7. Proper electrical wiring
This manual provides the information needed to
meet these requirements. Review all application and
installation procedures completely before continuing
the installation.
2B. Field Assembly
The HH-PH boiler is shipped from the factory
with the top assembly in the low-profile configuration
for outdoor installations.
The HH-PH boiler is design certified for indoor
installation when equipped with a drafthood, which
must be installed without modification. Check the
rating plate on the boiler for the correct Laars part
number.
Follow this procedure to make the conversion:
a. Remove the top filler plate, stamped “HOT,” by
slipping a fine-blade screw driver into the slot at
HOT
HOT
Figure 2. Top Filler Plate.
Figure 3. Adapter Plate.
the rear of the plate and gently prying it up (see
Figure 2).
b. Remove the two screws attaching the adapter
plate to the top assembly and lift it out (see
Figure 3).
c. Remove the vent cap or drafthood from its
package.
d. Disengage the flue transition ring from the stack
extension and place it on top of the collector
assembly as shown in Figure 4.
Figure 4. Flue Transition
Ring.
Figure 5. Vent Cap with
Adapter Plate
e. Slide the adapter plate over the bottom of the
stack extension as shown in Figure 5. Fit the
stack extension down over the flue transition
ring. Seat the adapter plate on the top assembly
and secure it with two screws (see Figure 6).
f. Find the vent damper box which is located in the
boiler package (boiler models 175 to 250 only)
(see Figure 8).
g. Install the vent damper directly to the top of the
draft hood outlet. The damper operator should
face to the front of the boiler, and the flow
direction arrow should point upward. Use the
vent damper wire harness to connect the vent
damper to the boiler. The bracket end of the
harness should be connected to the vent damper
actuator.
Mighty Therm HH-PH Hydronic Boilers
r
Figure 6. Drafthood with
Adapter Plate.
Figure 7. Drafthood Switch
Receptacle.
Page 5
2C. Site Location
2C-1. Installation Information
WARNING
Improper installation or maintenance can cause
nausea or asphyxiation from carbon monoxide in
flue gases which could result in severe injury,
property damage, or death.
Locate the boiler to provide clearances on all
sides for maintenance and inspection. There must also
be minimum distances maintained from combustible
surfaces (see Table 1 and Figure 9).
h. Plug the wiring for the drafthood switch into the
receptacle on the left side of the vent damper box
(see Figure 7).
i. Do not modify the automatic vent damper
device. The venting system must be arranged so
that only the boiler is served by the vent damper
device supplied with the boiler. Provide at least
six inches clearance between the automatic vent
damper and combustible construction, and be
sure to allow access for servicing the damper.
WARNING
Do not force motor operation when the operator is
fastened to the damper by moving the damper
blade, turning the shaft, or turning the position
indicator.
VENT DAMPER
DRAFT HOOD
VENT DAMPER
HARNESS
Indoors Outdoors
Clearance from: inch mm inch mm
Top 37 940 Unobstructed
Water conn. side 12 305 Unobstructed
Opposite side 6 152 6 152
Front Alcove Unobstructed
Rear 6 152 6 152
Vent* 6 152 —
Flooring Combustible Combustible
Service clearance = 36 inches (914mm) at front of heater,
and 18 inches (457mm) at water connection side.
*1" (25mm) if double wall vent is used.
Table 1. Minimum Boiler Clearances
From Combustible Surfaces.
Heater
Closet Installation
(unacceptable)
A closet is any 4 sided enclosure
which is less than 16* times the
total volume of all the gas fired
appliances within the enclosure.
Room Installation
(acceptable)
A room is any enclosure which is
at least 16* times greater than the
total volume of all the gas fired
appliances within the enclosure.
Figure 8. Vent Damper Installation (Models 175 and
250 only).
Alcove Installation
(acceptable)
Heater
* When the cieling height exceeds 8 feet, you are only allowed to consider 8
feet when calculating the total volume of the enclosure.
An alcove suitable for the
installation of a heater is a
restricted section of a room not
separated from the room by a doo
or partition and which meets the
minimum clearances specified in
this manual.
Figure 9. Alcove Installation.
Page 6
LAARS HEATING SYSTEMS
The boiler must be isolated or otherwise
protected from any source of corrosive chemical
fumes, such as trichlorethylene, perchlorethylene,
chlorine, etc. Install the boiler so that the gas ignition
system components are protected from water
(drippings, spraying, rain, etc.) during operation and
service. Locate the boiler on a waterproof floor with a
floor drain and a 6 inch (152 mm) minimum curb on
all four sides to protect the building if boiler repairs
are needed.
2C-2. Outdoor Installation (U.S. Only)
Caution
Outdoor installations are not recommended in
areas where the danger of snow blockage exists.
HH-PH boilers can be installed in the “low-profile,”
grate top configuration as received from the factory,
or with an optional vent cap/stack.
Locate the boiler in an open, unroofed area. Do
not locate the boiler below or adjacent to any doors,
windows, louvers, grills, etc., which connect in any
way with an inhabited area of a building, even though
the access might be through another structure such as
a garage or utility room (see Figure 10 and Table 1).
There must be a minimum of 4 feet (1.2 m)
horizontally between the boiler and any door, window,
or gravity inlet to a building (see Figure 11). Also, the
horizontal clearance should be maintained from any
electric meters, gas meters, regulators, or relief
equipment.
If the boiler is installed close to a structure,
protect it from rain water runoff with rain gutters on
the roof or other measures. Do not locate the boiler
near sprinkler systems that could spray water on it.
Avoid locations where wind deflection off
nearby structures might cause wind loading and
downdraft conditions. Where downdraft conditions
exist, locate the boiler at least 3 feet (0.9 m) from the
structure.
2C-3. Flooring - Typical Installation
All boilers are equipped with a special base, as a
standard part of the boiler. The unit is designed and
certified for installation on combustible flooring.
Never install the boiler on carpeting. Never store
objects on or around the base of the boiler.
For rooftop installation, see Figure 12 through
Figure 14.
WINDOW
OR GRILL
INDOOR
ROOM
Figure 10. Incorrect Outdoor Installation.
4 ft.
(1.2 m)
4 ft.
(1.2 m)
4 ft.
(1.2 m)
Figure 12. Standard Base for Combustible Floor.
Figure 11. Outdoor Location.
Figure 13. Typical Roof Mounting with Standard
Combustible Mount Base.
Mighty Therm HH-PH Hydronic Boilers
Page 7
Required Net Free Opening Area
Directly from Outside
At Top At Bottom
Model in.
175 44 284 44 284
250 63 406 63 406
325 82 529 82 529
400 100 645 100 645
Note: For screens or louvers, add 50%.
Table 2. Air Openings to Outside.
2
cm
2
in.
2
cm
2
Figure 14. Typical Roof Mounting.
2D. Combustion and Ventilation
Air Supply
All indoor installations must have openings to
outside air for combustion, ventilation and dilution of
flue gases from inside the building (see Figure 15 and
Table 2). Laars does not recommend indoor
installations that do not provide combustion air from
outside the building.
Boiler rooms which are confined spaces require
two permanent air supply openings: one within
12 inches (305 mm) of the ceiling, the other within 12
inches (305 mm) of the floor.
NOTE: Check with louver manufacturers for net
free area of louvers. If not available, add 50 percent
for each screen/louver to the net free area. Check all
local codes applicable to combustion air.
2D-1. Outdoor Air Supply
When combustion air comes directly through an
outside wall, each opening must have a minimum free
area of at least one square inch for each 4,000 BTU/h
input of the total input rating of all appliances in the
enclosed area. (In Canada, refer to CGA B149.1
and .2.)
2D-2. Indoor Air Supply
Confined and non-confined areas have different
requirements for installation. Consult the latest edition
of the National Gas Code for installation requirements.
2D-3. Exhaust Fans or Vents
Any equipment which uses air or removes air
from the boiler room can use up the combustion air
supply or reverse the natural draft action of the
venting system. This could cause flue products to
build up in the boiler room. More air must be supplied
to make up for the decrease. This must be designed by
a qualified engineer.
Notes:
1. The drafthood must sit directly on top of the boiler
as shown and must not be altered in any manner.
2. An Underwriters' Laboratories listed vent cap is
required to eliminate downdraft and allow the
boiler to function properly.
3. Use approved roof fitting.
4. Vent damper is required on models 175 and 250.
Figure 15. Indoor Installation Venting.
2E. Venting of Combustion Products
2E-1. General Information
When installed indoors, the drafthood and the
vent damper device (models 175 and 250) must be
connected to a venting system without alteration. The
venting system must be installed by a qualified
installer and in accordance with the latest edition of
ANSI Z223.1. In Canada, the installation must be in
accordance with CAN1-B149.1 or .2, and any local
codes that apply.
The vent pipe must have a listed vent cap and
extend at least 2 feet (0.6 m) above any object within a
10 foot (3.0 m) radius (see Figure 15).
Page 8
LAARS HEATING SYSTEMS
NOTE: Do not use sheet metal screws at the
snap lock joints of Type B gas vents.
Do not weld or bolt the vent pipe to the boiler
drafthood or the vent damper if one is installed. The
weight of the stack must not rest on the boiler. The
drafthood and boiler top must be easily removable for
normal boiler service and inspection.
WARNING
Avoid ending boiler vents near air conditioning or air
supply fans. The fans can pick up exhaust flue
products from the boiler and return them inside the
building, creating a possible health hazard.
Avoid horizontal runs of the vent pipe, and 90
degree elbows, reductions and restrictions. Horizontal
runs should have at least a ¼ inch (6 mm) rise per foot
in the direction of flow. Support a vent connector for
the design and weight of the material used to maintain
clearances and prevent physical damage and
separation of joints.
Always use double-wall or insulated vent pipe
(Type B or equivalent).
WARNING
In cold weather, uninsulated outside vents can chill
the rising flue products, blocking the natural draft
action of the venting system. This can create a
health hazard by spilling flue products into the boiler
room.
fans, including range hoods and bathroom
exhausts, so they will operate at maximum
speed. Do not operate a summer exhaust fan.
Close all fireplace dampers.
4. Place in operation the appliance being inspected.
Follow the lighting instructions for the unit.
Adjust the thermostat so the appliance will
operate continuously.
5. After 5 minutes of main burner operation, test for
spillage at the draft hood relief opening. Use the
flame of a match or candle, or smoke from a
cigarette, cigar, or pipe.
6. The tests should show that each appliance
connected to the common venting system vents
properly. Return all doors, windows, exhaust
fans, fireplace dampers and any other gas-burning
appliances to their previous condition of use.
7. Any improper operation of the common venting
system should be corrected. The installation
should conform with the National Fuel Gas
Code, ANSI Z223.1. When resizing any portion
of the common venting system, the system
should be sized to approach the minimum
practical size. Refer to the tables in Appendix G
in the National Fuel Gas Code, ANSI Z223.1. (In
Canada, at the time the boiler is removed from
the common venting system, the common
venting system should be resized. The
installation should conform to CAN/CGA
B149.1 or .2.)
Avoid oversize vent piping or extremely long
runs of the pipe which may cause too much cooling
and condensation of flue gasses.
2E-2. Replacement of Existing Boiler
At the time of the removal of an existing boiler,
the following steps shall be followed with each
appliance remaining connected to the common venting
system. During the testing of each unit, the other
appliances remaining connected to the common
venting system should not be operated.
1. Seal any unused openings in the common
venting system.
2. Visually inspect the venting system for proper
size and horizontal pitch. Determine that there is
no blockage or restriction, leakage, corrosion, or
other deficiencies which could cause an unsafe
condition.
3. As far as possible, close all building doors and
windows. Also close all doors between the space
in which the appliances remaining connected to
the common venting system are located and the
other spaces of the building. Turn on any clothes
dryer and any appliance not connected to the
common venting system. Turn on any exhaust
2F. Water Flow System
2F-1. Reversible Water Connections
NOTE: This procedure is not recommended for
the PH pump-mounted models.
Laars ships the HH boiler with the water
connections on the right side. The HH boiler can be
installed with the water connections on either side. It
could be necessary, or helpful, to switch the
connections to the left side to improve access for
installation service. Perform this modification
installing the boiler using the following procedures:
1. Remove the front door.
2. If there is a vent cap or drafthood installed, it
must be removed before removing the grate top
assembly. On indoor installations (models 175-
250), the drafthood switch must be disconnected
at the vent damper receptacle on the left side of
the boiler.
3. If the unit is in the low-profile outdoor
configuration, remove the hex-head screws (see
Figure 16) and lift the top assembly straight up.
4. Remove the screws that fastens the flue collector
hold-down clamps and remove the clamps (see
Figure 17).
before
Mighty Therm HH-PH Hydronic Boilers
Page 9
REAR TILE COVER
HEAT EXCHANGER
ASSEMBLY
DRAIN PLUG
DRAIN VALVE
REAR TILE
COVER
HEX HEAD
SCREWS
MANUAL RESET
HIGH LIMIT
SWITCH BOX
Figure 16. Heat Exchanger Removal.
FLOW SWITCH
CONDUIT
GAP CLOSURE
GROMMET
DRAIN
VALVE
METAL CHANNEL
(FOR CAPILLARY TUBE)
TERMINAL STRIP
Bracket
Clamp
Flue Collector
Clamp
In/Out Header
Heat Exchanger
Figure 17. Flue Collector Holddown Clamps.
Bracket
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