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Direct fired heaters discharge combustion by-products with
the heated air in to the area being heated.  These include
CO, CO

2

, NO, NO

2

, and Ethylene.  These gases can result in

harm to the worker or the plants.

This greenhouse heater has been specificallyveloped for
very low levels of these combustion by-products.  However,
it is necessary to have an exchange of air within the
greenhouse to avoid accumulation of these gases to a
harmful level over an extended period of operating time.

Greenhouses have a natural air leakage factor.  This natural
leakage is influenced by the design and physical condition
of the greenhouse as well as wind conditions and other
factors.  This natural leakage factor can not be relied upon
as being sufficient to provide the necessary air exchange
within the greenhouse.  Proper installation of this heater
must include provision for adequate air exchange as
follows:

Indoor Mounted Heater:

An exhaust fan capable of providing at least 595 
m3/hour of discharge air.

An inlet shuttered louver of at least 774 sq.cm. 
area.

The inlet shutters must be electromachanically 
operated and electrically interlocked with the 
heater such that the heater can not operate if the 
inlet shutters do not open when heating is 
required.

Refer to Indoor Ventilation Requirements in this 
manual.

Outdoor Mounted Heater:

An exhaust shuttered louver of at least 645 sq. cm.
area.

1.

Read all safety precautions and follow L.B. White
recommendations when installing this heater.  If
during the installation or relocating of heater, you
suspect that a part is damaged or defective, call a
qualified service agency for repair or replacement.

2.

Make sure the heater is properly positioned before use
and is hung level.  Observe and obey all minimum safe
distances of the heater to the nearest combustible
materials.  Minimum safe distances are given on the
heater nameplate and on page 4 of this manual.

3.

The heater may be used either indoors or outdoors.
For heaters intended for outdoor installation, the
heater is to be installed at least 45.7 cm. above the
ground or to a height that would prevent snow
blockage of heater’s air inlet.  Refer to instructions
provided in the optional L.B. White outdoor mounting
and ducting kit, part number 23579.

4. The heater must have the proper gas regulator installed

for the application.  A regulator must be connected to
the gas supply so that gas pressure at the inlet to the
gas valve is regulated within the range specified on the
dataplate at all times.  Contact your gas supplier, or the
L.B. White Co., Inc. if you have any questions.

5.

The heater’s gas regulator (with pressure relief valve)
s h o u l d   b e   i n s t a l l e d   o u t s i d e   o f   b u i l d i n g .     A ny
regulators inside the buildings must be properly
vented to the outside.  Local, state and national
codes always apply to regulator installation.  Natural
gas regulators with vent limiting device may be
mounted indoors without venting to outdoors.

6.

All gas pressure regulators must be installed in strict
accordance with the manufacturer’s safety instructions.
These instructions accompany each regulator.

7.

Insure that all accessories that ship within the heater
have been removed from inside of heater and
installed.  This per tains to air diver ters, hose,
regulators, etc.

8.

Make certain that a sediment trap is installed at the
gas valve inlet to prevent foreign materials (pipe
compound, pipe chips and scale) from entering the
gas valve.  Debris blown into the gas valve may cause
that valve to malfunction resulting in a serious gas
leak that could result in a possible fire or explosion
causing loss of products, building or even life.  A
properly installed sediment trap will keep foreign
materials from entering the gas valve and protect the
safe functioning of that important safety component.

9.

Any heater connected to a piping system must have
an accessible, approved manual shut of f valve
installed within 1.83 m. of the heater it serves.

10.

Check all connections for gas leaks using approved
gas leak detectors.  Gas leak testing is performed as
follows:

-- Check all pipe connections, hose connections,

fittings and adapters upstream of the gas
control with approved gas leak detectors.

-- In the event a gas leak is detected, check the

components involved for cleanliness and
proper application of pipe compound before
further tightening.

-- Furthermore tighten the gas connections as

necessary to stop the leak.

-- After all connections are checked and any

leaks are stopped, turn on the main burner.

-- Stand clear while the main burner ignites to

prevent injury caused from hidden leaks that
could cause flashback.

-- With the main burner in operation, check all

connections, hose connections, fittings and
joints as well as the gas control valve inlet and
outlet connections with approved gas leak
detectors.

7

Installation Instructions

GENERAL

WARNING

Fire and Explosion Hazard

Do not use open flame (matches, torches, candles,
etc.) in checking for gas leaks.  

Use only approved leak detectors.  

Failure to follow this warning can lead to fires or
explosions.

Fires or explosions can lead to property damage,
personal injury or loss of life.

Summary of Contents for Therma Grow HW220

Page 1: ...row Greenhouse Heaters View this manual online at www lbwhite com ATTENTION ALL USERS This heater has been tested and evaluated by C S A International in accordance with Canadian Gas Association Stand...

Page 2: ......

Page 3: ...ents paint thinner dust particles or unknown chemicals Failure to follow these instructions may result in a fire or explosion Fire or explosions can lead to property damage personal injury or loss of...

Page 4: ...y questions about the use of the equipment or its application The L B White Co Inc has a policy of continuous product improvement It reserves the right to change specifications and design without noti...

Page 5: ...cally operated and electrically interlocked with the heater to prevent heater operation if air inlet and exhaust outlet do not open when heating is required Model Indoor Mounting Air Exchange Requirem...

Page 6: ...fore you return Properly trained service people must repair the leak check for further leakages and then relight the appliance for you WARNING Do not use this heater for heating human living quarters...

Page 7: ...te this heater with any safety device that has been bypassed Do not operate this heater unless all of these features are fully functioning 6 Do not operate the heater with its door open or panel remov...

Page 8: ...range specified on the dataplate at all times Contact your gas supplier or the L B White Co Inc if you have any questions 5 The heater s gas regulator with pressure relief valve should be installed ou...

Page 9: ...ure you know how to shut off the gas supply to the building and also to the individual heater Contact your fuel gas supplier if you have any questions 17 Any defects found in performing any of the ser...

Page 10: ...rovided in the duct kit Ensure the motorized air inlet and the heater s air inlet are kept free of any blockages FIG 4a Blower Outlet View FIG 4c Side View FIG 4d Alternate Air Inlet Locations ENG BYN...

Page 11: ...IG 6 2 Assemble eyebolts and chain according to the illustration and tighten all eyebolts securely FIG 7 3 Ensure the heater is securely fastened to overhead supports and is hanging level Check crossw...

Page 12: ...ent position the heater fan operates continuously In the vent mode the heater then supplements or provides air circulation within the greenhouse This heat vent capability can be controlled by a buildi...

Page 13: ...GREEN BROWN BROWN YELLOW YELLOW GAS CONTROL VALVE GROUND RED BLACK WHITE GREEN HI LO C BUILDING CONTROLLER HEAT CONTACT TO CONTROL FROM CONTROL LEAVE WIRE NUT ON LEAD HIGH LIMIT SWITCH GAS CONTROL VAL...

Page 14: ...s view is to show general assembly of the components only The regulator must always be mounted so its vent regardless of location on the regulator is always pointed downward 3 Tighten all connections...

Page 15: ...art again and shortly thereafter ignition will occur NOTE It is normal for air to be trapped in the gas hose on new installations The heater may attempt more than one trial for ignition before the air...

Page 16: ...ther flammable vapors and liquids 2 Have your gas supplier check all gas piping annually for leaks or restrictions in gas lines 3 Regulators must be periodically inspected to make sure the regulator v...

Page 17: ...air or a soft dry rag Do not use files drills broaches etc to clean the orifice Doing so may enlarge the hole causing combustion or ignition problems Replace the orifice if it cannot be cleaned proper...

Page 18: ...icates the contacts of the switch have opened 4 Allow the switch cool down for about a minute before firmly pressing the red reset button on the switch 5 Check for electrical continuity across the swi...

Page 19: ...e inlet pressure is correct but the burner manifold pressure does not agree with that specified on the dataplate then the HI and LO heat output feature of the gas control valve requires adjustment 5 T...

Page 20: ...d shield 3 Ensure the igniter is located so the its lip on back side of igniter is resting on the edge of the mounting bracket and the mounting hole in the igniter aligns with the mounting hole in the...

Page 21: ...ermostat Thermostat closes and returns 24 volts to terminal W on ignition control Red light on ignition control is illuminated Ignition control sends flame sense current to flame sensor Ignition contr...

Page 22: ...ed to power supply Check breakers Is proper voltage delivered to selector switch Check all wiring for defects Repair or repalce if needed Yes Does selector switch send voltage to the transformer Check...

Page 23: ...f ignition is not achieved after the third trial the heater will lock out and the ignition control module will present the three time flash pattern Either recycle the heater or wait for heater to atte...

Page 24: ...sary No Is fan wheel plugged with dirt Is there an obstruction in blower outlet preventing air proving switch closure No Are 115 volts sent from ignition control terminal IND to motor relay No If impr...

Page 25: ...e and component Repair or replace as necessary or replace ignition control Provide proper pressure to heater and check with a gauge Check for voltage to switch Check wiring and repair if defective If...

Page 26: ...mbly and housing Repair or replace as necessary Yes Reconnect wires to capacitor Defective capacitor Replace the motor No Yes Are wires disconnected from capacitor No Five Times Rapid On Off cycling o...

Page 27: ...26 Electrical Connection and Ladder Diagram 115 Volt Supply...

Page 28: ...27 230 Volt Supply TRANSFORMER 24 VOLT 120 VOLT...

Page 29: ...box within the appliance that provides an area where burner flame mixes with combustion air thereby providing heat High Limit Switch Safety device wired into the control system which is used to break...

Page 30: ...Parts Identification PARTS SCHEMATIC 29 39 40 41 26 38 25 21 29 27 31 37 36 35 34 33 14 13 15 18 20 19 16 17 6 7 8 9 10 11 12 4 3 2 1 5 28 24 23 22 32 30...

Page 31: ...9 19 Flame Sensor 520139 20 High Limit Switch LP Gas 572501 Natural Gas 505566 21 Heat Chamber LP Gas 572499 Natural Gas 572500 22 Boot Selector Switch 571939 23 Selector Switch w Boot 571906 24 Contr...

Page 32: ...of the equipment and in any event L B White s liability in connection with the equipment including for claims based on negligence or strict liability is limited to the purchase price Some states do no...

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