Landa MHC3-24324 User manual

9.800-950.0 - BM 07/18/23
Landa MHC
Hot Water - Gasoline Powered - Diesel/Oil Heated
Operator’s Manual
Pressure Washer
SenDEC
TACH/HOUR1/10
MHC43500E
MODELS: MHC3-24324
1.110-087.0
MHC3-30324
1.110-038.0
MHC4-30324
1.110-039.0
MHC4-30324E
1.110-040.0
MHC4-30324E/S
1.110-041.0
MHC4-35324E
1.110-042.0
MHC4-35324E CAL
1.110-084.0
MHC4-35324E/B
1.110-077.0
MHC4-35324E/B CAL
1.110-081.0
For the Landa Dealer nearest
you, consult our web page at
www.landa.com

2Landa MHC 9.800-950.0 - BM
Machine Data Label

3
Table of Contents
Machine Data Label . . . . . . . . . . . . . . . . . . . . . . . . . .2
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
How To Use This Manual . . . . . . . . . . . . . . . . . . . . . 4
Safety
Introduction & Safety Information . . . . . . . . . . . . . . . 5
Important Safety Information. . . . . . . . . . . . . . . . . . .5
Operations
Component Identification . . . . . . . . . . . . . . . . . . . . 10
Assembly Instructions . . . . . . . . . . . . . . . . . . . . . . .12
Operation Instructions. . . . . . . . . . . . . . . . . . . . . . .13
Detergents And General Operating Techniques. . .14
Thermal Pump Protection . . . . . . . . . . . . . . . . . . . .14
Shutdown Instructions. . . . . . . . . . . . . . . . . . . . . . . 15
Maintenance
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
After Extended Storage. . . . . . . . . . . . . . . . . . . . . .16
Engine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 16
Maintenance And Service . . . . . . . . . . . . . . . . . . . .17
Unloader Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Winterizing Procedure. . . . . . . . . . . . . . . . . . . . . . . 17
High Limit Hot Water Thermostat . . . . . . . . . . . . . . 17
Pumps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Cleaning of Coils. . . . . . . . . . . . . . . . . . . . . . . . . . .17
Rupture Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Burner Nozzle . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Landa MHC Oil Burner . . . . . . . . . . . . . . . . . . . . . .18
Landa MHC Burner Air Adjustment. . . . . . . . . . . . .18
Removal of Soot and Heating Coil . . . . . . . . . . . . .19
Coil Re-installation . . . . . . . . . . . . . . . . . . . . . . . . .19
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Preventative Maintenance . . . . . . . . . . . . . . . . . . .23
Landa MHC 9.800-950.0 - BM

4
How To Use This Manual
This manual contains the following sections:
• How to Use This Manual
• Safety
• Operations
• Maintenance
• Parts List
The HOW TO USE THIS MANUAL section will tell you
how to find important information for ordering correct
repair parts.
Parts may be ordered from authorized dealers. When
placing an order for parts, the machine model and
machine serial number are important. Refer to the
MACHINE DATA box which is filled out during the
installation of your machine. The MACHINE DATA box
is located on the inside of the front cover of this manual.
The model and serial number of your machine is
located on a decal attached to the pressure washer.
The SAFETY section contains important information
regarding hazardous or unsafe practices of the
machine. Levels of hazards are identified that could
result in product damage, personal injury, or severe
injury resulting in death.
The OPERATIONS section is to familiarize the operator
with the operation and function of the machine.
The MAINTENANCE section contains preventive main-
tenance to keep the machine and its components in
good working condition. They are listed in this general
order:
• Storage
• Engine Maintenance
• Maintenance And Service
• Unloader Valves
• Winterizing Procedure
• High Limit Hot Water Thermostat
• Pump
• Cleaning of Coils
• Rupture Disk
• Fuel
• Burner Nozzle
• Landa MHC Oil Burner
• Landa MHC Burner Air Adjustment
• Fuel Pressure Adjustment
• Removal of Soot and Heating Coil
• Coil Reinstallation
• Troubleshooting
• Preventative Maintenance
The PARTS LIST section contains assembled parts
illustrations and corresponding parts list. The parts lists
include a number of columns of information:
•REF – column refers to the reference number
on the parts illustration.
•PART NO. – column lists the part number for
the part.
•QTY – column lists the quantity of the part used
in that area of the machine.
•DESCRIPTION – column is a brief description
of the part.
•NOTES – column for information not noted by
the other columns.
NOTE: If a service or option kit is installed on your
machine, be sure to keep the KIT INSTRUCTIONS
which came with the kit. It contains replacement parts
numbers needed for ordering future parts.
NOTE: The manual part number is located on the
lower right corner of the front cover.
Model:
Date of Purchase:
Serial Number:
Dealer:
Address:
Phone Number:
Sales Representative:
Landa MHC 9.800-950.0 - BM

5
Safety
Introduction & Safety Information
Thank you for purchasing this Pressure Washer.
We reserve the right to make changes at any time
without incurring any obligation.
Owner/User Responsibility:
The owner and/or user must have an understanding of
the manufacturer’s operating instructions and warnings
before using this pressure washer. Warning information
should be emphasized and understood. If the operator
is not fluent in English, the manufacturer’s instructions
and warnings shall be read to and discussed with the
operator in the operator’s native language by the
purchaser/owner, making sure that the operator
comprehends its contents.
Owner and/or user must study and maintain for future
reference the manufacturers’ instructions.
The operator must know how to stop the machine
quickly and understand the operation of all controls.
Never permit anyone to operate the engine without
proper instructions.
SAVE THESE INSTRUCTIONS
This manual should be considered a permanent
part of the machine and should remain with it if
machine is resold.
When ordering parts, please specify model and
serial number. Use only identical replacement
parts.
This machine is to be used only by trained
operators.
Important Safety Information
WARNING: To reduce the risk of
injury, read operating instructions
carefully before using.
AVERTISSEMENT: Pour réduire le
risque de blessures, lire attentive-
ment les instructions de
fonctionnement avant l'utilisation.
ADVERTENCIA: Para reducir el
riesgo de lesiones, lea cuidadosa-
mente las instrucciones de operación antes de
usar.
1. Read the owner's manual thoroughly. Failure to
follow instructions could cause malfunction of the
machine and result in death, serious bodily injury
and/or property damage.
2. Know how to stop the machine
and bleed pressure quickly. Be
thoroughly familiar with the
controls.
3. Stay alert — watch what you are
doing.
DANGER: Keep wand, hose, and
water spray away from electric
wiring or fatal electric shock may
result.
AVERTISSEMENT: Garder la lance, le boyau et le jet
d'eau à l'écart de tout câblage électrique ou des
chocs électriques mortels pourraient survenir.
ADVERTENCIA: Mantenga la varilla, la manguera y el
rocío de agua lejos del cableado eléctrico, ya que
podrían producirse descargas eléctricas fatales.
4. All installations must comply with local codes.
Contact your electrician, plumber, utility company
or the selling dealer for specific details
Landa MHC 9.800-950.0 - BM
WARNING
READ SAFETY
INSTRUCTIONS PRIOR
TO INSTALLING OR
SERVICING MACHINE
OPERATIONS
SAFETY
MAINTENANCE
DANGER
KEEP WATER
SPRAY AWAY FROM
ELECTRICAL WIRING.

6
Safety.
WARNING: This machine exceeds
85 db appropriate ear protection
must be worn.
AVERTISSEMENT: Cette machine
excède 85 dB et une protection de
l'ouïe appropriée doit être portée.
ADVERTENCIA: Esta máquina
supera los 85 dB, se debe usar
protección auditiva adecuada.
WARNING: High pressure spray
can cause paint chips or other
particles to become airborne and
fly at high speeds. To avoid
personal injury, eye, face, hand
and foot safety devices must be
worn.
AVERTISSEMENT: Un jet haute
pression peut écailler la peinture
ou provoquer l'émission d'autres particules dans
l'air et leur projection à hautes vitesses. Pour éviter
les lésions corporelles, une protection des yeux,
du visage, des mains et des pieds doit être portée
lors de l'utilisation de cet équipement.
ADVERTENCIA: El rociado a alta presión puede
hacer que las partículas de pintura u otras
partículas se transporten por aire y vuelen a altas
velocidades. Para evitar lesiones personales, se
deben usar dispositivos de seguridad para ojos,
manos y pies.
5. Always wear properly rated eye protection such as
safety goggles or face shield while spraying.
(Safety glasses do not provide full protection.)
6. Keep operating area clear of all persons.
WARNING: Flammable liquids can create fumes
which can ignite, causing property damage or
severe injury.
AVERTISSEMENT: Des liquides inflammables
peuvent produire des vapeurs qui peuvent
s'enflammer, causant ainsi des dommages à la
propriété ou des blessures graves.
ADVERTENCIA: Los líquidos inflamables pueden
generar vapores que pueden encenderse y causar
daños a la propiedad o lesiones graves.
WARNING: Risk of explosion — Operate only where
open flame or torch is permitted.
AVERTISSEMENT: Risque d'explo-
sion-Utiliser uniquement dans des
endroits où l'utilisation d'une
flamme nue ou d'une torche est
permise.
ADVERTENCIA: Riesgo de
explosión. Opere sólo donde se
permitan llamas abiertas o
soplete.
WARNING: Risk of fire — Do not
add fuel when the product is
operating or still hot.
AVERTISSEMENT: Risque
d'incendie-Ne pas ajouter de
carburant pendant que la machine
fonctionner ou est encore chaude.
ADVERTENCIA: Riesgo de
incendio — No agregue combus-
tible cuando el producto está en funcionamiento o
aún está caliente.
WARNING: Do not use gasoline crankcase
drainings or oil containing gasoline, solvents or
alcohol. Doing so will result in fire and/or explo-
sion.
AVERTISSEMENT: Ne pas utiliser d'essence, de
drainage du carter de moteur ou d'essence
contenant de l'huile, de solvants ou de l'alcool.
ADVERTENCIA: No utilice el drenaje del cárter de
gasolina ni aceite que contenga gasolina,
solventes o alcohol. Hacerlo resultará en incendio
y/o explosión.
WARNING: Risk of fire — Do not
Spray flammable liquids.
AVERTISSEMENT: Risque
d'incendie-Ne pas pulvériser de
liquides inflammables.
ADVERTENCIA: Riesgo de
incendio — No rocíe líquidos
inflamables.
7. Allow engine to cool for 2
minutes before refueling. If any fuel is spilled, make
sure the area is dry before testing the spark plug or
starting the engine. (Fire and/or explosion may
occur if this is not done.)
Gasoline engines on mobile or portable equipment
shall be refueled:
a. outdoors;
b. with the engine on the equipment stopped;
Landa MHC 9.800-950.0 - BM
WARNING
EAR PROTECTION
MUST BE WORN
WARNING
USE PROTECTIVE
EYE WEAR
AND CLOTHING
WHEN OPERATING
THIS EQUIPMENT.
WARNING
RISK OF EXPLOSION:
OPERATE ONLY WHERE
OPEN FLAME OR TORCH
IS PERMITTED
WARNING
RISK OF FIRE.
DO NOT ADD FUEL
WHEN OPERATING
MACHINE.
WARNING
RISK OF FIRE.
DO NOT SPRAY
FLAMMABLE LIQUIDS

7
Safety
c. with no source of ignition within 10 feet of
the dispensing point; and
d. with an allowance made for expansion of the
fuel should the equipment be exposed to a
higher ambient temperature.
In an overfilling situation, additional precautions
are necessary to ensure that the situation is
handled in a safe manner.
WARNING: Risk of injury. Disconnect battery
ground terminal before servicing.
AVERTISSEMENT: Risque de blessures.
Débrancher la borne de mise à la terre de la batterie
avant de procéder à des opérations d'entretien.
ADVERTENCIA: Riesgo de lesion. Desconecte la
terminal de tierra de la bateria, antes de realizar
servicio.
8. When in use, do not place machine near
flammable objects as the engine is hot.
9. Oil burning appliances shall be installed only in
locations where combustible dusts and flammable
gases or vapors are not present. Do not store or
use gasoline near this machine.
Use heating oil or diesel. If diesel is used, it is recom-
mended to add a soot remover to every tankful to
reduce soot build up on the heating coil.
10. Use No. 1 or No. 2 heating oil (ASTM D306) only.
NEVER use gasoline in your fuel oil tank. Gasoline
is more combustible than fuel oil and could result in
a serious explosion. NEVER use crankcase or
waste oil in your burner. Fuel unit malfunction could
result from contamination.
11. Do not confuse gasoline and fuel oil tanks. Keep
proper fuel in proper tank.
WARNING: Risk of injury. Hot
surfaces can cause burns. Use
only designated gripping areas of
spray gun and wand. Do not place
hands or feet on non-insulated
areas of the pressure washer.
AVERTISSEMENT: Risque de bles-
sures. Les surfaces chaudes
peuvent causer des brûlures.
Utiliser uniquement les zones de
prise désignées du pistolet pulvérisateur et de la
lance. Ne pas placer les mains ou les pieds sur des
endroits non isolés de la laveuse à pression.
ADVERTENCIA: Riesgo de lesiones. Las superfi-
cies calientes pueden causar quemaduras. Use
sólo las áreas de agarre designadas de la pistola
rociadora y la varilla. No coloque las manos o los
pies en áreas sin aislamiento de la lavadora a
presión.
12. Transport/Repair with fuel tank EMPTY or with fuel
shut-off valve OFF.
WARNING: Hot discharge fluid. Do
not touch or direct discharge
stream at persons or animals or
severe injury or death will result.
AVERTISSEMENT: Liquide de
décharge chaud. Ne pas toucher
ou décharger directement le jet
vers des personnes ou des
animaux, car cela risquerait de
causer des blessures graves ou même la mort.
ADVERTENCIA: Fluido de descarga caliente. No
toque ni dirija el flujo de descarga a las personas.
WARNING: This machine produces hot water and
must have insulated components attached to
protect the operator.
AVERTISSEMENT: Cette machine produit de l'eau
chaude et doit comporter des composants isolés
attachés pour protéger l'opérateur.
ADVERTENCIA: Esta máquina produce agua
caliente y se deben tener componentes aislados
para proteger al operador.
13. To reduce the risk of injury, close supervision is
necessary when a machine is used near children.
Do not allow children to operate the pressure
washer. This machine must be attended during
operation.
Landa MHC 9.800-950.0 - BM
WARNING
RISK OF INJURY.
HOT SURFACES
CAN CAUSE BURNS
WARNING
HOT DISCHARGE FLUID:
DO NOT TOUCH OR
DIRECT DISCHARGE
STEAM AT PERSONS
OR ANIMALS.

8
Safety
WARNING: Grip cleaning wand
securely with both hands before
starting. Failure to do this could
result in injury from a whipping
wand.
AVERTISSEMENT: Agripper la
lance de nettoyage avec les deux
mains avant de commencer. Le
non-respect de cette consigne
pourrait mener à des blessures
causées par le mouvement violent de la lance.
ADVERTENCIA: Sujete la lanza de limpieza firme-
mente con ambas manos antes de comenzar. De lo
contrario, podría sufrir lesiones a partir de un
latigueo de la lanza.
14. Never make adjustments on machine while in oper-
ation.
15. Be certain all quick coupler fittings are secured
before using pressure washer.
WARNING: High pressure developed
by these machines will cause
personal injury or equipment
damage. Keep clear of nozzle. Use
caution when operating. Do not
direct discharge stream at people or
animals, or severe injury or death
will result.
AVERTISSEMENT: La haute pression
générée par ces machines causera
des lésions corporelles ou des dommages à l'équipe-
ment. Se tenir à l'écart de la buse. Faire preuve de
prudence lors de l'utilisation. Ne pas décharger
directement le jet vers des personnes ou des animaux,
car cela risquerait de causer des blessures graves ou
même la mort.
ADVERTENCIA: La alta presión desarrollada por estas
máquinas causará lesiones personales o daños al
equipo. Manténgase alejado de la boquilla. Tenga
cuidado al operar. No dirija el flujo de descarga a las
personas, ya que se producirán lesiones graves o la
muerte
WARNING: Protect machine from
freezing.
AVERTISSEMENT: Protéger la
machine contre le gel.
ADVERTENCIA: Proteja la máquina
contra congelamiento.
16. To keep machine in best operating conditions, it is
important you protect machine from freezing. Failure to
protect machine from freezing could cause malfunction
of the machine and result in death, serious bodily injury,
and/or property damage. Follow storage instructions
specified in this manual.
17. Inlet water must be clean fresh water and no hotter
then 90°F.
DANGER: Risk of asphyxiation. Use
this product only in a well venti-
lated area.
DANGER: Risque d'asphyxie.
Utiliser ce produit uniquement dans
un endroit bien ventilé.
ADVERTENCIA: Riesgo de asfixia.
Use este producto sólo en un área
bien ventilada.
18. Avoid installing machines in
small areas or near exhaust fans. Adequate
oxygen is needed for combustion or dangerous
carbon monoxide will result.
19. Manufacturer will not be liable for any changes
made to our standard machines or any compo-
nents not purchased from us.
20. The best insurance against an accident is precau-
tion and knowledge of the machine.
WARNING: Be extremely careful
when using a ladder, scaffolding or
any other relatively unstable
location. The cleaning area should
have adequate slopes and drainage
to reduce the possibility of a fall due
to slippery surfaces.
AVERTISSEMENT: Faire preuve
d'une extrême prudence au moment
d'utiliser une échelle, des
échafaudages ou toute autre surface
relativement instable. La zone de nettoyage doit avoir
une pente et un drainage adéquats pour réduire la
possibilité d'une chute due à une surface glissante.
ADVERTENCIA: Tenga mucho cuidado al usar una
escalera, andamios o cualquier otra ubicación
relativamente inestable. El área de limpieza debe
tener pendientes y drenaje adecuados para reducir la
posibilidad de una caída debido a las superficies
resbaladizas.
21. Do not allow acids, caustic or abrasive fluids to
pass through the pump.
Landa MHC 9.800-950.0 - BM
WARNING
RISK OF INJURY
FROM FALLS WHEN
USING LADDER.
DANGER
RISK OF
ASPHYXIATION.
USE THIS PRODUCT
ONLY IN A WELL
VENTILATED AREA.
WARNING
PROCTECT FROM
FREEZING
WARNING
RISK OF INJECTION
OR SEVERE INJURY
TO PERSONS. KEEP
CLEAR OF NOZZLE.
WARNING
TRIGGER GUN KICKS
BACK — HOLD WITH
BOTH HANDS

9
Safety
22. Never run pump dry or leave spray gun closed
longer than 1-2 minutes.
23. Machines with shut-off spray gun should not be
operated with the spray gun in the off position for
extensive periods of time as this may cause
damage to the pump.
24. Protect discharge hose from vehicle traffic and
sharp objects. Inspect condition of high pressure
hose before using or bodily injury may result.
25. Before disconnecting discharge hose from water
outlet, turn burner off and open spray gun to
allow water to cool below 100ºF before stopping
the machine. Then open the spray gun to relieve
pressure. Failure to properly cool down or maintain
the heating coil may result in a steam explosion.
26. Do not overreach or stand on unstable support.
Keep good footing and balance at all times.
27. Do not operate this machine when fatigued or
under the influence of alcohol, prescription medica-
tions, or drugs.
28. Use only kerosene, No. 1 home heating fuel, or
diesel in burner fuel tank. If diesel is used, add a
soot remover to every tankful.
WARNING: Do not spray machine or
any people, animals or electrical
parts.
AVERTISSEMENT: Ne pas vaporiser
sur la machine ou les gens, les
anomaux ou les pièces électriques.
ADVERTENCIA: No rocíe la
máquina ni a las personas,
animales o partes eléctricas.
Follow the maintenance instructions
specified in the manual.
Landa MHC 9.800-950.0 - BM
WARNING
DO NOT SPRAY
MACHINE OR ANY
PEOPLE, ANIMALS OR
ELECTRICAL PARTS.

10
Operations
Landa MHC 9.800-950.0 - BM
Pump — Delivers a specific gpm to the high pressure
nozzle which develops pressure.
Spray Gun — Controls the application of water and
detergent onto cleaning surface with trigger device.
Includes safety latch.
Detergent Injector — Allows you to siphon and mix
detergents.
Wand — Must be connected to the spray gun.
High Pressure Hose — Connect one end to water
pump high pressure discharge nipple and the other end
to spray gun.
Rupture Disk — Secondary pressure release in the
unlikely event the unloader valve fails.
Unloader Valve — Safety device which, when the
spray gun closes, prevents over pressurization (not
shown).
NOTE: If trigger on spray gun is released for more
than 2 minutes, water will leak from the pump
protector. Warm water will discharge from pump
protector onto floor. This system prevents internal
pump damage
Component Identification
SenDEC
TACH/HOUR1/10
MHC43500E
Water Supply
Hose
(not included)
Variable Pressure
Control Wand
Trigger
Control Wand
Handle
Nozzle
Quick
Coupler
Wand
Coupler
Brass Soap
Nozzle
Spray Gun
High Pressure
Hose
Discharge
Manifold
Gasoline
Tank
Thermostat
Quick
Coupler
Fuel Oil Tank
Pump and
Unloader Valve
Burner
Switch
Battery
Box

11
Operations
Component Identification - MHC3-24324
High
Pressure
Nozzle
Quick
Coupler
Brake
Fuel Oil
Tank
Oil
Burner
Spray
Gun
Control Handle
High Pressure
Hose
Detergent Bucket
(not included)
Brass Soap
Nozzle
Variable Pressure
Control Wand
Burner
Switch
Thermostat
Garden Hose
Inlet Connector
Strainer
Water Supply
Hose
(not included)
Hour Meter
Stackless Top
Adapter Kit
Stackless Top
Adapter Kit
Gasket
8.717-425.0
Flue Adapter
8.717-745.0
(Optional 8.903-430.0)
High
Pressure
Hose
Discharge
Nipple
Coupler
Collar
Detergent
Injector
Landa MHC 9.800-950.0 - BM

12
Operations
Assembly Instructions
STEP 1: Attach a 3/4" garden hose
to inlet connector. Minimum flow
should be 5 gpm.
STEP 4: Check oil level on sight
glass on side of pump. Oil should
be visible one-half way up sight
glass (SAE 10W-40 non-foaming).
The oil level can also be checked
by using the dipstick on the top of
the pump.
STEP 2: Attach high pressure hose
to discharge nipple using quick
coupler. Lock coupler securely into
place by pulling back coupler collar
and inserting it onto discharge
nipple, then pushing collar forward
to lock in place.
NOTE: If using detergent injector,
attach detergent injector to
discharge nipple using quick
coupler. Attach high pressure hose
to other end of detergent injector.
STEP 5: Fill gasoline tank and
check engine oil. Fill fuel tank. Do
not confuse gasoline and fuel oil
(diesel) tanks. Keep proper fuel in
proper tanks.
STEP 3: Attach wand to spray gun
using teflon tape on threads to
prevent leakage. Attach swivel
connector on discharge hose to
spray gun using teflon tape on
threads. Attach swivel connector on
high pressure hose to spray gun
using teflon tape on threads.
Engage safety latch to prevent from
triggering gun.
STEP 6: On electric start models
only, you will need to install a
battery making sure that the red
cable is attached to the positive
terminal. Use a Group U1 garden
tractor style type of battery rated for
300 CCA (battery not included).
CAUTION: These machines are
intended to be protected from
outside environments.
ATTENTION: Ces machines sont
conçues pour être protégées
contre l'environnement
extérieur.
Landa MHC 9.800-950.0 - BM
Inlet
Connector Inlet
Connector
Water Supply Hose
(not included)
For: MHC3-24324
C43500E
High Pressure Hose
Discharge Nipple
Detergent
Hose
Detergent
Injector
SenDEC
TACH/HOUR1/10
MHC43500E
Gasoline
Fuel
Oil
Safety
Latch High
Pressure
Hose
Spray
Gun
Wand
Dipstick
POS NEG
Red
Black

13
Operations
Operation Instructions
STEP 1: Turn on water at faucet
and pull trigger on spray gun
allowing water to flow until all air
has discharged from system.
Check for water leaks; tighten as
needed.
STEP 4: With spray nozzle pointed
away from you or anyone else,
press trigger on spray gun to obtain
pressurized cold water spray.
STEP 5: For hot water, turn burner
switch ON when a steady stream of
water flows out of the spray gun.
Burner will light automatically.
NOTE: Do not start machine with
burner switch on.
STEP 2: Before installing nozzle,
turn on water supply and run
machine allowing water to flush
through the system until clear. Pull
wand coupler collar back and insert
desired pressure nozzle into
coupler then secure by pushing
coupler collar forward.
NOTE: Variable pressure control
wand handle must be turned
clockwise to enable water to flow
out of the high pressure nozzle.
STEP 3: Read engine manual, turn
on gas valve and choke. Turn the
engine switch to the START
position and hold it there until the
engine starts.
NOTE: Do not use the electric
starter for more than five seconds
at a time. If the engine fails to start,
release the switch and wait ten
seconds before operating the
starter again. When the engine
starts, allow the engine switch to
return to the ON position. If the
engine is to be started without the
battery, turn switch to start position
and pull rope to start. Turn off
choke.
WARNING: Starter cord kickback
(rapid retraction) can result in
bodily injury. Kickback will pull
hand and arm toward engine
faster than you can let go.
ALWAYS relieve spray gun
pressure before pulling starter
cord. Pull starter cord slowly
until resistance is felt, then pull
rapidly.
AVERTISSEMENT: Le retour du
cordon de lancement (rétraction
rapide) peut causer des lésions
corporelles. La rétraction rapide
de la corde du démarreur (recul)
attire la main et le bras vers le
moteur plus vite qu'il n'est
possible de lâcher la corde.
Toujours retenir la charge
solidement en place avant de
conduire. Tirer lentement sur le
cordon de lancement jusqu'à ce
qu'une résistance soit sentie,
puis tirer rapidement.
CHAUD!
Gas
V
alve
Choke
Engine
Switch
Landa MHC 9.800-950.0 - BM
Collar
SenDEC
TACH/HOUR1/10
Burner
Switch
Burner
Switch
For:
MHC3-24324
Variable Pressure
Control Handle
Trigger
Variable Pressure
Wand (VP)
High Pressure
Nozzle
Brass
Soap
Nozzle
Selection of high or low pressure is accompanied by turning the handle.
NOTE: High pressure nozzle must be inserted at end of wand to obtain
high pressure. To apply soap read Detergents and General Operating
Techniques section.

14
Operations
Detergents And General Operating
Techniques
WARNING: Some detergents may
be harmful if inhaled or ingested,
causing severe nausea, fainting or
poisoning. The harmful elements
may cause property damage or
severe injury.
AVERTISSEMENT: Certains
détergents peuvent être
dangereux s'ils sont inhalés ou
ingérés, provoquant de fortes
nausées, des évanouissements et l'empoisonnement.
Les éléments dangereux peuvent causer des
dommages à la propriété ou des blessures graves.
STEP 1: Use detergent designed specifically for pressure
washers. Household detergents
could damage the pump. Prepare
detergent solution as required by the
manufacturer. Fill a container with
pressure washer detergent. Place
the filter end of detergent suction
tube into the detergent container.
STEP 2: Apply safety latch to spray
gun trigger. Secure black detergent
nozzle into quick coupler. NOTE:
Detergent cannot be applied using
the Yellow nozzle.
STEP 3: With the motor running, pull
trigger to operate machine. Liquid
detergent is drawn into the machine
and mixed with water. Apply
detergent to work area. Do not allow
detergent to dry on surface.
IMPORTANT: You must flush the detergent injection
system after each use by placing the suction tube into
a bucket of clean water, then run the pressure washer
in low pressure for 1-2 minutes.
Thermal Pump Protection
If you run your pressure washer for 3-5 minutes without
pressing the trigger on the spray gun, circulating water in
the pump can reach high temperatures. When the water
reaches this temperature, the pump protector engages
and cools the pump by discharging the warm water onto
the ground. This thermal device prevents internal damage
to the pump.
Cleaning Tips
Pre-rinse cleaning surface with fresh water. Place
detergent suction tube directly into cleaning solution and
apply to surface at low pressure (for best results, limit your
work area to sections approximately 6 feet square and
always apply detergent from bottom to top). Allow
detergent to remain on surface 1-3 minutes. Do not allow
detergent to dry on surface. If surface appears to be
drying, simply wet down surface with fresh water. If
needed, use brush to remove stubborn dirt. Rinse at high
pressure from top to bottom in an even sweeping motion
keeping the spray nozzle approximately 1 foot from
cleaning surface. Use overlapping strokes as you clean
and rinse any surface. For best surface cleaning action
spray at a slight angle.
Recommendations:
• Before cleaning any surface, an inconspicuous
area should be cleaned to test spray pattern and
distance for maximum cleaning results.
• If painted surfaces are peeling or chipping, use
extreme caution as pressure washer may remove
the loose paint from the surface.
• Keep the spray nozzle a safe distance from the
surface you plan to clean. High pressure wash a
small area, then check the surface for damage. If
no damage is found, continue to pressure
washing.
CAUTION - Never use:
• Bleach, chlorine products and other corrosive
chemicals
• Liquids containing solvents (i.e., paint thinner,
gasoline, oils)
• Tri-sodium phosphate products
• Ammonia products or acid-based products
These chemicals will harm the machine and will
damage the surface being cleaned.
ATTENTION: Ne jamais utiliser:
• Eau de Javel, produits à base de chlore et
autres produits chimiques corrosifs
• Liquides contenant des solvants (c.-à-d.
diluant à peinture, essence, huiles, etc.)
• Produits à base de tripolyphosphate de sodium
• Ammoniac ou produits à base d'acide
Ces produits chimiques endommageront la machine
et endommageront la surface étant nettoyée.
PRECAUCIÓN: Nunca utilice:
• Blanqueadores, productos con cloro u otros
químicos corrosivos.
• Solventes (por ejemplo: diluyente de
pintura, gasolina, aceites).
• Productos de fosfato trisódico.
• Productos de amoniaco.
• Productos a base de ácido.
• Estos químicos provocaran daño en la
máquina y dañarana superficie que se está
limpiando.
Landa MHC 9.800-950.0 - BM
WARNING

15
Operations
Shutdown Instructions
STEP 1: Remove detergent suction
tube from container and insert into
one (1) gallon of fresh water. Pull
trigger on spray gun and siphon
water for one minute.
STEP 4: Turn off water supply.
STEP 2: Turn burner switch off and
continue spraying, allowing the
water to cool below 100° F.
STEP 5: Open spray gun to relieve
remaining pressure.
STEP 3: Turn engine off.
Landa MHC 9.800-950.0 - BM
SenDEC
TACH/HOUR1/10
Burner
Switch
Burner
Switch
For:
MHC3-24324
HA
UD
!
Key
Switc
h
Rinsing
It will take a few seconds for the detergent to clear. Apply
safety latch to spray gun. Remove black soap nozzle from
the quick coupler. Select and install the desired high
pressure nozzle. NOTE: You can also stop detergent from
flowing by simply removing detergent siphon tube from

16
Maintenance
Storage
CAUTION: Always store your pressure washer in a
location where the temperature will not fall below 32°F
(0°C). The pump in this machine is susceptible to
permanent damage if frozen. FREEZE DAMAGE IS
NOT COVERED BY WARRANTY.
ATTENTION: Toujours entreposer la laveuse à
pression dans un endroit où la température ne sera
pas inférieure à 32°C (0 °F). La pompe sur cette
machine est susceptible de subir des dommages si
elle est exposée au gel. LES DOMMAGES DUS AU
GEL NE SONT PAS COUVERTS PAR LA GARANTIE
PRECAUCIÓN: Siempre almacene la hidrolavadora en
una ubicación donde la temperatura no llegue a ser
menor que 32ºF (0ºC). La bomba en esta máquina es
susceptible a daño irreversible si se congela. DAÑOS
POR CONGELAMIENTO NO ESTAN CUBIERTOS POR
GARANTÍA.
1. Stop the pressure washer, squeeze spray gun
trigger to release pressure.
2. Detach water supply hose and high pressure hose.
3. Turn on the machine for a few seconds, until
remaining water exits. Turn engine off immediately.
4. Drain the gas and oil from the engine.
5. Do not allow high pressure hose to become kinked.
6. Store the machine and accessories in a room
which does not reach freezing temperatures.
CAUTION: Failure to follow the above directions will
result in damage to your pressure washer.
ATTENTION: Le non-respect des directives ci-dessus
entraînera des dommages à la laveuse à pression.
PRECAUCIÓN: No seguir las instrucciones anteriores
pueden resultar en daños de tu hidrolavadora.
When the pressure washer is not being operated or is
being stored for more than one month, follow these
instructions:
1. Replenish engine oil to upper level.
2. Drain gasoline from fuel tank, fuel line, fuel valve
and carburetor.
3. Pour about one teaspoon of engine oil through the
spark plug hole, pull the starter grip several times
and replace the plug. Then pull the starter grip
slowly until you feel increased pressure which
indicates the piston is on its compression stroke
and leave it in that position. This closes both the
intake and exhaust valves to prevent rusting of
cylinder.
4. Cover the pressure washer and store in a clean,
dry place that is well ventilated away from open
flame or sparks. NOTE: The use of a fuel additive,
such as STA-BIL®, or an equivalent, will minimize
the formulation of fuel deposits during shortage.
Such additives may be added to the gasoline in the
fuel tank of the engine, or to the gasoline in a
storage container.
After Extended Storage
CAUTION: Prior to restarting, thaw out any
possible ice from pressure washer hoses,
spray gun or wand.
ATTENTION: Avant de redémarrer, faire
fondre la glace se trouvant sur les boyaux, le pistolet
pulvérisateur ou la lance de la laveuse à pression.
PRECAUCIÓN: Antes de reiniciar, descongele
cualquier posible hielo en las mangueras, pistola
pulverizadora o lanza.
Engine Maintenance
During the winter months, rare atmospheric conditions
may develop which will cause an icing condition in the
carburetor. If this develops, the engine may run rough,
lose power and may stall. This temporary condition can
be overcome by deflecting some of the hot air from the
engine over the carburetor area. NOTE: Refer to the
engine manufacturer's manual for service and mainte-
nance of the engine.
Preventative Maintenance
1. Check to see that the water pump is properly
lubricated.
2. Follow Winterizing Procedures to prevent freeze
damage to the pump and coils.
3. Always neutralize and flush detergent from system
after use.
4. If water is known to be high in mineral content, use
a water softener in your water system or de-scale
as needed.
5. Do not allow acidic, caustic or abrasive fluids to be
pumped through system.
6. Always use high grade quality Landa cleaning
products.
7. Never run pump dry for extended periods of time.
8. Use clean fuel-kerosene, No. 1 fuel oil or diesel.
Replace fuel filter every 100 hours of operation.
Avoid water contaminated fuel as it will seize up
Landa MHC 9.800-950.0 - BM

17
Maintenance
the fuel pump. Desoot coils monthly or use an
additive if diesel is being used.
9. If machine is operated with smoking or eye burning
exhaust, coils will soot up, not letting water reach
maximum operating temperature. (See section on
Air Adjustments.)
10. Never allow water to be sprayed on or near engine
or burner assembly or any electrical component.
11. Periodically delime coils as per instructions.
12. Check to see that engine is properly lubricated.
It is advisable, periodically, to visually inspect the
burner. Check air inlet to make sure it is not clogged or
blocked. Wipe off any oil spills and keep this equipment
clean and dry.
The areas around the pressure washer should be kept
clean and free of combustible materials, gasoline and
other flammable vapors and liquids.
The flow of combustion and ventilating air to the burner
must not be blocked or obstructed in any manner.
Maintenance And Service
Unloader Valves
WARNING: The unloader valve on this pressure
washer has been factory set and sealed and is a field
nonadjustable part. Tampering with the factory setting
may cause personal injury and/or property damage,
and will void the manufacturer warranty.
AVERTISSEMENT: La soupape de décompression sur
cette laveuse à pression a été réglée en usine, puis
scellée, et est une pièce non réglable. L'altération du
paramètre de l'usine pourrait causer des lésions
corporelles et/ou des dommages à la propriété, et
annulera la garantie du fabricant.
Winterizing Procedure
Damage due to freezing is not covered by warranty.
Adhere to the following cold weather procedures
whenever the washer must be stored or operated
outdoors under freezing conditions.
During winter months, when temperatures drop below
32°F, protecting your machine against freezing is
necessary. Store the machine in a heated room. If this
is not possible then mix a 50/50 solution of anti-freeze/
water into a 5 gallon bucket. Place a short section of
garden hose into the bucket and connect it to the
machine. Elevate the bucket and turn the pump on to
siphon the anti-freeze through the machine. If
compressed air is available, an air fitting can be
screwed into the inlet connector and, by injecting
compressed air, all water will be blown out of the
system.
High Limit Hot Water Thermostat
For safety, each machine is equipped with a high limit
control switch. In the event that the temperature of the
water should exceed its operating temperature, the
high limit control will turn the burner off until the water
cools.
Pumps
Use only SAE 10W-40 non-detergent oil. Change oil
after the first 50 hours of use. Thereafter, change the oil
every three months or at 500 hour intervals. Oil level
should be checked by using the dipstick found on top of
the pump or the red dot visible through the oil gauge
window. Oil should be maintained at that level.
Cleaning of Coils
In alkaline water areas, lime deposits can accumulate
rapidly inside the coil pipes. This growth is increased by
the extreme heat build up in the coil. The best preven-
tion for liming conditions is to use high quality cleaning
detergents. In areas where alkaline water is an extreme
problem, periodic use of Landa Coil Descaler (part
#8.914-296.0) will remove lime and other deposits
before coil becomes plugged.
Periodic descaling of the heating coil is recom-
mended so please consult your local Landa Dealer
for instructions.
Rupture Disk
If pressure from pump or thermal expansion should
exceed safe limits, the rupture disk will burst allowing
high pressure to be discharged through hose to ground.
When disk ruptures it will need to be replaced.
Torque the replacement rupture disk to 35 foot pounds.
Fuel
Use clean fuel oil that is not contaminated with water
and debris. Replace fuel filter and drain tank every 100
hours of operation.
Use No. 1 or No. 2 Heating Oil (ASTM D306) only.
NEVER use gasoline in your burner tank. Gasoline is
more combustible than fuel oil and a serious explosion
could result. NEVER use crankcase or waste oil in your
burner. Fuel unit malfunction could result from contami-
nation.
Landa MHC 9.800-950.0 - BM

18
Maintenance
Fuel Control System
These machines utilize a fuel solenoid valve located on
the fuel pump to control the flow of fuel to the combus-
tion chamber. This solenoid valve, which is normally
closed, is activated by a flow switch when water is
flowing through it. When an operator releases the
trigger on the spray gun, the flow of water through the
flow switch stops, turning off the current to the fuel
solenoid. The solenoid then closes, shutting off the
supply of fuel to the combustion chamber. Controlling
the flow of fuel in this way allows for an instantaneous
burn or no burn situation, thereby eliminating high and
low water temperatures, and combustion smoke
normally associated with machines incorporating a
spray gun.
CAUTION: Periodic inspection is recommended to
insure that the fuel solenoid valve functions
properly. This can be done by operating the
machine and checking to see that when the trigger
on the spray gun is in the off position, the burner is
not firing.
ATTENTION: Une inspection périodique est
recommandée pour assurer que l'électrovalve
d'alimentation en carburant fonctionne
correctement. Cela peut être effectué en utilisant la
machine et en s'assurant que le brûleur n'est pas
allumé lorsque le pistolet pulvérisateur se trouve
en position d'arrêt.
PRECAUCION. Es recomendado realizar una
inspección periódica para asegurar que la válvula
solenoide de combustible funciona
adecuadamente. Esto se puede realizar operando
la máquina y revisar si al momento de estar el
gatillo de la pistola pulverizadora en posición de
apagado, el quemador no esta encendido.
Burner Nozzle
The oil burner on this machine is preset for operation at
altitudes below 500 feet. If operated at higher altitudes,
it may be necessary to adjust the air band for a #1 or #2
smoke spot on the Bacharach scale.
To adjust, start machine and turn burner ON. Loosen
two locking screws found on the air band and close air
band until black smoke appears from burner exhaust
vent. Note air band position. Next, slowly open the air
band until white smoke just starts to appear. Turn air
band halfway back to the previously noted position.
Tighten locking screws.
For higher altitudes, the air band opening may need to
be increased; for lower altitude, the .air band may need
to be decreased.
For higher humidity, the air band opening may need to
be increased; for lower relative humidity, the .air band
may need to be decreased.
For higher ambient temperatures the air band opening
may need to be increased; for lower ambient tempera-
tures, the air band opening may need to be decreased.
Adjust to your operating location's environment as-
needed for best smoke spot and performance
compliant with local, state, and federal regulations.
Landa MHC Oil Burner
Burner Air Adjustment: To adjust fuel pressure, First
install a pressure gage into the port just after the pump
fuel exit. Turn the adjusting screw (located at the
regulator port) clockwise to increase, and counterclock-
wise to decrease. Do not exceed 200 psi or lower the
pressure below 130 PSI, when checked at the post-
pump pressure port.
The fuel pressure may need to be adjusted due to
altitude. For every 500 ft altitude above sea level, the
boiling point of water goes down 1 °F. At high altitude
environments, this boiling point change may require the
heat input to be lowered so the water input does not
turn to steam earlier than at the factory settings and
activate the pressure sensors and pressure relief
equipment when the unit is operated and much higher
altitudes from factory settings or local dealer site
settings. Check with your dealer before making local
site fuel pressure adjustments.
Also, as ambient temperature changes seasonally, the
fuel temperature in the feed tank and air temperature
inlet can impact fuel flow. In more extreme tempera-
tures, this local-site adjustment may also require
different fuel nozzles for fuel inlet temperatures that are
at seasonal extremes (higher or lower) in locations
where the temperature changes are beyond moderate
temperatures of between 40°F and 90°F. Colder
temperatures will make for a thicker flow and less fine a
fuel spray while hotter temperatures will make for a
thinner flow a more fine spray with the same nozzle.
Consider alternate nozzle configurations from the
baseline factory-supplied nozzle for operating in such
temperature extremes if performance is not meeting
needs with air band and fuel pressure settings alone.
NOTE: When changing fuel pump, a by-pass plug
must be installed in return line port or fuel pump will
not prime.
Landa MHC 9.800-950.0 - BM

19
Maintenance
Landa MHC Burner Air Adjustment
CAUTION: If white smoke appears from burner
exhaust vent during start-up or operation, discon-
tinue use and readjust air bands.
ATTENTION: Si de la fumée blanche s'échappe de
l'évacuation du brûleur pendant le démarrage ou le
fonctionnement, cesser d'utiliser et réajuster les
bandes d'air.
PRECAUCIÓN: Si se presenta humo blanco del
escape del quemador durante el arranque u
operación, detenga la operación y reajuste las
bandas de aire.
NOTE: If a flue is installed, have a professional
serviceman adjust your burner for a #1 or #2 smoke
spot on the Bacharach scale.
Removal of Soot and Heating Coil
In the heating process, fuel residue in the form of soot
deposits may develop on the heating coil and block air
flow which will affect burner combustion. When soot
has been detected on visual observation, the soot on
the coil must be washed off after following the coil
removal steps.
1. Disconnect hose from pump/unloader to inlet side
of the coil.
2. Remove thermostat sensor.
3. Remove the tank head assembly by unscrewing
six screws and lifting the top wrap off.
4. Fold back insulation blanket.
5. Remove the two pipe nipples and associated
fittings.
6. Remove bolt Item 75, , that hold down coil to
bottom wrap.
7. Lift the coil out of the bottom wrap.
CAUTION: The coil weighs about 80 lbs. Use proper
lifting techniques.
ATTENTION: La bobine pèse environ 36.3 kg (80lb).
Utiliser des techniques de levage appropriées.
PRECAUCION. El peso del intercambiador de calor
es aprox. 36.3 kg (80 lbs). Utilice técnicas apropi-
adas para el levantamiento.
8. Replace or repair any insulation found to be torn or
broken.
9. Clean, repair and replace the coil by reversing the
above steps.
Coil Re-installation
Reinstall by reversing the above steps 9 through 1.
Final Note
The 12 VDC burner systems can draw as much as 18
amps! For such motors to run properly, the battery and
engine charging system must be kept in good condi-
tion, and the engine must run fast enough to
adequately charge the battery. Do not throttle down the
engine for any length of time.
Landa MHC 9.800-950.0 - BM

20
Maintenance
Troubleshooting
PROBLEM POSSIBLE CAUSE SOLUTION
LOW
OPERATING
PRESSURE
Water supply is insufficient Use larger supply hose; clean filter at water inlet.
Spray nozzle is old, worn or incorrect Match the nozzle number to the machine and/or
replace with new nozzle.
Belt slips Tighten or replace belt; use correct belt.
Plumbing or hose is leaking Check plumbing system for leaks. Re-tape leaks with
teflon tape.
Unloader is faulty or mis-adjusted Adjust unloader for proper pressure. Install repair kit
when necessary or replace.
Packing in pump is worn Install new packing kit.
Discharge valve in pump or inlet is fouled
or dirty Check inlet and discharge valve.
Discharge valve or inlet is worn Replace with valve kit.
Spray nozzle has obstruction Remove obstruction.
Steam pressure control valve is leaking
(where applicable) Rebuild or replace as necessary.
Engine RPM is slow
Set engine speed at proper specifications. See serial
plate. The gasoline engine is preset for operation at
altitudes below 1000 feet above sea level. If operated
at higher altitudes, it may be necessary to install a
high altitude main jet in the carburetor. Contact you
local authorized engine sales and service center for
details.
BURNER WILL
NOT LIGHT
There is little or no fuel Fill tank with fuel.
Improper fuel or water in fuel Drain fuel tank and fill with proper fuel.
Fuel line is clogged Clean or replace fuel line.
Fuel filter is plugged Replace fuel filter as needed.
Burner air bands are mis-adjusted Readjust air bands for clean burn.
Little or no fuel pressure from fuel pump Increase fuel pressure to specification and/or replace
fuel pump.
Burner transformer is faulty Test transformer for proper arc between contacts.
Replace as needed.
Electrical wiring is disconnected or has
short in it
All wire contacts should be clean and tight with no
breaks in wire.
Flex coupling is slipping on fuel pump
shaft or burner motor shaft Replace if needed.
ON-OFF switch is defective Check for electrical current reaching burner assembly
with burner switch on. Replace switch if needed.
Heavy sooting on coil and burner can
cause interruption of air flow and shorting
of electrodes
Clean as required.
Electrode setting is improper Check and reset according to diagram in manual.
30 amp circuit breaker tripped Push in reset button.
Bridge rectifier defective Test and replace.
12V DC relay defective Test and replace.
Fuel is not reaching combustion chamber
Check fuel pump for proper flow. Check solenoid flow
switch on machines with spray gun control for proper
on-off flow control.
Landa MHC 9.800-950.0 - BM