15
After the piping and meter have been checked
completely, purge the system of air.
DO NOT
bleed the
air inside an enclosed room.
During pressure testing of the system at test pressures
in excess of 1/2 PSIG, the pressure washer and its indi-
vidual shut-off valve must be disconnected from gas
supply piping system or damage to the gas valve will
occur.
The pressure washer includes a collar that will mate
with standard HVAC ducting. The user will be respon-
sible for installation of an exhaust stack. The exhaust
stack should include a Draft Diverter/Inducer, Damper,
Sampling Port and Rain Cap. An adapter can be
installed between the collar and stack to adjust the
diameter from 10” to 8” or 12” to 10”.
Size the stack according to the following (see also
applicable local and national standards regarding
installation of gas-fired appliances):
•
3.5 to 4.4 gpm 10” Collar 8” Stack
•
4.5 to 5.5 gpm 10” Collar 10” Stack
•
6.3 gpm 12” Collar 10” Stack
•
8 – 10 gpm 12” Collar 12” Stack
Draft Diverter/Hood:
The draft required to vent
combustion gases is created by the heat inside the
pressure washer coil. A draft diverter helps improve
draft into the stack without pulling more air through the
combustion box and decreasing combustion efficiency.
The draft diverter can also help prevent back drafting
that can inhibit combustion. The draft diverter should be
installed a minimum of 36” above the flue collar.
Power Vent (Draft Inducer):
If this machine is going to
be installed on a 90° or extended exhaust vent run
length which may restrict air flow it is recommended
that a contractor install a power vent. When a
contractor has found it impossible to vent straight
through the roof power venting is recommended to
help eliminate exhaust restriction of this natural draft
machine. This draft inducer (power vent) must be
installed by a licensed contractor who can calculate
size, operation connections and associated damp-
eners. Since we are a manufacturer and not a licensed
contractor and as such we are unable to make recom-
mendations for suitable make and model of power
vents and compliance with local building codes.
Damper:
An exhaust stack can reduce thermal effi-
ciency by drawing in too much combustion air. This can
be controlled by adding a damper just below the draft
diverter. 8.753-473.0 - 8" Damper, 8.753-474.0 -10”
Damper, 8.753-418.0 - 12" Damper.
NOTE: Closing the damper can create high levels of
CO in the exhaust. Adjustments to the damper should
only be performed by a trained technician using a flue
gas analyzer. If an analyzer is not used the damper
should be set in the fully open position.
Sampling Port
: A port for sampling flue gases and
measuring the flue gas temperature should be placed
18” above the flue collar. The port should be covered
when sampling is not being performed. The size of the
port should be only slightly larger than the probe for the
flue gas analyzer.
Rain Cap:
A rain cap should be installed on top of the
stack to prevent rain water, leaves and debris from
entering the stack. Your installer may also recommend
specialty caps for high wind areas or cold weather
zones to help prevent back drafting. 8.717-731.0 - 10"
Raincap, 8.717-732.0 - 12" Raincap.
Gas Pressure:
The incoming gas pressure must be a minimum of 9.0
wc-in and must not exceed 13.8 wc-in or ½ psig to the
control valve. Line pressure above ½ psig must be
regulated prior to the machine. The ideal supply
pressure is 13.0-13.5 wc-in. If the required BTU input
can not be achieved consult the factory for instructions
regarding changes to the nozzle orifice size and an
appropriate manifold setting.
NOTE: Any changes to the burner and manifold
pressure setting should only be performed by a
trained technician and adjusted using a flue gas
analyzer.
The manifold pressure has been preset at the factory
according to the table below for optimum operation at
sea-level. The manifold pressure and BTU input will be
listed on the specification plate for the machine.
Landa VHG Operator’s Manual 8.913-952.0 - BR
Draft Diverter
Required
8.717-728.0 8"
9.801-040.0 10"
8.717-730.0 12"