LAARS Rheos+ RHHV - Install and Operating Manual - Manual (Page 10)

Rheos+ Boiler and Water Heater Page 9
Term Description
Pipe Single-wall galvanized steel pipe, 24 gauge
minimum (sized per section 1.9)
Joint Permanent duct tape or aluminum tape
Sealing
Insulation Not required, but recommended R5 insulation
for cold installations (consult American Society
of Heating, Refrigerating, and Air Conditioning
Engineers (ASHRAE) handbook
Table 4 - Required Combustion Air Piping Material.
The connection for the intake air pipe is in the
back of the unit. Take the plate off the back to reveal
the collar on the filter box. 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 Rheos+ loses less than 1 percent of
its input rating to the room, but other heat sources may
be present.
2.2 Venting
The Rheos+ is a Category IV appliance and
must be installed with a stainless steel venting system
that complies with the UL 1738 Standard (see Table
5). It must be installed per this installation manual
and the venting system manufacturer’s Installation
Instructions. The unit’s vent can terminate through the
roof, or through an outside wall. It can be installed
through walls that are from 3" (7.6cm) to 12" (30cm)
in thickness.
See Table 2 to select the appropriate vent pipe
diameter. The vent pipe must be pitch upward, toward
the vent terminal, so that condensate will run back to
the Rheos+, to drain. Route the vent pipe to the heater
as directly as possible. Seal all joints and provide
adequate hangers 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
upwards not less than ¼ inch per foot (21mm/m) from
the unit to the vent terminal. Up to five elbows can
be used with the 50 feet (15.2m) of pipe. Subtract 10
allowable linear feet for every additional elbow used.
IMPORTANT NOTE ABOuT COMMON VENTING:
A single vent that is shared by multiple Rheos+
units MUST be engineered by a competent venting
specialist, and involves the selection of draft inducing
equipment, hardware and controls to properly
balance flue gas pressures. Do not common vent
Rheos+ units unless the vent system meets this
requirement. Rheos+ units are never permitted to
share a vent with Category I appliances.
A condensate drain is built into the Rheos+. A
pressure switch monitors the condensate drain pan, and
will trip if the condensate level gets too high. This will
prevent the Rheos+ from firing if there is a blockage or
overflow.
Connect a clear plastic tube, minimum 3/8"
diameter, between the drain connection and a floor
drain (or condensate pump if a floor drain is not
accessible).
Caution
Condensate is mildly acidic, and may harm some
floor drains and/or pipes, particularly those that
are metal. Ensure that the drain, drainpipe,
and anything that will come in contact with the
condensate can withstand the acidity, or neutralize
the condensate before disposal. Damage caused
by failure to install a neutralizer kit or to
adequately treat condensate will not be the
manufacturer’s responsibility.
A neutralizer kit is available from LAARS. The
kit includes a condensate pump.
The condensate tray must be primed before starting
the unit. Fill the tray with water through the exhaust
vent connection on the back of the unit. Continue
filling until water flows out of the condensate drain
port. This prevents the flue gases from escaping through
the condensate drain. The condensate drain must be
installed so as to prevent accumulation of condensate.
When a condensate pump is not used, the tubing must
continuously slope downward (except for the trap loop)
toward the drain with no spiraling.
Consult local codes for disposal method.
Term Description
Venting Sealed stainless steel
system certified to UL1738.
Insulation Not required, but recommended R5
insulation with protective cover for cold
installations (consult American Society of
Heating, Refrigerating, and Air Conditioning
Engineers (ASHRAE) handbook)
Table 5 - Required Venting Material
2.3 Locating Vent & Combustion Air
Terminals
2.3.1 Horizontal 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: