Packaged Rooftop Ventilator
14
Optional Coil Piping
Chilled Water and Hot Water Configuration
Factory-installed chilled water and hot water coils are
mounted in the coil section of the unit except for the
XRV-10 housing in which the hot water coil will be
directly downstream of the supply fan. The coil section
is downstream of the supply filter bank and upstream of
the supply fan.
Note:
For XRV-10, XRV-75 and XRV-110 coil connections
are located internal of the unit.
For XRV-25 and XRV-45 coil connections are located
external through the side of the unit with the option for a
piping vestibule.
Package DX/Split DX and Hot Water Configurations
Factory-installed cooling components are mounted in
the coil section of the unit. Hot water coil connection
location is based on housing size.
Note:
For XRV-25 and XRV-45 hot water coil will be located
below the supply fan for. Coil connection will be internal
below the compressor/electrical compartment.
For XRV-10 hot water coil will be located directly
downstream of supply fan with coil connections internal
through the supply fan section.
For XRV-75, and XRV-110 the hot water coil will be located
in the coil section with coil connections internal in the unit.
Water Coils
1. Piping should be in accordance with accepted
industry standards. Pipework should be supported
independently of the coils. When installing couplings,
do not apply undue stress to the connection
extending through the unit. Use a backup pipe
wrench to avoid breaking the weld between coil
connection and header.
2. Connect the water supply to the bottom connection
on the air leaving side and the water return to the
top connection on the air entering side. Connecting
the supply and/or return in any other manner will
result in very poor performance. Be sure to replace
factory-installed grommets around coil connections
if removed for piping. Failure to replace grommets
will result in water leakage into the unit and altered
performance.
3. Water coils are not normally recommended for
use with entering air temperatures below 40
°
F. No
control system can be depended on to be 100% safe
against freeze-up with water coils. Glycol solutions
or brines are the only safe media for operation of
water coils with low entering air conditions. If glycol
or brine solutions are not used, coils must be drained
when freezing conditions are expected.
If required,
vent and drain connections must be field-
piped, external to the unit.
4. Pipe sizes for the system must be selected on
the basis of the head (pressure) available from the
circulation pump. The velocity should not exceed
6 feet per second and the friction loss should be
approximately 3 feet of water column per 100 feet
of pipe.
5. For chilled water coils, the condensate drain
pipe should be sized adequately to ensure the
condensate drains properly. Refer to Drain Trap
section.
Direct Expansion (DX) Coils (Split DX)
1. Piping should be in accordance with accepted
industry standards. Pipework should be supported
independently of the coils. Undue stress should not
be applied at the connection to coil headers.
2. The condensate drain pipe should be sized
adequately to ensure the condensate
drains properly. Refer to Condensate
Drain Trap section.
3. When connecting suction and liquid
connections make sure the coil is free
from all foreign material. Make sure all
joints are tight and free of leakage. Be sure to replace
factory-installed grommets around coil connections if
removed for piping.
4. Manufacturer does not supply compressor,
condensing units, or thermal expansion valve (TXV)
with standard models. For further instruction on
DX coil installation and operation contact your
compressor and/or condenser manufacturer.
Condensate Drain Trap
This unit is equipped with a stainless steel condensate
pan with a stainless steel connection is installed
underneath the cooling coil. It is important that the
condensate pan drain connection must be fitted with a
P trap to ensure proper drainage of condensate while
maintaining internal static pressures and to prevent
migration of sewer gas back into the unit.
A P trap assembly (kit) is supplied with each unit,
except for housing
110 a
nd is to be assembled and
installed as local conditions require and according to
the assembly instructions provided with the P trap. If
local and area codes permit, the condensate may be
drained back onto the roof, but a drip pad should be
provided beneath the outlet. If local and area codes
require a permanent drain line, it should be fabricated
and installed in accordance with Best Practices and all
codes.
In some climates, it will be necessary to provide freeze
protection for the P trap and drain line. The P trap
should be kept filled with water or glycol solution at all
times and it should be protected from freezing to protect
the P trap from damage. If severe weather conditions
occur, it may be necessary to fabricate a P trap and
drain line of metal and install a heat tape to prevent
freezing.
Condensate Overflow Switch
This unit is equipped with an optional factory-mounted
condensate overflow switch. In the event that a high
level of condensate is detected, the microprocessor
controller will trigger an alarm and shutdown the unit.
Piping Installation
