Installation & Operation Manual
19
2
General
venting
Common venting
Crest boilers may be common vented; however, the following
criteria MUST BE followed:
1. Only Crest boilers may be connected to common flue
applications. DO NOT mix other manufacturer’s
appliances or other Lochinvar models. Common air
intake is not allowed.
2. Crest boilers connected to the common vent must all be
of the same size.
3. Each Crest boiler must have a Lochinvar supplied flue
damper installed (see Table 2D).
4. Only vertical direct vent, positive pressure, Category
IV or vertical/chimney vent, negative pressure, Category
II may be used when common venting Crest boilers.
Sidewall venting is not allowed.
5. Crest boilers in a common vent must be connected and
controlled with the integral Crest SMART TOUCH
Cascade.
a. The Leader may be controlled through the Crest
SMART TOUCH control through BMS (external
0 - 10V signal), ModBus or its own internally
calculated
set
point.
b. The Cascade (Members) must be controlled by the
Crest Leader boiler using the Lead/Lag Cascade
option.
For approved common vent sizing, contact the factory.
WARNING
When Crest boilers are common vented,
the criteria above MUST BE followed.
Failure to follow all these requirements
will result in severe personal injury, death,
or substantial property damage.
Table 2D Flue Damper Kits
Flue Damper Kits
Model
Damper Size
Kit Number
FB0751
6"
100056142
FB1001
6"
100056142
FB1251
8"
100141561
FB1501
8"
100141561
FB1751
8"
100141561
FB2001
8"
100141561
NOTICE
When Crest boilers are common vented,
hot water generators MUST BE piped
to the primary heating loop and tank
thermostats must not be connected to the
Crest.
Installing vent and air piping
Use only cleaners, primers, and solvents
that are approved for the materials which
are joined together.
NOTICE
PVC/CPVC
All PVC vent pipes must be glued, properly
supported, and the exhaust must be
pitched a minimum of a 1/4 inch per foot
back to the boiler (to allow drainage of
condensate).
NOTICE
WARNING
The vent connection to the appliance
must be made with the starter CPVC pipe
section provided with the appliance if
PVC/CPVC vent is to be used. The field
provided vent fittings must be cemented
to the CPVC pipe section using an “All
Purpose Cement” suitable for PVC and
CPVC pipe. Use only the vent materials,
primer, and cement specified in Table 2E
to make the vent connections. Failure to
follow this warning could result in fire,
personal injury, or death.
WARNING
Insulation should not be used on PVC
or CPVC venting materials. The use of
insulation will cause increased vent wall
temperatures, which could result in vent
pipe failure.
This product has been approved for use with the PVC/CPVC
vent materials listed in Table 2E on page 20.
Factory installed vent connections are sized
for stainless steel venting.
NOTICE
NOTICE
A field supplied inline condensate
collection section MUST BE installed
directly above the backflow preventer.
NOTICE
When using polypropylene common
vent a field supplied polypropylene to
stainless steel adapter MUST BE installed
between the backflow preventer and the
unit connection.
