P-K SONIC
®
Gas Fired Boiler
Technical Service 1.877.728.5351
Revised: June 2, 2017
Released: June 2, 2017
HARSCO Industrial, Patterson-Kelley 2017
All Rights Reserved.
1004905978 P-K SONIC NURO Installation and
Owners Manual (Rev F Jun-2017).docx
Page 29
Venting for Multiple Boilers
While the vent design parameters outlined in
still apply, achieving those same parameters
in a combined vent system adds a significant degree of complexity. Therefore, venting systems for
multiple appliances shall be designed by experienced and knowledgeable venting professionals. The
venting system shall be designed to prevent backflow of exhaust gas through idle appliances. For
combined breeching installations, please follow recommendations of a qualified venting
engineer/manufacturer.
Harsco Industrial, Patterson-Kelley recommends that common venting systems be designed for a
maximum continuous exhaust pressure of
-
0.04” W.C.
when measured in the common vent. Locking
inline dampers are recommended on the exhaust connection of each individual appliance in order to
control the exhaust back pressure within the appliance and upstream of this damper. The -0.04
” W.C.
in the common flue will also help make sure the exhaust gases from an online appliance does not
backflow through offline appliance(s).
In addition, Harsco Industrial, Patterson-Kelley also recommends the use of motorized combustion air
dampers in the combustion air intake ductwork of each individual appliance. When an appliance is
offline, its combustion air damper will remain closed which will also help prevent the backflow of flue
gases from online appliances. Please refer to
for more information.
If the common venting system uses a draft inducer fan or damper
device, this
MUST
be interlocked with the appliances. In the event this
draft inducer device fails, the interlock circuits to the appliances must be
opened in order to prevent operation. Failure to do so could result in
appliance operation under excessive back pressure conditions which
could result in damage to the appliance and lead to serious injury or
death.
The design of any common venting system
MUST
prevent backflow of
combustion gases through offline boilers or water heaters. Failure to do
so could result in damage to the appliance and lead to serious injury or
death
.
