John Wood Atmospheric Gas (Non-FVIR) - Manual (Page 11)

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VIII) HEATING AND SPACE HEATING
(COMBO HEATING)
This section serves as a guide for the installation and use of
“Combo” heating systems utilizing a domestic water heater which
has been specifically approved for such use. It is written for those
knowledgeable in the required trades and professionals involved
in the design and installation of Combo Heating Systems.
It is the responsibility of the installer/ designer to
follow all applicable codes to ensure the
effectiveness and safety of the installation.
Caution
READ BEFORE PROCEEDING
The following requirements must be met for the installation of
Combo Heating Systems:
1. All components used for the distribution of water in the heating
loop must be suitable for potable water. These include all piping,
fittings, solder and fluxes, pumps for circulation of water, valves,
etc.
2. The water heater must not be connected to a hydronic
heating system that has been used previously.
3. No boiler treatment chemicals of any kind shall be introduced
into the system.
4. The Combo System components must be selected and sized to
meet and maintain the total calculated demands for both domestic
service hot water and space heating requirement. The sizing and
installation must be performed in accordance with good
engineering practice such as ASHRAE Handbooks, HRAI,
Hydronics Institute Manuals, CGA B149, NFPA 54, ANSI Z223.1,
CSA F280, National/Provincial Building Codes, CSA C22.1,
ANSI/NFPA 70, CSA B51 and/or codes having jurisdiction.
5. The air handler (fan coil) and/or the circulating pump in a
baseboard hydronic loop will require a dedicated 120V circuit.
This must be provided and identified for this purpose.
6. All piping between the water heater and the air handler or
hydronic baseboard loop must be adequately insulated to reduce
heat loss.
7. If the local jurisdiction requires a back-flow preventer in the cold
water line, an expansion tank of adequate size must be installed.
8. To reduce the scald hazard potential, a mixing valve must be
installed.
INSTALLATION
The heating mode may be one of the following options:
A-
A fan coil/air handler (figure 9).
B- A hydronic baseboard (finned tube) loop/ In floor heating (figure
10).
The following is a list of requirements for the installation of the
heating loop to the water heater.
a)
Install shut-off valves and unions so that the water heater can
be isolated from the heating module should servicing of the water
heater become necessary.
b)
Install a drain valve at the lowest point of the heating loop so
that water can be drained from the heating module without
affecting the water heater.
c)
If the air handler does not have a venting means at the highest
point of the piping arrangement, install an air bleed at the highest
point of the plumbing arrangement.
MAINTENANCE
The installation and maintenance of the water heater must follow
all of the instructions described in sections I to VII of this manual.
Heater failure that is a result of the heating system is not covered
by warranty.
Figure 9
Figure 10