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12
3 Hydronic piping
System water piping methods
The outdoor boiler is designed to function in a closed loop
pressurized system not less than 12 psi. A temperature and
pressure gauge is included to monitor system pressure and
outlet temperature and should be located on the boiler outlet.
It is important to note that the boiler has a minimal
amount of pressure drop and must be figured in when
sizing the circulators. Each boiler installation must have
an air elimination device, which will remove air from
the system. Install the boiler so the gas ignition system
components are protected from water (dripping, spraying,
etc.) during appliance operation for basic service of circulator
replacement, valves, and others.
Observe a minimum of 1/4 inch (6 mm) clearance around all
un-insulated hot water pipes when openings around the
pipes are not protected by non-combustible materials.
Low water cutoff device
On a boiler installed above radiation level, some states and
local codes require a low water cutoff device at the time of
installation.
Chilled water system
If the boiler supplies hot water to heating coils in air handler
units, flow control valves or other devices must be installed to
prevent gravity circulation of heater water in the coils during
the cooling cycle. A chilled water medium must be piped in
parallel with the heater.
Freeze protection, heat exchanger
Freeze protection for new or existing systems must use glycol
that is specially formulated for this purpose. This includes
inhibitors, which prevent the glycol from attacking the
metallic system components. Make certain to check that
the system fluid is correct for the glycol concentration and
inhibitor level. The system should be tested at least once
a year and as recommended by the producer of the glycol
solution. Allowance should be made for the expansion of the
glycol solution in the system piping.
General piping information
Basic steps are listed in this section along with illustrations on
the following pages (FIG.’s 3-4 thru 3-10), which will guide you
through the installation of the outdoor boiler (reference FIG.’s
3-2A and 3-2B).
1. Connect the system return marked “Inlet”.
2. Connect the system supply marked “Outlet”.
3. Install purge and balance valve or shutoff valve and drain
on system return to purge air out of each zone.
4. Install a backflow preventer on the cold feed make-up water
line.
5. Install a pressure reducing valve on the cold feed make-
up water line, (15 psi nominal). Check temperature and
pressure gauge (shipped separately), which should read a
minimum pressure of 12 psi.
6. Install a circulator as shown on the piping diagrams in this
section. Make sure the circulator is properly sized for the
system and friction loss.
7. Consult the factory for a pump and/or pump cover. If a
field-supplied pump is used, install per the manufacturer’s
specifications in regard to indoor or outdoor location. An
outdoor rated pump is recommended.
8. Install an expansion tank on the system supply. Consult the
tank manufacturer’s instruction for specific information
relating to tank installation. Size the expansion tank for the
required system volume and capacity.
9. Install an air elimination device on the system supply.
10. Install a drain valve at the lowest point of the system.
Note: The boiler cannot be drained completely of water
without purging the unit with an air pressure of 15 psi.
11. This appliance is supplied with a relief valve sized in
accordance with ASME Boiler and Pressure Vessel Code,
Section IV (“Heating Boilers”). Pipe the discharge of the
safety relief valve to prevent injury in the event of pressure
relief. Provide piping that is the same size as the safety relief
valve outlet. Never block the outlet of the safety relief valve.
Use only inhibited propylene glycol
solutions, which are specifically formulated
for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used
in hydronic systems.
ƽ WARNING
Outdoor Knight Boiler Installation & Operation Manual