10
4. GENERAL PIPING
•
All plumbing must meet or exceed all
local, state and national plumbing codes.
•
Use pipe dope or tape suitable for potable
water on the domestic piping.
•
Use isolation valves to isolate sys-
tem components.
•
Install unions for easy removal of com-
bination heater. Use dielectric unions or
couplings to protect hot and cold water
fittings from corrosion when connect-
ing dissimilar materials such as copper
and galvanized iron pipe.
•
If plastic is used for primary water con-
nections, it must not exceed a maximum
oxygen diffusion rate of 0.1 mg/liter-
day for combination heater protection.
•
When water supply pressure is higher
than T&P relief valve rating, install a
pressure reducing valve on cold water
supply line to prevent water loss
through T&P relief valve.
5. INNER TANK (DOMESTIC) PIPING
•
A thermostatic mixing valve and check
valve are factory installed on the
domestic hot water outlet.
•
Install U tube assembly, (factory assem-
bled & provided with the combination
heater), to the mixing valve/check valve
outlet and to the factory assembly tee at
the cold water inlet.
- If there is a need to alter the piping
such as adding a tee upstream of the
mixing valve to deliver 140º water to
the dish washer, (if local codes per-
mit) the installer must re-install this
mixing valve prior to operation of the
combination heater.
The mixing valve must remain mounted
on the domestic hot water outlet at all
times. Removal of automatic mixing
valve from combination heater will
result in severe personal injury or death.
•
For recommended domestic water pip-
ing arrangement see Fig. 7 page 11.
•
For recommended domestic water pip-
ing with recirculation see Fig. 8 page 11.
To prevent potential scalding hazard, recircu-
lation must be controlled by an additional
aquastat. Do not use continuous recirculation.
6. OUTER TANK SYSTEM PIPING
• Recommended piping shown page 12
and 13.
• Install expansion tank:
Diaphragm-type expansion tank. Ensure
tank pressure and size will handle system
fill pressure and water volume.
- Fill pressure may be adjusted at
tank for design conditions. Follow
manufacturer’s instructions.
- Locate expansion tank near the unit,
before the inlet of the circulator.
Closed-type expansion tank. Size tank
to system requirements. Refer to man-
ufacturer’s instructions.
Undersized expansion tanks can cause sys-
tem water to be lost from relief valve and
makeup water added through fill valve
Eventual outer tank failure can result.
•
If antifreeze is used in system water,
local codes may require a backflow pre-
venter on cold water supply line.
Use antifreeze specifically intended for
hydronic heating systems. Inhibited
propylene glycol is recommended.
•
System water (including additives) must
be practically non-toxic, having toxicity
rating or class of 1, as listed in Clinical
Toxicology of Commercial products.
CAUTION
DANGER
DANGER
INSTALLATION
