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4. Y-Type Strainer or Filter Ball
®
Valve: PB Heat recommends
the use of a strainer device in the system to prevent dirt or
sediment from clogging the heat exchanger. A 20 mesh
stainless steel screen is adequate to protect the heat
exchanger. The strainer should be cleaned often in the first
several months of operation. The Filter Ball
®
Valve from
Jomar International incorporates a strainer into a ball
valve which allows the technician to isolate the water
circuit while cleaning the strainer.
5. Flow Control Valve: Flow control valves such as the
TACO Flo-Chek or Bell & Gossett Flo-Control™ are
used to prevent gravity circulation by incorporating a
check valve with a weighted disc.
6. Pressure Reducing Valve: A pressure reducing valve,
such as the Bell & Gossett B-38 or a TACO #329, is
used in a hydronic system to automatically feed water
to the system whenever pressure in the system drops
below the pressure setting of the valve. These valves
should not be used on glycol systems unless close
supervision of the glycol solution is practiced.
7. Back Flow Preventer: A back flow preventer (check
valve) is required by some jurisdictions to prevent water
in the hydronic system from backing up into the city
water supply. This is especially important on systems in
which glycol solution is used as the heating medium.
8. Pressure Relief Valve: The boiler pressure relief valve
is shipped separately for field installation. The valve is
to be installed as shown in Figures 4.2 or 4.3. Pipe the
discharge of the relief valve to within 12" of the floor
and close to a floor drain. Provide piping that is the
same size or larger than the relief valve outlet.
WATER PIPING AND CONTROLS
Figure 4.1: Piping Symbol Key
Use only inhibited propylene glycol solutions which
are specifically formulated for hydronic systems.
Ethylene glycol is toxic and may cause an
environmental hazard if a leak or spill occurs.
WARNING
Do not operate this appliance without installing the
pressure relief valve supplied with the boiler or one
with sufficient relieving capacity in accordance with
the ASME Rating Plate on the boiler heat exchanger.
WARNING
Pipe the discharge of the relief valve as close as
possible to the floor and away from high traffic areas.
Pipe the discharge to a floor drain. Failure to do so
may result in personal injury and/or property
damage.
CAUTION
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