15
A. GENERAL
1. Size water supply and return piping in accordance
with system requirements. Do not use smaller
diameter piping than the boiler connections.
2. If the P
UREFIRE
®
boiler is used to replace an existing
boiler, make sure that the system piping is thoroughly
cleaned and free from debris before installing this boiler.
3. In hydronic systems where sediment may exist, install
a strainer in the boiler return piping to prevent large
particles and pipe scale from entering the boiler heat
exchanger. Use a large mesh screen in the strainer.
4. Install this boiler so that the gas ignition system
components are protected from water (dripping, spraying,
etc.) during operation and service (circulator replacement,
condensate trap cleaning, sensor replacement, etc.).
B. OPERATING PARAMETERS
1. The PUREFIRE
®
boiler is designed to operate in a
closed loop hydronic heating system under forced
circulation. This requires the system to be completely
filled with water and requires a minimum water flow
rate through the boiler to assure proper flow
distribution.
2. The minimum system operating pressure is 14.5 PSI
(69 kPa).
3. Table 4.1 lists the minimum flow rates for each
P
UREFIRE
®
model covered in this manual. Also shown
is the minimum flow rate for 50% glycol solution. For
other glycol concentrations, contact your PB Heat,
LLC representative for the minimum flow rates.
4. Section 4.E provides detailed information about using
glycol for freeze protection. Table 4.2 provides the
water volume of the heat exchangers for calculating
the system volume.
C. SYSTEM COMPONENTS
Figure 4.1 shows the symbol key for piping diagrams in
this section. The following are brief descriptions of system
components.
1. Pressure/Temperature Gauge: A combination
pressure/temperature gauge is provided with each
P
UREFIRE
®
boiler to be mounted in the piping from the
boiler supply to the system as shown in Figure 4.2.
Most local codes require this gauge.
2. Air Elimination: Closed loop hydronic systems require
air elimination devices. As the system water is heated,
dissolved oxygen and other gases will separate from
the liquid. An air elimination device (such as a TACO
Vortech
®
Air Separator) is required to remove the
dissolved gases preventing corrosion in the piping
system and eliminating noise.
3. Expansion Tank: An expansion tank (such as a Bell &
Gossett Series HFT) is required to provide room for
expansion of the heating medium (water or glycol
solution). Consult the expansion tank manufacturer's
instructions for specific information regarding
installation. The expansion tank is to be sized for the
required system volume and capacity. In addition, be
sure that the expansion tank is sized based on the
proper heating medium. Glycol solutions may expand
more than water for a similar temperature rise.
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.
4. WATER PIPING & CONTROLS
Use only inhibited propylene glycol solutions which
are specifically formulated for hydronic systems.
Unlike automotive antifreeze, solutions for hydronic
applications contain corrosion inhibitors that will
protect system components from premature failure
due to corrosion.
CAUTION
Use only inhibited propylene glycol solutions which
are specifically formulated for hydronic systems.
Ethylene glycol is toxic and may cause any
environmental hazard if a leak or spill occurs.
WARNING
PUREFIRE
®
Model
Minimum Flow Rate
Water
GPM (LPM)
50% Glycol Solution
GPM (LPM)
PF-850 39.5 (149.5) 49.4 (187.0)
PF-1000 46.5 (176.0) 58.2 (220.3)
Table 4.1: Minimum Boiler Flow Rates
PUREFIRE
®
Model
Total Water Capacity
Gallons Liters
PF-850 6.2 23.4
PF-1000 7.2 27.1
Table 4.2: Heat Exchanger Water Capacity
WATER PIPING & CONTROLS
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