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The gas valve is provided with pressure taps to
measure gas pressure upstream of the gas valve and
downstream which is the same as the manifold pres-
sure.
WATER CONNECTIONS & SYSTEM PIPING
The pipe size for water connections is shown on
page 3. Typical piping systems are shown on pages 11
to 13.
The boiler is supplied as standard with a circulator
and a built -in by-pass to insure the required minimum
water flow in the boiler. The by-pass on models H-0135
and H-0180 is provided with an adjustable valve that is
factory set in the full open position. The handle is
shipped loose. The full open position is appropriate for
most systems, and insures adequate flow through the
boiler. If system flow is inadequate, (indicated by
excessive temperature drop through the system) the by-
pass valve can be throttled slightly. Care must be taken
against over throttling which may lead to inadequate
flow through the boiler and boiler harmonics (a humming
sound from the heat exchanger). If adequate system
flow cannot be obtained without causing harmonics, an
additional pump is required. The factory mounted
circulator will provide adequate water flow for systems
designed at a 20°F temperature drop, and system
pressure drop or head not exceeding that is shown
below.
When the total system head exceeds the available
head pressures, a primary/secondary pumping system
is recommended.
The minimum boiler operating temperature
should be 105°F. When operating at low tempera-
ture applications, ÐT (temperature rise) must be
20°F or less.
Propylene glycol solution is commonly used in the
heating system when freeze protection is required. This
will affect the system design and pump performance. As
a "rule of thumb", 50% solution of propylene glycol will
require the system flow (GPM) to increase by 14%, and
the system head (Ft/Wtr) by 23% in order to maintain the
same heat transfer load.
10
GAS SUPPLY CONNECTIONS
The inlet gas connection of the boiler gas valve is
1/2". Provide an adequate gas piping supply line no
smaller than 1/2", according to the chart below:
Maximum Equivalent Pipe Length (Feet)
Gas piping must have a sediment trap ahead of the
boiler gas controls, and a manual shutoff valve located
outside the jacket. All gas piping should be tested after
installation in accordance with local codes.
CAUTION: The boiler and its manual shut off valve must
be disconnected from the gas supply during any pres-
sure testing of that system at test pressures in excess
of 1/2 psig (3.45 KPA). Dissipate test pressure in the
gas supply line before reconnecting the boiler and its
manual shut off valve to gas supply line. FAILURE TO
FOLLOW THIS PROCEDURE MAY DAMAGE THE
GAS VALVE. OVER PRESSURED GAS VALVES ARE
NOT COVERED BY WARRANTY. The boiler and its
gas connections shall be leak tested before placing the
appliance in operation. Use soapy water for leak test.
DO NOT use open flame.
NOTE: Do not use teflon tape on gas line pipe thread.
A flexible sealant suitable for use with Natural and
Propane gases is recommended.
GAS PRESSURE-SPECIFICATIONS
Inches W.C. Regulator
Min. Max. Setting
Natural 7.0 14.0 3.5
Propane 12.0 14.0 11.0
Sediment Trap Gas Valve
Manual Union
Valve
Fig. # 8192.0
MODEL NAT PRO NAT PRO NAT PRO NAT PRO
0030 &
0042
125 350 500 - - - - -
0066 60 160 175 460 - - - -
0090 30 80 125 325 400 - - -
0135 15 40 60 155 200 500 - -
0180 - 20 35 90 115 300 425 -
1/2" Pipe 3/4" Pipe 1" Pipe 1 1/4" Pipe
System Maximum
Models Flow System Head
(GPM) (Ft/Wtr)
H-0030 2.5 9.0
H-0042 3.5 8.0
H-0066 5.3 8.5
H-0090 7.3 6.5
H-0135 11.0 10.0
H-0180 14.6 7.0