Laars NeoTherm NTH Installation and operation instructions manual - page 14
LAARS Heating Systems
Page 14
gas by checking the rating plate. NeoTherm will
function properly without the use of high altitude
modification at elevations up to 10,000 feet (3050 m).
2.
The maximum inlet gas pressure must not exceed
13" W.C. (3.2kPa). The minimum inlet gas
pressure is 4" W.C. (1.0kPa).
3.
Refer to
Tables 6A, 6B, 6C and 6D
to size piping.
4.
Run gas supply line in accordance with all
applicable codes.
5.
Locate and install manual shutoff valves in
accordance with state and local requirements.
6.
A sediment trap must be provided upstream of the
gas controls.
7.
All threaded joints should be coated with piping
compound resistant to action of liquefied
petroleum gas.
8.
The appliance and its individual shutoff valve
must be disconnected from the gas supply piping
during any pressure testing of that system at test
pressures in excess of 1/2 PSIG (3.45kPa).
9.
The unit must be isolated from the gas supply
system by closing its individual manual shutoff
valve during any pressure testing of the gas supply
piping system at test pressures equal to or less than
1/2 PSIG (3.45kPa).
10.
The appliance and its gas connection must be leak
tested before placing it in operation.
11.
Purge all air from gas lines.
WARNING:
Open flame can cause gas to ignite and result in
property damage, severe injury, or loss of life.
NOTE: The NeoTherm appliance and all other gas
appliances sharing the gas supply line must be firing at
maximum capacity to properly measure the inlet supply
pressure. The pressure can be measured at the supply
pressure port on the gas valve. Low gas pressure could
be an indication of an undersized gas meter, undersized
gas supply lines and/or an obstructed gas supply line.
Some NeoTherm units are equipped with low and high
gas pressure switches that are integrally vent limited.
These types of devices do not require venting to
atmosphere.
SECTION 4.
Water Connections
4.1 Heating System Piping: Hot Supply
Connections
NOTE: This appliance must be installed in a closed
pressure system with a minimum of 12 psi (82.7kPa)
static pressure at the boiler.
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with this
appliance. Due to expansion and contraction of copper
pipe, consideration should be given to the type of
hangers used. Rigid hangers may transmit noise through
the system resulting from the piping sliding in the
hangers. It is recommended that padding be used when
rigid hangers are installed. Maintain 1" (2.5cm)
clearance to combustibles for hot water pipes.
Pipe the discharge of the relief valve (full size) to
a drain or in a manner to prevent injury in the event of
pressure relief. Install an air purger, an air vent, a
diaphragm-type expansion tank, and a hydronic flow
check in the system supply loop. Minimum fill pressure
must be 12psig (82.7kPa). Install shutoff valves where
required by code.
Suggested piping diagrams are shown in
Figures
10 through 16
. These diagrams are meant only as a
guide. Components required by local codes must be
properly installed. The NeoTherm boiler’s efficiency
is higher with lower return water temperatures.
Therefore, to get the most of low return temperature
with multiple boilers, pipe as shown in
Figure 13
.
All NeoTherm models are built standard with a
pump mounted inside the jacket. Sizes 399 and 500 can
be ordered without the pump, as an option. If the boiler
is a size 399 or 500, it is important to know whether
there is an internal pump in the unit or not.
NeoTherm boilers that are pump-mounted MUST
be piped in a primary-secondary fashion (using either
piping or a hydraulic separator) such that the pump that
is mounted on the boiler ONLY serves the boiler.
For best results, the NeoTherm boiler should be
located within 15 feet (4.6m) of the supply and return
header (or the hydraulic separator). The pump is sized
for a maximum of 30 feet (9.1m) of piping and the
headloss of the boiler only
(see Table 7)
.
If a pump-mounted boiler must be installed with
longer piping runs, then larger diameter tubing may be
used. Consult the Applications Engineering Department
at the factory for assistance.
Models 399 and 500 can be ordered without a
mounted pump. If ordered without the pump, a field-
supplied pump should be chosen to supply the boiler
only. Primary/secondary piping methods should still be
used, to ensure proper water flow through the unit.
4.2 Cold Water Make-Up
1.
Connect the cold water supply to the inlet
SCHED 40 METAL PIPE CAPACITY FOR 1.50 SPECIFIC GRAVITY
UNDILUTED PROPANE
NOMINAL PIPE SIZE
@
11" W.C. INLET AND 0.5" W.C. PRESSURE DROP
SIZE
1/2"
3/4"
1"
1-1/4"
1-1/2"
2"
LENGTH
MAXIMUM CAPACITY IN THOUSANDS OF BTU PER HOUR
20
200
418
787
1616
2422
4664
40
137
287
541
1111
1664
3205
60
110
231
434
892
1337
2574
80
94
197
372
763
1144
2203
100
84
175
330
677
1014
1952
NOTES: 1. Follow all local and national LP gas codes for line sizing and
equipment requirements. 2. Verify that inlet gas pressure remains between
4 and 13 inches of water column before and during operation.
Source: ANSI Z223.1-80 National Fuel Gas Code.
Table 6D.