LAARS Mighty Therm LO-NOx PH (Sizes 250/400) - Install and Operating Manual - Manual (Page 15)

Mighty Therm LO-NOx Hydronic Boiler Page 15
For systems with lower than 110°F (43°C)
temperature, boiler must be protected from low
temperature return water. There are many methods of
achieving low temperature protection. Figure 23
shows an example of such a system. Damage caused
by condensation is not covered under the terms of the
limited warranty.
2.7 Gas Supply and Piping
(Natural Gas Only)
2.7.1 General Instructions
Review the following instructions before
continuing the installation.
1.
Gas piping installation must be in accordance
with the latest edition of ANSI Z223.1. In
Canada, the installation must be in accordance
with CSA-B149.1 and all local codes that apply.
2. Check the rating plate to make sure the boiler is
fitted for the type of gas being used. Laars LO-
NOx boilers are normally equipped to operate
with natural gas below a 2000 foot (609 m)
altitude.
3. If a gas pressure regulator is required, the
installation must be in accordance with the latest
edition of ANSI Z223.1. In Canada, the
installation must be in accordance with CSA-
B149.1 and all local codes that apply.
4. The figures in Table 5 should be used to size the
gas piping from the gas meter to the boiler.
5. Install a sediment trap (drip leg) ahead of the gas
controls (see Figure 26). Fit the trap with a
threaded cap which can be removed for cleaning.
6. Install a non-restrictive manual gas shutoff valve
for service and safety. Check the local codes.
7. Disconnect the boiler and its individual shutoff
valve from the supply gas system during pressure
6. Support the weight of all water and gas piping
with suitable hangers or floor stands.
7. Check piping diagrams with local applicable
plumbing, heating and building safety codes.
2.6.7 Filling the System
1. Close all air vents and open the makeup water
valve. Let the system fill slowly.
2. If a makeup water pump is used, adjust the
pressure switch on the pumping system to
maintain at least 12 psi (82.7 kPa) at the highest
point in the heating loop.
3. If a water pressure regulator is installed on the
makeup water line, adjust the pressure regulator
to provide at least 12 psi (82.7 kPa) at the highest
point in the heating loop.
4. Open air vents on all radiation units at the high
points in the piping throughout the system, unless
automatic air vents are installed at those points.
5. Run the system circulating pump for at least 30
minutes with the boiler shut off.
6. Recheck all air vents as described in Step 4 above.
7. With the system full of water and under normal
operating pressure, the air pressure in the expansion
tank should be at least 12 psi (82.7 kPa).
8. Start up the boiler following the instructions
found on the inside of the boiler.
9. Operate the whole system, including the pump,
boiler, and radiation units for 1 hour.
10. Shut down the entire system and vent all
radiation units and high points in the system
piping as described in Step 4 above.
11. Close the makeup water valve and check the
strainer in the pressure reducing valve for sedi-
ment or debris. Reopen the makeup water valve.
12. Check the gauge to make sure the water pressure
is right, and check water level in the system. If
the water level indicated above the boiler shows
that water is at the highest point in the circulating
loop, then the system is ready for operation.
13. Within 3 days of start-up, recheck all air vents
and expansion tank as described in Steps 4 and 8
above.
2.6.8 Minimum Boiler Temperature
The boiler inlet water temperature must be
minimum 110°F (43°C) when the system has come up
to normal operating conditions. Lower temperature
inlet water may allow the production of condensation
on the outside of the copper finned tubes, which can
block the flue gases and/or cause improper
combustion, leading to heat exchanger sooting.
Distance from Gas Meter or Last Stage Regulator
0-100 feet 100-200 feet 200-300 feet
0-30 m 30-60 m 60-90 m
Boiler Nat. Nat. Nat.
Size in. (NPT) in. (NPT) in. (NPT)
250 1¼ 1¼ 1½
400 1¼ 1½ 2
Notes:
1. These numbers are for natural gas (0.65 Sp. Gr.) and
are based on ½ inch (13mm) water column pressure
drop. Check supply pressure with a manometer, and
local code requirements for variations.
2. Check supply pressure and local code requirements
before preceding with work.
3. Pipe fittings must be considered when determining gas
pipe sizing.
Table 5. Pipe Size Requirements (natural gas).
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