LAARS SUMMIT SMW-250 - Install and Operating Manual - Manual (Page 7)

SUMMIT BOILER OR WATER HEATER Page 7
8. Begin cementing the intake and exhaust pipes,
start at the vent terminals and work back towards
the appliance. Note: The intake terminal is the
90° elbow fitting that is designed to be
installed facing down.
9. Support both horizontal vent pipes with pipe
hangers every 5'. The weight of venting must not
be supported by appliance connectors.
10. Tighten the flexible couplings to connect the
appliance to the vent. DO NOT CEMENT
VENT PIPES TO APPLIANCE — USE
COUPLINGS PROVIDED.
SECTION 3.
Gas Connections
3.1 Gas Supply and Piping
Gas piping should be supported by suitable
hangers or floor stands, not the appliance.
Review the following instructions before
proceeding with the installation.
1.
Verify that the appliance is fitted for the proper
type of gas by checking the rating plate. Laars
Heating Systems appliances are normally
equipped to operate at elevations up to 2000 feet.
However, the SUMMIT appliance will function
properly without the use of high altitude
modification at elevations up to 4500 feet (1372
m). Appliances equipped to operate at higher
altitudes have appropriate stickers or tags
attached (next to the rating plate).
2. Referring to Table 2, size supply piping to keep
flow capacity to the appliance above 250 cubic
feet per hour (CFH) per installed appliance.
3. Run gas supply line in accordance with all
applicable codes.
4. Locate and install manual shutoff valves in
accordance with state and local requirements.
5. Install drip leg and ground joint union (Figure 6).
6. All threaded joints should be coated with piping
compound resistant to action of liquefied
petroleum gas.
7. The SUMMIT 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).
It 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).
8. The SUMMIT appliance and its gas connection
must be leak tested before placing it in
operation.
9. Purge all air from gas lines.
Caution:
Do not use open flame to check for leaks.
NOTE: The SUMMIT 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 (Figure 20).
Low gas pressure could be an indication of an
undersized gas meter, undersized gas supply lines and/
or an obstructed gas supply line.
10. The correct burner manifold gas pressure (offset)
is pre-set at the factory, and normally requires no
further adjustment. See Section 7.2.2.1 Offset
Figure 6. Gas Supply Piping.
Table 2. Gas Supply Piping.
Length
of
Pipe
Capacity of Pipe in MBTU/HR (.6
Specific Gravity)
¾" 1" 1¼"
10' (3m) 278 520 1,050
20' (6m) 190 350 730
30' (9m) 152 285 590
40' (12m) 130 245 500
50' (15m) 115 215 440
75' (23m) 93 175 360
100' (30m) 79 150 305
150' (46m) 64 120 250
Additional length to be
added for each tee or
bend
1.7'
(0.5m)
2.2'
(0.7m)
2.7'
(0.8m)