Midco J121-DS - Manual (Page 4)

chamber over-fire draft, 0 to minus 0.5" W.C., a fixed damper should be installed in
the vent connector between the barometric and chimney to restrict the chimney
draft to a point within the controlling capacity of the barometric. After final setting,
the damper should be permanently fastened into position per ANSI Z223.1-latest
edition "National Fuel Gas Code", or latest edition available from American National
Standards Institute to prevent tampering.
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The supply piping to the burner should branch off from the main line as close to the
source as possible (NATURAL gas meter or PROPANE tank regulator). When
branching off from an existing gas line, do not tap off the bottom of a horizontal
section. Use new black pipe and malleable fittings free from cutting and threading
burrs or defects.
Use pipe joint compound resistant to liquid petroleum gases when using either
NATURAL or PROPANE gas. Piping must comply with the local and national codes.
If the burner piping must be rearranged because of space limitations, be sure to
carry out the general configuration shown in Figure 3.
A suitable Main Gas Pressure Regulator should be installed as shown in Figures
1 or 3. Choose a regulator(s) to adjust the available gas pressure to the pressure
shown in SPECIFICATIONS, page 2.
CAUTION: The regulated gas pressures must not exceed 14" W.C. or Main
Automatic Gas Valve and Ignitor Regulator will be damaged. If excessive gas
pressure is prevalent, the regulator must be a tight shut-off type to prevent
high pressures from developing during stand-by.
For full input, refer too SPECIFICATIONS, page 2, for minimum gas pressure
required. For reduced capacities, refer to Firing Rate Curves, Table 2.
CAUTION: If gas supply pressure is below its specified range during
adjustment, an over-fire condition could result when pressure returns to
normal, particularly if the regulator adjustment screw is bottomed out.
ALWAYS confirm that at least the minimum rated pressure is being supplied
during regulator adjustments, and NEVER BOTTOM OUT regulator screw.
When selecting the burner supply piping size per Table 1, the permissible
pressure drop must be based on the pressure available at the inlet to the supply
pipe branch line when all other gas equipment fed by the same source (NATURAL
gas meter or PROPANE tank regulator) is firing at full rate. Also take into account
any other INCINOMITE burners to be attached to the same branch line.
When pressure testing the supply piping, the burner valve train must be
protected. If the test pressure is 0.5 PSIG or less, closing the Main Manual Shut-Off
Valve will suffice.
CAUTION: If the test pressure is over 0.5 PSIG, the test must be made
without any burner components connected, including Main Manual Shut-Off
Valves.
WARNING: EXPLOSION HAZARD. DO NOT USE OXYGEN FOR PRESSURE
TESTING. AN EXPLOSION COULD OCCUR DURING INITIAL START-UP.
4
Part 1 Installation
Capacities shown are for total
pressure drop of 0.3"W.C. For
higher permissible pressure
drops consult your fuel supplier.
Source: Gas Engineers
Handbook-1974
Industrial Press Inc. NY, NY
NPT
PIPE
SIZE
3/4"
1"
1 1/4 "
1 1/2"
2
275
450
520
800
800
---
---
---
---
---
200
300
350
550
730
800
800
---
---
---
130
200
245
385
500
790
760
800
800
---
100
165
195
300
400
630
610
800
800
---
---
125
150
235
300
480
460
725
800
800
TYPE
OF
GAS
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
APPROXIMATE CAPACITY-MBH
LENGTH OF PIPE / FEET
Table 1 Schedule 40 Pipe Capacities in MBH
10 20 40 60 100
Part 1
Installation
Continued
V Piping