HydroTherm MultiTemp MR Series, Installation Manual And Replacement Parts List, Page: 16 / 36

FROM
METER
LUBRICATED
PLUG VALVE
GAS HEADER
GROUND JOINT UNION
SUPPORT
GAS MAIN
SEDIMENT
TRAP
SUPPORT
For any pressure testing in excess of 1/2 psi, the module
and its individual shutoff valve must be isolated from the
piping system by disconnecting them and capping the
outlet(s). For any pressure testing equal to or less than
1/2 psi, module must be isolated from the piping system
by closing its manual shutoff valve. Minimum pressure required at the gas valve inlet is 5"
W.C., 5.5” W.C. on R300 modules (natural gas) and 11"
W.C. (propane). Maximum pressure allowable at the gas
valve inlet is 12" W.C. If the gas pressure is above these
limits, a pressure regulator must be installed. If the gas
pressure is below these limits, contact the local utility.
FIGURE 6.1
SECTION 6: INSTALLING GAS PIPING
16
STEP 1: GAS MAIN & GAS HEADERS
STEP 2: TEST GAS PIPING
1. Gas pipe (gas main and gas headers) must be sized to
provide a total maximum pressure drop of 0.3” W.C. (nat-
ural gas) or 0.5” W.C. (propane) between gas meter and
each module’s gas valve. If shop drawings with approved
pipe sizes are not available, use sizing guidelines rec-
ommended in Appendix B at the rear of this manual.
2. Gas main (from meter to gas headers) must have a
non-restrictive lubricated plug valve installed close to the
modules as well as a full-sized sediment trap at the
lowest point in the gas main. The vertical rise of sedi-
ment trap must be a minimum of three times gas main
pipe diameter.
3. The gas header is the manifold t which each module’s
gas valve is connected; the connection at each gas valve
inlet requires a ground joint union. If total equivalent pipe
length (straight pipe plus fittings) from gas valve inlet to
header is 5-feet or less, use a pipe diameter that match-
es gas valve inlet; over 5-feet, calculate pipe diameter.
4. All piping must be supported with floor supports or by
hangers, not by the boilers or accessories. Always follow
good piping practices.
Pipe joint compound must be
compatible with gas being used. Check local codes and
utilities for any special requirements.
DANGER: Before placing gas piping into service, carefully test it to assure every joint is gas tight.
Bubble test all joints with soap solution. NEVER TEST WITH AN OPEN FLAME AS FIRE
OR EXPLOSION WILL RESULT.
WHEN PRESSURE TESTING IS COMPLETED, CLOSE MAIN GAS SHUT-OFF VALVE & SET
BOILER COMBINATION GAS VALVES IN “OFF” POSITION