Mr. Heater MHVFRD20 NGBT Operating Instructions And Owner's Manual page 9

CAUTION: Never connect heater to private (non-
utility) gas well. This gas is commonly known as well-
head gas.
IMPORTANT: Check your gas line pressure before
connecting heater to gas line. Gas line pressure
must be no greater than 14 inches of water. If gas
line pressure is higher, heater regulator damage
could occur.
CAUTION: Use only new black iron or steel pipe.
Internally-tinned copper tubing may be used in certain
areas. Check your local codes. Use pipe of larger
enough diameter to allow proper gas volume to heater.
If pipe is too small, undue loss of pressure will occur.
Installation must include an equipment shutoff valve,
union and plugged 1/8" NPT tap. Locate NPT tap within
reach of test gauge hookup. NPT tap must be upstream
from heater (see fi gure 12).
3/8" NPT Pipe Nipple
Ground Joint Union
Equipment
Shutoff Valve
From Gas Meter
(4" W.C. to 10.5"
W.C. Pressure)
3" Minimum
Figure 12
*A CSA/AGA certifi ed equipment shutoff valve with 1/8"
NPT tap is an acceptable alternative to test gauge con-
nection. Purchase the CSA/AGA certifi ed equipment
shutoff valve from your dealer. See Accessories, page 17.
IMPORTANT: Install an equipment shutoff valve in an
accessible location. The equipment shutoff valve is for
turning on or shutting off the gas to the appliance.
Apply pipe joint sealant lightly to male threads. This will
prevent excess sealant from going into pipe. Excess
sealant in pipe could result in clogged heater fuel train.
CAUTION: Use pipe joint sealant that is resistant to
natural gas.
Install sediment trap in supply line as shown in fi gure
12. Locate sediment trap where it is within reach for
cleaning. A sediment trap traps moisture and con-
taminants. This keeps them from going into heater. If
sediment trap is not installed or is installed improperly,
heater may not run correctly.
IMPORTANT: Hold pressure regulator with wrench
when connecting it to gas piping and/or fi ttings.
Unvented Natural Gas Vent Free Room Heaters
Pressure
Regulator
Heater
Cabinet
Test Gauge
Connection
Tee Joint
Reducer Bushing
to 1/8" NPT
1/8" NPT Plug Tap
Tee Joint
Sediment
Pipe Nipple
Trap
Cap
9
CHECKING GAS CONNECTIONS
WARNING: Test all gas piping and connections for
leaks after installing or servicing. Correct all leaks
at once.
WARNING: Never use an open fl ame to check for
a gas leak. Apply a mixture of liquid soap and water
to all joints. Bubbles forming show a leak. Correct
all leaks at once.
PRESSURE TESTING GAS SUPPLY PIPING
SYSTEM
Test pressure in Excess of ½ psig (3.5kPa)
1. The appliance and its appliance main gas valve
must be disconnected from the gas supply
piping system during any pressure testing of
that system at test pressures in excess of
psi (3.5 kPa). The appliance must be isolated
from the gas supply piping system by closing
its equipment shutoff valve during any pressure
testing of the gas supply piping system at test
pressures equal to or less than
kPa).2. Cap off open end of gas pipe where
equipment shutoff valve was connected.
3. Pressurize supply piping system by either using
compressed air or opening main gas valve on
or near gas meter.
4. Check all connections and joints in gas supply
piping system. Apply mixture of liquid soap and
water to gas joints. Bubbles forming show a
leak.
5. Correct all leaks at once.
6. Depressurize and relieve pressure in supply
piping system.
7. Reconnect heater and equipment shutoff valve
to gas supply.
8. Reconnected fi ttings must be checked for leaks
in next section.
Test Pressure Equal To or Less Than ½ psig (3.5 kPa)
1. Close equipment shutoff valve (see fi gure 13).
2. Pressurize supply piping system by either using
compressed air or opening main gas valve on
or near gas meter.
3. Check all joints from the gas meter to equip-
ment shutoff valve (see fi gure 14). Apply
mixture of liquid soap and water to gas joints.
Bubbles forming show a leak.
4. Correct all leaks at once.
5. Depressurize and relieve pressure from supply
piping system.
Installation Instructions and Owner's Manual
½
½
psi (3.5