Rheem 199,000 Btu/hr, Руководство пользователя, Страница: 37 / 80

1-29
INSTALLATION
TANKLESS WATER HEATER 199
1.8 GAS PIPING
The unit must have an inlet gas pressure of at least 4.0" w.c. for natural gas and
propane. For either fuel, the inlet pressure shall be no greater than 14.0" w.c.
Confirm this pressure range is available with your local gas supplier.
The inlet gas connection of the unit’s gas valve is ¾" NPT (male).
Use two wrenches when tightening field piping onto the boiler. Use one wrench to
hold the boiler fitting still while tightening with another wrench.
Adequate gas supply piping must be provided with no smaller than 1/2" Iron Pipe
Size and a 1" w.c. pressure drop, in accordance with the following chart:
MODEL 1/2" IPS 3/4" IPS 1" IPS
199,000 Btu/hr 199,000 Btu/hr (Natural Gas) 10' 40' 150'
199,000 Btu/hr 199,000 Btu/hr (Propane) 30' 125' 400'
Table 6: Maximum Pipe Length (ft)
Gas piping must have a sediment trap ahead of the unit’s gas valve
(see Figure
29).
A manual shutoff valve must be located outside the unit, in accordance with
local codes/standards. All threaded joints in gas piping must be made with an
approved piping compound resistant to the action of natural gas/propane. Use
proper hangers to support gas supply piping as per applicable codes.
Before placing the boiler into operation, the boiler and all gas connections must
be checked for leaks.
•
Close the gas shutoff valve during any pressure testing equal to or less than ½
psi (3.5 kPa).
•
Disconnect the boiler and gas shutoff valve from the gas supply during any
pressure testing greater than ½ psi (3.5 kPa).
The gas valve is provided with pressure taps to measure gas pressure upstream
(supply pressure) and downstream (manifold pressure) of the gas valve
(see
Figure 28).
Note that manifold pressure varies slightly in accordance with firing
rates with the modulating series units, but will always be close to 0" w.c.
CHECK LOCAL CODE FOR
SIZE REQUIREMENTS
WARNING
This tankless water heater
can burn either natural gas
or propane. Refer to section
3.3 for further instruction. If
converting a unit from one
fuel to another, you must
order a conversion kit prior
to the conversion. Install the
conversion kit according
to the detailed instructions
supplied with the kit. Failure
to perform the required fuel
conversion correctly can
result in serious injury or
death.
NOTE
It is essential to check gas
supply pressure to each
unit with a manometer or
other high-quality precision
measuring device. Pressure
should be monitored before
firing the unit, when the
regulator is in a “lock-up”
condition and during operation,
throughout the unit’s full
modulation range.
Pay special attention to retrofit
situations where existing
regulators may have an over-
sized orifice and/or worn seats,
causing pressure “creep” and
high lock up pressures.
WARNING
Failure to support the boiler
fitting with a second wrench
while tightening field piping
may lead to boiler damage.
Figure 28: Gas Valve
WARNING
Do not check for gas leaks
with an open flame, use the
bubble test. Failure to use
the bubble test or check
for gas leaks can cause
substantial property damage,
serious injury, or death.
Figure 29: Gas Piping