Access Considerations; Electrical Connection; Pressure Regulation And Testing - Holman Ultra-Max UM1854Q-NAT Installation And Operation Instructions Manual

GAS SUPPLY RATING AND SIZING
Calculations for pipe sizing must take into account the maximum usage rate of all other appliances in
the kitchen or one or more of the appliances will suffer from inadequate or dangerous performance. The
1/2" NPT connection for the oven is generously sized for use in the control box of the oven. However,
unless the oven installation is within 10 feet of the main building gas supply, the supply must be larger.
For each oven, a 3/4" NPT flexible quick connect hose and full port gas shut-off valve is recommended
as a MINIMUM. The main pipe supplying each oven branch may need to be larger depending on the
number of appliances serviced, the number of elbows in the piping, and the pressure. This should be
sized and installed by a professional familiar with any local codes that may also affect the installation.
ACCESS CONSIDERATIONS
Locating the gas valve(s), quick connect hose(s) and electrical outlet(s) at the control box end of the
oven will allow easier access for any service visits. This improved access should make any necessary
service quicker resulting in less kitchen disruption. It will also allow easier disconnection of electricity,
gas, and restraints for cleaning around and behind the oven.
ELECTRICAL CONNECTION
Before making any electrical connections to this unit, check that the power supply is adequate for the
voltage, amperage, and phase requirements stated on the rating plate. A wiring diagram is included
herewith.
When installed, this appliance must be electrically grounded and its installation must comply with the
National Electric Code, ANSI-NFPA 70, latest version, manufacturer's installation instructions, and
applicable local municipal building codes. In Canada, all electrical connections are to be in accordance
with CSA C22.1 - Canadian Electrical Code Part 1 and/or local codes.
PRESSURE REGULATION AND TESTING
Each oven has been adjusted at the factory to operate with natural gas. Parts can be ordered for
conversion for use with propane.
Each oven is supplied with a regulator to maintain the proper gas pressure. The regulator is essential
to the proper operation of the oven and should not be removed. A pressure reading can be taken at one
of the 1/8" NPT test ports on the bottom or side of the combination valve. The reading should be taken
while the oven is heating up. The regulator is located on the bottom of the gas combination valve, just
inside the control box. There is no need to install an additional regulator where the oven connects to
the gas supply unless the supply exceeds the maximum.
NOTE: The supplied regulator is evaluated for a maximum gas supply pressure of
14" water column (34.5 mBar). The recommended maximum gas supply pressure
is 12" water column (29.9 mBar).
Installation must conform with local codes or, in the absence of local codes, with the National Fuel Gas
Code, NFPA54/ANSI Z223.1 - Latest Edition, the Natural Gas Installation Code CAN/CGA-B149.1 or
the Propane Installation Code CAN/CGA-B149.2 as applicable.
During pressure testing note the following:
1. The oven and its individual manual shut-off valve must be disconnected from the gas supply piping
CAUTION system during any pressure testing of that system at test pressures in excess of 1/2 psig (3.45 kPa).
Turn OFF main gas shut-off valve or main gas supply line.
2. The oven must be isolated from the gas supply piping system by closing its individual manual shut-
off valve during any pressure testing of the gas supply piping system at test pressures equal to or
less than 1/2 psig (3.45 kPa).
3. If incoming pressure is over 14" water column, a separate regulator for the oven must be installed
before the gas supply to the oven. For LP it must regulate pressure to 11" water column (27.1 mBar)
maximum and 6" for NAT.
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