Filter
Top Products
Part number 550-141-951/1002
Gas-fired
water boiler
Conversion Instructions
STOP! Read this notice
These instructions are only for propane conversion of a boiler that has already
been installed
. If you are converting a new boiler, not yet installed, do not use
these instructions. Instead, read and follow all instructions in the Boiler Manual.
Perform the propane conversion procedure on page 9 of the Boiler Manual
only in the proper sequence.
These instructions are for conversion of the following boilers from natural gas to propane
gas. (The propane gas orifice is located in the Propane Conversion Kit envelope.)
Boiler Model Orifice stamping
Ultra-155 .................................155-LP
Ultra-230 .................................230-LP
Ultra boilers are shipped ready to fire natural gas ONLY. You must install the
propane orifice if the boiler will be connected to propane. Follow all instructions
in this document and the Boiler Manual. Failure to comply could result in severe
personal injury, death or substantial property damage.
This conversion must be installed by a qualified installer/service technician in
accordance with the Weil-McLain instructions and all codes and requirements
of the authority having jurisdiction. The qualified agency performing this work
assumes responsibility for this conversion.
Follow all instructions in proper order.
Do not tamper with orifice size. DO NOT change or modify orifice in any way.
Do not leave an uninstalled orifice in the building.
Verify the following before proceeding:
Propane gas operation requirements
Pipe sizing for propane gas
1. Contact propane gas supplier to size piping, tank and install a 100% lockup gas pressure
regulator, or to verify size and condition of existing piping and equipment.
Propane supply pressure requirements
1. Adjust propane supply regulator provided by gas supplier for 13" w.c. maximum pressure.
2. Pressure required at gas valve inlet pressure port:
• Maximum: 13" w.c. with no flow (lockup) or with boiler on.
• Minimum: 4" w.c. with gas flowing (verify during boiler start-up per Boiler Manual).
3. After connecting propane gas line to boiler, and BEFORE operating, check gas pressure. If
gas pressure is not in the range above, close manual gas valve and contact gas supplier to
correct the problem before attempting to start or operate the boiler.
Natural to Propane Gas