Weil-McLain ULTRA 550-141-951-1002 User Manual

Gas-fired

water boiler

Conversion Instructions
Natural to Propane Gas

STOP! Read this notice

These instructions are only for propane conversion of a boiler that has already

been installed

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.

. If you are converting a new boiler, not yet installed, do not use

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.

Part number 550-141-951/1002

GAS-FIRED WATER BOILER — Propane Conversion Instructions

You must read and have the Ultra Boiler Manual with you to
proceed with these instructions.

Install propane gas orifice

1. Turn off electrical power to boiler at external line switch or breaker.

2. Remove jacket front door by removing two knurled head screws at
lower front.

3. Lift door away from boiler to remove.

4. Shut off gas to boiler by closing the manual gas valve (Figure 1).

5. Remove propane orifice disc from conversion kit envelope. Read the
stamping on the orifice.

The orifice stamping must agree with the boiler size (see
front page). DO NOT proceed with installation if orifice is
incorrect. Installing the wrong orifice could result in severe
personal injury, death or substantial property damage.

6. Disconnect the gas line union (Figure 1).

7. Remove (3) star-drive screws securing gas valve to venturi (Figure 2).

8. Place orifice in the black rubber grommet in the gas valve outlet port
(Figure 2).

9. Reposition gas valve against venturi and replace (3) screws securing
valve to venturi.

10. Reconnect gas line union.

11. DO NOT ADJUST gas valve pressure. See WARNING, bottom right.

12. Perform leak test and gas pressure checks given on page 19 of Boiler
manual. Verify gas pressure at gas valve inlet pressure tap is in the range
given on the front page of this document and in Boiler Manual.

Figure 1 Gas component locations

Figure 2 Installing propane orifice

Perform Boiler Manual start-up

Follow all instructions in Boiler Manual Section 7, pages 24
through 30, to start-up the boiler after converting for
propane. Because the boiler has been changed, you must
verify correct operation, including checking combustion
with test instruments both at high fire and low fire as
described in the Boiler Manual. Failure to comply could
result in severe personal injury, death or substantial property
damage.

Replace boiler jacket front door

Replace boiler jacket front door after servicing. The boiler
front door must be securely fastened to the boiler to prevent
boiler from drawing air from inside the boiler room. This is
particularly important if the boiler is located in the same
room as other appliances. Failure to keep the door securely
fastened could result in severe personal injury or death.

Apply conversion label

1. After installation is complete, attach the propane conversion label (in
instruction manual envelope) next to the boiler rating plate.

DO NOT adjust or attempt to measure gas
valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas and
propane, requiring no field adjustment.
Attempting to alter or measure the gas
valve outlet pressure could result in
damage to the valve, causing potential
severe personal injury, death or substantial
property damage.

Part number 550-141-951/1002