Install Instructions

Part number 550-100-055/0618
10
gas-fired water boilers — Heat Exchanger Block Replacement Instructions
Ultra-155, -230, 299, 310 & 399 Heat Exchanger Block Replacement
You must refer to the Ultra Boiler Manual to follow these instructions. DO NOT proceed with the replacement
procedure without having an Ultra Boiler Manual. Failure to comply can result in severe personal injury, death or
substantial property damage.
e boiler contains ceramic ber materi-
als. Use care when handling these materi-
als per Ultra Boiler Manual. Failure to
comply could result in severe personal
injury.
ELECTRICAL SHOCK HAZARD —
For your safety, turn o electrical power
supply at service entrance panel before
making any electrical connections to avoid
possible electric shock hazard. Failure to
do so can cause severe personal injury or
death.
Refer to the Ultra Boiler Manual for compo-
nent locations and illustrations.
Weil-McLain changed the Ultra heat exchanger sen-
sors in June 2014. Ultra Series 1 & 2 boilers utilized
a supply and return temperature sensor that has an
M4 thread with two stake on terminals. Series 3
Ultra boilers utilize a supply and return temperature
sensor that has an M4 thread with a 4 pin molex con-
nector. Aer June 2014, Weil-McLain began using a
supply and return sensor with an M6 thread with a
4 pin molex connector.
All replacement heat exchangers come with the supply
and return sensor with the M6 thread. To connect
the sensors to the Ultra Series 3 wiring, simply plug
in the supply and return, 4 pin molex connector to
the new sensors in the heat exchanger. To connect the
new sensors in the replacement heat exchanger to the
Ultra Series 1 & 2 sensor wiring, two (2) 4 pin molex
adapters with butt connectors are included with the
heat exchanger replacement kit. To connect the new
4 pin molex connectors to the Series 1 & 2 wiring, cut
and strip the boiler sensor wiring close to the stake on
terminals, connect and crimp the sensor wires into the
butt connectors of the adapters. Aer crimping the
butt connectors, plug in the 4 pin molex connector
to the supply sensor and the return sensor.
See Figures 14 below and 15 on page 11, showing location
of the M6 sensors with adapters.
STOP!
Read before proceeding
Shut off power to the boiler and close
main gas valve. Close all isolation valves
.
Failure to do so can result in severe personal
injury, death or substantial property damage.
Wait for the heat exchanger to cool down
before proceeding
. Failure to do so can
result in severe personal injury.
Reinstall boiler front door after start-up
or servicing
. e boiler front door must be
securely fastened to the boiler to prevent
boiler from drawing air from inside the
boiler room. is is particularly important
if the boiler is located in the same room as
other appliances.
Inspect boiler jacket door gaskets. Gaskets
must be in good condition, with no tears or
gaps. Replace if necessary.
Failure to keep the door securely sealed
and fastened could result in severe personal
injury or death.
Removing and reinstalling components can
change boiler behavior. Aer any mainte-
nance procedure, you must prove the boiler
is operating correctly. To do so, follow the
complete procedure for boiler and system
start-up as instructed in the Boiler Manual
.
Failure to comply could result in severe per-
sonal injury, death or substantial property
damage.
Figure 14 M6 sensor (Lower sensor)
NOTICE !
For new Ultra Series 3 boilers manufactured aer
July 2016 (tagged, and visually marked/stamped on the
right side of the block):
Limit cleaning to the use of vacuum or water-
only rinsing for the first 5 years of operation.
No tool cleaning is necessary.