Installation Guide
Part number 550-100-066/0608
91
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Maintenance (continued)
Accessing & cleaning exchanger: Ultra-155,
-230, and -310 Only
Close the external manual gas valve.1.
Disconnectwiring:•gasvalveelectricalplug•twoelectricalmolex2.
plugsfromtheblowerassembly•ignitioncable•groundwire.
Disconnect the exible gas line at its are fitting.3.
Remove the air silencer by lifting the plastic clamp off of the gas line 4.
and then gently sliding the air silencer down and off the valve.
Remove hex head nuts (10mm box end wrench) from heat ex-5.
changer cover plate and remove burner cover plate from heat
exchanger.
Pull the entire blower/venturi/gas valve/cover plate assembly out 6.
of the boiler. (See Replacement parts section for component iden-
tification and locations.)
Remove three M4 hex head screws (7mm box end wrench) and 7.
burner clips securing burner to cover plate. Remove cover plate.
Use a vacuum cleaner to remove any accumulation on the heating 8.
surfaces. Do not use any solvent.
If the vacuum cleaner is unable to clean completely, wash the 9.
heating surfaces with clean, warm water. If further cleaning is
necessary, use the Heat Exchanger Cleaning Tool (see Replacement
parts at the end of this manual) or a piece of 20-gauge or lighter
sheet metal ¾” wide by about 18 inches long to loosen deposits.
See Figure 98, page 90.
Inspect the heat exchanger cover plate insulation and gasket. Re-10.
place if damaged. Read the ceramic fiber WARNING on page 79
before handling or disposing of ceramic fiber materials.
Replace the burner, hex head screws and burner clips removed in 11.
step 7. See Figure 93, page 82.
Place cover plate gasket in groove of heat exchanger cover plate. 12.
Replace cover plate.
Reinstall hex head nuts on the cover plate mounting studs and 13.
tighten in a staggering pattern until cover plate is uniformly
tightened.
You must gradually tighten the cover plate nuts. For
Ultra-155 through -310, follow the tightening sequence
shown in Figure 99, making two or three passes with a
torque wrench. The final torque MUST NOT exceed
50 inch-pounds, +/- 10 inch-pounds.
Reinstall air silencer by sliding on gas valve venturi and securing 14.
clamp to gas line.
Reconnectwiring:•gasvalveelectricalplug•twoelectricalmolex15.
plugsfromtheblowerassembly•ignitioncable•groundwire.
Reconnect the exible gas line and gas valve electrical plug.16.
Perform a soap suds leak test on all interior gas piping after start-17.
ing the boiler.
Cleaning the heat exchanger — water side (ALL
models)
Follow the procedure given in 1. “Clean the cast aluminum heat
exchanger,” page 72 to clean the water side of the exchanger.
Follow the complete procedure for boiler and system start-up, 2.
beginning on page 70.