Product Overview

36
CAUTION
LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING CONTROLS. WIRING ERRORS
CANCAUSEIMPROPERANDDANGEROUSOPERATION.VERIFYPROPEROPERATIONAFTER
SERVICING.
10) Inspect the vent system:
• Make sure that the vent system is free of obstructions.
• Make sure that all vent system supports are intact.
• Inspectjointsforsignsofcondensateoruegasleakage.
• Inspect venting components for corrosion or other deterioration. Replace any defective vent components.
11) Inspect the boiler and system for leaks.
12) Inspect the low water cut-off:
• For Hydrolevel CG400A low water cut-offs - Remove and inspect the probe for scale and sediment buildup. Clean
any sediment or scale from the probe with a scouring pad or steel wool. Consult the Hydrolevel CG400 manual for
any additional maintenance information. Test the low water cut-off before placing the boiler back into service.
• ForMcDonnell&Miller#67lowwatercut-offs-Removeandinspectswitchandoatmechanism.Inspectoat
bowlformudaccumulation.Cleanasrequired.Replacetheswitchandoatmechanismeveryveyearsor100,000
cycles. Consult the McDonnell and Miller #67 manual for any additional maintenance information. Test the low
water cut-off before placing the boiler back into service.
13) Allow the boiler to cool to room temperature. Remove the drain valve and 2 x 3/4 bushing on the left side of the boiler.
Useaashlighttoinspectthebottomrowofpushnipplesforaccumulatedscaleormud.Ifasignicantamountis
present, use the following procedure to clean the inside of the heat exchanger:
a) Temporarily install a 1 1/4 inch or larger full port ball valve in place of the boiler drain. Temporarily pipe the outlet
of this valve to a location where hot water and steam can be safely discharged.
b) Make sure that this valve is closed and that the water level is at the normal water line.
c) If a king valve is present in the steam main takeoff, close it. Alternatively, temporarily replace enough of the
 ventsonthemainsand/orradiatorswithplugssothat2-5psicanbedevelopedwhentheboilerisred.
d) Fire the boiler and allow it to steam until 2-5 psi is registered on the gauge.
e) Turn off the burners and immediately fully open the 1-1/4 valve.
f) Allow the boiler to blow down until either the water runs clear or the water level reaches the bottom of the gauge
glass.
g) Allow all parts of the boiler to cool to room temperature. Drain the boiler completely and remove the 1-1/4 valve.
h) Ifsignicantmudorscaleisstillpresentinthebottomoftheboiler,repeatsteps(b)through(g)untilallmudor
scale is removed.
i) Once all mud or scale is removed, replace the 1-1/4 valve and temporary blow-down piping with the standard drain
 valve.Afterallpartsoftheboilerareatroomtemperature,relltheboilertothenormalwaterline.
14) Place the boiler back in operation using the procedure outlined in “Start-up”. Check the pilot line and any other gas
piping disturbed during the inspection process for leaks.
XII. Service Instructions (continued)