Refractory Replacement - Bmk5000 & 6000 Only; Shutting Boiler Down For Extended Period - Watts AERCO Benchmark BMK5000 Operation And Service Manual

Benchmark Platinum-Edge [ii]: Operation-Service Manual
SECTION 8 – MAINTENANCE
Refractory Replacement – BMK5000 & 6000 ONLY
8.9
A low mass, fiber-based material insulates the front and rear end plates of the combustion
chamber. This material has very low thermal conductivity and is not susceptible to thermal shock
conditions that cause failures of hard-faced refractory materials.
WARNING!
The heat exchanger insulation utilizes ceramic fiber material. Wear a fitted NIOSH-approved
particulate respirator (3m n95 or equivalent) When servicing the heat exchanger and burner
assemblies. At high temperatures, ceramic fibers can be converted to crystalline silica fibers,
which have been identified as carcinogenic when inhaled.
In the event that access to the unit's combustion chamber is required, the preferred method is to
remove the rear refractory first, since it is a much less complicated procedure; removing the front
refractory requires first removing the blower, burner and air/fuel valve assemblies before reaching
the refractory material.
If either the front or rear refractory needs to be replaced, obtain one of the Benchmark 5000/6000
Refractory Replacement kits from AERCO. There are three kits available:
•
P/N 58197-1 – Front Refractory for units with Front Burner Plate 42255
•
P/N 58197-2 – Front Refractory for units with Front Burner Plate 43071
•
P/N 58197-3 – Rear Refractory
Instructions for replacing both are included in technical Instruction Document TID-0221, included
with the kit.

8.10 SHUTTING BOILER DOWN FOR EXTENDED PERIOD

If the boiler is to be taken out of service for an extended period of time (one year or more), the
following instructions must be followed.
Shutting Boiler Down for An Extended Period Instructions
1. Set Enable/Disable switch on the front panel to the Disable position to shut down the boiler's
operating controls.
2. Disconnect AC power from the unit.
3. Close the water supply and return valves to isolate boiler.
4. Close external gas supply valve.
5. Open relief valve to vent water pressure.
6. Open the drain valve and drain all water from the unit.
7. If the temperature in the storage location will ever get below freezing, for even a short
time, you must drain all water from the unit before the temperature falls below freezing.
Step 6 is not sufficient, as it leaves some water in the bottom of the heat exchanger
chamber. You must then use a suction pump inserted through the inspection ports to
remove all water from the bottoms of the heat exchanger chamber and base assembly.
WARNING!
If the temperature will ever fall below freezing, failure to drain all water can cause heat
exchanger tubes to crack and fail.
OMM-0137_J •
12/20/2022
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