AERCO ECS Retrofit - Manual (Page 9)

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2.1 Isolating Water Heater
To isolate the Water Heater from all facility energy sources (steam, water, electrical power), proceed
as follows:
1. Disconnect and Lock-Out/Tag-Out external AC power supplied to the Control Box and any
other devices connected to the Heater.
2. Using a voltmeter, check to ensure that all incoming voltage readings are zero Before
continuing.
3. If the Heater is equipped with a Pneumatic Control Valve Actuator, close the valve supplying
air inlet pressure to the Pneumatic Controller.
4. Close all stop valves in the Steam Inlet and Condensate Outlet lines. On water-to-water
systems, do not rely on the Boiler Water Out Check Valve to stop the flow of water.
5. On the water-side, close the stop valves in the following order:
(a) Hot water outlet line
(b) Recirculation line
(c) Cold water inlet line
6. Carefully open the Relief Valve located on the Top Head to relieve pressure in the Heater
Shell. Water should stop flowing from the valve within one minute. If water continues to flow
from the Relief Valve, one of the water stop valves is not securely closed.
2.2 Draining Water Heater
Allow the Water Heater to cool sufficiently prior to draining the unit. When sufficiently cooled, drain as
follows:
1. After ensuring there is no pressure build-up in the Heater Shell (para. 2.1, step 6), block open
the Relief Valve in the Top Head to avoid creating a vacuum in the Heater Shell when it is
drained.
2. Open the Drain Ball Valve in the Bottom Head and allow the potable water in the Heater Shell
to drain completely. If the unit is a Double-Wall Heater (DW-24, DW-45 or DW-68), the Drain is
located on the Shell and may either be plugged with a 3/4” NPT Plug or equipped with a Ball
Valve and additional drain piping. Remove Plug or open Drain Ball Valve as applicable.