AERCO SmartPlate - Manual (Page 44)

SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 6 – SCHEDULED MAINTENANCE
Page 44 of 138 AERCO International, Inc.  100 Oritani Dr.  Blauvelt, NY 10913 OMM-0069_0E
PRI: 11/26/2013 Phone: 800-526-0288 SP-100
Example:
BW inlet temperature = 180ºF
Domestic water setpoint = 140ºF
Calcium Hardness level = 40 mg/L
Heat exchanger Cleaning Frequency: Start out with semi-annually (every six months) schedule
(180ºF BW falls under semi-annually and the DHW setpoint and calcium hardness level fall
under annually). Observe the next few cleanings on how much scale is removed to determine if
an annual (yearly) cleaning frequency is more appropriate.
The domestic water differential pressure can also be checked to determine if the heat
exchanger needs cleaning. Check the differential pressure on the domestic water side of the
SmartPlate Heater as follows:
1. Turn OFF the external power circuit breaker to the SmartPlate and also turn OFF the
POWER Switch on the side of the ECS/SP Control Box.
2. Connect a hose to the DHW Drain Valve (Figure 6-2).
3. Close both Isolation Ball Valves on the DHW piping.
4. Open the Heater Drain Valve.
5. Remove the 1/4” NPT plug from the DHW Strainer to allow air to enter the piping while
draining.
6. When domestic water has drained, remove the 1/4” NPT plugs from the domestic water
inlet and DHW outlet isolation ball valves.
7. Refer to Figure 6-2 and Install pressure gauges at each 1/4" NPT connection on the DHW
piping where the 1/4" plugs were removed. Both gauges should have PSI scales which
have upper limits of 1.5 to 2 times the water inlet pressure and a resolution sufficient to
recognize a 5 psi pressure difference.
8. Close the DHW Drain Valve that was opened in step 4.
9. Connect a hose to the Blow-Down Valve on the Inlet Strainer. Open this Blow-Down Valve
on the Strainer to vent air during the filling process.
10. Open the lower Isolation Ball Valve (DHW Outlet).
11. Next, close the Blow-Down Valve on the Inlet Strainer and open the upper Isolation Ball
Valve (DHW Inlet).
12. Check the pressure readings on the gauges to ensure that the difference is 5 psig or less
at the design flow rate of the heater.
13. If the difference between the pressure readings is greater than 5 psig, this indicates that
the heat exchanger requires de-scaling. Refer to paragraph 8.2.1 for Heat Exchanger De-
Scaling procedure. For Double-Wall Models with harder scale deposits, manual cleaning
by disassembly can be performed (see paragraph 8.6.2).
14. After de-scaling, if the difference between the pressure readings is still greater than 5
psig, replace the plates or heat exchanger as necessary. Refer to paragraph 8.4 for
Single-Wall Heat Exchangers or 8.9 for Double-Wall Heat Exchanger replacement
procedures.