SmartPlate EV Installation, Operation and Maintenance Manual
CHAPTER 6
– SCHEDULED MAINTENANCE
OMM-0147_C
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SENSOR CHECKS
Instructions
7. On the flow meter, remove the U-Clip from the retaining slot on the tee. Examine the
sensor body for scale. Check the paddlewheel for free spin by blowing lightly on the rotor.
Take extreme caution to avoid dropping or otherwise damaging the paddlewheel
while out of the assembly piping.
Reinstall the flow meter and U-Clip.
8.
Check pressure transducers for scale.
6.7 PERIODIC CLEANING OF HEAT EXCHANGER
It may be necessary to de-scale the heat exchanger periodically, depending on water conditions
and temperature settings. See Section 8.2 for descaling instructions.
The frequency of cleaning can be determined locally based on the performance of the heater
and/or prior experience with similar equipment. Generally, the cleaning requirements will follow
the trends shown in Table 6-2:
TABLE 6-2. Heat Exchanger Cleaning Guidelines
Operating Conditions
Projected Cleaning Frequency
Bi-Annually
Annually
Semi-Annually
Monthly
Boiler Water Inlet Temp
<150°F
150 -170°F
170 - 190°F
Domestic Water Setpoint
<130°F
130 - 160°F
160 - 180°F
Calcium Hardness Level
<60 mg/L
60 - 120 mg/L
120 - 180 mg/L
>180 mg/L
If calcium hardness level, boiler water inlet temperature, and domestic water setpoint fall under
different cleaning intervals in Table 6-2, the heat exchanger may be cleaned between those
periods, starting with the most frequent interval. During the next few cleaning intervals observe
how much scale is removed to determine if less frequent intervals can be followed.
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.
NOTE:
Refer to Section 8.2.1 for heat exchanger maintenance procedure.
