Innovation - Edge [i] Installation, Operation, Maintenance Manual
CHAPTER 6
– MAINTENANCE
OMM-0143_A
• GF
-216
•
9/6/2019
Technical Support
•
(800) 526-0288
•
Mon-Fri, 8 am - 5 pm EST Page 86 of 170
6.8 WATERSIDE INSPECTION AND CLEANING
6.8.1 Waterside Inspection-Cleaning Schedule
For units installed at sites with hard water (>3.5 grains/gal, >59.9 mg/L), AERCO strongly
recommends use of Watts
OneFlow
®
anti-scaling system (note, this system does not protect
against orthophosphates, which can also cause scale deposits). It provides an economical,
chemical free treatment of hard water, allowing the water heater to perform at its peak heat
transfer efficiency, thereby reducing heating cost.
AERCO requires
that the unit’s heat exchanger be inspected per the schedule in Table 6-8,
below. If scale deposits are observed at the top inspection port (the most likely area for scale
deposits), the heat exchanger must be cleaned, as described in Section 6.8.3.
The frequency of cleaning can be determined at each site based on inspection results,
performance of the unit, and/or experience with similar equipment. The cleaning frequency may
be affected by the quality of the inlet water (see Section 6.2: Water Quality Guideline), but it
generally follows the inspection schedule shown in Table 6-2.
If the inlet water contains orthophosphates, the unit must be inspected every 6 months and
cleaned as needed.
TABLE 6-8: Required Heat Exchanger Inspection and Cleaning Schedule
Operating
Conditions
Inspection/Cleaning Frequency
24-months
12-months
6-months
Monthly
Domestic Water
Setpoint
<130ºF
(54.4 ºC)
140 - 160ºF
(60 - 71ºC)
160 - 180ºF
(71 - 82ºC)
>15 grains/gal
(>257 mg/L*)
Calcium Hardness
Level at water inlet
<7 grains/gal
(<120 mg/L*)
3.5
– 9.9 grains/gal
(60 - 170 mg/L*)
3.5
– 15 grains/gal
(60 - 257 mg/L*)
* 1 mg/L = 1 ppm
NOTE:
In Table 6-8, if calcium hardness level, and domestic water setpoint fall under different
cleaning intervals, the heat exchanger must be cleaned at 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.
For example, if: Domestic water setpoint = 125ºF (51.7ºC) and
Calcium Hardness level = 9.5 grains/gal (163 mg/L)
Start with
a 12 month cleaning frequency (125ºF setpoint
falls under “24-months” and calcium
hardness falls under “12-months”). Observe the next few cleanings to determine how much
scale is removed to decide if 18-month cleaning frequency is more appropriate.