35
12.6 - air heat exchanger
We recommend, that finned coils are inspected regularly to
check the degree of fouling. This depends on the environment
where the unit is installed, and will be worse in urban and
industrial installations and near trees that shed their leaves.
For coil cleaning, two maintenance levels are used, based on
the AFNOR X60-010 standard:
level 1
•
If the air heat exchangers are fouled, clean them gently in
a vertical direction, using a brush.
•
Only work on air heat exchangers with the fans switched off.
For this type of operation switch off the HVAC unit if
service considerations allow this.
Clean air heat exchangers guarantee optimal operation of
your HVAC unit. This cleaning is necessary when the air
heat exchangers begin to become fouled. The frequency of
cleaning depends on the season and location of the HVAC
unit (ventilated, wooded, dusty area, etc.).
level 2
•
Clean the coil, using appropriate products.
We recommend TOTALINE products for coil cleaning:
Part No. P902 DT 05EE: traditional cleaning method
Part No. P902 CL 05EE: cleaning and degreasing.
These products have a neutral pH value, do not contain phos-
phates, are not harmful to the human body, and can be disposed
of through the public drainage system.
Depending on the degree of fouling both products can be used
diluted or undiluted.
For normal maintenance routines we recommend using 1 kg of
the concentrated product, diluted to 10%, to treat a coil surface
of 2 m
2
. This process can either be carried out using a high-
pressure spray gun in the low-pressure position. With pressurised
cleaning methods care should be taken not to damage the coil
fins. The spraying of the coil must be done:
-
in the direction of the fins
-
in the opposite direction of the air flow direction
-
with a large diffuser (25-30°)
-
at a minimum distance of 300 mm from the coil.
The two cleaning products can be used for any of the following
coil finishes: Cu/Al, Cu/Al with Italcoat protection.
It is not necessary to rinse the coil, as the products used are pH
neutral. To ensure that the coil is perfectly clean, we recommend
rinsing with a low water flow rate. The pH value of the water
used should be between 7 and 8.
WARNING: Never use pressurized water without a large
diffuser. Do not use high-pressure cleaners!
Concentrated and/or rotating water jets are strictly forbidden.
Never use a fluid with a temperature above 45°C to clean the
air heat exchangers.
Correct and frequent cleaning (approximately every three
months) will prevent 2/3 of the corrosion problems.
Protect the control box during cleaning operations.
12.7 - Water heat exchanger maintenance
Check that:
•
the insulating foam is intact and securely in place.
•
the cooler heaters are operating, secure and correctly
positioned.
•
the water-side connections are clean and show no sign of
leakage.
12.8 - Characteristics of R-410a
See the table below.
saturated temperatures (°C) based on the relative
pressure (kPa).
saturated
Relative
saturated
Relative
temperature
pressure
temperature
pressure
-20
297
25
1552
-19
312
26
1596
-18
328
27
1641
-17
345
28
1687
-16
361
29
1734
-15
379
30
1781
-14
397
31
1830
-13
415
32
1880
-12
434
33
1930
-11
453
34
1981
-10
473
35
2034
-9
493
36
2087
-8
514
37
2142
-7
535
38
2197
-6
557
39
2253
-5
579
40
2311
-4
602
41
2369
-3
626
42
2429
-2
650
43
2490
-1
674
44
2551
0
700
45
2614
1
726
46
2678
2
752
47
2744
3
779
48
2810
4
807
49
2878
5
835
50
2947
6
864
51
3017
7
894
52
3088
8
924
53
3161
9
956
54
3234
10
987
55
3310
11
1020
56
3386
12
1053
57
3464
13
1087
58
3543
14
1121
59
3624
15
1156
60
3706
16
1192
61
3789
17
1229
62
3874
18
1267
63
3961
19
1305
64
4049
20
1344
65
4138
21
1384
66
4229
22
1425
67
4322
23
1467
68
4416
24
1509
69
4512
70
4610
Aquasnap Puron units use high-pressure R-410A refrigerant
(the unit service pressure is above 40 bar, the pressure at 35°C
air temperature is 50% higher than for R-22). Special
equipment must be used when working on the refrigerant
circuit (pressure gauge, charge transfer, etc.).
