LG ARNH08GK3A2 - Manual (Page 441)

Management of plate-type heat exchanger
Bruksanvisning 25 Hydro Kit
NORSK
Management of plate-type heat exchanger
The efficiency of the plate-type heat exchanger will decrease, or the exchanger can be broken due
to freezing and bursting by the flux decrease, as much as scale formation is accumulated.
Because of these reasons, it is necessary to manage the exchanger periodically to avoid scale
formation.
The following items should be checked before the season for use is started. (Interval: Once a year)
1. Analyze water to see if the standard condition is met or not.
2. Clean the strainer.
3. Check whether the flux is proper.
4. Check whether the operating environment is proper.
(Pressure, flow, water outlet temperature, etc.)
Follow the following procedure to clean the plate-type heat exchanger. (Interval: Once a year)
1. For chemical solvent cleaning, check if the water pipe is equipped with service port.
The proper chemical solution for scale cleaning includes formic acid with 5% dilution, citric acid,
oxalic acid, acetic acid, and phosphoric acid. Acetic acid, phosphoric acid, etc. is appropriate.
(※ Never use hydrochloric acid, sulfuric acid and nitric acid as they are corrosive.)
2. When cleaning, make sure to check whether the gate valve of water pipe inlet/outlet and valve of
water discharge pipe are firmly closed.
3. Connect the pipe for chemical solution cleaning through the service plug of the water pipe; and fill
the detergent in 50℃ ~ 60℃ in plate-type heat exchanger and circulate with a pump for 2 ~ 5
hours.
The circulation time depends on the detergentʼs temperature or the degree of the scale formation.
Therefore, observe the color change of the chemical solution well to determine the circulation time
to remove scales.
4. After the solution circulation work, drain off all chemical solutions inside the plate-type heat
exchanger; and fill in 1 ~ 2% concentrated sodium hydroxide (NaOH) or sodium hydrogen car-
bonate NaHCO3 and circulate for 15 ~ 20 minutes to neutralize the heat exchanger.
5. After the neutralization work, wash the inside of the plate-type heat exchanger with clean water.
You can check whether the chemical solution has been successfully removed by measuring pH
concentration of water.
6. In case where other detergent that is available on the market is used, be sure to check in advance
whether it has any corrosive reaction with stainless or copper.
7. For more detail about chemical detergents for cleaning, get consultation from the expert in the
related field.