• VRV
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Systems • Installation procedure
11
• Installation procedure
1
Installation of outdoor
1 - 6 Handling of the plate type heat exchanger
1 - 6 - 5
Maintenance of plate type heat exchanger
The performance of a plate type heat exchanger may decline due to scale accumulation. It may be damaged by freezing due to the drop of flow rate.
For this reason, it is necessary to carry out programmed maintenances at a regular interval in order to prevent the scale from being generated.
1
Before entering the season for use, carry out the following inspections:
•
Conduct a water quality test and make sure that it is within the standard.
•
Clean the strainer.
•
Make sure that the flow rate is correct.
•
Make sure that the operational conditions (pressure, flow rate, outlet temperature, etc.) are normal.
2
Because the plate type heat exchanger has a structure which does not permit disassembling and cleaning, follow the following procedures for
cleaning:
•
Make sure that a connection port for piping has been reserved for cleaning by chemicals. For chemicals to clean the scale, solution with 5%
diluted formic acid, citric acid, oxalic acid, acetic acid, phosphoric acid, etc. is recommendable.
Never use hydrochloric acid, sulfuric acid, nitric acid, etc., because they have strong corrosive features.
•
Make sure that a valve has been reserved for each before the inlet connection port and after the outlet connection port.
•
Connect the piping for circulation of cleaning chemicals to the inlet piping of plate type heat exchanger. Fill the cleaning solution of 50 - 60°C
for a while in the plate type heat exchanger.
Then, circulate the cleaning solution by a pump for 2-5 hours.
The time for cleaning depends on the temperature of cleaning solution or the degree of scale accumulation.
Therefore, please watch the change of the dirtiness (color) of cleaning solution to determine the level of removal of scale.
•
After circulating the cleaning solution, discharge the solution from the plate type heat exchanger, fill the heat exchanger with a solution of 1-
2% sodium hydroxide (NaOH) or sodium bicarbonate (NaHCO3). Circulate this solution for 15-20 minutes for neutralization purpose.
•
After the process of neutralization has been completed, rinse the inner part of the plate type heat exchanger with care using fresh and clean
water.
•
When using any cleaning agent sold in the market, check in advance that such agent has no corrosive features against stainless steel and
copper.
•
For details of cleaning method, ask the manufacturer of related cleaning agent.
3
After cleaning has been completed, make sure that the unit can be operated in a normal fashion.
