5)
Check the joints of gas, heat carrier and water subject to disassembling for air tightness (see p
16.2.1, page 39).
16.1.3.
Internal cleaning (washing) of heat exchanger
During the exploitation there is a chance of scale deposit appearance on the inner surfaces of the heat
exchanger 2 (see p. 13.1, page 7).
To remove scale deposit it is necessary to:
1)
Demount the heat exchanger (see p. 17.2, page 42) and put it into a tank;
2)
prepare 10% solution of citric acid (100 g of powdered citric acid for 1 liter of warm water);
3)
Fill this solution into heat exchanger’s pipeline;
4)
Keep this solution there for 10-15 minutes, then drain it and wash heat exchanger’s pipeline (coil)
thoroughly with water and if necessary to repeat all the procedure;
5)
Mount the heat exchanger with new gaskets;
6)
Check the joints of gas, heat carrier and water subject to disassembling for air tightness (see p.
16.2.1 , page 39).
Also it is necessary to clean the DHW water filter. It is located in the DHW flow sensor and can be
demounted by means of screwdriver or any other sharp instrument.
16.1.4.
Internal cleaning (washing) of the secondary heat exchanger
During the exploitation there is a chance of scale deposit appearance on the inner surfaces of the
secondary heat exchanger pos. 3 (see p. 13.1, page 27).
You must demount the secondary heat exchanger (see p. 5), page 44).
The instructions on scale deposit removal are represented in 16.1.3.
Also it is necessary to clean the DHW water filter. It is located in the DHW flow sensor and can be
demounted by means of screwdriver or any other sharp instrument.
16.2
Boiler’s operation check
At every boiler’s technical service it is necessary to check:
1)
Constant voltage regulator presence;
2)
Voltage and frequency of inlet current in the boiler in accordance with indicated technical requirements on
the data plate (see p. 2.2, page 5);
3)
Whether natural gas is supplied with the rated pressure 1,3-2,0 kPа (130-200 mm w.g.) or liquefied gas
with the rated pressure 2,9 kPa (300 mm w.g.) It is necessary to measure pressure while the boiler is on.
Before checking gas and hydraulic systems for air tightness, or any other safety device, it is necessary to put a
casing and sealing cap off from the boiler (see p. 17.1, page 41, the first 7 points).
16.2.1
Checking the boiler’s gas, heating and DHW systems’ on air-tightness.
CAUTION! Checking of gas joints’ air-tightness is performed by soap solution bubble test (or any other
safe methods without using open flame sources). Appearance of bubbles means gas leakage.
Check of air-tightness is performed in such joints as: gas supply regulator with gas supply pipe, gas pipe with
burner block and gas supply regulator, and also in the control points A and B of gas supply regulator (see scheme
13, page 25).
Checking the heating and DHW systems for air-tightness is performed alternatively in heating and DHW
modes. The joins of the boiler with the heating system and DHW, the heat exchanger with the hydraulic group,
the air-tightness of hydraulic group elements are checked. Leakage in the joints is not allowed.
In case of gas, heat carrier or water leakage detection it is necessary to remove it by tightening the nuts
(gauges) or installing a new sealing.
16.2.2
Checking of safety device operation
16.2.2.1
Checking of heat carrier pressure sensor in the heating system
Before switching the boiler on, put the cables off from the pressure sensor 14 (see p.13.1, page 27). At
launching attempt the boiler will show the symbol "04" on display, signaling about the emergency situation in the
CH..
After eliminating the reasons of boiler’s emergency switching off (connecting the cables to the thermo
relay),and pressing the button K6 (RESET), the boiler should automatically switch on.
16.2.2.2
Checking of heat carrier overheating protection in the heating system
Put the cables off from the thermo relay 15 from the operating boiler (see p. 13.1, page 27). The boiler should
switch off and show the symbol "02" on display. After eliminating the reasons of the emergency switching off
(connecting cables to the thermo relay) and pressing the button К6 (RESET) ,the boiler should automatically
switch on.
16.2.2.3
Checking of bypass valve operation
When the boiler is working in the heating mode (see p. 3.2.4, page 10) it is necessary to shut off a stop valve
on the heating system inlet. Bypass valve 20 (see p. 13.1, page 27) should direct the heat carrier bypass from the
heating system through the bypass pipe. The bypass pipe must warm up. After checking it is necessary to open a
stop valve on the heating system inlet.
16.2.2.4
Checking of safety valve operation
Checking of operation of the safety valve 22 (see p.13.1, page 27) implies turning the knob on the valve to the
left (counterclockwise) in order to let water ejection out of the valve. The valve should close by itself.