Viessmann VITOCAL 151-A Installation And Service Instructions Manual page 145

Extracting the refrigerant
Before commencing work, note the "Checklist for main-
tenance work" on page 136 136 onwards.
Also take into account the following points:
■ Only extraction equipment authorised for R290 (pro-
pane) that has been regularly inspected may be
used.
Check the condition of the extraction equipment,
including the service record.
■ Only use refrigerant bottles suitable for R290, e.g.
special recycling bottles. The refrigerant bottles must
be correspondingly labelled.
The refrigerant bottles must be equipped with a
safety valve and permanently attached shut-off
valves.
■ Check whether a sufficient number of recycling bot-
tles is available.
■ Do not mix together different refrigerants in a single
recovery bottle.
Have suitable transport equipment ready for the
■
refrigerant bottles (if required).
■ Check the availability of personal protective equip-
ment and its proper use.
■ Ensure the refrigerant circuit and all connections
used are free from leaks.
Provide calibrated scales to determine the amount of
■
extracted refrigerant.
01. Check the condition of the heat pump. Check
whether the service intervals have been adhered
to.
02. Isolate the system from the power supply. Safe-
guard against unauthorised reconnection.
Danger
Escaping refrigerant can lead to explosions
that result in very serious injuries.
Do not introduce any power sources or igni-
tion sources into the safety zone.
03. Check whether the safety instructions for work on
the refrigerant circuit are being adhered to: See
"Safety instructions".
04. Place the refrigerant bottle on the scales.
05. Connect the refrigerant bottle to the extraction
equipment. Connect the extraction equipment to
the refrigerant circuit Schrader valve via the mani-
fold.
Outdoor unit maintenance
06. Extract the refrigerant from all parts of the refriger-
ant circuit using the extraction equipment.
Note
■ The refrigerant extraction must be continuously
monitored by an authorised contractor.
Do not overfill the refrigerant bottle, max. 80 %
■
of the permissible capacity.
■ Do not exceed the permissible design pressure
of the refrigerant bottle.
■ Do not mix the refrigerant with other refrigerants.
■ Observe the following technical rules on opera-
tional reliability and hazardous materials:
TRGS 510, TRBS 3145, TRGS 745
07. Separate the refrigerant bottle from the refrigerant
circuit. Close the connection securely. Label the
refrigerant bottle according to the statutory
requirements. Dispose of the refrigerant bottle in a
suitable disposal/recycling facility.
08. Purge the refrigerant circuit with oxygen-free nitro-
gen for 5 min at least twice.
■ On no account use air or compressed air.
■ Observe the permissible operating pressure of
the refrigerant circuit: See "Specification".
09. Release the positive pressure.
10. Evacuate the refrigerant circuit.
Absolute pressure for vacuum according to
EN 378: < 2.7 mbar (< 270 Pa)
Danger
Escaping refrigerant can lead to explosions
that result in very serious injuries.
Ensure the vacuum pump outlet is outside
the safety zone.
11. Carry out a static vacuum test:
Absolute pressure may not exceed 10 mbar
(1 kPa) for at least 30 min.
If the vacuum is not maintained, repeat from
step 8.
12. Repeat steps 8 to 10 until there is no more refrig-
erant in the refrigerant circuit.
Note
On the final purging process, release the positive
pressure down to atmospheric pressure. Do not
evacuate further.
This is especially important if brazing/soldering
work is to be carried out on the refrigerant circuit.
13. Once the refrigerant has been completely evacu-
ated, close the Schrader valves so they are gas-
tight. To achieve this, counterhold the valve body.
Torque for dust cap union nut: 15 Nm
145