Page 24 Section 7: Maintenance
7.4 EXPANSION VESSEL SERVICING
Two expansion vessels are supplied tted to Grant QR integrated
indirect heat pump cylinders. One serves the primary circuit and
the other serves the secondary circuit. Refer to Figure 2-2 for
location.
In order to gain access to the vessels for servicing, it will be
necessary to rst remove the expansion vessel cover plate.
To do this:
1. Hinge open upper front panel (see Figure 2-1) to expose the
expansion vessel cover plate.
2. Carefully remove the ve screws securing the expansion
vessel cover plate and remove the cover plate.
3. Retting is the reverse of removal.
Service the expansion vessels as follows:
7.4.1 PRIMARY CIRCUIT EXPANSION VESSEL
1. Ensure that the system is cold.
2. Use the primary system pressure gauge on the hot water
cylinder control panel (refer to Figure 2-2 for location) to
ensure that the primary circuit water pressure is zero bar.
If it is not, drain the system as per the heating appliance
manufacturer’s instructions.
3. With the cylinder expansion vessel cover plate removed,
locate the primary circuit expansion vessel (see Figure 2-2)
and unscrew the black cap covering the expansion vessel
Schraeder valve.
4. Check the expansion vessel charge pressure using a tyre
pressure gauge and re-pressurise as necessary using a
suitable pump.
The expansion vessel charge pressure should always be
slightly greater than the maximum static head of the system,
in bar, at the level of the vessel (1 bar = 10.2 metres of
water).
The charge pressure must not be less than the actual static
head at the point of connection.
The primary circuit expansion vessel is supplied with a pre-
charge of 1.0 bar.
5. Replace the expansion vessel if necessary.
6. When the primary circuit expansion vessel charge has been
checked and re-charged as necessary, re-ll the primary
circuit according to the heating appliance manufacturer’s
instructions.
7.4.2 SECONDARY CIRCUIT EXPANSION
VESSEL
1. Isolate the cold water supply to the cylinder.
2. Open hot water taps.
3. Drain cylinder to below the expansion vessel connection.
Refer to Section 6.2.
4. With the cylinder expansion vessel cover plate removed,
locate the secondary circuit expansion vessel (see Figure
2-2) and unscrew the black cap covering the expansion
vessel Schraeder valve.
5. Check the expansion vessel charge pressure using a tyre
pressure gauge and re-pressurise as necessary using a
suitable pump. The correct air-pressure charge for the
secondary circuit expansion vessel is 3.0 bar.
6. Replace the expansion vessel if necessary.
7. Close cylinder drain o cock and turn on cold water supply.
8. Rell cylinder, refer to Section 6.1.
9. When water is owing freely from taps close taps.
To Next Page
Loading...
Need help?
General
