Changing The Pre-Pressure Of The Expansion Vessel; To Check The Water Volume: Examples - Daikin EGSQH10S18AA9W Installer's Reference Manual

FHL1...3 Floor heating loop (field supply)
T1...3 Individual room thermostat (optional)
M1...3 Individual motorised valve to control loop FHL1...3 (field
supply)
Maximum water volume
Use the following graphs to determine the maximum water volume
for the calculated pre-pressure. For brine, this is dependent on the
variation of brine temperature in the system. Example: throughout
the year, the temperature of the brine can fluctuate between –7°C
and 10°C, as in graph 1, or between 0°C and 10°C as in graph 2.
Graph 1: Brine temperature fluctuation is 17°C
a
2.5
2
1.5
1
0.5
0.3
0
0 200 400
20
a Pre-pressure (bar)
b Maximum water volume (l)
Space heating vessel
40% propylene glycol (brine expansion vessel)
29% ethanol (brine expansion vessel)
Graph 2: Brine temperature fluctuation is 10°C
a
2.5
2
1.5
1
0.5
0
0 500
20
a Pre-pressure (bar)
b Maximum water volume (l)
Space heating vessel
40% propylene glycol (brine expansion vessel)
29% ethanol (brine expansion vessel)
Minimum flow rate
Check that the minimum flow rate (required during defrost/backup
heater operation) in the installation is guaranteed in all conditions.
EGSQH10S18AA9W
Daikin Altherma ground source heat pump
4P351748-1D – 2016.02
600 800 1000
b
1000 1500 1750
b
NOTICE
When circulation in each or certain space heating loops is
controlled by remotely controlled valves, it is important that
the minimum flow rate is guaranteed, even if all valves are
closed. In case the minimum flow rate cannot be reached,
a flow error 7H will be generated (no heating/operation).
Minimum required flow rate during backup heater operation
12 l/min
See the recommended procedure as described in
during commissioning" on page 55.
6.3.4 Changing the pre-pressure of the
expansion vessel
NOTICE
Only a licensed installer may adjust the pre-pressure of the
expansion vessel.
When changing the default pre-pressure of the expansion vessel
(1 bar) is required, take following guidelines into account:
▪ Only use dry nitrogen to set the expansion vessel pre-pressure.
▪ Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system.
Changing the pre-pressure of the expansion vessel should be done
by releasing or increasing nitrogen pressure through the schräder
valve of the expansion vessel.
a
a Schräder valve
6.3.5

To check the water volume: Examples

Example 1
The indoor unit is installed 5 m below the highest point in the water
circuit. The total water volume in the water circuit is 100 l.
No actions or adjustments are required.
Example 2
The indoor unit is installed at the highest point in the water circuit.
The total water volume in the water circuit is 300 l.
Actions:
▪ Because the total water volume (300 l) is more than the default
water volume (280 l), the pre-pressure must be decreased.
▪ The required pre-pressure is:
Pg = (0.3+(H/10)) bar = (0.3+(0/10)) bar=0.3 bar.
▪ The corresponding maximum water volume at 0.3 bar is 350 l.
(See the graph in the chapter above).
▪ Because 300 l is lower than 350 l, the expansion vessel is
appropriate for the installation.
6 Preparation
"9.4 Checklist
a
Installer reference guide
21