Mamiya C32 manual Mini HE C24, mini HE C28, Size of expansion vessel

GENERAL

Table 5 mini HE C24, mini HE C28

System charge pressure	0.5		0.7	1.0
(bar)
Safety valve setting			3.0
Vessel pre---charge pressure		0.7
(bar)
System volume (litres)	Volume of expansion vessel
	in addition to 6 litre unit
		fitted to boiler
75	---		---	---
100	0.3		0.8	1.4
125	1.8		2.5	3.2
150	3.4		4.2	5.0
175	5.0		6.0	7.0
200	6.5		7.6	8.7
225	8.1		9.3	10.6
250	9.6		11.1	12.4
275	11.2		12.8	14.3
300	12.8		14.5	16.1
Multiply this factor by	0.063		0.069	0.074
system volume and deduct
6 litres to obtain size of
additional vessel for other
system volumes.

5Size of expansion vessel

For the system water expansion to be contained by the 6 litre expansion vessel fitted to the following models:

mini HE C24, mini HE C28

the cold system volume must not exceed:

96 litres when pressurised to 0.5 bar (cold)

88 litres when pressurised to 0.7 bar (cold)

81 litres when pressurised to 1.0 bar (cold)

Table 6 mini HE C32

System charge pressure	0.5		0.7	1.0
(bar)
Safety valve setting			3.0
Vessel pre---charge pressure		0.7
(bar)
System volume (litres)	Volume of expansion vessel
	in addition to 7 litre unit
		fitted to boiler
75	---		---	---
100	---		---	0.4
125	0.8		1.6	2.3
150	2.5		3.4	4.1
175	4.0		5.1	6.0
200	5.6		6.8	7.8
225	7.2		8.6	9.7
250	8.8		10.3	11.5
275	10.3		12.0	13.4
300	11.9		13.7	15.2
Multiply this factor by	0.063		0.069	0.074
system volume and deduct
7 litres to obtain size of
additional vessel for other
system volumes.

For the system water expansion to be contained by the 7 litre expansion vessel fitted to the following model:

mini HE C32

the cold system volume must not exceed:

111 litres when pressurised to 0.5 bar (cold)

101 litres when pressurised to 0.7 bar (cold)

95 litres when pressurised to 1.0 bar (cold)

If the pressure exceeds 2.65 bar when the boiler is up to temperature with all radiators in use then an additional expansion vessel MUST be installed on the return pipework.

If the pressure exceeds 2.65 bar when the boiler is up to temperature with all radiators in use then an additional expansion vessel MUST be installed on the return pipework.

For expansion volumes see Table 5.

For expansion volumes see Table 6.

Guidance on vessel sizing is given in BS 7074:1 and BS 5449

For IE refer to the current edition of I.S. 813.

6Hydraulic Loss Remaining pump capacity

mH2O

6

5

4

3

2

1

0

0 200 400 600 800 1000 1200 1400

7Draining the system

Draining taps MUST be located in accessible positions to permit the draining of the whole central heating system, including the central heating side of the boiler. The taps should be at least 1/2” BSP nominal size and be in accordance with BS 2879.

Flow rate l/hour

mini HE --- Installation & Servicing 11