The cyclic changeover will balance the runtimes of the connected heat generators.
The cyclic changeover sequence (a 4 digit number) can be defined with the parameter CYC-01. The first two (thousands and hundreds) define the start position and the last two digits the stop position number for cyclic changeover.
E.g. 0204 mean that the cyclic changeover happens between the heat generators with position numbers 2 and 4. Position 1 is the leading boiler which will always stay on position number 1, regardless of the setting of its maximum runtime.
If the total number of heat generators in the group is higher than the maximum number of the sequence, the last heat generators will not be cycled considering that they are redundant.
ATTENTION:
When a heat generator’s position number is in the cyclic changeover range, it shall have a minimum runtime (see heat generators SYS-04 maximum boiler runtime) different of „0“.
If the heat generator runtime is set to the value “0, it will decrease its position number during every cyclic changeover and finally reach the first position and stay there.
ATTENTION:
The cyclic changeover occurs immediately when the hours run are exceeded if one of the following conditions are true:
If the cyclic changeover conditions are not fullfiiled till 1:00 o’clock:
Example: Cyclic changeover
CYC-01 = 0103 – cycle between position numbers 1 and 3.
Heat generator |
Position number |
Max hours run |
Actual hours run |
Boiler A |
1 |
200 |
90 |
Boiler B |
2 |
100 |
70 |
Boiler C |
3 |
150 |
30 |
Boiler D |
4 |
Does not care |
Does not care |
After 30 hours boiler B reaches its maximum hours run assuming that all 3 boilers being switched on during that time.
Boiler B will initialize the cyclic changeover:
After 30 hours before cyclic changeover:
Heat generator |
Position number |
Max hours run |
Actual hours run |
Action |
Boiler A |
1 |
200 |
120 |
None |
Boiler B |
2 |
100 |
100 |
position number to end of sequence; reset hours run |
Boiler C |
3 |
150 |
60 |
decrement position number by one |
Boiler D |
4 |
does not care |
does not care |
After 30 hours after cyclic changeover:
Heat generator |
Position number |
Max hours run |
Actual hours run |
Boiler A |
1 |
200 |
120 |
Boiler B |
3 |
100 |
0 |
Boiler C |
2 |
150 |
60 |
Boiler D |
4 |
does not care |
does not care |
Table 12. Parameter List
Description |
Value Range |
Default Value |
Unit |
CYC-01: cyclic changeover sequence; e.g. 0203 means that boilers 2 to 3 will perform cyclic changeover. |
1516 |
0116 |