80
17.3.6 Speed control of centrifugal fans (P10 = Centrifugal):
P21 is hidden. This configuration is not available. The HP is controlled via the air blades. Refer to the section on controlling the air blades.
17.3.7 Speed control of electronically commutated pressure fans (P10 = Pressure):
This function provides the same functionalities as the variable speed drive described above with the added possibility of allowing the customer
to limit the speed of the fans in order to lower the sound level or best adjust the available pressure..
This function is enabled when:
P10 = pressure P2 = Air-to-Water or Reversible Air-to-Water,
P180 (No. of HP control stages) = 1 = hidden,
P21 (speed control) = 2 hidden,
P181 and P183 = visible and P11 (coil type) visible.
In cooling mode, the speed is controlled by the HP pressure sensor and the 0-10 V outputs on the main board. In heating mode, the fans run
at maximum speed once a compressor stage turns on.
If several electronically controlled fans are on the same circuit, the 0-10 V supplies must be wired in series (two maximum).
The speed of the fans is limited by parameter P192 which is set by default to 8 V but may be adjusted to between 5 and 10 V in increments of 0.5 V.
Control:
Regardless of the value of P11, the control system is on as soon
as a compressor stage is on.
- One circuit used: The fans are controlled in response to the high
pressure on the circuit.
- Two circuits used: The fans are controlled in response to the
highest pressure read by either sensor on the two circuits.
The fans are controlled simultaneously.
The cases for forced control and control during defrosting are the same as those described in section
17.3.5.
17.4 Low Noise control (single-fan units only
– Aquaciat2)
This function is available only on single-fan units, i.e. if P180 = 1. To see if the function is enabled, go to parameter P191 (Low Noise
operation), which is set to
„Yes‟ by default. Visible only if P180 = 1.
This function disappears if a variable speed drive is used (P21 = Yes).
The fan must be shut off when switching from LS to HS and back. To do so, open contact J3, terminal 2 before actuating J3, terminal 3.
LS is obtained by energising fan relay 1 (terminal 2 on terminal
block J3) and fan relay 2 remains open.
HS is obtained by energising fan relay 2 (terminal 3 on terminal
block J3) and fan relay 1 remains open.
In cooling mode:
- If P191 (LOW NOISE) = Yes:
As long as HP < P54 - P195
– 3 b, low speed must remain on. When the HP rises above this value, shift to high speed (cut off terminal 2,
terminal block J3; cut off terminal 3 on terminal block J3; restore terminal 2 on terminal block J3). LS is resumed when HP < P54 - P195
– 7 b.
- If P191 (LOW NOISE) = No:
The system must be switched to high speed very quickly in order to deliver a maximum amount of power to the customer.
- If HP > P181 + P183, turn on LS
- If HP > P181 + P183 + P184, turn on HS
The system does not switch to LS before turning off. It is shut off when HP = P181.
- Forced and self-adjusting control:
Case1:
On if P64 (optimised frost protection) = No
- If HP > P54 - P195 - 0.5, the fans are already running at HS unless the frost limiter on the water or refrigerant line is on. In this case, remain
at LS and let the HP protection do its job.
Case2:
Regardless of the value of P191
- If the fan turns on more than 5 times in 10 minutes, increase the stage differential by 4.5 b. Normal control mode resumes (extra 4.5 b
pressure eliminated) if HP > P54 - P195 - P196 or if HP > P181 + P183 for 10 minutes.
The following message appears when P180 = 1 and stage 1 turns on more than 5 times in 10 minutes:
In heating mode:
The fan runs at HS.
17.5 Total recovery control
The total recovery function and its associated parameters (P29 and P193) are accessible only if P2 = air-to-water:
P R E S S U R E C O N T R O L
H P S H I F T E D
P 2 9
T O T A L
R E C O V E R Y N O
Fans 1 and 2
Содержание Magister 2 Series
Страница 2: ......
