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6. Setting up the Unit and Unit Logic
The ACH1 box can be used for different solutions. The unit can run all modes (DHW, UFH and UFC) on one PQFY system, but follows logic to
enable the best performance possible from the system. There can be any combination of modes. The next section details different scenarios and
explains how the unit responds.
Note: a PAR21 controller is needed along side the ACH1 and set to Auto mode
28°C. To see how this applies and is implemented please see the PQFY
manual.
6.1. DHW no Immersion Heater (IH)
Used when standalone immersion control is available.
•
Volt free connection is made between terminals 7 and 8 [Fig 5.3]
•
Unit will sense temperature from T1 thermistor (connected on terminals 1 and 2)
•
Desired temperature can be set on dipswitch (DHW) whereby ON = 1, OFF = 0 (see table 6.1 for binary coding and corresponding temperatures in each
mode)
o
Unit can be set from 41°C (0001) up to 55°C (1111)
•
Unit will switch off when T1 senses the set temperature.
•
Thermistors work to a diversity of ±1
°C.
6.2. DHW with Immersion Heater
Immersion can only be used when T1 is attached to the tank as in [5.3.2. type (a)]
and
when the immersion is submerged in the same tank as the
water heated from the PQFY.
•
Volt free connection is made between terminals 7 and 8 [Fig 5.3]
•
Unit will sense from T1 thermistor (connected terminals 1 and 2)
•
Temperature set to 45°C (0000) all OFF on DHW dipswitch.
•
When T1 reaches 44°C, a signal will be sent to the IH to come on and stay on until 60°C is sensed on T1 even if the DHW signal is lost on terminals 7
and 8.
•
If T1 drops below 45°C, the PQFY will come on and the immersion will switch off. IH will then come on again at 44°C until T1 has achieved 60°C.
•
If DHW signal is lost and T1 is below 45°C and 60°C hasn’t been achieved within one DHW cycle (i.e. signal is not renewed), immersion will come on and
heat the water to 60°C.
•
Once 60°C is reached on T1 (legionella is controlled) in any case within one cycle (signal is not renewed), the immersion will not come on again. The
immersion will only be re-started if the DHW signal is lost, then renewed.
6.3. UFH
Used when under floor heating only is required.
•
Volt free connection is made between terminals 9 and 10 [Fig 5.3]
•
Unit will sense from T2 thermistor (connected terminals 3 and 4)
•
Desired temperature can be set on dipswitch (DHW) whereby ON = 1, OFF = 0 (see table 2.1 for binary coding and corresponding temperatures in each
mode)
o
Unit can be set from 30°C (0000) up to 45°C (1111)
•
Unit will switch off when T2 senses the set temperature.
6.4. UFC
Used when under floor cooling only is required.
•
Volt free connection is made between terminals 11 and 12 [Fig 5.3]
•
Unit will sense from T3 thermistor (connected terminals 5 and 6)
•
Desired temperature can be set on dipswitch (DHW) whereby ON = 1, OFF = 0 (see table 2.1 for binary coding and corresponding temperatures in each
mode)
o
Unit can be set from 10°C (0000) up to 20°C (1011). Note anything above 1011 will equal a set temperature of 20°C.
•
Unit will switch off when T3 senses the set temperature.
