WATER PUMPS AND MIXING VALVES SETTINGS

Owned by Marco Serpelloni
Last updated: Feb 20, 2024
6 min read

Water Pump Control

When a circuit is active (in Comfort, Economy, Antifreeze mode), the associated pump in the “Circuit Water Pump Management” section is switched on:

It is possible to enter a delay between the time when the circuit is switched on and the time when the pump is switched on via the parameter Delay ON (seconds); for example, it is possible to enter a delay of a few minutes to allow the header of a manifold to open before the pump is switched on.

It is also possible to enter a pump After Operation (seconds) to keep the pump switched on even after the circuit has been switched off; this after operation is typically used to dissipate accumulated heat in the circuits.

This graph illustrates the relationships between the time when the circuit is switched on/off, the switching on of the pumps, the switching on of the valve and the sources associated with the circuit:

The individual pump is seen as PUMP A and it is possible, if the pump has one, to assign to an input of the REG or its I/O modules the pump block signal of the pump itself and configure it to Water Pump A Input Block (see ANALOG AND DIGITAL INPUT MULTIPLEXER).

Detection of pump block registers the alarm, blocks pump A and shuts down the generators.

If Single Pump Blk NC is chosen as pump type instead of Single Pump, the Pump Blocking input is reversed (from NO becomes NC, so closed no block, open block).

Twin Pump Control

The system is able to manage twin pump and, again, there are two options:

  • Twin Pump

  • Twin Pump Blk NC

Even for twin pumps, it is possible to set digital inputs to the system to detect if the pump/pumps are blocked. In the case of twin pumps, the block detection not only registers the alarm, but also causes the switching to the twin pump, preserving the functionality of the system.

If both pumps are running (i.e. neither pump is blocked), the system automatically switches between pump A and pump B every 4 days.

The parameters that determine to which inputs the alarm signals of the pumps are connected are:

  • Water Pump A Input Block: Digital input to detect the Blocking of Pump A.

  • Water Pump B Input Block: Digital input to detect the blocking of Pump B.

The way these inputs are interpreted, depends on the setting of parameter P. Twin/P. Twin Blk NC. 

Note

It is possible to achieve the same result by inverting the digital input Water Pump A Input Block: select REG / IA1 instead of REG IA1, as indicated in the example.

Mixing Valve Control

Each Circuit/Manifold can manage a mixing valve with 3-point or 0/10V control.

0/10 V Valves

In the case of 0/10V valves, the PID output is the valve position! 

The tPWM corresponds to how often the REG reiterates the calculation. For a mixing valve with 0/10V control starting from an error (setpoint - measured temperature) and coeff. I = 0

the PID output [%] = [(P*error)/163,4] *100

where 

  • P is the proportional part of the PI calculation and is a dimensionless parameter

  • 163,4 an internal coefficient of the REG.

For example, if the error were 1 K and P = 20 (dimensionless), this would result in output PID = 12.2 %. So the 0/10V valve position would be 12.2 % open (1.2 V output), as long as the error does not change.

For this reason, in the 0/10V valves, it is also necessary to set the Coefficient I (Integral part), which takes into account the variation of the error over time: the higher the Coefficient I increases, the faster the valve will open for the same P and error.

In the case of 0/10V valves, it is possible to assign a minimum opening of 1 or 2 V for example.

3-Points Valves

In the case of 3-point valves, the coefficient I should not be considered, as the information given to the valve is a speed and not a position.

The tPWM corresponds to how often the REG reiterates the calculation, but also to the total opening (or closing) time of the valve. For a mixing valve with 3-point control starting from an error (setpoint - measured temperature) and coeff. I = 0

the PID output [%] = [(P*error)/163.4] *100

where 

  • P is the proportional part of the PI calculation and is a dimensionless parameter

  • 163.4 an internal coefficient of the REG.

For example, if the error were 1 K and P = 20 (dimensionless), PID output would be 12.2 %. So if the tPWM were 60 seconds and assuming the valve is fully closed at the start, the valve would open for 12% of 60 seconds, so about 7 seconds, for the other 53 seconds it would stand still.

For 3-point valves it is possible to consider a shut time to be set on Configuration Page 2, after that the closing relay is also released:

 So if the shut time is 120 seconds, after this period both the open and closed valve relays will be open, so no more current will flow to the valve.

For both valves, a dead band PID can be considered, which is always set in Configuration 2:

 The dead band (delta K) is a range within which no corrections are made to the PID output, essentially ignoring the error. If it is = 0, it is not taken into account.

Circuit overheating management

If the Temperature Limit on the Circuit Page is not set (=0), but the parameters for overheating control in Configuration 2 are set, once the limit time past the overheating alarm will appear if the circuit is ON! So even if this alarm is not interesting for that specific circuit insert anyway a value different from zero!

Vice versa, if the parameters in Configuration 2 are not set, but the limit temperature is set, the overheating control does not work. All 3 parameters for overheating control must be set, otherwise the alarm will not appear.

Once the overheating alarm is reached, it is not enough for the circuit probe to cool down, the system must also be switched off and on again!

The indicated times are added together, so if 10 seconds is entered for each, if within 30 seconds the temperature does not fall below the maximum allowed, the system will signal an overheating alarm for circuit x.

Warning

The overheating alarm also occurs if the same circuit is called upon to work in both heating and cooling mode at the same time.

Dew Point Management

Concerning the Dew Point Correction Limit of the “Valve Management Parameters” section of the Circuits Page, see DEW POINT MANAGEMENT.

Ambient Compensation

Concerning the Ambient Compensation Limit in the “Valve Management Parameters” section of the Circuits Page see AMBIENT COMPENSATION.

AVAILABLE DIGITAL OUTPUTS

The digital outputs available for the circuits are:

  • 64. Pump A Circ. 1 - switching on and off the water pump A of manifold 1

  • 65. Valve Open Circ. 1- opening of 3-point mixing valve of circuit 1

  • 66. Valve Close Circ. 1 - closing mixing valve 3 points of circuit 1

  • 67. Pump B Circ. 1 - switching water pump B of  circuit 1 on and off

68 to 95 are the same for circuits 2 to 8.

AVAILABLE ANALOGUE OUTPUT

The analogue output available for the circuits is:

  • 1. Circuit 1 - corresponds to the 0/10 V mixing valve position of circuit 1

is the same for circuits 2 to 8.