Datasheet
Heat Pump Controller with 6 x Relay Outputs
HPC / DIN / 6R / ...
Main Features Registration & Demand Collation for up to 200 Zones / Fan Coils Used to control Central Plant Heat Pumps E.g. Air-to-Water type providing Hot or Chilled Water to 2-Pipe Changeover Fan Coils, or Water-to-Air type providing Warm or Cool Air to a Plenum serving Terminal Units

Summary Features

General

The Heat Pump Controller is a derivative of the SeaChange Floor Controller. It is used to control Central Plant Heat Pumps which serve Terminal Units (e.g. Fan Coils, VAV's). It contains System Housekeeping and can support Registration for up to 200 Zones.

Central Plant Heat Pumps typically feed a number of Terminal Units. An example of Central Plant Heat Pumps are Air-to-Water Heat Pumps which are feeding Hot or Chilled Water to a group of 2-pipe Changeover Fan Coils which each have only one control valve and coil which can heat or cool. The Changeover from Heating to Cooling mode can be done automatically, if the plant will allow; the Fan Coils send their demand signals to the Heat Pump Controller, which assesses which mode to run in and changes over if necessary. The Fan Coils can monitor the Flow Temperature from the Heat Pump via the network and can thus decide whether they are able to heat or cool; if the medium is in the wrong mode i.e. they are trying to heat the space, and the Heat Pump is delivering Chilled Water, their valves will remain closed. If the main plant needs manual intervention to switch from Heating to Cooling, the Automatic Changeover function can be ignored; a Volt-Free Contact from the manual changeover switch can be wired as an input to force the Heat Pump Controller into Heating or Cooling mode.

Another example of Central Plant Heat Pumps are Water-to-Air Reversible Heat Pumps which feed a plenum; the plenum feeds multiple VAV Terminal Units, often used in air-conditioned apartments (see River Mill House later). Here again the Terminal Units can dictate the mode of the Heat Pump - supplying either Hot or Cold Air; the VAV Controllers monitor the plenum temperature which is monitored by the Heat Pump Controller and Broadcast over the network so all of the Terminal Units can access this Temperature without any Interconnect being specifically set up and so can control their air volumes accordingly. Usually the Heat Pump will come with its own built-in controls for compressor cycling, reversing valve, defrost control of outdoor unit etc. as appropriate. The SeaChange Heat Pump Controller is designed to overlay these simple controls to provide management of the Heat Pump.

As the system housekeeper, the controller also monitors and broadcasts Outside Temperature, either hardwired to input ' f ' (terminals 15-16) or registered as an intelligent sensor. If an intelligent Temperature or Temp+Humidity sensor is used the Humidity value can also be monitored (on parameter S7 in the monitoring parameters).

Description of Features

System Housekeeping

A SeaChange system needs certain system-wide functions to be provided by a single Controller to ensure synchronisation, and to avoid conflicts. These functions are known as System Housekeeping Functions and can be provided by the Heat Pump Controller.

Firstly, it contains the real-time clock, which broadcasts time-of-day and day-of-week information to any modules that may need it. The clock may be set from any Zone Controller, and the time information is backed up by a Capacitor, which means that the correct time is retained for a minimum of 8 hours in the event of power failure (providing that power has been applied for at least 1 hour).

Secondly, it performs an important role in the unique SeaChange registration process; it is responsible for the automatic allocation of system addresses during registration.

Thirdly, it broadcasts Outside Temperature to any other modules that may need it; it acquires the temperature either from a sensor directly connected to its input terminals 15-16, or from a Networked Outside Temperature Sensor.

Alternatively, System Housekeeping Functions may be provided by another SeaChange Controller (e.g. Boiler Controller, AHU Controller, Floor Controller).

It is important that only one SeaChange Controller in a System provides the System Housekeeping Functions, unless the system is a Multi-Domain system where a Registration (Housekeeping) device is provided on each Domain (separated by Routers) but only the Housekeeper with the lowest Domain number provides the Real-Time and Outside air temp functions.

Demand Collation

The heat pump controller can receive heating or cooling demands in a form of percentage demand from zone controllers.  If the heat pump controller is used in conjunction with AHU controllers or other modules that operate on CT demand, you must use a heating and cooling secondary circuit module to collate the demands from one or more AHU controllers.  Once the heating or cooling constant temperature demands are collated by the associated secondary circuit controller, they can be sent to the HPC controller as a percentage demand.  These demand signals may be used to drive main plant which is not controlled by SeaChange via the Heat Pump Controller’s output relays. There are 3 relays each provided for Heating and Cooling demand, indicating low/medium/high demand for each medium, however there is also a wide range of other output options available.

These sequenced outputs may be driven in one of two ways:
1) Maximum demand: the relays will be driven according to the maximum demand received for heating and/or cooling from the Zones.
2) Average demand: the relays will be driven according to the average demand received for heating and/or cooling from the Zones.

In addition, the relays can be inhibited from energising until a certain number of Zones are demanding heating or cooling. This prevents main plant being called to run for just one Fan Coil, for instance. The minimum number of Zones may be set to Zero, if this feature is not required.

Modes of operation

In all modes, the drivers are configurable so a wide range of output options are available for Heat Pump control and Fan control.  For  details of the drive settings, please contact SC Controls.

Driver Only- SPTY=1

Here the Heating/Cooling Mode and number of stages will be set directly by the Zone/Fan Coil Demands; the Heat Pump plant's own controls will control the flow temperature. This is the usual method of control where the Heat Pump has its own embedded Temperature Controller. Set SPTY Parameter to 1 in Heat Pump Controller. In this mode the highest heating demand received is passed to the Heating driver and the highest Cooling demand is passed to the cooling driver.

Temperature control- SPTY=2

This mode is used to control a common media, e.g. common pipe work providing hot or chilled water to 2-pipe fan coils with changeover valves, based off the demands received from the consumer modules registered to the Heat Pump Controller. SPTY must be set to 2.

A temperature sensor must be fitted to input ' c ' and/or input ' d ' (terminals 9-10 and/or 11-12). These inputs are combined as max, min or average using SACT similar to other SeaChange products.

The controller becomes occupied if either the heating demand or cooling demand is greater than minimum demand as set on MIND.

The setpoint for the control is calculated from the MAXH, MINH config limits for heating demands and from the MAXC, MINC limits for cooling demands. Only one setpoint is calculated if both heating and cooling demands exist - the highest will be used.

Note -this controller is not suitable for providing control of Cassette type Heat Pumps.  For this type of Heat Pump, use a SeaChange Fan Coil Controller.

Operation with Remote User Switch/Trim Pot or Interlock

A switch can be connected to input c (terminals 9-10), which when made will force the Controller to Occupied.

This is achieved by adding an extra config variable input mode INMD. The following values are supported.

In addition if a 1K resistor and a 10K potentiometer are connected to input 'e' (terminals 13-14) then a 5 degree trim (operational only whilst occupied) is possible. The trim is slightly non linear (the applied resistance is affected by the parallel resistance on the board which helps linearise the thermistor when fitted, mechanical centre position of the pot gives -0.7C). The zero point can be adjusted to give the correct (0 degree trim) by backing off any error using the software trim SPTR parameter. Suggest pot is marked Hotter/Colder or +/- .

The voltage generated by the pot will be converted to a setpoint Trim only for control modes SPTY 0 or 1

Standard Configuration (Default Factory Setting)

The Heat Pump Controller internal driver settings are configured during production to provide the following control outputs for standard heat pump applications.  The media temperature measured on input C is broadcast to other modules (e.g. actuator sub module, zone controller) that have been setup to operate in heat pump mode (see configuration parameter TWOP on ACT and ZON modules)

Fan Speed Control

The controller will automatically control fan speed, if the multi-speed fan driver is used. If either the heating or cooling demand is greater than 90% for a period longer than FPRD (seconds/10 to match other periods) then the fan speed will be incremented up to the next speed. If both the heating and cooling demand is less than 10% then the Fan Speed is reduced after the same delay time. While occupied the controller will maintain a minimum of Fan Speed 1.

Provision is made for the fan speed to be controlled from a network variable (nviFanSpeed), from a (hotel style) zone controller for example, if this network variable is non zero then this will override the automatic fan speed control.

Interlocks

Setting HDLY negative sets the on delay in minutes for the fan or pump; and setting HDLY positive sets run on time in minutes for fan or pump to run after heating shut down .

Typically negative values will be used for wet batteries to provide start up protection against frost and positive (run on-) values would be used with electric heating batteries.

The same features are available for cooling using CDLY.

Occupation Only

The selection of OCC or OSS is now made by setting OCCO to 1 on controllers where the control is only required when the building is in occupation. The default (OCCO=0) is for control during OSS and OCC.

Frost Protection

This is defined with a config parameter FRPT and it defines the controllers action when it receives a 'frost alarm' from the boiler controller.

Demand Signals

Heat/Cool Demand

Heat and Cool demands can now be sent to Heat and Cool sources within the Controller's domain and also to controllers on other domains. These links need to be setup manually for the time being, until other controllers can be changed to recognise that this controller now has this feature. Either change configuration parameters HTSC and CLSC to point to the required Target module using the values in the following table, or use the drag and drop engineering features of InSite.

Occupancy Demand - Occupation Destination OCDS

The controller can send it's Occupancy state to any other module which supports receiving OCDS, at present that is AHU, DHW, HSC and CSC controllers. This enables the demand fan-in to be done in this Controller which then sets say a Fresh Air AHU to run. To avoid the inevitable confusion regarding whether a heat/cool demand link or an OCDS link is being made this feature is restricted to manual setting of OCDS in the sending controller, the table sets out the rules for OCDS numbering.   The InSite software can be used to easily setup these links using the drag and drop Occupation Demand Structure view.

Alarms

The Controller supports sensor fail SENF alarm, this is raised if the sensor(s) fail and the controller is in a mode which requires the sensor connections. The Input Mode INMD can also be set up to generate an alarm for either a short or open circuit.

Alarm mode and Alarm State config variables have been added to the config variable list.

Alarm State ALST determines which input state 0 or 1 is considered to be the alarm condition when using an external VFC input for the alarm as set by INMD.

Sub module Registration

The HPC controller will support registration of up to 2 Actuator sub modules and 2 Pump Changeover Sub modules and 1  Intelligent Sensor.

Doorway codes

Floor Controllers are addressed with [H1].

Submodules are addressed as follows:

Actuators [H1Am] where m= submodule number.
Item codes follow the normal conventions.

Options and Product Codes

Heat Pump Controller

HPC / DIN / 6R / [option]

Options

SC Controls Ltd
PO Box 313
Wadhurst
East Sussex
TN5 6WH

phone 08707 606040
fax 08707 606041
e-mail seachange@sccontrols.co.uk
http:// www.seachange.co.uk