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Heat-calculator unit VKT-5


Heat calculation unit is intended for operation as a part of heat meter which ensures metering and control of heat medium parameters and heat energy of water and steam (superheated, saturated) in open and closed heat supply system of heat energy consumers and producers.

Application field

Possibility to configure measurement inputs according to Customer's request allows using heat meter in any water and steam heat supply system.

General technical specifications

Functional capabilities

  • 2-line symbolic and digital LCD indicator with backlight;
  • 8-key keyboard;
  • Pipelines used can be freely configured to any heat consumption model (including for metering at supply source) for any number of consumers (up to 8). Pressures and temperatures can be measured or set as stipulated, at customer's option;
  • Possibility to extend flow rate measurement range by using two flow rate meters with variable difference on a single pipeline;
  • Works with sensors with output signals proportionate to flow rate, difference or squared root of the difference;
  • Works with all types of heat medium (water, saturated and overheated steam);
  • Hourly, daily, cumulative total, emergency situations archiving, easy to view;
  • Indication of current temperatures, flow rates, pressures;
  • Recording contingency situations in heat consumption system and cases of heat medium exceeding specified limits. The information processing volume is programmed from the keyboard;
  • Possibility to send ready reports to printer;
  • Calculation unit is powered from AC mains 220 V;
  • In case of power voltage failure the calculation unit will register the time of such failure and store measurement and settings information.

Recording measurement results indications

Archiving depth for hourly and daily heat medium parameters is 45 days minimum.
Archive and settings in case of power failure are stored during unlimited period of time.

Metrologic characteristics

Indicated and/or registered parameter

Input signal, its value

Limits of permissible error


Flow rate, volume, weight, pressure, differential pressure Current:
(0-5) mA
± 0.15%; ± 0.2% Specified transducing error
(0(4)-20) mA ± 0.1%
Volumetric flow rate Frequency ± 0.1% Relative tranducing error
Volume Frequency ± ΔV м3 Absolute transducing error, ΔV - low order unit
* - Resistance 50 Ohm at 0°С
Temperature Resistance ± 0.1°С;
± 0.15°С*
Temperature difference Resistance ± 0.05°С
Mass flow rate, mass  - ± 0.05% Relative computing error
Heat energy  - ± 0.05%
Time  - ± 0.02% Relative measurement error

Unit calibration interval - 4 years.

Connection of sensors

  • 8 temperature measurement channels (TSM/TSP -50, 100, 500); 
  • 8 current measurement channels (0-5, 4-20, 0-20 mA); 
  • 8 frequency measurement channels (up to 1,000 Hz);


  • RS232: connection of computer, modem, printer, panels for reading archives and downloading them to computer;
  • RS485: for connecting devices to network when connecting to computer;
  • CENTRONICS for printer connection.

Regulator based on VKT-5
Based on VKT-5 heat calculation unit, up to two automatic heat consumption parameter control system can be built. The regulator is indended for measuring control input which is exerted by control system to the object via actuating mechanism with the purpose of reaching specified control target. Regulator functions in the system are performed by
VKT-5 heat calculation unit. Governing valve or regulable hydraulic ejector can be used as actuating mechanism.
Each regulator creates control input on two control outputs. Control signals have TTL-level voltage and are sent to actuating mechanism via interface unit (for example, BU-2).
Regulators are working independently, solving one of the following tasks:

  • Air temperature regulation within the premise;
  • Pressure or pressire difference regulation;
  • Flow rate regulation;
  • Hot water supply temperature regulation.

Warranty period

Heat calculation unit warranty period - 6 years.