For the Contractor

Disclaimer: Please consult site specific literature including data sheets before commencing works.

General Note: Don’t under estimate the intricacies of Designing a control System - Place your order on time.

Installation Works

  • Ensure Outside Temperate Sensors are Mounted on a north facing wall
  • Ensure Outside Frost Thermostats are Mounted on a north facing wall
  • Ensure Immersion Frost Thermostats are Mounted on the Return Header Pipework

3-Port Valves – Mixing Application

Valves should be mounted on the Flow pipe with the common port, as indicated by “AB” or an arrow head,

facing into the suction aside of the pump. For 3 Port valves in diverting application see AHU Section below.


When Mounting Duct Frost Thermostats ensure the Main Body of the Unit is not mounted in a location that is

cooler than that being experienced by the capillary Tube.

Ensure Frost Thermostats are serpentined across the discharge side of the Heater battery covering the whole


Should non IP rated Devices be positioned outdoors please ensure that a cladding or other protection is


In this instance we use 3 Ports mixing valves in a diverting application. The Valves should be mounted on the

Return Pipe with the common port, as indicated by “AB” or an arrow head, facing back to the Return Header,

away from the coil.

Space Sensors

Mount  at 1.4metres high and away from influences such as Doors, supply grilles, Radiators, external walls etc.

If mounting Return Air Temperature Sensors for Fan Coil Units please mount at the return Grill to experience

the space temperature – mounting in a plenum will not reflect the space temperature.


Some meters can only be mounted on Horizontal pipework – consult your data sheet.

It is essential that meters have straight inlet and outlet pipe – As a guide we would recommend a minimum of 5

times the pipe diameters.

Meters should be sized on flow rates as opposed to line size. Request sizing questionnaires from your vendor.

We would recommend that bypasses and isolation valves be fitted at all mechanical meters.

For Heat Meters the manufacturer will have designed the meter to go on either the flow or the return pipe.

Please ensure you know which (usually the return as standard) or make sure you inform the vendor of specific

mounting requirements.

Electrical Installation

Should the Controls Specialist not be installing the cabling it is advisable that the Electrical Contractor is given 

site specific seminar on the devices being utilised on the project and is requested to follow a common tagging

and colour coded termination scheme.

3rd Party Interfacing BEMS and Mechanical and Electrical Plant - Low Level

It is a common requirement for 3rd party interfacing on Projects. For example:

  • Boiler On/Off
  • Boiler Setpoint Modulation
  • AC Unit Enable & Fault
  • Booster Fault
  • Generator Alarms
  • Meter Reading Pulsed Outputs

Quite often these are sold as “Accessories” so please select accordingly when ordering to avoid program

issues later when interfaces cant be completed.

3rd Party Interfacing BMS and Mechanical and Electrical Plant - high Level - Serial Communication

It is a common requirement for serial communication to be required between the BMS and Mechanical and

Electrical plant such as Boilers, Chillers, Meters, Generators, Electrical Meters, AC units etc.

The following should be considered prior to placing an order for this plant:

  • Ensure the necessary communications protocol card is supplied with the Meter (often declared an accessory)
  • Ensure the Protocol matches exactly what your BMS Vendor need – for BACnet/Ip or BACnet/MSTP – Consult your BMS Vendor first!
  • Confirm the lead in time for the Vendor to supply a suitably qualified engineer to commission the interface with the BMS - These are never plug and play! - The plants needs to be set up correctly
  • Confirm the vendor has the skilled after sales service to maintain the technology for the end user

General Troubleshooting:

All Plant is not working in "Auto" but working in "Hand".

  • Are Time Schedules off?
  • What Is the Outside Hold Off temperature set point?

Plant Wont Work in "Hand" or "Auto" but Control Circuit Live Light is illuminated

  • Is the Pressurisation unit Locked out on Low Pressure?
  • Has there been a Fire Alarm Activation that has not been reset?

Pumps and/or boilers coming on outside of time schedule?

  • Pumps only – most Likely an outside frost activation. These have an automatic reset
  • Pumps Only – could it be a heat dissipation Strategy? It should end after a period of time
  • Pumps and Boilers – Most Likely an Immersion Frost Activation. These have an automatic reset
  • Has any remote Override Function been activated?



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