Keston Rigs User Manual

Prefabricated Plant Rigs

Installation & Control

Instructions

34 West Common Road

Hayes, Bromley, Kent BR2 7BX

Tel. [phone] Fax. [phone]

Email : [e-mail] web : www.keston.co.uk

WD309/0/2003 The Keston Prefabricated Plant Rigs

1.0 INTRODUCTION
The Keston Pre-Fabricated Plant Rigs are designed as complete heating plant
packages for rapid site installation and commissioning. The units are supplied
to site pre-piped and pre-wired on a floor standing frame (a wall hung option is
available for the two boiler rigs). The rigs are supplied complete with a Keston
Rig Controller module.

2.0 PIPE CONNECTIONS
Although most pipework is already complete within the rig. The final
connections for gas, condensate, flue exhaust and air supply will need to be
made to each boiler. The connections should be made following all
requirements laid out in the boilers Installation & Servicing Instructions.

The rigs are provided complete with a balance header which is prepiped to
each boiler. A pair of system tappings, flow and return, are provided on the
header plus connection points for fill point, expansion vessel, air vent and
drain off. The diagram below shows the relative position of these connection
points and their intended purpose.

3.0 CONTROL MODULE

The Keston Rig Controller is a comprehensive controller offering a wide range of
facilities to the end user. However, it is recognised that customers control
requirements vary widely and that some functions are not always required. The rigs
are supplied preset for option 1) Basic Sequence Control. To enable modes 2), 3) or

4) additional sensors may be required. In addition, commissioning set-up will be
required by Keston Boilers Ltd, or its approved agents.

Installation & Control Instructions

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WD309/0/2003 The Keston Prefabricated Plant Rigs

3.1 AVAILABLE FUNCTIONS

To enable simple application the functionality is divided into four distinct groups as
detailed below:

3.1.1 Entry Level (Factory Default)

This is the mode in which all rig controllers are set by the factory, and therefore no
further components or action are necessary to realise these facilities.

Boiler Sequencing
In this mode the controller sequences the operation of the boilers to ensure the
required flow temperature is maintained with the minimum boiler operation. The
required flow temperature is set by the user.
Boiler Load Averaging
The switching order of the boilers is changed once per week, based on the hours
each boiler has run, to ensure even usage of each boiler over time.
Frost Protection
The Controller also provides frost protection, which will fire the boiler(s) in the
event the main flow temperature falls below 5OC. The boiler will remain on until
the flow temperature is raised above 15OC.
System Pump Overrun & Seizure Protection
The controller also provides a 230VAC output for connection to a system pump.
The pump is run when the rig is enabled and will also provide a 2 minute overrun
on shutdown. The controller will also operate the system pump at least once daily
to prevent seizure.
Fault Signal
A volt free pair of contacts are provided which move the closed circuit in the event
of a fault being identified
Control Signal
The Controller will fire the boiler(s) when enabled via a volt free contact pair.

3.1.2 Compensated Heating & Time Control
This mode provides all the features detailed in “Basic Sequence Control” plus the
additional features detailed below. However, to access this mode an outside
temperature sensor (part no C.17.4.17.00.0) is required. These are available from
Keston Boilers Ltd via your preferred stockist.

Weather Compensated Heating Control
The boiler flow temperature is adjusted automatically according to the outside
temperature. This provides even building temperatures and maximises boiler
efficiency.
Comprehensive Heating Time Control
The controller features an integral time programmer for heating periods permitting
a different heating pattern for each day of the week with up to two heating periods
per day. Holiday dates can also be programmed. The user may then specify three
temperature levels – day, night and holiday. The room temperature is estimated
based on outside temperature, boiler flow temperature and the building
construction.
DHW Override
In the event a volt free signal is received from the hot water system the weather
compensated heating control is suspended and the unit runs at the specified flow
temperature until the volt free signal is removed.
Outside Temperature Frost Protection
The outside temperature is constantly monitored such that, in the event the
outside temperature falls below 3OC the boiler is fired to maintain a boiler flow
temperature of 20OC. Once the outside temperature rises to 4OC or above this
action is stopped. This feature is design to ensure protection of system pipes
against freezing. However, it can be disabled if required.

Installation & Control Instructions

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