• 0-10V output for actuator
• Limitation of supply or return temperature
• Relay for pump
• Relay for boiler
• Timed overrun of pump
• LED indication of sensor error

The EMR temperature controller is designed to operate with several different types of control requirement, and these MODES are selected on the 6 dip switches on the top of the unit. The following explains how each MODE operates and the sensors that are used. The heating installer must select the appropriate mode for the installation and set the DIP-switches accordingly.

To control the heating temperature, the EMR will operate a 24V powered modulating control valve via a 0-10V DC control signal. The valve can be a two port type that allows water to be injected into the underfloor circuit, or a four port valve that allows water to be mixed from the boiler circuit down to the underfloor circuit in the correct proportion. The two port system is primarily for use where the hot water for the underfloor is being taken from a radiator circuit, whereas the four port is generally used on larger systems and where the boiler is allowed to produce water within a primary circuit. For underfloor heating applications the two most frequently used modes will be Mode 1 and Mode 2.

Mode 1 is a system where there is a single area of underfloor heating, and control is required via a room temperature sensor (not a thermostat).

Mode 2 is a system where there may be multiple areas of underfloor heating, each controlled by a room thermostat, wired via an EZC MICROCENTER, and where the demand signal from the Microcenter is used to start and stop the EMR.

In each mode the EMR will provide two relay (volt free) outputs to start both a pump and a boiler. Further information on this switching facility is shown below.

Product program

Setting & Installation

Mode 1
The controller should have a room temperature sensor ETF connected and a clamp on pipe sensor ETF connected. The EMR will control the motorised control valve to the temperature selected on the ROOM SETPOINT KNOB, and will open and close this valve to maintain the level of heat required.

However, should the temperature of the water entering the system exceed the setting on the LIMIT SETPOINT KNOB, then the control valve will close to prevent the floor becoming overheated. In this mode there is no provision for demand signalling from a multi zone wiring centre. Boiler and Pump relays will be ON if the control valve is open.

Mode 2
The controller should have a clamp on pipe sensor ETF-1899 connected. A demand signal from a multi zone controller EZC should be connected to terminals 35 & 36. When the demand signal is present, the EMR will monitor the water temperature entering the system and will modulate the control valve to prevent the temperature exceeding the setting on the LIMIT SETPOINT KNOB. Boiler and Pump relays will be ON if the control valve is open.

If the demand signal from the multi zone controller is removed, the control valve will close and the boiler and pump relays will switch OFF.

In addition to the above the EMR can be used in Mode 0 where hot water for the system does not need to be controlled to avoid excessive temperatures in the pipe work. Thus the EMR will then work as a modulating room temperature controller only.

Mode 0
The controller should have a room sensor ETF connected. The EMR will now control to the temperature selected on the ROOM SETPOINT KNOB, and will open and close the control valve to maintain the level of heat required. In this mode there is no limitation of the flow temperature, and no remote signalling from a multi zone wiring centre. Boiler and pump relays will be ON if the control valve is open.

Auxiliary outputs

Boiler relay
Applicable in all modes.
A dedicated boiler relay is provided to enable the boiler to run if there is a demand for heat. The boiler relay will be ON once the control valve has reached 20% open, and will remain on until the control valve is 90% closed. A built-in delay action creates a 30-secs. pause between off/on actions to prevent short cycling of the boiler.
The boiler relay is a 5-amp switch, and is volt free.

Pump relay
A dedicated Pump relay is provided to enable the secondary (underfloor) pump to be started when there is a demand for heat. The Pump relay will be ON once a requirement for heat is present via the output signal to the control valve, and will remain on whilst this signal exists. When the signal is turned off (0V) it will remain running for 2 minutes to circulate any residual heat entering the system, and, in the event of a high limit action, to circulate water past the limit sensor.
The Pump relay is a 5-amp switch, and is volt free.

Sensor options

Limit sensor
The limit sensor should be strapped to the return pipe immediately after the manifold. In certain applications it may be acceptable to have this sensor on the flow pipe, and if so the limit setting should be to reflect the design temperature drop across the system, generally 8-10°C.

Room sensor
The room sensor supplied will be an OJ ETF944/99-H sensor. This is of the NTC pattern and is not adjustable. Here it is also possible to get an adjustable sensor, by using an EMRF-99.  ETF944/99-H & EMRF-99 should be fixed to an internal wall and should not be influenced by direct sunlight or any heat emissions from other equipment.

If a secondary mechanical limit is required, then a suitable pipe thermostat should be used.

Control valve output
EMR uses a 24V AC powered control valve that is positioned via a 0-10V DC signal. The 24V power is provided from the EMR. The maximum power available from the EMR is 6VA.

Night setback
EMR has the facility for automatically reducing the room temperature during a night-time period, or when the heating is not required. The reduced temperature setting should be set on the setback (NSB) knob. A time switch or programmer should be connected.

Frost protection
The EMR has automatic frost protection in all modes. If the room temperature as measured by the room sensor in mode 1 falls below 10°C, or if the flow temperature as measured by the limit sensor falls below 10°C in Modes 1 or 2, the EMR will open the control valve and turn on the boiler and pump. If separate protection of the boiler plant is required a frost thermostat mounted in the boiler house should be connected in parallel with the time switch contacts.

Technical data