Danfoss RAS-C2 Combi - User Manual

INSTRUCTION
Radiator Thermostat RAS-C
2
Combi
BI-DIRECTIONAL VALVE WITH FLOW-SELECTABLE FEATURE
1
Close all radiator valves by turning
the valve cover cap clockwise.
Leave system to cool.
2
Start boiler/heating.
3
Open one valve and determine
flow direction. Which pipe heats
first?
4
Remove cap and turn setting
ring according to the drawings -
the setting ring is turned by hand
only.
5
Repeat step 3 and 4 until all valves have
been set correctly. Sensor may now be fit-
ted or the valve cap temporarily refitted.
Setting ring
013R9355 013R9355
Installation of valve
The valve is a bi-directional valve * and can be installed
horizontally or vertically in either the flow or return
pipe.
A built in flow direction selection feature can be used to
eliminate the risk of water hammer.
Troubleshooting
In the unlikely event of water hammer being encountered
turn the setting ring (see diagram 4) to the other setting.
Alternatively if commissioning the whole system,
establish the flow direction through each valve using
the diagrams below.
If the flow direction needs to be changed there is
no need to remove the valve, simply turn the setting
ring.
* Maximum pressure drop should not exceed 0.45 bar
VISXM302/Danfoss DKCD 05/2011
Keymark reference: This package contains sensor 013G6040, valve 013G6281 (15mm) or valve 013G6283 (8/10 mm)

Summary

Bi-Directional Valve with Flow-Selectable Feature

Installation and Flow Direction

Details the bi-directional valve's installation options and the process for selecting flow direction to prevent water hammer.

Troubleshooting Water Hammer

Provides guidance on resolving water hammer by adjusting the valve's setting ring.

Installation Guide

Fitting the Sensor to the Valve

Step-by-step instructions for correctly attaching the thermostat sensor to the radiator valve.

Removing the Sensor

Procedure for safely detaching the thermostat sensor from the valve using the locking mechanism.

User Guide

Setting Room Temperatures

Explains how to set the desired room temperature by turning the thermostat head.

Thermostat Usage Recommendations

Advises on not covering the thermostat and details the positive shut-off feature for maintenance.

Lockshield Valve Information

Provides details about the lockshield valve (type RLV-D) and its associated product codes.

Understanding Thermostatic Radiator Valves (TRVs)

Explains the function of TRVs in regulating room temperature and how they interact with heating systems.

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The Danfoss Radiator Thermostat RAS-C2 Combi is a device designed to regulate the temperature of a room by controlling the flow of water through a radiator. It features a bi-directional valve with a flow-selectable feature, allowing for flexible installation and optimization of heating performance.

Function Description

The primary function of the RAS-C2 Combi is to sense the air temperature around it and regulate the flow of water through the radiator to which it is fitted. This allows for individual room temperature control, contributing to energy saving and comfort. The valve is bi-directional, meaning it can be installed in either the flow or return pipe of a heating system, horizontally or vertically. A key feature is its ability to select the flow direction, which helps to eliminate the risk of water hammer – a common issue in heating systems that can cause noise and potential damage.

The thermostat head, which is fitted to the valve, allows users to set their desired room temperature. The settings range from frost protection (*) to various temperature levels (II, III, 8, 12, 16, 20, 24 °C), with specific markings for common room types like bedroom, living room, and bathroom. The device also includes a "Positive SHUT-OFF" feature, allowing the water flow to be completely shut off by turning the head past the frost protection setting to "0". This is useful for maintenance, such as draining and removing the radiator.

Usage Features

Installation of the Valve: The valve itself is designed for flexible installation. It can be installed horizontally or vertically in either the flow or return pipe. To prevent water hammer, the built-in flow direction selection feature can be utilized. If water hammer is encountered after installation, the setting ring on the valve can be turned to the other setting to adjust the flow direction without needing to remove the valve. For initial system commissioning, the flow direction through each valve can be established by following a simple procedure:

1. Close all radiator valves by turning the valve cover cap clockwise and allow the system to cool.
2. Start the boiler/heating system.
3. Open one valve and determine the flow direction by observing which pipe heats first.
4. Remove the cap and turn the setting ring on the valve by hand according to the visual guides provided, which illustrate the correct orientation for different flow directions.
5. Repeat this process for all valves until they are correctly set.

Fitting the Sensor (Thermostat Head):

1. Remove the protective cap from the valve.
2. Turn the sensor to its maximum position.
3. Ensure the union nut on the sensor is loosely turned up towards the sensor body, leaving it slightly free of the lower part.
4. Press the sensor firmly onto the valve. If installing horizontally, ensure the scale pointer is at the top. If installing vertically, ensure the scale pointer is at the front.
5. While holding the sensor firmly on the valve, secure the connection by turning the union nut clockwise by hand.
6. For a fully tightened connection, use parrot nose pliers to tighten the grey union nut while still holding the sensor firmly on the valve.
7. Once fitted, set the desired room temperature by turning the head.

Setting Room Temperature: The desired room temperature is set by turning the thermostat head. The markings on the head correspond to approximate temperatures, ranging from frost protection to 24°C. Turning the TRV to a higher setting will not make the room heat up faster; the speed depends on the boiler and radiator size. Similarly, a lower setting will result in a lower controlled temperature and save energy.

Important Considerations for Usage:

• Placement: The thermostat must not be covered by thick curtains, furniture, or any other obstruction, as it needs a free flow of air to accurately sense the room temperature. If obstruction is unavoidable, a thermostat with a remote sensor should be used.
• System Integration: TRVs regulate individual radiators but do not control the boiler. For whole-house temperature control, a room thermostat is also needed. In rooms with a room thermostat, the TRV on that radiator should typically be set to its maximum setting, with the room thermostat managing the overall temperature.
• Water Hammer: The device is designed to mitigate water hammer through its flow-selectable feature. If water hammer occurs, adjusting the setting ring on the valve can resolve the issue.

Maintenance Features

Troubleshooting Water Hammer: If water hammer is encountered after installation, the setting ring on the valve can be turned to the other setting to adjust the flow direction. This can be done without removing the valve, making troubleshooting straightforward.

Removing the Sensor: To remove the sensor, turn it to its maximum position. Then, turn the union nut anti-clockwise to release the locking mechanism. The sensor can then be separated from the valve. This allows for easy replacement or temporary removal if needed.

Draining the Radiator: The "Positive SHUT-OFF" feature allows the water flow to be completely shut off by turning the thermostat head to the "0" setting. If the lockshield valve is also shut off, the radiator can be drained and removed for maintenance or decoration purposes, simplifying tasks that require the radiator to be isolated from the heating system.

The Danfoss Radiator Thermostat RAS-C2 Combi is designed for user-friendly installation, operation, and maintenance, providing effective and efficient room temperature control while addressing common heating system issues like water hammer.

Danfoss RAS-C2 Combi Specifications