Prices Inc. VATPrices Ex. VAT
November, 2017
We recently wrote about how to control warm air space heaters if only one is being installed. This week we will explore the options for controlling the space heaters when there are two or more installed in one area.

1. Individual Units.

The first option is to simply control them as individual units and not integrate them in any way.

Options are for individual units are:

  1. No Controls
  2. Two port Zone Valve Only
  3. 3 Stage Speed Controllers with Thermostat
  4. 5 Speed Fan Controller
  5. Manual Thermostat
  6. Programmable Room Thermostat

See our previous blog for all of the details for the above.


2. Temperature and Time Control

Temperature control can be achieved by a number of methods.

(a) The simplest method is to wire in a simple thermostat and use it to control the fans in the area you want to heat. A manual thermometer will maintain a constant temperature within an area until the thermometer is turned down or the power is switched off. This is ideal for premises where a constant temperature is required 24/7.

(b) Upgrading the simple thermometer to a programmable room thermostat will allow the heating to be switched on or off at a specified time and the temperature maintained at whatever is required. For example, it’s a simple task to set this unit up to provide one level of heating during work time and a lower (possibly for frost protection) temperature out-with work time.

(c) The 3 stage speed controllers with thermostats are only suitable for individual fans.


3. Fan Speed Control

Fan speed control of multiple fan coil heaters is best achieved by using one of the 5 speed controllers. These units are supplied in many different sizes. The smallest controller is rated at 0.6A and can only control one of the smaller heaters.

These controllers come in sizes 1.2A, 3.0A, 5.0A 7.0A, 11.0A and 14.0A.

The bigger the current rating the bigger the number of fans that can be controlled by one unit. Each heater has its own current rating and it’s important to balance the ratings of the heaters with the speed controller selected.

We are happy to assist with this. We will also seek advice from the manufacturers if the design requirements are out of the ordinary.

We are happy to explain all these options in more detail. Call us on 0141 459 3141 or send any questions to