Hot water systems and towel rails

The Domestic Hot Water (DHW) system, supplying hot water to baths, showers, etc, may be a storage or instantaneous system connected to the main heating boilers, or a stand-alone system heated by gas or electricity. Whichever method is used, smartModules may be installed to control their operation.

towel rail heating controlThe most common system uses a storage cylinder (or several in parallel) fed from the primary circuit of the boiler system. With conventional controls, a cylinder-mounted thermostat causes an on/off valve to open, allowing primary water to flow in the coil of the cylinder. When the cylinder reaches temperature, the thermostat will shut the valve. A timeclock interrupts the power supply to the valve.

Whilst this arrangement works in a small, basic house, as properties grow in size, control problems multiply as well. Multiple boilers may be fitted, which will need to be interlocked with timeclocks from the heating and hot water systems. Often secondary DHW circulation pumps are used, to ensure that hot water is available instantly at any tap, and these also require controlling.

A smartkontrols solution minimizes any unnecessary complications.

- A dedicated smartModule controls the existing on/off valve. The thermostat is replaced by a sensor.
- The smartModule can also control the secondary pump, if fitted.
- The hot water service can now be controlled individually for timed operation and temperature, from the wall (using a Zone Controller or Touchscreen),or from a PC.

Towel Rails have traditionally often been plumbed into the primary circuit feeding the hot water cylinder. The theory being that after a bath, the DHW cylinder would be calling for heat, and hence the towel rail would be hot. Although this works well enough in houses with a single bathroom, today the combination of multiple bathrooms and secondary DHW circulation mean that the DHW cylinder will frequently “top up” its heat content. This results in the towel rails running almost continuously, and if they are large architectural rails, causing significant overheating of the house.

In such situations, smartkontrols recommends:
- The use of a separate towel rail circuit with a zone valve or pump.
- This valve/pump can be controlled by a smartModule, giving timed operation of the rails; normally, two on/off times for the rails will suffice
- If the appropriate user interface is used, a “Dry the Towels” button can be created for towel drying out of hours.
- Electric towel rails can be switched in the same way.