Thermalec 12THR Series 9kW Spa Heater 1 & 3 phase

Overflow weirs are cast into the inside of the heater vessel at the inlet and outlet nozzles. These ensure that the vessel is kept filled with water to a constant level at all times. A baffle plate is suspended inside the heater across its width, downstream of the  inlet weir. A similar baffle plate is suspended upstream of the outlet weir. The top edges of each of the cast weirs are slightly sloped. This patented combination of  weirs and baffles is designed to impart a spiral regime to the flow of water through the heater. It also prevents the direct impingement of cold water directly on to the heating elements.

The inlet and outlet pipework are connected to the heater by uPVC solvent weld socket stub flanges. These are attached to the inlet and outlet ports on the cast iron vessel by a steel backing flange, ensuring that the uPVC socket can be replaced if ever that were necessary.

The outer sheath metal of the spiral circular heating elements is in highly corrosion resistant Titanium. The heating elements are suspended inside the vessel from the thick uPVC element holding plate that covers the top of the vessel and from which the removable baffles are also suspended.  The heating elements are fitted with their smallest profiles facing the direction of flow. The terminal ends of each element pass through glands in the element holding plate and into the heater control enclosure that is fixed to the top of it. Two temperature pockets protrude into the vessel through the element holding plate, one at the inlet end and the other at the outlet end . These contain the probes of the control and safety over-temperature liquid-filled capillary type thermostats, respectively. The joint between the uPVC element holding plate and the top flange of the cast iron vessel is made tight by a temperature resistant silicone rubber gasket.

The powder coated steel heater control enclosure houses the electrical switchgear, the power connection terminals and control components. For spa applications, some models are fitted with oversized enclosures to assist heat dissipation from the electrical switchgear.

A mains ON/OF switch is provided on the heater. Power is supplied to the elements through heavy duty contactors. An interlock relay is provided to ensure that no mains power can be supplied to the heating elements if the interlock signal from the main pool filter pump is absent.

The supply of power to the heating elements is also conditioned by the control thermostat and the over-temperature safety thermostat, which must both be set for power to be supplied to the elements. The over-temperature thermostat causes the contactor to trip on attainment of the factory set maximum water temperature. This trip must be manually reset to permit power to be supplied to the elements.

A fuse protects the heater control circuits and the heater status indicator lamps.

The front face of the enclosure forms the heater control panel and accommodates the mains on/off switch, the pool temperature setting dial, heater status indicator lamps and the overtemperature thermostat  manual reset button.

Main Features of Thermalec 12THR Series Pool and Spa Electric Heaters

The construction of the heater is solid and robust, to ensure years of safe and reliable service.

The contact materials are highly resistant to corrosion from pool chemicals. Thermalec® pool and spa heaters can safely be used with sea water pools as well as in demanding  applications such as Hydro- and Thalasso- therapy.

The watts density of the heating elements is  very low, ensuring minimal scale build-up and long element life.

The heating elements are always submerged in water. Any air bubbles entering the heater pass through it above the water and across the unheated parts of the elements, preventing any damage to the latter.

The patented weir and baffle system inside the heater causes the water to flow through it in a spiral. This increases uniformity of the water temperature inside the heater and prevents direct impingement of cold water onto the elements. 

The spiral flow regime of the water inside the heater discourages scale formation, extending element life.

The heaters have no flow switch. These are notoriously unreliable. Any air bubbles passing through the heater will cause any flow switch to make and break repeatedly in rapid succession, causing the contactors to do the same, thus shortening their life.

Thermalec® heaters are flexible: The water flow direction is normally left to right. If required, this can be easily changed on installation by means of a simple modification. Most models may be easily changed by a qualified electrician from single to three phase operation and vice-versa.   

The thermostats used in Thermalec® pool and spa heaters have a low operating differential. This is essential to maintain the swimming pool at a virtually constant temperature. Heaters with higher operating differentials are likely to allow the pool to cool to an uncomfortably low temperature  before switching the heating on. 

Top quality contactors have been used and their ratings generously selected to give a long service life and minimum risk of operational problems, particularly in pool plant room conditions. 

As a safety precaution, the heaters are provided with an interlock relay, which has to be connected to the filter pump control circuit. The heater will not operate unless the interlock is wired and the filter pump is energised.

Status indicator lamps on front of panel to facilitate   troubleshooting and diagnostics.

Thermalec® pool and spa heaters comply with all current and relevant EU regulations and directives.

Thermalec® pool and spa heaters have a two-year guarantee.

Thermalec® pool and Spa heaters are CE marked and comply with:

EU Council Directive 89/336/EEC   & 93/068/EEC on Electromagnetic compatibility

EU Council Machinery Directive 98/37/EEC

EU Council Low Voltage Directive 2006/95/EEC  &  72/23EEC

Harmonised Standards: EN55014, EN55104, EN5501, EN5502, CEI801-2, CEI801-3 and EN60335-2-35

Cast in BS-EN-1561-1997-ENGJL-200 iron, with a heavy fusion bonded epoxy coating impervious to chemically treated pool water, constructed in accordance with British Patent 2.092,282 Design pressure of 35psi (2.46kg/cm2) with 3/4" safety valve(s) set to operate at the maximum normal working pressure of 30psi (2.1kg/cm2) giving protection to both the heater and and the installation as a whole against over pressure. A 1/2" drain valve at the lowest point allows the heater to be left empty in winter. Flow connections consist of easily removable uPVC stub flanges into which the pipes may be fitted using suitable adhesive, as the flanges can be released easily from the heater no unions are required, nor is any form of heat sink needed. Flow direction is from left to right, but may be reversed quite simply on site following the installation instructions.