Technical Support

The central heating system must be on.
If in doubt, contact us on 01245 324560

General Notes

A. There is an uninterrupted supply of electricity available from the fused spur (check fuse).

B. The system is two pipe pumped (not single pipe).

C. Pump and pipe work are designed to supply a minimum of 50gph (optimum 75gph).

D. The boiler temperature is set to maximum with all room thermostats calling for heat.

System Balancing

System Balancing is a relatively simple process of adjusting the valves on the panel radiators and fan-assisted radiators (or flame-effect radiators) to enable adequate distribution of hot water to all heating products on the central heating system.

The process must be carried out to avoid poor water flow and resultant poor/low heat outputs at points on the system. Balancing cannot be attempted if there are any air locks in the system and therefore the whole system should be checked for this.

Different sizes of panel radiator have different resistance to water flow, and the same applies to fan-assisted radiators (or flame-effect radiators), which have a higher resistance. If the fan-assisted radiator (or flame-effect radiator) is an addition to an existing system, or replaces a panel radiator, the system will require general balancing before the fan-assisted radiator (or flame-effect radiator) will operate correctly.

Failure to adequately balance the system to accommodate the fan-assisted radiator (or flame-effect radiator) may result in the unit cycling on/off on its integral low temperature cut out, or prevent operation altogether.

In this event, the system must be balanced again until higher water flow rates through the fan-assisted radiator (or flame-effect radiator) are achieved. Noticeably higher temperatures on both flow and return connections at the fan-assisted radiator (or flame-effect radiator) can be identify this. If using multiples of fan-assisted radiator (or flame-effect radiator), balancing the system between them will be necessary.

Symptom Fault Action
Unit not working Water temperature low Check general notes above, and check boiler setting - see note D
Water flow under 50gph Check pump - see notes B and C
Central Heating on, but fan not working Air lock Vent system via bleed screw (not applicable to Sterlings); check that flow/return temperature is over 50°C. Bypass LTC
Low Temperature Cutout (LTC) If the unit works, replace LTC. Check A,B,C and D
Fan runs on one speed only Wire broken Check wiring and spade connections on motor and switches are secure
Units run intermittently System poorly balanced. Balance the system see System Balancing above
Unit was working now stopped Air lock Vent system - see symptom 2 - also see general notes C and D
Power failure Vent system - see symptom 2 - also see general notes C and D
HTG off Vent system - see symptom 2 - also see general notes C and D
Heat output poor Boiler temperature Check boiler thermostat set at maximum
Poor flow rate Check pump, required flow rate 75gph
Low water temperature at unit. Optimum temperature on flow pipe 80ºC See notes b & symptom 1 & 4
Pipe temperature correct, heat output poor Airgap incorrect restricting airflow Check gap - Should be 20mm (Space Saver models only) Check b, c & symptom 1 & 4
Unit works, but not to specification Unit undersized Check required heating load of room against output of unit. Aee symptoms 1 & 6, and notes B, C and D