Most electric actuators used in facade or window automation systems generally speaking have a 12 month or 10,000 to 20,000 cycle warranty, or which ever of the two occurs first. The 12 month period should always lapse first. Ok, there are exceptions, even finely engineered machines fail sometimes.
Some or most of the problems when an actuator fails within the warranty period are down to the following, which can all usually be avoided:-
- Incorrect selection of product
- Newton force of actuator not great enough for type/size of window. The window may be too heavy for motor or chain strength. If the window is on a sloping plane the opening force required increases considerably. A chain actuators maximum N force may be designed for bottom hung open out windows and not top hung (awning windows). The N force might be strong enough but the chain itself might not be.
- Opening radius of window is too great for actuator chain (when pivot brackets are omitted) causing over deflection of the chain.
- Tandem limit switch, sometimes known as a synchronization module is not installed when using actuators in tandem. Actuators can become out of sync. which can cause damage to the actuators (excessive force) and can twist the window vent frame.
- Incorrect power supply to actuator
- Mains power (220-240v AC) supplied incorrectly directly to 24v DC Actuator. This can happen when the full system is not finished and trades or other occupants want to open the window. It’s assumed that the actuators are mains voltage and the actuator fly lead is connected to the mains, needless to say the actuator needs replacing.
- Excessive voltage applied to DC Actuator.
- Field cable type incorrect for amperage draw of actuators and cable distance between power source and actuator in 24v DC systems, causing voltage drop. (actuator is not faulty in this scenario although it appears so to the user).
- Control Strategy Incorrect
- Actuator motor is burnt out due to excessive cycles in short space of time. Usually when operated via a Building Management system (BMS) and sensor inputs such as temperature, wind/rain, etc do not have a lock out period. This causes an effect known as hunting where every slight change in input signal causes the BMS to power the actuators open & closed. A lock out period of say 3-5 minutes between change in input signals eradicates this.
How can you tell if it’s the window actuator that’s faulty if there is no physical sign of damage and it is not operating? The simple answer is you cannot, it maybe a controls issue. So who do you call out, the window actuator supplier or the controls supplier? You could call both out and end up with a false call out charge from one of them. Alternatively if both the actuators and controls system are supplied by the same company then life is a lot simpler and less expensive.