A customer called the office requesting a visit from one of our engineers as they were experiencing a peculiar problem with their hot tub. The symptoms were that the tub keeps ‘tripping’ intermittently however it’s not turning the MCB or RCD protection off at the consumer unit. If he the ‘banged’ the cabinet, the hot tub would turn back on.
On arrival the hot tub was running and up to temperature. So, any other engineer may consider that there is no problem at all. Secondly, another engineer may consider that it’s just the electric supply and tell the customer that they require an electrician to test the supply.
Once I had removed the cabinet and gained access to the hot tubs control box, I began inspecting the PCB for any visible signs of damage or anything out of the ordinary. Upon first inspection to the untrained eye everything seemed fine. No signs or smells of burning or corrosion. The PCB looked like it came straight from the factory.
At the terminals on the PCB there was the expected voltage between the conductors, so fast becoming a ‘head scratch’ as on the face of it there seemed to be nothing wrong with the hot tub or the supply.
So, this is when we start to work backwards and think about the control philosophy of the hot tub. If the hot tub was losing power, but there was a consistent 230 volts to the board, where was the power being lost? Resulting in the spa to intermittently shut off.
Part of the distribution of power was from the transformer on the board. This plugs into the PCB via a small amp plug. I thought this was a good place to start. By removing the amp plug from the board, the problem became blatantly obvious! One of the pins in the plug was loose. Once I had readjusted the pin in the plug, I then connected back to the PCB. Funnily enough… no more intermittent ‘tripping’ job done! This was work was carried out on a Spa Net Controller in Alsager, Cheshire East.
