The Importance of Electrical Testing Prior to Replacing Parts on a Hot Water Storage Tank

April 7, 2019

Common electrical testing routines should always be carried out before replacing a part on a hot water storage unit. Why should that be the case? Think about it from a contract electrician’s point of view. This journeyman feels certain a heating element or thermostat has bit the dust. Feelings aren’t enough, though, not in this business. Besides, there’s a more immediate concern on the contractor’s mind.

Reducing the Risk Factors

Hot water storage tank parts fail in various ways. A straightforward system breakdown takes the whole system out of service. Either the water heater discharges cold water or it keeps on tripping a circuit breaker. There’s a continuity break in the element, or maybe the appliance thermostat has failed in the open-circuit position. Again, these are suppositions, educated guesses. A trained electrical worker can use such symptoms as diagnostic clues. What he can’t ever do is make assumptions. Taking no risks whatsoever, the appliance is switched off, the power is isolated on the fuse board, and then the continuity check on the suspected damaged part begins.

The No-Risk Diagnostic Approach

Electrical shocks can kill. That’s a fact that’s covered in every regulatory guide book. In water storage tanks, the risk factor actually increases. There’s water in the mix now, and this fluid conducts electricity. At best, the parts replacement work is happening because the old part is water-damaged or corroded. Perhaps it’s just worn out, so it has reached the end of its lifespan. At worst, however, the water has created a short-circuit, and the exposed metalwork is live. Again, assumptions cannot be tolerated here, not when the water and energies flowing inside the equipment could produce a life-threatening electrical shock.

The Pre-Work Test Sequence

Prior to replacing a part, the tank is turned off and electrically isolated. Visually, the equipment is checked for leaks or any obvious signs of water damage. The electrician pulls out his multimeter, confirms the appliance’s depowered status, and then he carries out a series of pre-work checks. Conductor continuity comes first, then there’s a second continuity test, which measures the resistance between the part’s conductors and the appliance ground. In other words, is this normally powered component short-circuiting? With these baselines properly established, the diagnostic checks proceed so that he can narrow down the damage and pull in a replacement part.

All of this pausing and testing might feel like overkill at first, but it’s an important way of approaching any electrical damage. The electrical contractor or heating engineer doesn’t know what’s wrong in there, so he works off of a worst case scenario policy. That policy saves lives, for water and electricity really don’t mix.

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