While some people might love to take a cold shower for therapeutic purposes, most people hate the idea and, consequently, get frustrated when things go wrong with the hot water in their shower. They may frantically turn the dial one way and the other before coming to a gradual realisation that there is something wrong with the water heater. If you have found yourself in this situation and have a gas water system installed, what should you do?
Water heaters have to put up with some extreme conditions and will, therefore, wear out after a number of years. It may be possible to extend their life with regular maintenance, but if you've not been as attentive in this department as you should have been, it may be time for a replacement.
Where to Look
In the meantime, you may be able to conduct some repairs, and the first thing to do is check the pilot light. It may seem obvious, but if it is not lit then you will be unable to heat the water, and if it does not activate if you try to reactivate it, you'll need to look further. You may find that the gas burner is in need of a deep clean, but if it looks okay, the issue could be related to the thermocouple.
The thermocouple is basically a safety device and is meant to shut down the gas should the pilot flame blow out. It may have malfunctioned, however, and is not allowing the pilot light to come on in any circumstances. In other words, it is forcing the gas valve to stay in the 'off' position and will need to be replaced.
However, this is not a straightforward job and will typically need to be done by a professional plumber. Indeed, they may have to remove the burner assembly and surrounding parts completely before they can get at the thermocouple, so it's not a task that you can easily do at home. However, if the thermocouple appears to be okay, then the issue could be related to a faulty gas control valve. Either way, one or both of these parts is basically getting in the way and blocking the flow of gas to the heater itself.
When you bring in a gas heater repair professional, ask them to service the tank, check the various valves and flush out any sediment at the same time.