Typically, a water heater tank takes 30 to 40 minutes to heat up so if your water heater is still working, you can count on having more hot water come back in that amount of time as long as your system is still working adequately.
Based on the specs above, after waiting 1 hour, your water heater will almost be at full hot water capacity again (it's a 30-gallon water heater, and the recovery rate is 29 gallons).
The common problem with instantaneous systems can have several causes. Some of these include a faulty gas meter diaphragm, a faulty showerhead, and low hot water pressures. Furthermore, there may be an inadequate gas input to the hot water system. This can result from an under-sized gas bottle.
Make sure the gas valve or tap to the hot water system is on. In the same way, the valve (i.e. the tap handle) should be in line with the copper gas line. Also check the continuous flow is plugged into it's electrical socket.
Gas water heaters have a faster initial heating rate and faster recovery times than electric water heaters.
Tank sediment: Minerals in your water supply settle to the bottom of the storage tank, where the burners often are. Sediment buildup in the hot water tank makes it hard for the burners to heat properly, and you end up getting lukewarm water from the water heater.
An average 40-gallon heater will only take about 30 to 40 minutes to provide heat water, while you can expect hot water from a larger tank (80-gallons) in approximately 60 to 70 minutes.
Why does it take so long for hot water to come out of your shower and other faucets? There are several reasons; the distance from the water heater, the diameter of the piping, and the flow rate of the water.
Not only does your home have a thermostat, so does your water heater. When you run out of hot water, try resetting your water heater thermostat. If the issue persists, raise the thermostat temperature to see if your water heater is at the wrong temperature.
Determining how much hot water your water heater should provide per shower depends largely on the size of your hot water tank. For instance, a typical shower uses about 10 gallons of hot water. So, if you have a 40-gallon hot water tank, you should be able to get four average-length showers out of your hot water tank.
For gas water heaters, it usually takes on average 30 to 40 minutes for the water in the tank to be completely heated.
One way to know that your water heater is not working as it should is if you're experiencing inconsistent water temperatures. Inconsistent water temperature could signal an issue with the thermostat, but it could also point toward a problem with the heating element, which is a bigger issue to address.
There are two main types of gas hot water systems: Storage – Water is heated and stored in an insulated cylinder, ready to use when needed. Instantaneous (continuous flow) – Water is heated only when needed.
An instant gas hot water system works by heating water as and when you need it, as opposed to using a storage tank. Cold water travels into the system and is heated by a gas burner as it flows through a coiled pipe called a heat exchanger.
Is your gas water heater not hot enough? If you find yourself in this situation, there are usually three common culprits: a broken dip tube, a buildup of sediment in your tank or a malfunctioning heating system.
Gas water heaters are much less expensive to operate long term. Overall, you'll likely spend less money running a gas water heater than using an electric water heater. Still, because the costs of both natural gas and electricity vary by region, you should compare the price of each before making your final decision.
Homes without a gas line or propane tank can also enjoy the advantages of on-demand hot water by installing tankless units powered by electricity. These units, which heat water with thick copper rods, are quieter and about a third smaller than gas or propane tankless heaters.
The disadvantages to a water heater fueled by gas are: Generally more expensive on the front-end cost. Requires more maintenance. Less efficient when it comes to heat loss.
Water intermittently goes cold when in use
Low gas flow will affect the heat exchanger efficiency. If using bottled gas is the bottle big enough or is it nearly empty. Faulty diaphragm affecting gas flow. Call a Gas Fitter/Plumber.
If you have a low-flow showerhead installed, you can expect to use about two gallons of water per minute, equalling 20 gallons throughout a 10-minute shower. With a standard showerhead, around half a gallon more water will emerge each minute, so a 10-minute shower would use somewhere close to 25 gallons.
How much water you use during a 20-minute shower will depend on what type of shower system – and in particular, showerhead – you have installed. Low-flow showerheads will emit around two gallons of water per minute, equating to 20 gallons per 10-minute shower, and 40 gallons over the course of a 20-minute shower.