When is it time to replace your hot water tank? This is a big question with lots of different answers. It seems that every month we are replacing a tank that was left to deteriorate to the point where water damage was caused to their home. Below is a list of "tell-tale signs" to help you know when its time to change your water heater hopefully before its too late.

Water heater is leaking, but I can't see where

Water not as hot as it used to be

Pieces of white plastic in my aerators

Unable to release water through the drain valve

Gas pilot will not stay lit

Little or no pressure on the hot side

Hot or cold connections are rusty on top of tank

The T&P valve is rusty or letting water past

The most common sign that the hot water tank needs to be replaced is that it is leaking. If your tank is more than six years old (9-12 is most common) and is leaking from someplace that you cannot find, it is likely that it has deteriorated to the point that it is leaking through a side-wall seam, a welded join, or steel thread has rusted through. These things are non-repairable so most likely your tank will need to be replaced. There have been times we have come out and discovered that the leak was unrelated to the tank itself (such as an overly exuberant trap primer) and was thankfully fixable, but this is rare.

If you find yourself increasing the temperature setting on your gas valve or increasing the thermostat setting on your electric tank, you can know your tank is nearing the end of its days. Corrosion on the inside of your tank has deteriorated the dip tube, coated your electric elements, or has over-worked the gas valve.

The wire screen assembly that is right where your faucet's water comes out is called an aerator. The aerators job is to produce a nice even flow of water coming out of your tap. If you've noticed that your water heater produces hot water, but only for a short period of time, unscrew a couple of your aerators and look for some small chunks of white plastic inside of them.

A new hot water tank has a white plastic dip tube that runs from the top of the cold inlet to the bottom of the tank. Just like hot air, hot water rises so the dip tube's job is to get the cold water down to the burner where the heat is. As the water heats, it rises to the top of the tank where the hot outlet is and from there heads off to your shower or sink or whatever fixture is calling for hot water. With age, the plastic dip tube can begin to deteriorate into small broken pieces. When this happens, there is no longer a dip tube forcing the cold water down to the burner, so the cold water is able to enter the top of the tank then immediately exit back out through the hot side without adequately being heated.

If your hot water tanks dip tube has deteriorated to this point, this is a strong indicator that the tank has other components deteriorating inside as well.

We always recommend that you drain your hot water tank at least once a year to remove any sediment that may have settled to the bottom of your tank. Most people neglect to do this until the tank starts acting strange. Of the tanks we replace, 1 in 5 are so full of sediment that we have to pump the water out of the top of the tank.

When a hot water tank develops a layer of sediment at its bottom, it quickly deteriorates the bottom of the tank. What happens is that the flame has to burn for an extended period because the sediment acts as a buffer between the flame and the water that its trying to heat. This is both inefficent and damaging to the bottom of the tank. Whenever you hear about the "bottom falling out" of someone's water heater (a sudden 40 gallons of water onto the floor), sediment build-up is typically the cause.

If no water comes out when you open the drain valve, you could try pumping the water out from the top of the tank and then vaccuming the sludge out (I've heard of this being done), but I'd have to say that realistically, your tank has already deteriorated enough that it would be a waste of money. You need to replace your water heater.

If you have an atmospheric John Wood water heater manufactured in the 2006-2012 range this is a common problem. Most likely the safety limit switch on the burner assembly is cooked. This is an inexpensive part, but changing the limit switch is a very short-lived fix and doesn't solve the underlying problem. There is a fine screen at the bottom of the water heater that lets air into the sealed burn chamber. Over time, this screen becomes saturated with fine dust particles and needs to be cleaned. If this screen doesn't let enough air inside the chamber, the flame rolls out towards the front of the burner assembly, triggers (burns out) the safety high limit (it's doing its job!) which no longer allows power from the thermocouple to keep the gas pilot lit. (Update: on April 3rd, 2013, the John Wood water heater parent company, AO Smith, discontinued manufacturing of the above mentioned John Wood water heaters. Currently, new model residential John Wood water heaters distributed in B.C. are A.O. Smith water heaters made in the AO Smith factory located in Ashland city Tennessee and have been branded as John Wood. This is the AO Smith design and differs significantly from the old John Wood water heaters manufactured in Fergus Ontario.)

If you have something other than the tank mentioned above, the problem is likely going to be the thermcouple or the gas valve. A thermocouple is a device made of disimilar metals that are combined at its tip and that when heated produces electricity (30 millivolts). Modern Bradford White tanks use a thermopile which is basically a number of thermocouples in a casing that produces 750 millivolts (enough to run its ICON System™ gas valve). When properly installed, the tip of the thermocouple should be about 1/2" into the pilot flame. This generates the 30mV (or 750mV) needed to power a tiny electromaget that keeps the pilot valve open. If the thermocouple is not 1/2" into the flame or if the thermocouple has been damaged, the pilot will not be able to stay lit because there is no power going to the electromagnet. Sometimes, when cleaning around the hot water tank, the wire lead to the thermocouple can be snagged on a broom or something which may pull the thermocouple out of the flame. Check to see if the thermocouple is properly positioned. If it is, then it may be that it was faulty from the outset and is no longer functioning. (Normally, a thermocouple should last the full life of the water heater.) If after replacing the thermocouple with a new one the pilot still will not stay lit, it could be that the electromagnet is no longer working (this means you need a new gas valve) or possibly that you need a new high limit switch.

If your tank is getting on in years (meaning outside of its warranty period) then it likely isn't worth it to replace the gas valve. Replacing the gas valve is something you should have a licensed gas fitter (us) do for you. If your tank is getting old, the cost of the gas valve and labour doesn't really make sense when you take into consideration that the tank is deteriorating inside as well.

In the last few years, one of the improvements made to modern hot water tanks is the addition of a check valve on the cold inlet side of the water heater. This is an energy saving idea that prevents hot water from running up the cold inlet waterline (wasting energy) when there is a drop in pressure on the colds side (say you turn your sprinkles on outside for example.)

However, this improvement has introduced two new problems:
1) restricting thermal expansion to the hot side waterlines only, and
2) providing a new mechanical device that can go wrong - that check valve gets stuck!

Thermal Expansion - When cold water is heated, it expands. Its got to go someplace, the hot water tank is already full of water, so when the water is heated, the tank will actually swell a bit, and so will the water lines in the house. Before check valves were an integral part of water heaters, the water could expand into both the hot and cold sides of the waterlines system, check valves reduces the available expansion area of your waterlines by half. This is why if you have 1/2" copper waterlines in your house (plastic lines expand much better than copper, and larger lines can absorb more expansion) you should consider having a small expansion tank installed on the hot side.

Check Valve Stuck? - The check valve is a small plastic ball in a short chamber that floats up to the top (sealing the cold inlet shut) when not under pressure and is pushed out of the way when under pressure. So when you open a hot water faucet someplace in your home, the pressure in your hot water tank is released out of that faucet, and the cold water coming into the tank pushes the plastic float down out of the way, allowing cold water into the tank. We've seen this ball get stuck in the "up" position so that even under pressure from the cold side, very little cold water was getting into the tank. If you are getting short bursts of pressure when you first turn on a hot faucet, or no pressure at all, then the check valve is likely stuck. How is this possible? When we've taken the cold side inlet apart and looked at the check valve, it was covered in scale from a deteriorating tank. In our case, simply changing the check valve would not have made good sense since the tank was already too far gone.

We're heard from our customers a number of times that they had just cleaned the top of their hot water tank a few months before and there was no rust at the time. So how did the hot and cold galvanized nipples rust out so quickly?

Inside of all hot water heaters is a sacrificial anode rod. Usually made of magnesium (sometimes zinc) the anode rod is the easiest part to rust in a hot water tank and in fact, that is its job. Inside a water heater, rust and corrosion always happens at the easiest point. The sacrificial anode rod is made to last (to rust) for at least as long as the warranty on the hot water tank. If you're tank has an eight year warranty and is now nine years old, you can be reasonably sure that your anode rod has rusted through.

Once the anode rod's life is at an end, rust and corrosion will attack the next weakest target which is usually the galvanized nipples at the top of the tank, or the T&P relief valve. With electric tanks the elements can also be what gets targetted. Once rust at these points becomes evident you can know the life your hot water heater is nearing its end.

The temperature & pressure relief valve is an important safety feature on your hot water tank. It is typically factory set to release water at temperatures exceeding 210 degrees Fahrenheit or at pressures exceeding 150psi. Temperature and pressure are tied together because of thermal expansion (see above). If for some reason (faulty aquastat or extreme sediment buildup) your tank begins to overheat, pressure will simultaneously build. For obvious safety concerns (think kaboom) this extra heat and pressure needs to be released from your tank and this is your T&P's job. We have shown up to replace a water heater and found that the home owner had removed the T&P and replaced it with a solid plug. Yikes! DON'T EVER DO THIS! If your T&P is intermittently letting water go, it might just be doing its job and keeping you safe! For a temporary fix you could pick up and install a new T&P valve (make sure you get one with the proper temperature and pressure relief rating for your water heater), but this is likely just a band-aid solution that may not address the actual problem.

T&P relief valves will also let water by when they start to rust from the inside. As mentioned previously, this would mean that the anode rod has run its course and the T&P is the next easiest target. Replacing the T&P might redirect the attacking rust to the inlet nipples, or the rust may also immediately target the newly installed T&P. Either way, the tank is aging and is ready to be replaced.

When your hot water heater needs replacement, you need it now – not tomorrow! We have hot water tanks in stock and ready to go. We can install your new tank today. Call us now for a quote and an installation time (604) 542-4663.

Care is always taken to keep your home free from water and rust damage. We wear quality easy to slip off shoes and always have booties on hand. With bad leakers special care must be taken. We use Bradford White's Water Heater Hauler system (shown below) as the ultimate precaution.

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