Tankless Water Heater FAQ’s

Will tankless water heaters work with hard water?

A: Although many heaters are currently working well without any water treatment, we recommend that homeowners in areas with hard water install a water softener or a de-scaling device in the water line before the heater. This should lengthen its lifespan as well as the time between servicing. In areas with exceptionally hard-water conditions, the heat exchanger inside the unit may require periodic flushing by a plumber to remove built-up scale. Keeping the temperature low also helps to prevent scale buildup in severe, hard-water conditions.

 

How long will a tankless water heater last?

A: We have found the average useful life to be 15 to 20 years, compared with 10 years or less for most tank-type models. In hard water areas, water treatment is essential to long heater life

 

Can homeowners do the installation themselves?

A: This product must be installed and serviced by a licensed plumber, a licensed gas fitter, or professional service technician. Improper installation and/or operation, as well as installation by an unqualified person, will void the warranty.

 

Will I get instant hot water with a tankless water heater?

A: No. This is a common misconception of tankless water heaters. A tankless water heater does heat water on-demand instantly, but just like a tank water heater, it will take the same amount of time for the hot water to travel through the plumbing inside your home. If you would like to get instant hot water, there are recirculation pump systems available to hook-up to your tankless water heater. Please ask your installer to see what options you may have in getting instant hot water in your home. Note: If a recirculation pump is used, we recommend an on-demand system, such as ACT/Metlund® Hot Water D’MAND® versus a aquastat/timer in order to keep the full warranty coverage.

 

Do I need to upgrade my gas line?

A: Yes. Tankless water heaters do need a larger gas line since its required Btus are higher than tank water heaters. The reason why the Btus are higher is because it needs the energy to heat the water to your set temperature in mere seconds. The actual gas line upgrade size will be depend on which tankless model you choose and the distance from the gas meter. However, the minimum gas line size is 3/4″ in most models with some recent models only requiring a 1/2″ gas line with sufficient pressure.

 

If a tankless heater requires higher Btus, doesn’t this mean it uses more gas?

A: No. The amount of energy or Btus required to heat water is the same. A simple way of explaining this is when you boil a pot of hot water on your stove. If you were to boil two identical pots of water, but one is on high heat and the other on low heat, the amount of Btus required to boil the water is exactly the same. The only difference is the amount of time it takes for the water to boil. So think of the tankless water heater as the high heat and the tank water heater as the low heat. The energy savings comes in where tankless water heater has a higher energy efficiency and only turns on to heat water when you need it. Whereas a tank water heater is less energy efficient and wastes gas by regularly heating the water in the tank to maintain the set temperature.

 

Why do I need electric power for my gas tankless?

A: A tankless water heater’s electric power requirement is 120V AC, which is the standard power outlet in U.S. homes. Some local codes have specific requirements on the electric connection. For example, some local codes do not allow extension cords when connecting to the power outlet. Our tankless heaters only come in gas models (natural gas or propane) to heat the water, but electricity is required for the digital remote and to power the PC board, which is the brain of the heater. Also since there is no stand-by pilot light, it uses an electric direct ignition. Electricity consumption is very minimal.

 

Can I use my existing venting for my tankless water heater?

A: No. By code, tankless water heaters must use Category III stainless steel venting. Category III venting is corrosion resistant and gas tight. The venting must be corrosion resistant because a slightly acidic condensate is formed during combustion. This condensation can eat away at your current vent pipe’s galvanized metal and cause major damage to your tankless water heater’s internal components. More importantly, the venting must be gas tight to avoid carbon dioxide leakage. Tankless heaters use a powered exhaust fan to push gas out, as opposed to tank water heaters which use natural draft. Note: Schedule 40 PVC or CPVC can be used for venting on the condensing technology tankless heaters only.

 

Do I need to install a water softener for my tankless unit?

A: No. It is not required to install a water softener, but if you live in an area that has hard water it will eventually harm the performance of your tankless water heater. Some things you can do is to add a water treatment system such as our Scale Scrubber Pro® which prevents scale from forming inside the heater’s copper piping, a whole-house water softener system such as nuvoH2O, or do a routine flush maintenance (frequency depends on your water hardness level). We can test your water hardness or you can contact your city’s water department for the water test report. Water hardness levels in excess of 12 grains per gallon entering the heater will significantly affect its performance and void your warranty.

 

What type of regular maintenance does a tankless water heater require?

A: There are two types of periodic maintenance that your service technician can perform to keep your Tankless Water Heater running smoothly:

The in-line screen filter should be checked periodically for debris (time between filter checks will be dependent on water quality).

The unit should be flushed periodically (time between flushes will be dependent on water quality) to keep the unit free of scale and lime. This process should be completed by a professional installer.

What is the “cold water sandwich” effect?

A: The term “cold water sandwich” effect is used to describe the introduction of cold water into the hot water supply line during frequent on/off operation of an instantaneous hot water heater. When present, this effect appears as a momentary drop in hot water temperature as it is discharged from a hot water supply outlet (i.e., shower, tub, or faucet). It’s a phenomenon that is present in the operation of all instantaneous and on-demand tankless water heaters.

Another reason for  this can be Cold water left in the piping after a faucet is used, for  Example, John takes a shower in bathroom one and fifteen minutes later Jane wants a shower, She starts up the shower in bathroom two and has hot water but when John finished his shower, the water in the pipes between bathroom one and bathroom two cooled down, once the demand for water is made for Jane to shower in bathroom two that cooler water is then forced along the pipes to Janes shower where she feels the effects of a “cold Sandwhich” Jane gets hot, then cold, then hot water for a moment while the cold water is bled out of the pipes.

 My sink in the spare bathroom doesn’t get hot water but the other parts of my house do, what is wrong?

A: A possible cause of this is that your sink doesn’t cause enough demand for the Tankless Water Heater to register the demand. A way to find this out is to open the hot water valve on your sink fully open and place a quart container under it, if the container fills in 36 seconds or less then the flow rate should be enough but if it doesn’t then your faucet does not cause enough flow demand for the Tankless water heater to register the demand. You could also have what is commonly referred to as a “Plumbing Crossover”.

What is a Plumbing Crossover?

A: The heater activates when there is sufficient water flow through its water valve, a minimum of 0.1 to 0.8 Gallon/Minute (3 l/m) is required (depending on brand and model). If there is a crossover in the plumbing, the necessary hot water flow rate though the unit may not be reached, even though the flow at the hot water tap may be sufficient. A plumbing crossover can be caused by a failed washer in a single lever faucet, incorrect plumbing or a faulty mixing valve in the piping. The crossover will create a back pressure on the water heater and prevent an adequate flow of water through it. To confirm there is no crossover in the plumbing, shut off the cold water supply feed to the water heater. Individually open each of the hot water taps. There should be no water flowing under a constant pressure. If there is a constant flow of water then the plumbing crossover must be corrected before the heater can operate properly.

No matter the cause, having a plumbing crossover is hazardous to your existing system, the reverse in pressure through the hot water line will work its way back to your tankless water heaters hot line and push up against the flow sensor. This causes damage to the valves, sensors and at the very least causes your system to work harder trying to heat the outgoing water to the set temperature. This is not something the heater will be able to do and it will not stop trying, thereby causing the system to eventually wear down and if you are lucky it will only code out with a cleaning code or loss of flame code instead of the main component going bad due to excess heating. Bottom line…be aware of plumbing crossovers and if you have one, fix it immediately.

How do I know if I have a Plumbing Crossover?

A: The easiest way to tell if you have a “Plumbing Crossover” is to turn off the cold water to the water heater by using the shut off valve located at the heater itself. If you do not have one installed, you will need to install one to continue with this test. Once you have this installed, turn off the cold water to the heater and then open all of the faucets in the house on the hot water side and wait 5 minutes. If after 5 minutes you have any water coming out of the faucet on the hot water side then you have a “Plumbing Crossover”.

How does a hand sprayer affect my tankless water heater?

A: In a commercial installation such as a restaurant or kitchen environment there will often times be a hand sprayer used to wash dishes or hi pressure spray down grease. If the source of the hot water used by the sprayer is from a tankless water heater then increased degradation of the units lifespan will occur. A tankless water heater isn’t like a conventional tank type water heater in that it does not have a storage of heated water just waiting to be used. Each time the sprayer is activated it causes the heater to start and stop. This can often result in the unit starting and stopping 30 or 40 times per minute. The tankless unit is not designed to operate like this on a long term basis. Starting and stopping the unit so many times in a short period will result in the unit failing due to ignition and electrical components being shorted out. The system is designed for continuous hot water and as such the components inside the unit are designed to support long term operation of a long term duration. The shortened bursts will only degrade the system and greatly shorten its lifespan.

As a preventative remedy to stop this degradation you can and should turn the sprayer to cold only. Doing this will still apply the pressure from the cold water in a spraying format so as to allow its use in breaking up harder food spots or debris but not hasten the failure of the tankless since no hot water is used while doing this. A simple fix such as this can greatly lengthen the lifespan of your tankless water heater and save you thousands of the duration in repairs. Keep in mind though that this fix is only one step in keeping your tankless water heater working well. A descale of the system every 9 to 12 months in crucial to its upkeep and all too often we see owners not doing so and having to repair or replace the unit as a considerable cost and hassle in time lost having hot water. Couple this with cleaning the combustion system every 18 to 24 months and you will be well on your way to having a dependable hot water source for years to come.

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