Importance of water quality for tankless hot water heaters

When it comes to performance, efficiency and longevity of tankless hot water heater we learn more every day that they need to have annual maintenance service performed by a qualified technicians, but seldom do we think of how important is the role of water quality going to these units.

Some water heating equipment manufacturers would even void the warranty the parts breakdown if caused by poor water quality. Hardness, rust & scale chlorine and abnormal PH levels are mostly seen to have been a cause for many service calls resulting in unexpected expenses and some frustration for most homeowners.

Some water heater manufacturers recommend descaling done with food grade vinegar every year as part of the maintenance to address this issue. 

EPA (Environmental Protection Agency) has a table of allowed maximum contaminant levels in  National Secondary Drinking Water Regulations (40 CFR Part 143.3). This can be helpful when testing local water quality and knowing what you are dealing with and widely used by a few water heater manufacturers.

Best practice would be to have the water tested by a lab and address the poor quality by prevention methods and filtration. Depending what you have in your water you can at least have an inexpensive scale inhibition water treatment filter installed on cold water inlet side of your water heater and easily replace the filter every six to 12 months depending on the contaminant levels of your water. This alone will save quite a bit of headache down the road and unexpected interruption of hot water and emergency service calls to plumbers. 

Check links below for Aqua-Pure Scale Inhibition Water Treatment System

Cleanliness of the hydronic heating system

We are more used to the traditional cast iron boilers that didn’t get affected significantly with untreated fluid in the system. Would that be the same with new nigh efficiency condensing boilers? Do they get hit by rust, magnetite (Iron oxide sludge) causing things to break down?
Servicing these units in the fields and talking to home owners has shown me that there are quite a few home owners who are not aware of the differences between new systems & old cast iron ones.
Dissimilar metals in system causing electrolysis and magnetite formation in untreated system can lower efficiency and cause number of part breakdowns in boilers as well as in ECM circulator pumps, especially when there is iron pipe work in the system or steel / cast iron radiators in the house as part of the system.
Europe has been dealing with this for years since efficiency is not a choice with the high energy cost there. With boiler manufacturers making high efficiency products in market to save on energy costs and the demand to fit in small areas of the homes brought low water mass wall hung boilers with small opening in heat ex-changers, tubing in boilers. The small pieces of rust debris, magnetize that was flowing much easier in old cast iron boilers now would be detrimental to the high efficiency boilers. This can affect also other equipment outside of new boilers such as ECM circulators, vales, piping etc.
We, also, should not undermine the role of heat transfer a clean fluid or water in system plays to deliver the heat in rooms of the house where it needs to go versus getting lost on mechanical room.
When replacing a cast iron boiler to a high efficiency one it’s best to inject a cleaning solution into the systems before removing the existing equipment, then clean flush the system. After installing the new boiler and removing all air out it injecting special inhibitors to slow down corrosion & prevent future rust formation.
As a second and more permanent layer of protection would be to install a magnetic filter / dirt separator on return line of the system before the boiler. This is one the best things a qualified technician can do for the homeowner to ensure the longevity of the system, to protect their investment and help to get most efficiency out of their new equipment.


What does it take to go Tankless ?

Why Tankless?

It seems like there is more tendency now to go Green on all our energy consumption whether it’s gas or electric. This is definitely a the way to go.

What we find often is while Tankless hot water heaters provide savings 50% on utility bills, not every home is ready for them. In number of cases there is going to be some retrofitting to be done depending on existing piping and other things listed below to accommodate to the family’s hot water consumption needs based on their lifestyle and the amount of plumbing fixtures installed at the residence.

Rinnai RUC180i installed in Woburn, MA

Other pros are Endless Hot Water,  Longevity of the unit & Consistent Performance.

Cold weather: Another factor is our New England winters that has an effect on the amount of hot water can be delivered at certain amount of fixtures. For this reason plumbers have to size units based on cold weather temperatures G.P.M. (Gallons Per Minutes) outputs and this can weigh on the cost of installation.

Gas pipe size: National Fuel Gas Code shows us that every time we install a new gas utilization equipment or replace with a different one we need to make sure the existing gas piping is going to be sufficient for new and all existing appliances. And often times converting your 40 to 80 thousand BTUs tank type water heater with a new 150 tp 200 thousand one will involve replace some of gas piping.

Electrical outlet: If you had natural draft gas water heater you didn’t have to have 120 volts power supply near water heater. This is not the case for tankless gas hot water heaters. Even though they consume gas to produce hot water they still need 120 V power supply to run the controls and sensors in the unit. In most cases manufacturer’s require a dedicated power supply that can be independently controlled from the panel.

Venting: When you choose a high efficiency condensing Tankless water heater plumber has to install new exhaust vent and fresh air intake piping to outdoors. In some cases you can install a liner in your existing chimney also.

If you have any more questions regarding converting to Tankless feel free to reach us at