Expansion tank questions

[sdbg]

Hi, I need a sanity check please.

Developed a pinhole leak in a watts etx-30 expansion tank, about a year old.

Contractor is coming back today to replace it. Googling the model, it appears this is a non-potable unit.

However, it's been installed on a branch of the cold water line that connects to the tankless heater (see photo). Upstream from that branch the same cold water line is feeding all the faucets in my home.

Does this seem right? Why would they use a non-potable unit at any point in my home? Worried that drinking water has been contaminated for the last year.

Thank you in advance.

 

[Fitter30]

Not the correct tank needs to be for potable. Ever turn on a faucet and get brown water just for a second that is rust. Water will be fine.

 

[Sponsor]

 

[sdbg]

Thanks. Yes we have see bouts of brownish water. So non-potable expansion tank is fundamentally just more prone to rusting?

 

[Chucky_ott]

Not a plumber and really don't know the answer but is an expansion tank required for a tankless heater?

 

[sdbg]

Apparently in this case the contractor installed it to eliminate squealing noises caused when the navicirc recirculator would turn on.. Presumably a result of warm water being dumped into cold pipe.

They just tried to reinstall the same unit. I had to explain to the technician the difference between potable and non-potable means because he didn't know. I feel like I just fell down a rabbit hole. Scrary. I'm not even sure who to report this to in Canada.

 

[John Gayewski]

Tankless heaters have a special expansion tank that is more like a hammer arrestor. You don't need a big expansion tank like that. They are like baseball sized.

 

[GReynolds929]

Is the exhaust vent on the water heater back graded or is it the angle of the picture?

 

[sdbg]

Both intake and exhaust are ever so lightly graded up away from the machine towards the exterior vents. Almost flat but there is a slight visual grade. Assuming that's correct atleast?

 

[Fitter30]

Ex tank can be any where in the system as long that there isn't a check or reducing pressure regulator before the tank. Most put them close to tank heaters because it easy with just screwed fittings.