Inline tankless coil/electric water heater

[Pete C]

I have a Smiths boiler about 17 years old. It came with a tankless coil. When I installed it, I did not use the TC as I installed a Bock indirect heater.

The Bock lasted a few years before my hard acid well water ate through the coil. Bock replaced under warrantee. The second one lasted a similar time, when it failed I utilized the TC for a few years...before it too corroded. I bought an unused indirect off CL at that time. My water killed it in about 3 years!!!

I finally pulled my head out of my ass and installed a softener/pH balancer system at that time and installed an electric water heater.

It works fine, but I sure do miss my endless hot water when I try to fill my rather large jacuzzi bath tub. I am considering buying a new tankless coil and putting it in line with the water heater. I would run the cold supply through the TC, then the electric. During the non-heating season, I would bypass the TC entirely.

This would give me 'endless' HW and the electric heater would act as a temp buffer, eliminating the need for a mixer valve coming off the TC. It should also lower my electric bill a bit when the TC is at work.

Has anyone tried this? Are there any possible issues I might not know about?

One other question.

Is it possible to install a heater in my tub to reheat water? This is a bathtub with jacuzzi jets. It is not a hot tub that is designed to remain full. Maybe a small electric water heater could be used? My concern would be water that sat in it for many months turning into a petri dish. Also, the water circulating through it would have soap and whatever else floating in it. A potable WH is supposed to have a clean supply.

 

[Master Plumber Mark]

I see the potential for you to get electrocuted ......

why not just hang an element down into the hot tub and hook i t up to some 220 volt wires
when the hot tub gets warm enough , just unplug it.......

 

[Sponsor]

 

[Jadnashua]

Some pumped, jetted tubs offer in-line heaters. You should call the manufacturer of the one you have and see if they offered that as an option for their tub. It may or may not be easily retrofitted. Trying to cobble one up yourself would be potentially dangerous. They are designed to maintain the temperature, not raise it, and it's not a good idea to try to leave that water in there...it should be drained after each use. Then, you'd have to probably run new power to the tub for that heater to function safely.