Hot Water - not!

No, I'm not in trouble... at least no more so than usual.

In this post in 2015, after we had lived in the house for several years, I managed to find and install a heater for the shop, and therefore could turn on the water to the shop.  This allowed for use of the toilet and the deep sink.  I was pretty happy about that, and I still am.

However, there has never been hot water.  The bathroom is plumbed and wired for a large hot water heater, but I've never installed one.  It's been a low priority - and frankly, I'm not sure I want to keep 50 gallons of water hot in a shop that I'm not consistently using.  That seems highly wasteful.

In the winter months, the tap water (which has been sitting buried in an underground pipe) comes out of the faucet at 33 degrees F.  Washing hands is absolutely miserable in such frigid water.

Our church just built a new sanctuary, and the new building came equipped with tankless hot water heaters under the kitchen sink and under the restroom sinks.  There was an issue with these heaters.  The water never got hot, just warm.  The church council decided to remove the tankless heaters and install 10 gallon electric water heaters under each sink.  That fixed the issue with the hot water at church.

The church recently held a garage sale, and those tankless water heaters were up for sale.  I inspected one of them, and found that it had an inlet screen that was almost completely plugged.  I thought this might be due to poor flushing of the new construction water piping.

I bought one heater for $20, thinking that that with a clean inlet screen, it just might be able to supply hot water for my deep sink.

Here it is on the work bench before I tried it out.  It came with the nice braided hoses.  Those alone are worth $20.

It's not very large

Specs.  Capacity .026 gallons.  Is that the flow rate or is it the volume of liquid inside the heater? 

I chopped up a heavy-duty extension cord and wired the heater (Tan cord at the bottom).   The top part with the spring and two black wires is the flow switch that turns on the heater when the tap is opened.  The bottom right black button is an overload that needed to be reset.  It seems odd that the cover has to be removed to reset the unit.  I know this is a reset switch, because it didn't work until I pressed it - with the power off, of course!

 Just for testing purposes, I connected the water and plugged it in, without bothering to mount it or install the cover.

It worked, just not very well - same as at church.  Right now, in mid-summer, the tap water comes out at 60 degrees F.  This heater was only able to increase water temperature to 77 degrees F, only a  17 degree increase.  That does not even qualify as warm water to me.  If it were coming out at 33 degrees, I would still be washing my hands in cold 50 degree water.

The tap flows at 1.7 gallons per minute, which is not a very high rate of flow.  Even at this modest flow rate, this little heater doesn't work well enough to qualify as a "hot" water heater. Obviously it was under-spec'd for the church, and it won't work for my deep sink, either!

Edit:  I just did a quick calculation.  This heater is rated at 2.4 KW and raised the temperature by 17 degrees.  If the relationship between power and temperature is linear, then to raise a 33 degree stream of water by 100 degrees would seem to require slightly over 14 KW.

This thing right here would do it for $231 (Amazon).  Sadly the price is a bit higher!