Undersink water heater question

[Ivan Vegvary]

I just placed an under-sink (Sinkerator brand) water heater into my wife's studio. I got her a laundry tub, and rather than run the hot water from 60± feet away, I bought one of these units. It comes with it's own faucet, BUT, I really wanted the hot water to come up through the standard mixing valve so she can wash her hands, etc. Bought a bunch of brass tees, fittings, etc., and tee-d off the hot water line running from the heater to the dedicated faucet. This tee-d line, in turn, I fed into the hot side of my mixing laundry tub faucet.

QUESTION: It turns out that nothing comes out of my tub faucet unless I turn the dedicated faucet on. Unfortunately it is spring loaded and this makes two-handed washing impractical. Turns out that only by turning the dedicated faucet does the heating unit receive water pressure to push out the warm water. In other words, there is no water pressure in the unit until water is requested. Does anybody here have any knowledge as to whether I can safely feed continuous pressure to the unit without subsequent damage?

BTW, they do sell heating units that plumb into your existing faucet, except not only did my HD not have one, they are about $140 more expensive. Dedicated heater =$160. Feed anything heater = $ 298.

All thoughts appreciated.

Ivan Vegvary

[rogersdawn2]

we bought a 6 gallon 120 volt unit at lowes put it under the sink and it works good. scott

[Goedjn]

If you're talking about an on-demand water heater, then it's deliberately designed not to try to heat unless the water is moving. (It ought to be a flow sensor, not a pressure sensor.) This keeps it from heating the water hot enough to scald, or even past boiling, when the fixture will then explode. Do not screw with the on-demand heater components. If it's integral with the handle, cut the spring, or figure out some way to jam the nob in the ON position.

--Goedjn

[jolt]

You need either a small electric water heater or a point of use heater. A small tank water heater will be more practical something like the 6 gal tank sold at Lowe's.

[John Grabowski]

The unit that you bought sounds like an instant hot water heater for tea or coffee. If so it is not designed for continuous use or to be plumbed into a faucet. You also run the risk of scalding as that water is closer to boiling than a normal water heater. You should buy a small tank water heater or a tankless water heater, both of which can be tied into the faucet and operate the way that you want.