Hot water heating system

[busing704]

I am looking of using a tank less water heater to heat the water instead of a aqua hot elect. I hope to have five zones. water bay,bedroom bath kitchen and living room I know I will need a pump (I have) fan heads (I have) what I need is What size heater do I need , and what heat temp. should it be and how do I control that. The tanks that I have looked at have one control to shut off at 190. and that is way to hot. Thank you for your help. Jerry  PS: this is for water to air heat ( hyd. heat )

[ruthi]

We put one in the new bus, and now isnt working. Dont know if something is wrong with it, or if maybe there just isnt enough water flow to operate right. It was for our kit. sink and bath sink, so, out of desperation on the road, purchased a small 2 and half gallon tank and installed under kit. sink. We have another one that the shower uses.

[robertglines1]

Ruthi  what kind did you get? I was going to try same thing and time is fast approaching for me to purchase.   according to literature it only requires 1 1/2 gal flow and 25 lb pressure minimum    Bob

[robertglines1]

A idea. The heater on my Jacuzzi (hot tub) that is activated by flow of water the heater element is 2400 watt 220 volt the small tank appears to be about 15 inch tall and10 inch in diameter. the thermostat turns the pump on.