Rinnai frustrations?

I don't have tons of expereince with tankless water heaters, but I think it has something to do with where the water heater is in relation to your faucet.  One way to combat that I think is to have multiple smaller units closer to their point of use.

the delay is because from the piping from heater to faucet is too long. rule of thumb is 1 second per meter. if you want to reduce the lag, you can get one item so called smart start. its basically a curculation pumps that kicks on whenever the temp of water dropped in the pipes. so whenever u switched on the faucet u get instant hot water or shorter lag.

thats my 2 cents

If you want to eliminate the wait time, and not waste water or energy-there is a product that will circulate water.  install this pump under the faucet farthest from the unit.  it is pricey, but is durable and approved to use with tankless water heater, does not run all the time and does not void you warranty.  go to my website for information www.yourtankless.com look under products.  you may be able to find a local distributer for this item.

Keith

It definitely sounds like tankless water heaters are best utilized when they are part of a whole house design (or at least considering the design when installing a unit).  Good to know.

 If you think about the basic concept of tankless, you cannot expect immediate hot water when the heater takes care of multriple outlets; i.e. there are distance from the heater to each outlet. This tankless heater was originally designed to the use right at the faucet, that is how most of this type of heaters are installed in Japan.

If you want hot warter as soon as you turn on a faucet, you need to install multiple tankless heaters at each faucet. Some of faucets may, however, not really need immediate response, it may be more practical and econimical to separate into two ways. For instance, you may need immediate response for kitchen. Install a small type next to faucet.