Rinnai

Alan(CaliforniaRadiant)Forbes

We are about to install a heating system using a Rinnai flash water heater for a new building with two commercial spaces here in Berkeley. One space will have radiators and the other will have both radiant downstairs and one radiator upstairs.

We will use 1°:2° piping; the primary pump will have to be a Taco 0013 because the Rinnai HX requires 6 gpm, 30' head; quite a bit.

I chose this make because there was no space to put the boiler and this model can fit in a thickened (9") stud bay; venting is a piece of cake as long as you have at least 5' to the property line and it's extremely quiet. Rinnai also has great engineering information and it's nicely documented.

We don't have to worry about low return water temperatures because it's a water heater, but don't ask me how it handles the condensation; osmosis.......magnets........voodoo?

The building has a small DHW load and I suppose we could have had the Rinnai do double duty, but we were all worried about Legionella propogation and decided against it.

I'll let you know how it turns out.



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Dan Peel

same lineage

This was today's wire & fire. This Rinnai tops up the temp to fixtures from the dual coil indirect (One coil receives from rooftop solar and the second coil delivers to heat loads). The Rinnai only sees the domestic water and has a stat controlled recirc loop into the top half of the domestic storage. There's even a heat makeup coil in the main floor high mass wood stove. This passive solar house is also off grid and includes a windmill. Have fun with your install...... Dan

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Steve Eayrs

Have done a few heat systems using the Rinnai

on-demand, continuumm water heater you described.
I am not impressed. The overall efficiency is low. They will just not cycle well. They are designed for colder returns, (as any on-demand water heater should be), and not for boiler applications, (where the Delta T is rather small) Also had a lot of complaints of vibration noises. I beleive I may end up having to tear out two of them and installing boilers instead. Even if the noise is solved, the fuel consumption is way to high.
These are no where even remotely close to being a Vitodens, so be prepared that they will not work the same.
Also if you look at the Rinnai concept drawings you will see some real problems. Definitley not drawn by anyone who knows hydronics. The high head required through the unit is not the only problem. I also did P/S piping on these systems.

Steve

Dan Peel

Suitability

Hi Steve, I'm not convinced the flash heaters are appropriate for space heating either but we "inherited" this job with pre-installed tubing and the Rinnai and had to make use of the materials at hand. I'm hoping by having the volume of the indirect we can minimize the # of cycles. Dan

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Tom Meyer

Rinnai

One developers put in a Rinnai for a two-story home in Northern Michigan. It runs both the DHW and heat. So far there has been no noticeable vibration, the efficiency has been acceptable and they received a 5 Star Plus rating.

I think we solved the Legionella threat (due to stagnant water) by making the primary loop directly from the Rinnai to the DHW and the heat side through a heat exchanger. When the heat system goes into demand, it starts a pump through the primary side of the heat exchanger creating flow to trip the internal Rinnai flow sensor. When a DHW source opens, it also causes water flow through the Rinnai.

Since this is a model for 103 more units, any comments (by email to me) would be greatly appreciated.

Senior Designer/Trainer
Precision Hydronics Corporation
www.precisionhydronics.com

Tom Meyer

Rinnai

I should have mentioned, we're reviewing Weil-McLain's Ultra as a alternative.

Senior Designer/Trainer
Precision Hydronics Corporation
www.precisionhydronics.com

Steve Eayrs

Rinnias



I should point out that the Rinnais we have installed are LP not NG. And the price of LP here is aprox. 50% more than oil fired, . AND thats when you have a decent boiler. These unit use more than that.
Steve