Replacing Open Hydronic System

k2p2

I need some help choosing a new system.  My home is located in pacific northwest and was built in 1999.  Square footage is 1,850 with 3 beds, 2.5 baths.  Currently there are two 40 gallon hot water tanks in my garage which feed Kitec Pex-Al-Pex tubing for wall fan-coil units as well as provide potable water for the home.  I have been told by many that this is a dangerous system. It is also proving to be quite expensive with natural gas bill.

Several heating contractors and plumbers over the years have left me with three choices: 1) modulating condensing boiler on the wall in garage with a 50 gallon hot water storage tank 2) two indirect water tanks ..one for heating and one for potable 3) a combi-boiler unit for both heating and domestic hot water.

I'm finally ready to replace the two tanks in the garage for a better system but have no idea how to proceed. 

icesailor

That's a bad one:

Some of us think that that is one of the worst ideas to ever come along.

Others may disagree with me.

I personally would install a Mod Con boiler, boiler only. Connect the heat zones through a Low Loss Header/Hydraulic seperator, and install a brazed flat plate heat exchanger and turn one water heater into a storage tank, fed with the FPX. That will be the most cost effective thing you can do. If you want to spend more, use an indirect. But you already have the water heaters.

Many are excited about Combi units. I've already seen expansion control devices fail under warranty and the potable water sides fail. Maybe with more time in the field.

I have an account with a Potable instantaneous water heater that goes through a flat plate to heat an air handler. It doesn't work well that way. If it was a Mod-Con boiler, heating the building and heating the potable water with an indirect, it would be fine.

JMO,

Zman

Mod con

I am assuming the 40 gallons tanks were the heat source and are tired? My first choice would be a firetube mod con for the heat with an indirect tank for DHW. I think there are some potentially great combi units out there, I have to agree with icesailor that they are largely unproven.

k2p2

Tanks are tired

One of the tanks "exploded" in year three.  Scary..shook the entire house.  Thankfully it was still under warranty.  The other tank needed a new blower motor unit last year for direct venting.  One tank is now almost 13 years old..the other 10.  Now one of them is making a popping sound when it ignites.  Bottomline, the whole operation makes me nervous. 

bld999

Open System

There were a lot of systems like this installed in the Puget sound area

with Turbonics wall mount fan coils. There is a company on Vashon [

Blueridge] that consulted on replacing or modifying systems like this

that were installed in an SHA housing project.



Dan over at Blueridge might have some ready optimized solutions and

contractor ideas. sounds like you need to get moving on correcting

this.  

bill_105

It exploded?

From the get-go It thought it was a bacteria concern. Breathing legionella and other stuff is certainly not healthly. Open systems should be a code violation.

But now an explosion!

Do yourself a favor tomorrow, beg,borrow, or steal. Get rid of what you have.

Paul Pollets

Help with system

I'd be happy to help. We're located in Seattle and I have extensive experience working with (and fixing or replacing) open systems.

Rich_L

A.R.T.

While I don't know Mr. Pollets or Advanced Radiant Technology personally, I do know he's been around and doing this work for a long time and really knows his stuff. I sincerely believe you could fully trust him to do a fabulous, efficient job for you. IMHO



And as others have, get rid of that open system ASAP. Those don't begin to meet code in my area and are a huge potential health risk.