I am lucky to have all this expertise available to bounce ideas off of. I've got a question for the group about doing an install with just a single loop, ie no heat exchanger just a manifold. The positives I know are lower cost and less complicated install, but am curious about negatives. I've talked to Precision Chem Water Treatment who said one negative might be that any problems that might develope in the Garn itself due its openness, i.e. bacteria or fungal growth, would spread through the whole system, which admittedly wouldn't be that hard to treat by adjusting chemicals. Just curious if anyone has any thoughts on the issue.

A little backround, the install will be in Lakeside, AZ. Yes a Garn in AZ...I believe I'll have the first. I'll be using a 1500 for heating 2400 sq ft, DMW and a hot tub. The house heat will be primarily radiators/wall panels with possibly some radient floor due to lack of wall space in some rooms. My wife and I designed and built our dream home almost 10 years ago without thinking about hydronic heat, a mistake I'm paying for now. The home is currently heated with propane forced air. My plan is to have two independent systems. Did I mention that I'm a retail pharmacist with no hydronic heating experience. I figure with my desire to learn, and this group and others at Hearth, I'm in for a grand time.

I will also post at Hearth so appologize for duplicate post.