Best option for new Hydronic system and Hot Water heater?

[jteneyck]

I have always had a conventional tank water heater and have zero complaints with them.  I bought the last one about 12 years ago specifically because it still had a pilot light and no power vent.  Simple and reliable, and it has been, no issues whatsoever.  But now I'm looking at replacing the boiler that supplies my baseboard radiators and wonder if it makes sense to think about an integrated system instead of separate ones.  There are potential advantages (energy savings, smaller footprint) and definitely some disadvantages the greatest being no hot water if the boiler goes down.  It's not a new build so I'll be using the existing soldered copper radiators and piping which means the hot water portion would have to have a heat exchanger.

Anyone have some thoughts and/or experience on what my options are?  I'm most interested in DIY solutions.

Thanks.

John

[jteneyck]

No one has any input?  Hard to believe.  Come on, what would you do/have you done?  

John

[blackhat]

I’ve designed, installed,, repaired, serviced, modified, bent, folded,stapled and mutilated literally thousands of residential and small commercial hydronic systems over the years. 

Your post is akin to saying I have 4 rims and tires. Help me build a vehicle. 

I can’t say I consider this a DIY job.

[blackhat]

I’ve designed, installed,, repaired, serviced, modified, bent, folded,stapled and mutilated literally thousands of residential and small commercial hydronic systems over the years. 

Your post is akin to saying I have 4 rims and tires. Help me build a vehicle. 

I can’t say I consider this a DIY job.

[jteneyck]

I’ve designed, installed,, repaired, serviced, modified, bent, folded,stapled and mutilated literally thousands of residential and small commercial hydronic systems over the years. 

Your post is akin to saying I have 4 rims and tires. Help me build a vehicle. 

I can’t say I consider this a DIY job.

I understand, however, those who know me well know that I'm not your average DIYer.  I sized and installed the boiler in my house, added several loops of radiant floor heat, installed the hot water heaters, etc.  I'm an engineer by both education and more than 30 years of industrial work experience, much of it related to thermal and fluid flow analysis.  I'm not looking for help in sizing or installing a new system.  I'm looking for input on what my options are with respect to separate or combined hydronic and potable hot water system, advantages/disadvantages besides the obvious, recommended manufacturers, etc.  I've always valued your advise in the past and would be very appreciative if you would offer some this time.  If not, that's fine.    

John

[blackhat]

Well, if we’re gonna build a buggy, at least I’m working with a mechanic and not a drywaller. 
  

You’ve mentioned radiant floor and baseboard rads as well as the possibility of DHW.   This is an area that the equipment manufacturers have really gotten on board with.   Most of the better brands now come with integrated controls that can handle 2 or 3 different heat loads/zones and the associated pumps or valves. You can have one water output temp for each and use outdoor reset logic to maximize efficiency.   
Indirect tanks are a great option when you have a boiler. The tank in tank stainless are near bullet proof. For an equivalent size tank, the indirect can allow you to dump 3 or 4 times as much heat as a conventional gas or electric. Recovery times can be good to great. Downside is that you don’t have the tank full of water availability. Most are top inlet and outlet so gravity won’t put it in a bucket. It would still be my choice if building from scratch for myself. 

I’ll be back when I can hit a keyboard instead of the phone.

[blackhat]

For a boiler, IMO, you want a low mass, modulating, condensing boiler. You get max efficiency and comfort levels if set up right. This will entail a completely different piping strategy from conventional boilers. It’s a design called primary-secondary piping. Essentially you build a loop out of and back into the boiler with a pump sized to the boiler and all your accessories like expansion tank, air separate, and feed water connection. This loop should be kept short to minimize loss into the space. In that loop are pairs of closely spaced tees serving your various loads and zones, each of which is served by its own pump sized to the zone. The extra pumps may seem wasteful but because they are only as big as needed for the application, you end up with greater efficiency and usually less noise.

[jteneyck]

For a boiler, IMO, you want a low mass, modulating, condensing boiler. You get max efficiency and comfort levels if set up right. This will entail a completely different piping strategy from conventional boilers. It’s a design called primary-secondary piping. Essentially you build a loop out of and back into the boiler with a pump sized to the boiler and all your accessories like expansion tank, air separate, and feed water connection. This loop should be kept short to minimize loss into the space. In that loop are pairs of closely spaced tees serving your various loads and zones, each of which is served by its own pump sized to the zone. The extra pumps may seem wasteful but because they are only as big as needed for the application, you end up with greater efficiency and usually less noise.

Thanks for you input.  We're thinking along the same lines.  My current hydronic system is a monoflow design; only one pipe with diverters for each section of baseboard.  One pump serves the single upstairs and basement zones, triggered by zone valves/thermostats.  Another pump supplies two radiant zones on a manifold, but it's controlled by the single upstairs zone.  The basement zone is a simple straight through design, not a monoflow.  

The monoflow system helps keep the temperature upstairs pretty uniform in the core of my ranch house, but the temperature at the two ends drops off several degrees despite my efforts to balance more flow to them.  Separate zones/pumps seems like a good way to address that issue.  I'll have to develop a drawing to show how the system currently is configured.  

The current boiler is a 30+ year old Burnham with electronic ignition, vented to a conventional chimney.  It's about 60K net BTU's I think; the house is a 1650 sf ranch with an attached garage that has a radiator, too, to keep it above freezing in the Winter. The HWH vents to the same chimney.  

I'll work on a drawing of the current system.  Thanks again.

John

[Cabinet Monkey]

This is the best hydronic heating solution. 


https://www.htproducts.com/elitepremier.html

[blackhat]

Sorry but not even close.