Tank or tankless ?

[5wndwcpe]

I'm finalizing the design for the hydronic heat in my soon to be built garage and the question begs : tankless or a tank type water heater ? Either will occupy the same space, use the same fuel (propane), vent the same way and connect to the manifolds in the same manner. It's a closed system with no concern for domestic hot water. I'm not as concerned with the overall efficiency as I am with the complexity of a tankless or the effects of short cycling. We've figured on a heat load of 52,000 btu's. Any comments from guys who are using one or the other ?
Thanks

 

[Vicious_Cycle]

Either will occupy the same space

That must be one GINORMOUS tankless if it takes the same space as a traditional water heater!

I vote for tankless. I'm running one now, and I love the fact that it takes up zero floor space, and it doesn't maintain heat in 40-80 gallons of liquid even when it's not in use. My Takagi TK Jr has no problem keeping up with demand in my 30x48 pole barn.

I don't see how you could have a short cycling problem when you are heating up a massive rock, regardless of which type tank you use. With the tankless, you set a couple of dipswitches and the heater outputs a consistent temperature. Mine is set (I think) at 119 DEG F. Works great!

 

[paul29]

Couldn't agree more on the Takagi , Have a T-kd20 unit for domestic in home NGas . The rating for the Propane model is input 19,000 btu to a wooping 175,000 btu. Was told this unit would easily heat the whole house if I had infloor heat , i also don't see how the unit would short cycle as the burner varies on demand , it ramps up or down to keep the outgoing fluid temp constant. Also have the temp and remote controller which gives a digital visual on the incoming water temp , outgoing water temp and the flow in gal/min . Have set at 122 and can vary temp up or down from the control display which is on another floor level from the heater. I use a Hot Dawg NG for garage heat.

 

[PhantomEB]

LOL I gonna have fun buggin my bud as he could of saved so much time installing a tankless under his bench than running hoses to the house and installin his boiler there!

 

[5wndwcpe]

Have you guys had any issues with the set up of your tankless unit ? The plumbing is pretty straight forward, but the more research I do, the more horror stories I come across with the tankless units working like $hit right out of the box. People either seem to love 'em or hate 'em, depending upon how they worked from the get go.

 

[kuhner]

I bought a Siesco electric boiler. Installed it last February. Worked perfect right out of the box. I think my BTU load was about 17000BTU/hr. The rep I spoke to recommended I buy the 47,000 BTU, Model SH 14. I bought the Seisco because it was built as a boiler, not a hot water heater.
I paid $675 for mine. Could have gotten it a little cheaper if I was willing to wait 6-8 weeks. If you decide to go this way order early, they get back logged early in the year.
Nice little unit, people cant believe how that little thing heats my garage. My garage is 32X40X10. 1/2 PEX, in four loops, two zones.


greg

 

[Vicious_Cycle]

I had one issue, but once I figured out the problem, it was very quickly and easily solved... for free.

The problem I had was due to the fact that mine is a closed system, so it isn't pressurized by a water supply.

When I first installed it (easy installation, BTW), I did not pressurize the system. Despite not having any pressure, the system worked fine. But whenever the pump turned off, the water stopped circulating (of course), and for a brief moment before the burner turned off, the water in the heater would boil, causing a loud noise that almost sounded like a stick hitting a fan.

I've been calling it 'water' for simplicity, but I actually used RV anti-freeze.

It took me a while to figure that one out. The solution was to pressurize it with a garden hose, close the inlet valve, and disconnect the garden hose. Just had to do it once, and the system has worked flawlessly since then.

 

[5wndwcpe]

Ok, since it seems the tankless guys are the majority here, what controls did you guys use to run the circulation pump ? Thermostat, aquastat, slab sensor etc...

 

[Vicious_Cycle]

I used a regular thermostat to control the circ pump. The tankless heater doesn't need anything, because it has in internal flow sensor, so it just fires when it detects flow.

I have the power to the pump and the power the tankless heater on separate switches so that if desired I can circulate the water without starting the heater, or I can kill the pump without touching the thermostat, or I can swap out either device without turning off circuit breakers, etc.

 

[kuhner]

I am going by memory on what the exact components are. I have a 5 loop manifold, with actuators to turn the loops on and off. A Taco controller, basically a relay that is wired into 110V, the thermostat is wired to the controller, the pump plugs into the controller, and the actuators are also wired into the controller, 24VAC, the one zone controller is about $50. When the thermostat contacts call for heat, the relay provides power for the pump, and actuators. When the pump kicks on the boiler senses the flow and turns itself on.
I have two rooms in my garage, and two thermostats. Each zone operated independant of the other, unless they both call for heat at the same time.
You can go the route of a thermostat with probe embedded in the concrete I did not. Maybe give a little more control. My heat overshoots about 5 degrees, I set for 55F and usually stays at 60F.
Dont know where you are located, I am in Ohio. I bought everything, except boiler, from Jupiter Heating in Wadsworth Ohio. They will do a heat loss suvey for you for 50 bucks that is refundable when you order your parts from them. They are happy to walk you through everything you need, and the prices are very competitive. www.jupiterheating.com I didnt know anything about radiant heat before I did my install, and I couldnt be happier on how it turned out.

 

[bobs409]

I wrote a letter to Siesco to find out what unit I should go with and was told the SH-09 would work for me. Here is the reply:

For your 728 sq ft garage I would use the Seisco SH-09 at 30,710 btus/hr. A quick
heat loss based on your info and use came up to be about 18,000 btus/hr.
Buy using the SH-09 you will be able to raise the temp to 65F if need.
Here is a like to our site for the Seisco SH-09
http://www.radiantandmore.com/seisco-sh09-microboil.html
Also you will need the mechanical equipment for your system, again here is a link to
the kit that will work the best for your project.
http://www.radiantandmore.com/kits-only-no-boiler-05.html
The kits are easy to put together if you enjoy soldering. Very good documentation in
included with very kit.

I'm probably going to go with this setup for next year.


Bob

 

[walrus]

In Maine everyone is using Rinnai Continuum for radiant floors. I heard nothing but good things about them?

 

[Oldram__Newram]

I turned my system on for the first time about 6 weeks ago. Floor space wasn’t much of an issue for me since I wanted to have any open flames way off the floor I built an 8x16’ loft for the heat system, the air compressor, and extra storage.

I went with an inexpensive 30 gallon for now a few reasons. 1. pay-back for the price difference was over 5 seasons worth of heat factoring in both the initial investment and the better efficiency of the tankless. Money is a little tight right now. 2. I built my system to be flexible; I can either heat the whole shed (1,600 sq ft) or sections of it by closing off loops and adding internal walls if needed in the future. To me the first few years are like a test-drive of the system and my layout of equipment / work space. 3. I wanted to make sure that everything was leak free and worked well before I invested in the expensive antifreeze, when that time comes I will most likely swap to a tankless for the added efficiency.

 

[chevelle64]

I went with Radiantec for my system design and suppies, except for the water heater. They do not recommend tankless water heaters, so I went with their advice. I went with a 30 gallon heater. Just got my system going the day after Christmas, so far so good.

 

[Kapt]

I wrote a letter to Siesco to find out what unit I should go with and was told the SH-09 would work for me. Here is the reply:



I'm probably going to go with this setup for next year.


Bob

This is the exact setup I just installed. I bought everything from Randiant and More and got it running last week. I did a lot of soldering, but the instructions that are included in the kit are extremely detailed with supporting photographs and well written instructions. Someone obviously thought this out very well. I filled my system with 50/50 distilled water and radiator fluid and so far everything is working well.