Best Condensing Boiler for small shop

[pjp01]

Hi all, I am preparing to install a boiler in my workshop.
The shop is a 32 x 24 section of my barn. I have R22 on walls and ceiling.
12 foot ceilings. 3 double pane windows one man door and a 10x10 overhead door. 2" foam board under poured slab with 3 x 290 ft loops.
Planning a primary secondary system. Located in Southern Ontario(around zero in winter).
Looking for a suitable condensing boiler to heat the shop. I do not have natural gas so likely going with propane.
Would consider electric, though hydro is pricey in Ontario. The barn does have 100 amps.
No water to the barn so DHW combi units not a requirement.
Interested to hear from others what type of boiler they used, brands size etc.

 

[LS6 Tommy]

If you use any type of condensing burner you need a condensate neutralizer and the condensate has to drain to a waste line. It can't legally go out on the ground and also because the line can't be subject to freezing temps.

Tommy

 

[finn]

If you use any type of condensing burner you need a condensate neutralizer and the condensate has to drain to a waste line. It can't go out on the ground because the line can't be subject to freezing temps.

Tommy

Yup. The devil is in the details. My condensate line runs into the sink drain, which goes under the slab of an enclosed, but I heated 16x60’ attached lean-to, then outside and into the sewer/holding tank.

The condensate flow from the pump was sporadic enough, and cold enough, that it froze under the slab.

Not sure that the condensing boiler was worth the hassle over a standard boiler, in my case.

Tommy is correct in that dumping the condensate out the wall, in addition to probably being illegal, will end up with a frozen line.

 

[Jackfre]

750 sq ft? You want the smallest heat only boiler you can find. Get one in the area of a 10-50kbtu firing range. That will put you into the wall hung only, I think. I am not aware of any cast iron units that can fire in those ranges. To the condensate issue, the ph of the condensate is about 3.2. That is pretty hot and not to be trifled with. I have seen people drill a hole in the floor and think, "out of sight, out of mind." They were surprised when the floor collapse due to the concrete being eaten from below. That good old lime based concrete was the neutralizer.
I love radiant heat but for a space the size you are looking at if you put in a Rinnai EX22 or 38 direct vent wall furnace you will have reliable efficient heat with the built in controls you need for your comfort. You will be money ahead.

 

[fitter30]

Could use a lp water heater for your boiler. Cheaper that a boiler 36k input , output probably29-30k btu's

 

[pjp01]

Thanks for the responses.
Will definitely need to deal with condensate issues if i go with a condensing boiler. It is a small space, had initially planned on heating loft as well but discovered i could heat that with a mini split.
Went with a Pioneer there and installed myself. Works great.
So in the shop, even with a modulating boiler, my heat loss calculation is about 27-35k btu. It seems even the smallest unit just gets down to that range and it appears it may be tough not to oversize the unit.
Hot water tank may be the way to go, though i have heard not that efficient. Menards has some small gas units but they are not that well reviewed.
Pipes already in and have most of the components already.

 

[yeldogt]

For that size -- and propane. Do check out the cost of electric. If you are in the .10 area -- it's about the same as propane.

Water heaters -- typically run in the 80% range .. so, factor the propane cost. Also -- what you are running with the 100amp together.

Electric boilers are small, inexpensive and easy to install.

 

[pjp01]

Thanks for the input.
I have 100A in the barn and run mostly small power tools and a mini split upstairs in the loft. It doesn't draw much.
The electric wh option is definitely a simple one. Nice not to worry about renting/buying a propane tank and a gas hook up.
Ontario has on/off peak billing but I think on average the cost is around 9cents per KWh. Plus delivery charges, debt service fees etc. Will have to look a little closer at my bill.
The Hydro Shark SH12 claims max 50 amps and 40956 BTUs. So that or something similar may work.
I actually got rid of the propane furnace in main house and installed a Water Furnace. Works well though hydro bills a little high.

 

[HoosierBuddy]

I agree that your space may be a bit small to justify a condensing boiler.

I'm using a New York Thermal modulating fully condensing boiler in my garage, but it's bigger, has a bonus room above and I'm using the same boiler for one zone in my attached breezeway. The smallest unit they have is rated at 100,000 BTU's and would likely WORK fine, as it is modulating (will run as low as 15,000 BTU's per hour and throttle from there as needed)...but a lot of green for your application.

Regarding the condensate. I did the no-no everyone pointed out and ran mine out the wall with an overflow plumbed in that would allow the condensate to just run out on the floor if the line ever froze. Garage floor with floor drain about 6 feet away.

In southern Indiana, it froze up once or twice every winter and made a bigger mess than what you might think even with the floor drain. Really, who wants to see a puddle on the floor of a new garage?

When I recently redid my garage sink, I ran the overflow to my sink drain. One less thing to worry about.

Phil

 

[yeldogt]

My studio space is 2x yours and I have a 40k 80% propane ... but it's being maintained with a 4500W 220 electric no as the propane service is being replaced .... putting out .. what 14k

I don't think you need 50k of heat -- if you did a decent job of insulating. Radiant needs to be running anyway or it's not going to work very well.

I think you will find with .09 electric -- the propane is out.

 

[pjp01]

Thanks,
I think i have ruled out the propane.
Looking at electric boiler options at this point. The 12W units give around 40kbtu which is plenty for me i think.
Quite well insulated and heated space above mostly.
Now need to figure out if i still need to use a primary/secondary system and if the two Grundfos Alphas I got on ebay will work for this application. Steep learning curve.