Condensing Boiler or just a boiler.

[ckrzysko]

My floor is ready to pour with pex already down. I started to look at boilers and realized that I need a drain. Oh Boy- what to do. Do I go with a noncondensing unit or somehow put a small pit to eject? Also worried that in cold winter nights the condensation will freeze after ejected?? Options?
1. somehow work in a sump pit and have it slightly raised in garage and discharge out the side or into landscape drain?

2. Place a sump pit above the floor and ejects to the outside?

3. Non condensing unit that is less efficient but I was told still need to drain? also -I dislike how you have to use Stainless to vent.

How much can it discharge? Live in northern part of Illinois. Detached garage
24x40 12 foot ceiling. keep at 55 degrees when working will be at 68 degrees. maybe 3 times during week.

 

[joe--h]

You need to provide a lot more info.

How much foam under the slab? Is the slab isolated from the footing?

How well insulated will the building be?

This type of heat does not respond well to the kind of temperature changes you are looking for. Takes a long time to move the temperature of a concrete slab 1 degree, you want 13 degrees.

More research required before you go any further.

Joe H

 

[Jackfre]

You will get a bit less than a gallon of water/therm of NG or propane. Its Ph is about 3.2 and it will eat concrete in a hurry. Dump it under the slab and it may eat the bottom out of the slab.

 

[LS6 Tommy]

You will get a bit less than a gallon of water/therm of NG or propane. Its Ph is about 3.2 and it will eat concrete in a hurry. Dump it under the slab and it may eat the bottom out of the slab.

All comdensing burner condensate lines require neutralizers.

Tommy

 

[goneflyin2002]

Yes you'll need a pit drain or something suitable.
That was the big mistake that I made during my build. I tried draining through the buried eavestrough drains. Froze up.
I've had to heat the drain using heater wire to deal with it.
For reference, I'm in southern ontario, and it's relatively mild winters. On the coldest days, it could be 10 deg F and my condensing boiler will make 3-4 gallons overnight.
I keep the heat at 62 all the time, never touch it all year. In the winter, the shop feels like 70 or so at that setting. I wouldn't bother too much with setting your temp back through the week. If it's insulated well, the savings would be nearly unnoticeable with a setback. And the slab is so big and heavy that swinging the temps would take a long time.
That's why the floor heat is so great- you can open a door and the room recovers super fast. Not to mention a lot of other real benefits.

 

[75gmck25]

You didn't mention what type of fuel, which is a significant consideration in the cost comparison. However, considering your infrequent use, have you compared the long term cost of condensing vs. non-condensing boilers? There higher efficiency non-condensing boilers that work well, and they are simpler to install and maintain than a condensing boiler. Look at your estimated fuel costs and determine the payback time for a more expensive boiler.

A standard boiler needs an emergency drain, but does not routinely run water down the drain. You could probably just install a standard floor drain and run it outside if you needed to drain the system for maintenance.

Bruce

 

[Jackfre]

All comdensing burner condensate lines require neutralizers.

Tommy

Not true Tommy! It is up to the AHJ. I see some areas around the country where it is required and others where it is up to the installer. Surprising after all these years.

 

[LS6 Tommy]

Not true Tommy! It is up to the AHJ. I see some areas around the country where it is required and others where it is up to the installer. Surprising after all these years.

I thought it was a national requirement now. Fireside Condensate Neutralizers are code in NJ. It's been required by the NPC for a while, but I realize not all AHJs have adopted the NPC.

Tommy

 

[BadgerBoilerMN]

The condensing boiler will pay for itself and give you the distinct advantage of sealed combustion (no open flame), direct vent (sidewall plastic pipe). It is also quiet.

You can neutrualize the condensate if you want to but it is not code anywhere. It is considered a must if you are draining into an exclusive cast iron drain (softener will neutralize it for you) or a septic system (destroys the natural microbe brew).

I did not have a drain in my garage so it went directly under the existing slab for my snow melting ModCon. A dry well would in order. If you sink a 50 gallon plastic drum into a reasonable perc soil with gravel and a neutralizer at the boiler gravity will do the rest.

PS. Don't over-size the boiler and don't forget the annual service.