Thanks for the great forum everyone. I'll be spending lots of time here as I work through my project. My project is to put radiant heat in the concrete slab for my shop. I am going to be pouring the concrete in late May, so I've got a bit of a time crunch. My shop is 1150 sq ft with 12' side walls. The heating/plumbing shop that I got a heating estimate from before I decided to DIY said I needed about 40k-50k BTU/hr to make my system work. From the couple heat loss calculators I found, I calc'd about 35k. The shop will be heated to about 45 degrees in the winter, with no heat once the temps stay above freezing. I live in Alaska and -40 degrees will be common for about 2-3 weeks every winter. My fuel source is heating oil; we have no gas. There don't seem to be any oil-fired products out there that put out that low of a BTU rating. The shop recommended a Bock oil-fired water heater as the heat source. By chance, I found a 5yr old Bock 32e on craigslist locally and picked it up for $300. I know, I got the cart ahead of the horse a bit, but I have two questions right now. 1) Does 35k-50k BTU/hr seem in the ballpark, or am I way out in left field? 2) Will the Bock water heater work for me, or do I need to be looking at something else? Thanks!

Hi, I am new to this and need some help piping (re-piping) and working on an 80 year old system.. I started doing some work on my 6500sf house that includes 2 boilers/seperate systems, a 300,000 btu gas/hot water and a 150,000 oil/steam boiler and figured this would be a good time to split up the one zone hot water system into 6 zones and also get rid of the 150,000 btu steam system and keep only the radiators that I would convert into 2 zones. I added an extension to the house for a new kitchen to replace an older kitchen that was not proportionate to the rest of the house. I built the kitchen with tubing in the floor slab for radiant heat. I did a heat loss and come up with 300,000 btu for the whole house, they realy did oversize in the past. I figured to do the piping now and replace the boiler at some later time with either multiple staged boilers or even maybe a condensing or multiple condensing boilers. At this time I am not sure of the boilers including make/model/manufacturer so all I want to do is the piping and preperation so that when I am ready all I will be doing is disconnecting the existing boiler and installing the new boiler(s). While looking for primary/secondary piping schematics I ran into this site and saw something here [url]http://i202.photobucket.com/albums/aa119/pro10is/bolier08.jpg[/url] similar to what I envisioned with some minor differances. Here are some questions that came up with for starters. 1. Is it correct/proper to connect the expansion tank on the return side? Is this something a manufacturer would have different ideas on or object to? 2. What size should the expansion tank be, how do I size it? Guestimates would be appreciated here guys. 3. What is the outcome of an undersized and/or oversized expansion tank? 4. What size pipe should the primary pipe/manifold be for a 300,000 btu system? Also on figure [url]http://i202.photobucket.com/albums/aa119/pro10is/bolier21.jpg[/url], I noticed only 1 drain valve on the return side before a ball valve, is this common to save on material instead of doing the one drain valve on each zone? Does this affect the filling of water or removing of air from any one zone? Also, the current 300,000btu boiler has 3 large 20+ gallon tanks that are connected to the boiler with a 3/4" pipe. These are probably expansion tanks because there is no other sign of any expansion tank on the system, are these neccessary. Any help/advice is appreciated.