Modine shop heater and low pressure steam??

Dumbsteamquestionguy

Can a Modine-type garage/workshop heater be made to work with one-pipe, low pressure (residential) steam? I'd like to heat my insulated garage with one. Jason

Dave in QCA

special piping and venting

it requires special piping and venting consideration, but yes, it can be done.  I am away from home and don't have access to materials to copy and post.  Hopefully someone else will find a diagram for you. 

Rod usually comes up with amazingly good illustrations and diagrams.  Hope he's watching.

Jason_44

Bump

Anybody else have experience piping one of these? Is it just one supply/return pipe and an air vent?

Steamhead

Somewhere

I have a diagram for this. I'll see if I can find it. 

Rod

Garage Radiator

Hi - Attached is the drawing for the piping configuration recommended by Modine.

There is also a diagram/discussion  on page 156 in "The Lost Art of Steam Heating".

i looked into this with a friend of mine for his garage and we were considering just dropping it into the wet return. The big problem is that most home garages don't have the height so you might run into a "A" dimension problem. We ended up running a water leg off the boiler and using HW. The only thing scary about that was that you had to keep it warm for fear of the pipes freezing but that was his problem and not mine!

Perhaps Steamhead has a solution. I'm not sure if you can use a "lift" in this situation as I've never had a need to study the principle and how it works.

- Rod

Edit: I forgot to mention that since we were considering running it straight into the wet return, we were going to put a tee where the strainer is located on the diagram and then a long vertical nipple with a radiator vent mounted at the top. We also considered a return water loop back to the main but as we weren't sure this would work abandoned the idea in favor of HW

Jason_44

Modine

Why does the Modine require a separate supply and return? Why can't I pipe it like the cast iron radiators (1-pipe) in the rest of my house? Jason

Rod

Shop Radiator

The tubes are too small. Your house radiators have big openings and big tubes and a big pipe that allows for the counterflow of the steam and condensate to and from the radiator in a single pipe. This has to be piped like you would a 1pipe steam convector, 

Steamhead

Will the Modine

be located above, or below, the steam main- and about how far?

Jason_44

Ahh...

Ok, that makes sense.



Is there another option for heating my garage with steam that would require less complicated piping? I'm hoping to do this myself using an existing riser that I capped during a recent remodel. I know the boiler is big enough to handle the connected load. I'm not a contractor, but have done quite a bit of steam and hydronic work in the past. I just don't think I have the skill needed to do a 2-pipe arrangement like Modine is suggesting. Also, adding a hot water loop to my steam boiler would be a bit too expensive for me.



Jason

Jason_44

Location..

Yes, the Modine would be about 2-3 feet above the main. I want to use an existing riser (currenly capped) that is roughly 15-20 feet away from where the Modine would be installed. Jason

Dave in QCA

questions

I have some questions regarding your system.

what is the maximum pressure that your boiler is set for?

Would it be possible to run an additional pipe the wet return piping connecting to your boiler?

How high above the boiler in feet, is the Modine heater proposed to be?

What is the riser size that you have to the area?

What is the pipe connection size of your modine heater?

How many BTU is the Modine heater?

Is the Modine heater intended for use with steam?

Rod

Need More Info

Hi Jason- There is a fairly simple way to pipe it. However there are certain height and clearance dimensions that have to maintained in order to make it work with steam. In a commercial building with a 16 ft high ceiling, it would be no problem, but in residential garage it might be pretty tight getting the height and clearance needed which is why Dave is asking you the questions in his post. He needs those to see if there might be a configuration that could work.

- Rod

Jason_44

Plenty of ceiling height

The piping would basically come into the garage at ground level, so I've got about 8 feet of height to play with.

World Plumber

size of the riser

We took a steam system out of a factory where they came off the main into the top of the modines came out of the bottom into the strainer and float trap and back into the same pipe. Would something like that work here ? Using the same drawing posted but both connections back to his same line?

Dave in QCA

Here is a diagram

Here is a diagram, from Hoffman Specialty.  Look on page 34, the first diagram entitled, "Low pressure closed gravity system" is what you want.



In this diagram it calls for a unit heater vent.  That would be Hoffman #74.

Also note, that the steam connection would be coming from your riser, extended up to the level of the intake of your Modine unit heater.  The return would be connected back to the same riser, through the check valve shown, (that would be a swing check) and make sure that your have the minimum 12" drop ahead of the check valve as shown in the diagram.



Additional things to think about.... What is the EDR of this unit heater, and do you have any excess capacity on your boiler.  If not, it may require you to shut off some of your radiators in order to get steam to flow to this unit heater.  Also, if the boiler is undersized, you may find that the unit heater is a steam hog and sucks the steam out of the system, leaving your radiators somewhat starved.  Of course, if you have excess capacity, it should work fine.



Also, it is usual in the set up of a unit heater to install a line voltage thermostat wired in series to a pipe mounted thermostat to operate the fan.  Both devices should be selected so that they have the ampacity to handle the electric load.  The pipe mounted t'stat is usually set for 180 and mounted on the supply line next to the inlet of the heater.  It prevents the fan from running unless their is steam present.  The room t'stat of course, shuts off the fan when the space temp reaches the set point of the t'stat.



Hope this is helpful.  Good luck with your project!