Heating the garage, rather unique situation.

[RustnGrease]

Here's my situation, 24Wx28Lx7'6"H attached two bay garage with 8x7 doors, ceiling and one wall is insulated as are the doors. Other wall is mostly under grade/ground level. 8" cement block construction, with no insulation in the block.
Coal fired hot water furnace/stoker sits in a 10x10 area behind the garage area but is still in the same walls. Natural gas isn't available here. Had a large electric heater hooked up, it worked but was costly to run. Also used a Propane turbo heater which worked nicely but took up 1/2 of a bay to run and it's loud.

My current thought/plan is to plumb a heater into a line returning to the furnace,from the house, using two t's and three valves so it can be shut off in the summer or for repair. Stoker only has two zones on it or i would just add one for the shop. As for a heater i was planning on using either a small modine unit with a switch to turn it on when needed or a cast iron radiator. Plan is to install it in the area of the coal bin which is only about 16" from the ceiling, so it blocks the heat from the furnace to get into the garage area.

Attached is a rough drawing/sketch of the layout of the garage. Yes i know more insulation would help but with the amount of stuff in the shop moving everything from the left side to insulate would be a week long project. Just looking for something that will take the chill off and keep it a little warmer. Also 1/2 of the garage is under the house so it will help with keeping the house warmer by not having the cold air underneath.

 

[anthony666]

man i haven't seen a residential coal boiler since the 70's

what is the temperature of your return line ?? short term your unit heater idea would work, providing there's enough return temp to operate efficiently .. and more importantly that you don't strip too much heat out of the return and thermally shock the boiler, which can lead to all kinds of problems

if it was me, i'd put closely spaced tees in the return line, a pump in the unit heater feed, and a tstat with a remote sensor and a normally open circuit to kill power to the pump if the temp back to the boiler falls below spec

 

[RustnGrease]

Thanks for the reply anthony, so you would run a pump after the t in the loop for the new heater? So if the return water temp dropped too much it would just bypass the loop for the new heater correct?

This is about the only feasible option i have found as of yet, due to space constraints.
The electric heater works but its an older one so not very efficient. I'm not looking to have a beach party, just something to take the chill off. I've even considered a heat reclaimer box that goes into the stove pipe coming out of the furnace.

Also to clear up the first post, the coal bin is approx 16" from the ceiling. The modine unit would be mounted on the ceiling in that area or the cast iron radiator would be mounted on the floor in that area. Sorry for any confusion.

This is one of the few areas where they're still popular due to the cost of coal. Even some people that own oil furnaces are switching back, local company is still manufacturing them also.

 

[Carl_WI]

In the pic below I added a zone with a pump. I think the "T"'s need to be 5 inches apart for it to work properly. The water flow is counter clockwise. I had to remove the check valve as air collected in the pump and would not pump. The pump is controlled with a relay center and thermostat.
I do not have the pex tubing hooked up yet in the pic or the cover on the electrical box.

 

[RustnGrease]

Carl, that's pretty much what i'd like to do, thanks for the reply. My issue is that i would be tapping off of an existing zone to heat whichever unit i decide to use. Still trying to figure out if this is feasible or not.

 

[TractorJeff]

As far as coal for heat.
Out in that area, some of the people are heating there homes for $3000 to $4000 a heating season as they are old drafty houses with fuel oil furnaces!
They can heat their houses with 4 ton of coal at $230/ton delivered for the same heating season! The OP living in NEPA maybe even getting coal delivered cheaper than that but the price I quoted is pretty much the norm!

 

[Carl_WI]

My issue is that i would be tapping off of an existing zone to heat whichever unit i decide to use.

It would still work to tap off the existing zone but the zone has to be circulating for it to work. The cleanest way would be to pipe back to the boiler and add the pump there.


Here is what I have in its basic form. There are 3 zones. The boiler zone is on all the time. The other zones are switched with thermostats and relay centers. This way I can add a new zone if needed to the boiler zone. I have to always move water on the boiler zone as there is always fire in the box. The arrows show the direction of water flow. It’s important that the zone pump be on the incoming side of the flow.

Hope this helps,

 

[Carl_WI]

One quick change on my drawing the Boiler zone pump is on the return side not the supply side. It's a little cooler there.

Carl_WI

 

[RustnGrease]

Tractorjeff what you said there is completely true, excep the fact that delivered rate for coal is about 200 a ton, picked up at the breaker is 160-180 depending on where and what size. I have a friend with a similar size house burning 3000 dollars plus worth of oil, whereas we might go through 1200 dollars worth of coal.

Carl I'm fully aware that the zone must be circulating to be worth anything, sorry i should have mentioned that. Also i forgot to mention that theres a boiler zone on mine too, it is bascially a bypass from the output to the input side of the boiler.

Attached is a rough sketch of the boiler and plumbing setup. Black lines are the outflow, Green is the inflow, Blue is the bypass line, grey box on bypass is temp sensor, from what i know it kicks on a circulator pump if boiler gets too hot. yellow boxes are circulator pumps.

I was too engrossed into tapping off of the return on the one zone to even remember about the bypass line, since it was so close to planned heater location. I guess i could tap off of that with a pump and run a new zone just for the garage correct? Since it would circulate only through the boiler?

 

[RustnGrease]

Forgot to add the boiler schematic, Thanks for all the advice

 

[Carl_WI]

I guess i could tap off of that with a pump and run a new zone just for the garage correct? Since it would circulate only through the boiler?

I like the idea of an independent zone for the garage. It keeps the design simple, especially when troubleshooting a problem.

Also i forgot to mention that theres a boiler zone on mine too, it is bascially a bypass from the output to the input side of the boiler.

The bypass is used when the boiler drops below 130 deg it helps prevent Flu gas condensation.

Carl_WI

 

[RustnGrease]

Well guys i think i've figured out what i'm going to do after talking to a bunch of people about my issue. Just going to have to add on to the existing outflow and return manifolds to add another zone, with valves and it's own thermostat just for the shop. It's only about 10' from the furnace to the proposed heater location so it wont be terribly expensive to do.

I believe this is the best possible route to take on this since i want to get away from propane and electric, and the fact that the furnace is right there so why use a supplemental heating source when i can just tie in to and exisiting proven and cheap source of heat.

Just a pain and a rush job, since the boiler and heating system would have to be drained down and the weather is going to get cold soon.
I should've been more on the ball and had it set up to do today since it was in the 60's after a week of 30 degree weather.

Another topic that came up during said discussion with friends was that locally most people dont have heaters in their attached garages. Not sure why especially being in northeast pa.

A friend of mine is doing the same with his outdoor wood burner to heat his detached shop. We had tried using a heater similar to a modine unit but it just couldnt keep up, so now he is installing cast iron radiators that will have 180 degree water circulating 24/7. Once his is done i'm going to check and see how it works then probably progress onto my project.

Sorry for the long post and i appreciate all of the help and info. Thanks!!!!!!!

 

[Carl_WI]

Post some pics of the completed new zone. Winter is here already in Wisconsin.

Carl_WI