Gas heater conversion

[SgtHawkUSMC]

I've been looking at picking up a used garage heater. ~100k btu. Most everything I see on craigslist etc is natural gas. I've plumbed gas lines and worked on heating systems before, but I haven't messed around with converting a heater/heating system from nat gas to LP.
My plan is to buy a Modine style hanging heater for the garage. If I buy a nat gas one, I should be able to just buy the conversion kit for any of them right? Three or four new nozzles and spring? Once that's installed I can use my manometer to set is at 10 right? I'm not over simplifying this am I?
I'm also going to T into the tank after the first regulator. My tank is right behind my garage. I should just need to install the same kind of regulator set up that's on the house right?
The sky is falling and you can't work on your own stuff kind of guys don't need to respond please...

 

[finn]

New hanging heaters are so inexpensive that I wouldn’t waste my time salvaging someone’s cast off unit.

The heat exchangers undoubtedly have a finite service life.

 

[mrramsey]

IF you have the means to DIY then I would agree with Finn. Get a new unit. As far as the manometer it will vary depending on the manufacturers spec. And they don't come factory set. I just had my nat gas unit installed yesterday and he made a large adjustment.

 

[The Cobbler]

be sure that the manufacturer sells conversion kit for the unit otherwise it's probably not compliant to change over .
having said that, if you do decide to change over yourself without a kit, you will need to change the orifices ( charts online to determine orifice size) and probably a new regulator, unless you can find conversion kit matched to the valve.
I've read where people solder up the orifice & re drill to to the correct (smaller ) hole for propane .

you may find by time you buy the parts, it won't be cost effective, unless the heater is really inexpensive

 

[joe_padavano]

Assuming you can get the parts, yes the changeover is as easy as you suggest. Definitely google the manual for whatever unit you are looking at to see the exact process. I recently did such a changeover on a kitchen stove. Five jets and turn the regulator. Instructions were provided. The hardest part was the disassembly necessary to get to the oven jet.

 

[naturalgas]

First , installing a 100k unit is pretty big unless you have very large space to heat. As stated above, best to google the unit for conversion kit.


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[SgtHawkUSMC]

Thanks for the feedback guys. Just what I was looking for. Different opinions that might make me look at it differently.
As far as unit size naturalgas, my garage is about 1,100 sqft. It's not insulated right now. I figured the 100k would be ok for now and once I insulate it, it won't be too big. Am I off in my thinking? I know about short cycling. I don't want that to be a problem either.
The Cobbler and joe_padavano. If I do end up doing it this way, once I settle on a unit to buy, I'll look it up for the conversion kit availability. If I can't get the kit, I probably won't buy it.
As far as cost savings go... There is a nearly new Modine 65k unit about 2 hrs away. The guy doesn't sound very knowledgeable about it and says it keeps cooking the transformer. I have a background in electronics, so I figured for $100 I couldn't go wrong. There are a bunch of other nat gas Modine units listed for under $200. I don't think a new one would be anywhere near that would it? When you say so inexpensive finn, what are you considering inexpensive?

 

[Jackfre]

Thanks for the feedback guys. Just what I was looking for. Different opinions that might make me look at it differently.
As far as unit size naturalgas, my garage is about 1,100 sqft. It's not insulated right now. I figured the 100k would be ok for now and once I insulate it, it won't be too big. Am I off in my thinking? I know about short cycling. I don't want that to be a problem either.
The Cobbler and joe_padavano. If I do end up doing it this way, once I settle on a unit to buy, I'll look it up for the conversion kit availability. If I can't get the kit, I probably won't buy it.
As far as cost savings go... There is a nearly new Modine 65k unit about 2 hrs away. The guy doesn't sound very knowledgeable about it and says it keeps cooking the transformer. I have a background in electronics, so I figured for $100 I couldn't go wrong. There are a bunch of other nat gas Modine units listed for under $200. I don't think a new one would be anywhere near that would it? When you say so inexpensive finn, what are you considering inexpensive?

Assuming good doors and windows, when you do insulate it the 100k unit will only be about twice as large as you need. The unit will short cycle like crazy.

 

[SgtHawkUSMC]

Assuming good doors and windows, when you do insulate it the 100k unit will only be about twice as large as you need. The unit will short cycle like crazy.

Ok. I'll check out what I need for btus again then. Thanks.

 

[SgtHawkUSMC]

Well that answers that! I dug around and found a great deal. I had been seeing everything $500 to upwards of $1g. That's why I was looking at used.
I just found this unit for $259 with free shipping. I thought I needed the 100k btu because I had plugged in no insulation in the calculator.
It looks like this one should fit the bill nicely. Now to run the gas from my 500 gal propane tank 15' or so to the garage and install a vent...

http://www.mrheater.com/50-000-btu-big-maxx-natural-gas-unit-heater-1215.html

 

[D45]

That is a great price!............But, I think that 50K will be too small for a non-insulated structure

I had a 45K in my 1,000 sq ft shop and felt that it took way too long to bring up temps and it ran a lot........my garage has insulated walls, so warm air escaped through the ceiling/roof

I swapped it would this summer for a 75K heater and I like it much, much better............more BTUs and a larger fan for a longer heat throw

 

[dave*99]

Give some thought to air circulation in your garage. I have a ceiling fan and use it to circulate the warm air down from the ceiling. My heater is in a corner and blows diagonally across the garage space.

 

[naturalgas]

That’s will be adequate . But that is a Naturalgas unit. Why convert it? Just get the LP unit


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[3rdgendslmech]

I'm not trying to hijack the thread or anything but this is a related question.....I'm probably going to go along the same route at SGTHAWK and convert to propane. Dont have any insulation up yet and probably wont get around to heating until next summer/fall

Here's my question: unless you have one already you have to buy a venting kit which comes 2 ways...horizontal or vertical. Horizontal being the most expensive one.
If you run 2-3 feet of horizontal pipe to get it to an exterior wall then run vertical is that okay? Basically whats the maximum horizontal pipe you can run?

 

[naturalgas]

Yes you can run horizontal, then vertical if you want3 ft is nothing . For long runs check manufacturer installation instruction. Don’t let horizontal go downhill.1/4” uphill pitch per foot horizontal run.


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[The Cobbler]

That’s will be adequate . But that is a Naturalgas unit. Why convert it? Just get the LP unit


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says in the specs ; Natural Gas to Liquid Propane conversion kit included

 

[finn]

Thanks for the feedback guys. Just what I was looking for. Different opinions that might make me look at it differently.
As far as unit size naturalgas, my garage is about 1,100 sqft. It's not insulated right now. I figured the 100k would be ok for now and once I insulate it, it won't be too big. Am I off in my thinking? I know about short cycling. I don't want that to be a problem either.
The Cobbler and joe_padavano. If I do end up doing it this way, once I settle on a unit to buy, I'll look it up for the conversion kit availability. If I can't get the kit, I probably won't buy it.
As far as cost savings go... There is a nearly new Modine 65k unit about 2 hrs away. The guy doesn't sound very knowledgeable about it and says it keeps cooking the transformer. I have a background in electronics, so I figured for $100 I couldn't go wrong. There are a bunch of other nat gas Modine units listed for under $200. I don't think a new one would be anywhere near that would it? When you say so inexpensive finn, what are you considering inexpensive?

Emenards has an 80k Mr. Heater on sale for $418. A 75k BM is $489.

I wouldn’t drive four hours to look at a used unit, with no warranty, to save maybe $150, after expenses.

 

[bobbyjean]

second the motion from Finn-big maxx on sale at northern..score coupon online..delivered to your door with warranty-get er done

 

[SgtHawkUSMC]

That is a great price!............But, I think that 50K will be too small for a non-insulated structure

Give some thought to air circulation in your garage. I have a ceiling fan and use it to circulate the warm air down from the ceiling. My heater is in a corner and blows diagonally across the garage space.

Emenards has an 80k Mr. Heater on sale for $418. A 75k BM is $489.

I wouldn’t drive four hours to look at a used unit, with no warranty, to save maybe $150, after expenses.

second the motion from Finn-big maxx on sale at northern..score coupon online..delivered to your door with warranty-get er done

I plan on insulating at some point. I'll probably at least knock out the ceiling this year. I know that's the biggest issue.
I already bought the 50k BTU Mr. Heater Big Maxx for $259 free shipping. It does come with the NG to LP conversion kit included. As soon as I saw that price, it was a no brainer. I just didn't want to pay over $500 for something. I would have bought an LP version so I didn't have to convert it, but it wasn't offered by the outfit I bought it from. They must have gotten a good deal on a lot of the NG versions or something.
That's a good point about the air circulation. I'll install something that will blow the air around a little more than just the units fan.
I'm trying to decide now if I should go vertical or horizontal with the vent. Either one would probably be pretty easy for me. I don't like going through the shingles if I don't have to though. Any thoughts on which is better and why? Something to consider is the wind. We have some crazy wind at times.
I'm also going to T off my 500 gallon tank behind the garage and install a regulator like the one on my house.

 

[finn]

Look at the pipe requirements for vertical vs horizontal venting.

I seem to recall that my units could use inexpensive B vent for vertical discharge, but require expensive stainless double wall for horizontal

 

[SgtHawkUSMC]

Look at the pipe requirements for vertical vs horizontal venting.

I seem to recall that my units could use inexpensive B vent for vertical discharge, but require expensive stainless double wall for horizontal

The 50k btu model says Horizontal is Cat III 4" with thimble. Vertical is Cat 1 3".

 

[D45]

My Duravent 3" vertical b-vent kit was only $65 shipped

Great, complete kit

 

[CNGsaves]

second the motion from Finn-big maxx on sale at northern..score coupon online..delivered to your door with warranty-get er done

^ ^ ^ This. Get additional COUPON CODE from www.RetailMeNot.com
Print out screenshot and bring to Northern Tool store for pricematch as they generally have that heater in stock . . . but do call ahead and verify.

https://www.northerntool.com/shop/tools/product_200577751_200577751

The ABOVE is 80K Btu (item # 27465) and ONLY $397 !!

Add the KeyCode promo code of . . . 256387 . . . for another $20 discount.

OP . . . since you don't have any insulation now, this 80K btu size heater would be more appropriate as don't think the 50K btu will handle your size shop.

 

[bobbyjean]

there was a code change for horizontal venting....the stainless i have seen is single wall...but has a mechanical lock (clamp) with a high temperature gasket to join section's
b-vent is double wall.. a-vent is used for oil fired..wood stoves...it is double wall with insulation between if i remember
clearance to combustible's is key with any of these type's of pipe
If wind is a concern...proper termination fittings should be available for horizontal...not a big issue on vertical

 

[finn]

there was a code change for horizontal venting....the stainless i have seen is single wall...but has a mechanical lock (clamp) with a high temperature gasket to join section's
b-vent is double wall.. a-vent is used for oil fired..wood stoves...it is double wall with insulation between if i remember
clearance to combustible's is key with any of these type's of pipe
If wind is a concern...proper termination fittings should be available for horizontal...not a big issue on vertical

That sounds correct. Been a few years since I installed mine. Both heaters are the same, in different buildings. The first one was bought before the code change, the second one after, and required the expensive vent.