Install Big Maxx Vertical vs Horizontal venting?

[penright]

The thread was asking about horizontal venting (https://www.garagejournal.com/forum/showthread.php?t=465876) and it has "almost" given me enough confidence to tackle my own heater. I was quoted $2,800 and that seemed a little high. It was turn-key at 45,000 BTU and a vertical vent. I was supplying the electric and Tstat.

So right now I am looking at what it would take to do it myself.
I will include some pictures to help give some context to my questions.

The picture of the wall is my plan. It was taken before I started adding infrastructure. The last picture is more what it looks like today. I drew the heater toward the left more over the bench, but in hindsight, I am thinking it needs to be more to right. Do I need to skip over to the next set of purlins?
I am assuming the purlins would be strong enough to hold the 70 pounds. I want to stay as close to the truss as possible.

My big question is do I go vertical or horizontal in the vent?
The vertical (Class 1) is about $100 and the horizontal (class 3) is about $350. I wonder how hard it will be to seal the transition through the roof on the vertical? How do you handle the insulations around the pipe? Since I have only the roof and no decking, there is nothing to screw the bottom square piece to.
Is horizontal easier to seal and give less trouble over the years?
The two pictures (gas line & soffit) were taken before sunrise and I can do better, but you can see there is no soffit to speak of. I should be able to flash up against the side and the vent does not have to stick out very far. Since this is class III would the thimble help protect the insulation? I am guessing that I am not the first to go through this style of a metal roof?


Gas should be pretty easy. Before the dirt work was started, I had a gas line run out to the corner. The trickiest part will be after coming in, making a 90 for the vertical, and then another 90 for the horizontal. I have not measured but the length coming into the build between my stub up and the 90, I need it to be up against the grits. Then the 90 at the top to go horizontal needs to off set back the 1/2" to go in between the poles and insulation. I have watched some videos on a fitting allowance, cutting, and threading. All that seems doable.

I am not 100% I know all the questions, I sure more will come up as I read posts.

The picture of the wall, red is gas. The yellow is the heater, mounting, and all thread. The orange is venting.


Vertical

Horizontal

 

[stokefire7]

Your drawings not showing up on my end.

 

[penright]

Your drawings not showing up on my end.

Thanks. I use google photos and I thought any pictures in my "shared" garage journal album would be shared. I did move them through my phone this time instead of chrome. Not sure if that would make a difference. I just shared each one this time, did that fix it?

 

[stokefire7]

Yes !

 

[das_V8]

Are you blowing out towards the garage doors? I’d orient that way and vent horizontal straight out the back wall. Would be easiest method. I’d keep an air gap around the round pipe in the wall thimble between pipe and insulation just to be sure but I believe they’re able to take batt fill next to them?


Sent from my iPhone using Tapatalk

 

[spudley]

Hmmm...I went vertical with my heater but I have shingles which makes the roof penetration easy to flash watertight. However I'm thinking of moving my heater across the shop (so I don't have to listen to an airplane taking off all day right over my head) and go with a horizontal through the sidewall vent. For your bldg, I'd go with the horizontal.

Is that gas line stub galvanized pipe?

 

[penright]

Is that gas line stub galvanized pipe?

Yes, and it was also permitted and inspected.

 

[stokefire7]

Have you bought the unit yet ? Curious which one.

 

[penright]

Are you blowing out towards the garage doors? I’d orient that way and vent horizontal straight out the back wall. Would be easiest method. I’d keep an air gap around the round pipe in the wall thimble between pipe and insulation just to be sure but I believe they’re able to take batt fill next to them?


Sent from my iPhone using Tapatalk

The shop is 25' x 30' with the front (doors) along the 30' side. The gable is on the 25' side. (picture below) The doors are on the west side. I call them entry door, garage door 1 (bay 1), and garage door 2 (bay 2).
The inside picture is looking toward the south wall and you are seeing the rails from garage door 2. If I leave the heater blowing across the shop toward the north, and I horizontal vent, the pipe would be a straight shot out the back of the heater and that wall, which is the side pictured showing the small-cap that would be the soffit.

If I vertical vent, the transition would be on the backside of the ridge (east side), the vent cap would be seen just over the ridge from the front. I think it would be close enough to the south side edge that you could work on it from the ladder without getting on the roof.

 

[penright]

Have you bought the unit yet ? Curious which one.

No, here is what I am looking at ...
Mr. Heater Big Maxx Natural Gas Garage/Workshop Unit Heater — 50,000 BTU, LP Conversion Kit, Model# F260550
Right now Northern tool has it on sale.
And the vent accessories I got from MrHeater after searching for the partnumber. Not sure if I could find the cat III cheaper somewhere else, have not looked.

 

[Mainiac Mat]

I'm in the same boat as you... Glad I tuned in, as I didn't know about Northern Tool's sale.

My shop is 26' x 30' stick framed with 10' ceilings and 10-12 pitch attic (room in room) trusses. I'm insulate with R-21 bat in the stud bays as well as the ceiling...

My heat loss calc. said I needed 40K BTU heat source and I was looking at the Modine 45K BTU Hot Dawg.

But I don't want to heat the garage 24-7, and when I'm able to go work out there in the winters, I want to heat up from stone cold quickly, so I leaning towards a 60K unit.

If you have the head room, you might consider going bigger. Unfortunately, the next step up Mr. Heater is 80K BTU.... but that sale price is killer.

 

[Mainiac Mat]

You can get a stainless steel cat. III horizontal vent kit for a lot less here.

 

[penright]

You can get a stainless steel cat. III horizontal vent kit for a lot less here.

I like it since I may not need a 45 or 90, but those are optional when comparing apples to apples.
Thanks for the resource.

But I don't want to heat the garage 24-7, and when I'm able to go work out there in the winters, I want to heat up from stone cold quickly, so I leaning towards a 60K unit.
If you have the head room, you might consider going bigger. Unfortunately, the next step up Mr. Heater is 80K BTU.... but that sale price is killer.

The 80k is $468. I do have the headroom and the 80K is only 2.5" taller.
Way overkill, but I am like you, it will not be running when I am not in there. I just want to knock the chill off, and if I am doing something extend there will be a thermostat.

 

[penright]

Did some more looking and now I have another question, the 50K shipping weight is about 70lb and the 80K is more like 90lb.

I was going to suspend it between two purlins. What's the thought on hanging 90lb? The back would be about 20" from the wall truss.

 

[Mainiac Mat]

What's the thought on hanging 90lb? The back would be about 20" from the wall truss.

Steel buildings are engineered pretty close to the wire to keep the material cost down. We worked up a design for a new factory building and the framing members sizes were increased when we told the company that we needed to hang dust collection pipe from the frame. Of course...our DC main is 28" dia., so we were talking about significant weight. But it did change the building design

Do you have any info from the manufacturer of your frame/kit. They should be able to help you out.

 

[penright]

Do you have any info from the manufacturer of your frame/kit. They should be able to help you out.

I just texted the guy who built it.
If I don't hang it from the purlin, what other option do I have?

 

[penright]

Got the OK from the builder to hang from the purlin.
One more question before I pull the trigger on the unit.
I was quoted a 45K. I was looking at 50K, then as was mentioned in this thread, for startup and recovery maybe goto an 80K. I have the room and can afford it.

Just out of curiosity, I searched for how to calculate the size.
The formula was (cubic feet * insulating factor)/1.6
If that is right I am 25 x30. The wall, to the bottom of the truss, is 10' so to do my calculations, I used 11' just avg out the truss area, and that may be a little low.
So my cubic feet is 25' x 30' x 11' = 8250 cubic feet. I have pretty good insulation, but being some conserved, let's say it is 1. Here in OK, let's say it is 30 outside and I want 50, would that be a rise of 30 degrees?
That is 247K. Is that right? So dividing by 1.6 is about 154K.

I hope there is something I am doing wrong here. Bad assumptions?

 

[D45]

Will it be heated 24/7 or just when you are out there?

 

[penright]

Will it be heated 24/7 or just when you are out there?

Just when I am out there.

 

[penright]

i love this type of garages that are easy to park..

That picture was just after the build. Right now it is not so clean, but I finally got enough infostructure so I can start to organize. Here is a more current picture with all the clutter.

I hope to have it where I can pull in cars in a couple of weeks.
I wanted to get the heater placed so I don't add pegboard or shelves in the way. Also, when I cleaning off the shelves as you can see here I created a lot of dust. I am talking about body shop amounts. I am moving from the other side toward the side of the picture and as you can see, I have not got to that side yet. Once I post some pictures of the heater install, then judge me.

I still need to know if 80K BTU is enough. I waiting to order the heater for this one last sanity check.

 

[SarcasticDwarf]

I still need to know if 80K BTU is enough. I waiting to order the heater for this one last sanity check.

I think it will be. I just installed a 50k in my garage up near Fargo. It is about 10% less cubic feet than yours but with a completely uninsulated attic. It hasn't been cold enough to run it much yet, but I can say that I have never seen one >80k in my neck of the woods.

 

[penright]

I think it will be. I just installed a 50k in my garage up near Fargo. It is about 10% less cubic feet than yours but with a completely uninsulated attic. It hasn't been cold enough to run it much yet, but I can say that I have never seen one >80k in my neck of the woods.

My kerosene is about 22K, I think and it was able to know the chill off, but it was just not there and took a while. My old 2 car was about 400 square feet with an 8-foot ceiling and very heavy insulated. The kerosene would make it toasty. The professional quoted 45K so I felt 80K would be enough, just wanted to double-check before spending that kind of money.

I feel like I have done enough due diligence that if I am wrong, I will not beat myself up.

 

[penright]

Pulled the trigger on the 80K.
This is the vent I went with. https://www.supplyhouse.com/sh/control/product/~product_id=2ZVWB04

 

[spudley]

I'm using a 75K in a 24x40x10' uninsulated shop. I'm thinking after insulating I'll replace it with a 45K unit. I heat as needed, not 24/7, as I don't live where the shop is located.

You'll be plenty warm at 80K in your bldg.

Thanks for the vent kit source.

 

[penright]

The next move is a TStat. I would like to find a simple wifi model that has an open API or better is already integrated with Home Assistant.

I have a z-wave laying around but the distance is too far.
It would be nice to have the home automation to make sure I don't leave it on. Since I went with the 80K, not a big deal, but might be nice if really cold outside to start warming up the shop while drinking coffee.

While searching I found this thread https://www.garagejournal.com/forum/showthread.php?t=267256 but it is old (2014). What is GJ etiquette? Should I resurrect the thread, it is the correct topic, or keep it in this thread?

 

[toyotadriver]

For a 24x30 shop in your area....I would have gone with a 45-50k. 80k is a bit on the large size. For a shop that is only heated occasionally, a bit oversize is good because you need the extra BTUs to bring up the temp of the building and everything in it but in my opinion, 45-50k is still slightly on the large size so ideal for your needs.

My shop is 30x40 and I heat it with an 80k. I heated it with a 45k for awhile and it would heat it but it took awhile to come up to temp. A 60k would have been perfect but wasn’t an option for Mr Heater so I went with the 80k.

 

[D45]

In my opinion, heat throw and fan size needs to also be taken in to account

Is the fan is small and the heat throw is short, you will still be cold in the shop and it will take too long to effectively circulate the heat

Example (Hot Dawg):

30K FAN SIZE: 10"
45K FAN SIZE: 10"
60K FAN SIZE: 14"
75K FAN SIZE: 14"

30K INPUT: 30,000
30K OUTPUT: 24,000

45K INPUT: 45,000
45K OUTPUT: 36,000

60K INPUT: 60,000
60K OUTPUT: 48,000

75K INPUT: 75,000
75K OUTPUT: 60,000

30K HEAT THROW: 25 feet
45K HEAT THROW: 27 feet
60K HEAT THROW: 36 feet
75K HEAT THROW: 38 feet

30K AMP DRAW: 3.7 (1/15 HP)
45K AMP DRAW: 3.7 (1/15 HP)
60K AMP DRAW: 2.5 (1/12 HP)
75K AMP DRAW: 2.5 (1/12 HP)

Entering Air Flow Velocity:
30K: 505 CFM
45K: 720 CFM
60K: 990 CFM
75K: 1,160 CFM

Outlet Velocity:
30K: 523 CFM
45K: 749 CFM
60K: 653 CFM
75K: 769 CFM

 

[Mainiac Mat]

I just bought a 60K BTU Hot Dawg from these guys. The unit and vent kit arrived two days later.

I chose to pay more for the Hot Dawg after reading many reviews about people having to replace the control boards in the Big Max.

My heat calc. said I needed ~39K BTU to heat the space, but like you, I'm only kicking the thing on when I want to work out there, and I want to be able to heat it up quickly.

I've got a ways to go before I'm ready to install it. But I wanted it on site so I could measure and plan accurately.

 

[penright]

In my opinion, heat throw and fan size needs to also be taken in to account

Good point. I could not find those specs for the Big Maxx. They did have a spec showing the distance between the face of the fan and the back of the motor.

50K = 5.5”
80K = 6.5”
120K = 8.08”

The only other size changes between the model are the placement of the vent height. That is why I stepped up a size, I have the room and the price delta was a little less than $100, $94 to be exact. The only negative is the 80K is heavier by about 15 pounds (guessing). As mentioned earlier in the post, I checked with the person who built it and he felt like the purlins would handle it.



Here is the snippet I got that out of.

 

[penright]

For my purposes, I may not need a wifi thermostat. Really all I need is a wifi relay that can interrupt the W wire. Even if I have a mechanical thermostat, if I leave it at what I normally run at, then when I am ready to go out, enable the relay that then completes the W wire. Then I can add a check to my home automation that checks for lights left on and someday a window left open and send an alert. I can also add a switch in parallel to the relay as a bypass. Or some sort of 3 way switch, that 1. connects the W to the relay (remote controlled), 2 connect the W period (bypassed), or 3 will interrupt the W (no way it can come on).

Somewhat related, the ESP8286 that was sensing window switches also has a temperature/humidity sensor. I don't know how accurate they are and I would not trust any of my devices to control temperature, but I can use them as warnings.

The way I was going to wire it, when heating, the mechanical thermostat has the final word on turning on the heater.

 

[penright]

When venting horizontally, how do you flash corrugated metal siding?
I bought the Z-Flex system.
The wall is corrugated metal screwed to girts with thick insulation sandwiched in between. The thimble smallest it will go down to is 5". I assume the code says I still have to use it even if I don't have a wall cavity.
Do I just leave the inside just sticking in the air?

 

[penright]

The heater came in and did some pre-wiring for the electrical.
The next step is figuring out how am I going to hang it.
The building builder said I could hang it from the purlins, but one of the light outlets is in the center of the trusses which are about 10' apart. They are at the peak and just a few inches apart. I screwed some lightweight C channel between them to get the fixture exactly in the middle. While there I tried and flex it with my weight. I could move it. Of course, this is in the middle of the span and 2.5 times more weight than the heater. The heater will be closer to the truss. I don't see how I can sister something to stiffen them up.
The purlins where the heater goes is 42" apart and I measured the height difference between them and the floor with a delta of 7". This morning I was playing with an online calculator and getting an angle of 80 degrees. Does 2 over 12 for a pitch sound right?
Anyway, after making my hanging bracket, in the proper space, I will recheck the deflection.

 

[crowwinger]

Good to see you pulled the trigger penright... and for what it's worth, I think you made the right decision to go with the 80k. I went with that unit and I couldn't be happier.

I couldn't find a smart thermostat that would go down to 30-35 degrees, so change direction and got a cheap $20 digital that goes to 35. But the 80k heats the room up fast and will be comfortable in 5-10 min.

If the low setting isn't an issue for you, check out the Wyze thermostat that should start shipping soon - $50.

 

[penright]

Good to see you pulled the trigger penright... and for what it's worth, I think you made the right decision to go with the 80k. I went with that unit and I couldn't be happier.

It has been sitting on the floor unboxed for over a week and it has not jumped up onto the purlins yet. So Monday/Tuesday I made a bracket that will hang from the purlins. I was in a hurry, measured once, so now I get to cut twice. It's a little short and will not reach the purlins, but I sat it next to the heater, hoping it would figure it out and install its self. Looked last night and still sitting where I left it. Go figure.

Seriously, measuring more than once is what got me into trouble. I laid out chalk lines on the floor to match the purlins.
The purlins and the metal for the brackets are C-channel. The part that connects with the purlin will just overlap the edges. The parts that connect to the purlin are parallel to the purlin. This makes a compound angle to figure out. The purlin on the right is higher for the pitch of the roof. Then I would like for it to sit at an angle to blow into the center of the shop. So I was mocking up all my pieces and laying them out on the floor. Where I had the chalk lines were not near the welder. But since I had all the lengths cut, if I measured both ends and the lengths were right, then the angles would work out. The connecting piece on the right is 7" higher for the pitch and some set back for the angle of the heater. The purlin is 44 3/4" between them. Right before I welded them, I measured where the purlin would sit and it was too long. The reason why is, because I was measuring between the connectors and I should have visually extended the left connector back, so I was measuring at right angles and not the angle the heater will be sitting at. The good news is I just tack welded and tested. I will have to grind the welds off, make a new piece between the connectors. The metal I am using are in 36" lengths, so I have to splice that piece anyway. I will try and remember to take some pictures. It was hard for me to picture it and why I had laid out chalk lines. If only I had paid more attention in trig class. But we would never use that in real life right.

I couldn't find a smart thermostat that would go down to 30-35 degrees, so change direction and got a cheap $20 digital that goes to 35. But the 80k heats the room up fast and will be comfortable in 5-10 min.

I have a plan for that now. My rule for home automation is everything has to work if the controller goes down. In my case, I am using HomeAssistant (HA). My plan is to just use a smart plug. For power, there will be an outlet next to the heater. Then I will use SO cord with a plug. This will give me a service discount, which is not needed since the heater is within 50' and the direct line of sight of the breaker. I bought a cheap mechanical TStat. I will just leave that at the temperature. The automation part will be either the heater is enabled or not. If enabled (power on) then the TStat will control it. I am not worried about pre-heating as much as forgetting to turn it off. When I leave, I tell Alexa that I am leaving and she makes sure the lights are off. I will add the smart plug to that, so the heater will not run even if the temperature is low.

More info than you care category. I bought the Echo a while back. I guess there must be some lady named Alexa on the Hallmark channel because the Echo kept going off. So my wife stuck her in a closet. Once I got my cat 6 connected to the shop, I added an AP. Besides the leaving automation, the other issue was I could not get a good radio signal into the metal shop. The big benefit is now I can stream radio stations. Of course, somehow I need to figure out how to change the name from Alexa to Jarvis.

 

[D45]

Will you have heat before winter?

 

[penright]

Will you have heat before winter?

Absolutely, without a doubt. Just not sure what year.
Here in OK, I have seen where it was 70 degrees one day and snowing the next.

Seriously, I do hope to use it sometime this winter. I finally got the mounting bracket finished and now putting some paint on it. That is taking some time to dry in the cold shop if only I had a heater. The next challenge will be waiting till either the son or sons-in-law are over to help lift it. Then cut the hole for the vent. The height, which I do have a ladder that I think is tall enough, but more so is getting the nerve up to cut a hole in the roof.

I do have a question for you guys. I went with Z-vent and the transition clamp looks to be hitting the frame before I am completely on to the rubber gasket. It presses hard and if I tighten down the clamp it is stuck pretty well.

Here are some pictures of what I mean and if you need more let me know.

Also, I assume the transition needs in such a way that gravity closes the flapper. Then the forced air will open it.

Here are a couple of pictures to show how the bracket will hang from the purlin. I did not total lift myself off the ladder, but I did put some significant weight and there was not deflection.

 

[crowwinger]

I do have a question for you guys. I went with Z-vent and the transition clamp looks to be hitting the frame before I am completely on to the rubber gasket. It presses hard and if I tighten down the clamp it is stuck pretty well.

Nice work on that frame... I couldn't picture what you were doing - impressive!

I know you're going vertical, but I used z-vent horizontal and after I had purchased they told me that the Universal Appliance Adapter wasn't going to work with this heater and that I needed a special adapter (2SVSRHA040, which was on backorder). I was too far into it to wait, so I ended up removing the clamp from the heater side of that adapter and was able to push it on a bit more (used a little lube). I don't have it clamped, but it is on really tight.

 

[penright]

I know you're going vertical, but I used z-vent horizontal and after I had purchased they told me that the Universal Appliance Adapter wasn't going to work with this heater and that I needed a special adapter (2SVSRHA040, which was on backorder). I was too far into it to wait, so I ended up removing the clamp from the heater side of that adapter and was able to push it on a bit more (used a little lube). I don't have it clamped, but it is on really tight.

I was going horizontal, but I think it would be better for me to go vertical. Since I have to deal with corrugated steel, I feel I can get a seal better with a boot that they make, that bends around the corrugation. Plus if I stuck it out that side would be able to see it from the front and from the drive. Going out the top, it is on the back and you will not see it from living areas, for example, the patio. When they get around to developing the field behind me, that neighbor will be able to see it.

What did you use for lube?

I was wondering if it would be worth notching the heater a bit?

Whose company is that part number for?

 

[penright]

I am thinking about sending back the Z Vent since I am looking at going vertical.
Now that I am going vertical, does that mean I can switch to Type B?

Something like these?
I notice some are aluminum and some are galvanized, which is better?
Also, do I need a special transition from the heater to the vent pipe?

https://www.lowes.com/pd/Lambro-4-in-x-4-in-Aluminum-Round-Duct-Elbow/3351542

https://www.lowes.com/pd/IMPERIAL-4-in-x-24-in-Aluminum-Round-Duct-Pipe/4129922

https://www.lowes.com/pd/Selkirk-4-in-x-8-in-x-4-1-2-in-dia-Galvanized-Cap-Fittings/1000068691

 

[crowwinger]

What did you use for lube?

I just used some silicon lubricant that I had on hand to help get the gasket around the heater flue.

I was wondering if it would be worth notching the heater a bit?

I was willing to try anything at the time to just get it done without a return

Whose company is that part number for?

That number was provided direct from z-flex, but I actually ordered parts through supply house (SupplyHouse didn't have this information because they don't officially "support" Mr. Heater products, but you could still order it from them).