Hot Dawg HDS concentric venting

[GearHd6]

I've got a Hot Dawg with the separated combustion that I'm using the concentric venting kit. So far I have the heater and concentric box but I'm in need of the piping. I'm having a hard time figuring out what I need. The heater requires 4" piping. I think I need a double wall pipe for the vent, single wall for the intake and then a short 6" diameter pipe that protrudes through the wall and supplies the intake air. Does anyone have any experience with this and can offer some assistance?

 

[fitter30]

Manufacturers of b vent don't make them universal fit each has their own fastening system. Contact the manufacturer of your concentric kit.

 

[clydesdale]

I too am in the same spot. I bought a Modine HDS125 Hot Dawg and concentric kit. I have been trying to learn how I am supposed to hook up the venting and I see that there are greenhouse websites that sell B-vent kits and Category III piping. I think it might actually be the Category III piping that is required. Can anybody shed some further light on this? Thank you.

 

[GearHd6]

I replied to your message.

 

[GearHd6]

I too am in the same spot. I bought a Modine HDS125 Hot Dawg and concentric kit. I have been trying to learn how I am supposed to hook up the venting and I see that there are greenhouse websites that sell B-vent kits and Category III piping. I think it might actually be the Category III piping that is required. Can anybody shed some further light on this? Thank you.

Hey. Ahh, yeah that concentric kit turned into a nightmare. Come to find out, it's not really meant for anything other than greenhouses it seems. You need Cat III stainless pipe and no double wall pipe fits that concentric correctly. I wound up just doing two separate pipes through the wall. The exhaust is obviously in a thimble and the intake is just through a hole without a thimble. It's all up and running and passed the inspection by the building official.

I had an HVAC guy I know call Modine and even they told him that the concentric kit isn't meant to do what we were trying to do.

 

[4x4Pete]

Unfortunately that type of problem is the norm in HVAC. Amazing that the manufacturer was able to give advice on their own product.

 

[clydesdale]

Thank you GearHd6 for your reply to my message and posting it here for the record. This is not great news. I bought the actual Modine concentric kit:

https://northstock.com/modine-32161-horizontal-concentric-adapter-kit-3h34930-3-3h034930003/?srsltid=AfmBOoox-MaE7_IKFaV6KI6uIHOSTI0ZkHlrreix4Zic2L-AL98iHqSu

If this is what you bought and it doesn't actually work, that is not cool. It sounds like I need Cat III pipe, correct? Where did you purchase that? I was looking at this kit:

Modine HD Hot Dawg Stainless Gas Heater Vent Pipe System - UL1738 Category 3 Venting Kits

Stainless steel venting kits for Modine HD gas unit heaters. Exhaust flue pipe and fittings are Category 3 UL1738 rated. Compatible with Sterling, Modine, Dayton, Mr. Heater, Heatstar, Big Maxx, and most other unit heaters. Compatible gas heaters: HD30, HD45, HD60, HD75, HD100, HD125, MHU50...

www.acfgreenhouses.com

 

[Firebrick43]

Thank you GearHd6 for your reply to my message and posting it here for the record. This is not great news. I bought the actual Modine concentric kit:

https://northstock.com/modine-32161-horizontal-concentric-adapter-kit-3h34930-3-3h034930003/?srsltid=AfmBOoox-MaE7_IKFaV6KI6uIHOSTI0ZkHlrreix4Zic2L-AL98iHqSu

If this is what you bought and it doesn't actually work, that is not cool. It sounds like I need Cat III pipe, correct? Where did you purchase that? I was looking at this kit:

Modine HD Hot Dawg Stainless Gas Heater Vent Pipe System - UL1738 Category 3 Venting Kits

Stainless steel venting kits for Modine HD gas unit heaters. Exhaust flue pipe and fittings are Category 3 UL1738 rated. Compatible with Sterling, Modine, Dayton, Mr. Heater, Heatstar, Big Maxx, and most other unit heaters. Compatible gas heaters: HD30, HD45, HD60, HD75, HD100, HD125, MHU50...

www.acfgreenhouses.com

You dont need cat 3 pipe, you need b vent called out in your manual. 4" for your HDS125. A long enough piece to be continous through the adapter box and clearances on both sides and a single wall adapter to couple it to your hotdawg.

https://modine.worksmartsuite.com/PORTAL/io_modules/IOGETIMAGE.php?type=stream&filename=6-584.pdf

 

[clydesdale]

Thanks Firebrick43. But, I still don't fully understand it. In a horizontal venting application, like I will have, it also mentions Cat III. It is at the bottom of page 7.

Horizontal Category III Vent System Determination • Horizontal vent systems terminate horizontally (sideways) (an example is shown in Figure 9.1). • Determine the venting configuration as follows: > For two building penetrations through the wall or roof (one for the combustion air inlet pipe and one for the vent pipe), proceed to “Section C - Horizontal 2-Pipe Venting”. > For a single larger building penetration through the wall or roof, through which both the combustion air inlet and vent pipes will pass, proceed to “Section D - Horizontal and Vertical Concentric Venting”.

I am attempting a horizontal concentric installation. That section D begins on page 10. Thanks.

 

[PoorUB]

Pretty certainin horizontal termination and a Hot Dawg, you need to so stainless. I am willing to bet that all unit heaters Modine, Reznor and Mr Heater with a horizontal install you need to go stainless.

I read through the instructions, very confusing!

 

[thammel]

I did a reznor separated combustion. I used stainless piping and if I recall it was Z-vent. Expensive stuff. But worked out well!

 

[Firebrick43]

Thanks Firebrick43. But, I still don't fully understand it. In a horizontal venting application, like I will have, it also mentions Cat III. It is at the bottom of page 7.

Horizontal Category III Vent System Determination • Horizontal vent systems terminate horizontally (sideways) (an example is shown in Figure 9.1). • Determine the venting configuration as follows: > For two building penetrations through the wall or roof (one for the combustion air inlet pipe and one for the vent pipe), proceed to “Section C - Horizontal 2-Pipe Venting”. > For a single larger building penetration through the wall or roof, through which both the combustion air inlet and vent pipes will pass, proceed to “Section D - Horizontal and Vertical Concentric Venting”.

I am attempting a horizontal concentric installation. That section D begins on page 10. Thanks.

The cat 3 is for 2 pipe systems not concentric. In the concentric it only list b vent for your furnace.

 

[clydesdale]

OK, great. Thank you. I am going to hang the heater early next week. Then mock up the piping. I will then remove the heater and sheetrock the area. I am sure I will have a few questions. If you don't mind, please keep an eye on this post. I will post pictures to help the next guy. Thanks.

 

[clydesdale]

Well, it took longer than expected, naturally, but heater is hung. I used a quick sling, but the unit is rear heavy and tilted back end down. So, I think I need to add superstrut to really hold it. I didn't need to do this with an h2o hot dawg, but this unit is much larger. Having the strut may also put me at ease, instead of having one single bolt holding the heater to the bar on the ceiling.
I have the concentric vent box and see that it fits right between my wall studs. So, That will be my next step, to get that mounted and I will get better pics. Anybody else have to use additional bracing to level and secure using a quick sling. Quick Sling says I can level with shims, but that does not sound like it will be the best way to go.

 

[clydesdale]

I ended up using unistrut to bolster and level the quick sling. So, I am now back to having to plumb the venting. I still don't fully understand the pipe differences. But, I have learned that all B-vent is double walled. I embarrassed to say I wasted several hours looking for a site that carried double walled b-vent.

 

[clydesdale]

Does anybody know if the Modine Concentric Venting box is supposed to go inside the wall studs?

 

[clydesdale]

I called their tech service and they do NOT advise putting the box inside the wall.

 

[thammel]

I have a reznor with a concentric venting box....Mine is mounted to the drywall on the inside. Reznor spec's expensive double wall stainless steel z-flex piping. Darn stuff was expensive and a pain to cut!

 

[clydesdale]

Thanks Thammel. Would you mind posting a pic or sending me one to my messages? I found these two videos that should help myself and others in the future with the Modine setup. Thanks.

 

[TurnipTruck]

My contribution


In the attic, on the other side of the same wall, before insulation:

 

[clydesdale]

Great contribution!!! Thank you so much. I was thinking I would see if I could use flex vent pipe for the intake. Thank you for that.

 

[beltfeed]

I had a 75K ceiling hung Reznor for 20 years. Finally, the heat exchanger on it crapped out. I put a 75K Hot dog in two years ago. The Hot dog is a giant pile of trash compared to the Reznor. The Reznor was quiet, the Hot dog is loud. The Reznor would bring my 1000 sq foot shop up from 36 to 70 in 30 minutes. The Hot dog takes an hour and 15 minutes for the same temp rise. Surface mount Hot dog puts a vibration into the wife's kitchen on the other side of the wall. I'm currently building a new 3200 sq shop. As soon as it's done, I will pull that pile of trash Hot dog out and junk it. Absolute garbage.

 

[thammel]

Thanks Thammel. Would you mind posting a pic or sending me one to my messages? I found these two videos that should help myself and others in the future with the Modine setup. Thanks.

Here are a few photos of my reznor setup...

A note of caution at least with the reznor. I initially bought an "appliance connector" I believe it was called. This connected to the exhaust but had a flapper (damper valve) inside it to prevent backflow. Part number Z-vent 2ZB04. The reznor sensed the output restriction and would cut off after a minute or less. Had to buy an output adapter without this damper. Now it's been working well for 10 years or so. Great unit! Reznor UDAS, separated combustion.

 

[PoorUB]

I had a 75K ceiling hung Reznor for 20 years. Finally, the heat exchanger on it crapped out. I put a 75K Hot dog in two years ago. The Hot dog is a giant pile of trash compared to the Reznor. The Reznor was quiet, the Hot dog is loud. The Reznor would bring my 1000 sq foot shop up from 36 to 70 in 30 minutes. The Hot dog takes an hour and 15 minutes for the same temp rise. Surface mount Hot dog puts a vibration into the wife's kitchen on the other side of the wall. I'm currently building a new 3200 sq shop. As soon as it's done, I will pull that pile of trash Hot dog out and junk it. Absolute garbage.

I have installed both. IMO, the Hot Dawg is a tougher unit. The heat exchanger will last longer than a Reznor. As for noise from vibration, use rudder or spring mounts. The only time I hear of noise from Hot Dawgs is when the mounting is very rigid. I have had noisy Rezonrs too. Just depends on the day of the week it was manufactured.

 

[beltfeed]

I have installed both. IMO, the Hot Dawg is a tougher unit. The heat exchanger will last longer than a Reznor. As for noise from vibration, use rudder or spring mounts. The only time I hear of noise from Hot Dawgs is when the mounting is very rigid. I have had noisy Rezonrs too. Just depends on the day of the week it was manufactured.

You are correct on the vibration. Modine sells a rubber isolater kit. I wish I new how much they vibrate before I mounted it. When installing the kit I will have to redo the gas line, power vent and inlet air due to the height change.

Modine HD/HDS - Vibration Isolation Kit - 4 Isolators per Kit : Vibration Isolation Kit Installation Manual

Find and download user guides and product manuals

www.manualshelf.com

 

[clydesdale]

I greatly appreciate everyone's help on this. I have a simple question at this time. The largest pipe going out the concentric box is right at 6 inches. Am I using a 6 inch hole saw and start from the outside and then sand a little here and there if it needs massaging. Or am I using a 6 1/8 inch saw hole saw? Any suggestions or advice is appreciated.

 

[xjfish]

I greatly appreciate everyone's help on this. I have a simple question at this time. The largest pipe going out the concentric box is right at 6 inches. Am I using a 6 inch hole saw and start from the outside and then sand a little here and there if it needs massaging. Or am I using a 6 1/8 inch saw hole saw? Any suggestions or advice is appreciated.

I did this some years back (concentric vent kit - was purchased from a greenhouse supplier). I believe I traced the actual pipe and cut it out with a jigsaw and sawzall. I had left that section of wall unfinished until heater install was done. It turned out great. I'm going to see if I can find a pic...

EDIT: Can't find a pic now, unfortunately I used an unreliable image hosting sight but do check out THIS THREAD, particularly my last post.

 

[clydesdale]

Thank you. I will check out that thread later this evening. I will have to make a nice cut through the vinyl siding and plywood to get to the interior.

 

[dave*99]

My contribution


In the attic, on the other side of the same wall, before insulation:

G2419.4 (408.4) Sediment Trap
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment trap shall be either a tee fitting having a capped ****** of any length installed vertically in the bottommost opening of the tee as illustrated in Figure G2419.4 or other device approved as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas fireplaces and outdoor grills need not be so equipped.

 

[TurnipTruck]

G2419.4 (408.4) Sediment Trap
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment trap shall be either a tee fitting having a capped ****** of any length installed vertically in the bottommost opening of the tee as illustrated in Figure G2419.4 or other device approved as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas fireplaces and outdoor grills need not be so equipped.

I am aware of the valve needing to be ahead of the trap.
My only excuse is a need for heat in late November 2019 and using what I had. I have since insulated and installed the right valve.

 

[clydesdale]

It looks like there are enough videos of hole saws through vinyl siding on youtube. The key seems to be cutting through the vinyl in reverse. So, next planning issue is: would you mount the concentric box directly to the sheetrock or mount it to wood or superstrut on then to sheetrock?
On Edit: it looks like it will need to go to wood as it fits between the studs and will not mount to studs.

 

[clydesdale]

Hey guys, I can use some help on deciding which elbows to use to attach the pipes. They make a galvanized and an aluminum. I will link them. I have 4 inch b vent going through the box and then and adapter that allows regular 4 inch pipe to attach to the 4 inch b vent on the inside wall. But, I need some elbows and some of the pics above seem to show some adjustable elbows. I don't think I need a b vent elbow because I have an adapter that does regular pipe to b vent. So, I just need to attach to that adapter. What do you recommend:

https://www.supplyhouse.com/Lambro-Industries-722-LAMBRO-4-90-Galvanized-Adjustable-Elbow-30-Gauge

https://www.supplyhouse.com/Lambro-Industries-2310-LAMBRO-4-Aluminum-Adjustable-Elbow-22-5-to-90

Thanks.

 

[clydesdale]

Does anybody know what kind of adapter is needed to go from the B vent to the Modine terminal cap? Also, Anybody know what is the best way or product to seal between the vinyl and the pipe? Thanks.

 

[clydesdale]

I spoke with Hart and Cooley, the company that makes the B vent that supplyhouse.com sells, and they told me what I can use, which is just a piece of single wall adapter from home depot.

 

[clydesdale]

I spoke with Hart and Cooley, the company that makes the B vent that supplyhouse.com sells, and they told me what I can use, which is just a piece of single wall adapter from home depot. The more I think about it, I may just buy a crimping tool and crimp the modine end cap so that it fits better into the B-vent and just skip the adapter.