Modine Hot Dawg Issue

[Peter Elliott]

Hi to all,

I have a 4yr Modine Hot Dawg natural gas heater in my shop. The heater ran perfect up until a 2 years ago. The time relay board went bad and this was a known issue with Modine. Apparently the timer on it was no good.

Through my dealer (bought online in the midwest), I had the relay board replaced at no cost to me. Installed it by there directions and the heater worked like before - no problems. Great service, etc.

Issue:
I did at the time notice a small hint of gas in the shop. Sometimes it was there, other times it was not. It never had a odor before this new board was installed.

Believe me this is a faint smell and disapates rapidily. As a firefighter in the city, I go to alot of gas leaks, to which this doesn't compare.

My hunch is a when the unit kicks on the un-ignited gas in the chamber is release until the unit fires up which would explain the new board theory.

Again, sometimes there is a slight odor other times there is not. I do turn the unit off each time. By electric thermostat only, not the gas line.

Anyone who owns a Hot Dawg, has this happen to you?

Thanks
Peter

[Al Willits]

I work for a Nat gas utility and fwiw, yes its possible your getting a bit of gas smell when it comes on...on the other hand, my money would be on a gas leak.
Where your a fireman at do they have any kind of sniffer?
Maybe the Nat gas utility has a service to locate leaks?
Worse case, take about 3/4 dawn/whatever dish soap to 1/4 water and use a paint brush to check for leaks.

If you don't find any, I might even remove the burners and wash them, let dry completely and see if that helps.

Better safe than sorry, and us guys don't smell gas anywhere near as well as the gals do, if you smell it, I'd spend some time to locate the reason...imho

Al

[Peter Elliott]

Yep, did the bubble test. We do that all the time at work.

I wish I could bring home the detector but the fire chief would not be happy.

It is so slight! Also, goes away once the unit is running. No build up or stronger smell.

I was hoping to hear someone had the issue with the new timing board. Modine had to replace this board. My unit was the first year out, I think... so most newer units had this new board on it. It was all related to the timer turning on the blower fan. The customer service guy said he had to warranty almost each one of these boards.

I retest the fittings tonight and wash out the other.

Anyone got a Dawg?

Thanks
Peter

[John Gregory]

I have one that I installed in 2002, but it runs on propane. No problems to date. I love the warmth it provides.

[John Miliunas]

'Nuther propane Hot Dawg here, season #3 now. Every now and again, on rare occasions, I will get the lightest hint of gas smell when she kicks on. Like you mention, probably unspent gasses in the chamber. The HVAC dude who hooked it up for me (friend) did the "lighter test" on all the joints and she was 100%. :) But, seeing as to where you work, I would still try and talk to the Chief real nice and see if you couldn't borrow the sniffer for just a bit to make sure. :) :cool:

[David G Baker]

Peter,
I have a natural gas fired 75,000 BTU Hot Dawg that I use to heat my 30x40x10 well insulated pole barn. I keep my thermostat set at the lowest setting to keep just enough heat in the building to keep the temp around 50 degrees. I leave the heater on all Winter 24/7. It costs me approximately $30 a month. I have not had the gas smell.
When my heater was installed the large fan motor locked up and would not turn so it had to be replaced. After having the unit shut off during the warm seasons it takes me quite a while to get the heater started. I have to go outside, close the main valve, remove a pipe cap, open the valve and bleed the line, put the cap back on and then go back into the barn, turn up the thermostat before it will fire up. This is an every year issue.
When my furnace first starts an interior fan comes on, this is where your gas smell could come from. Not sure what this smaller fan does. Is your fan vented straight out the side wall or do you have an elbow and vent through the roof?
I am glad you posted the information about the circuit failure, now when mine fails I will have some information to approach the dealer with.
David

[Al Willits]

Lighter test????
Not exactly the most professional way to check for leaks.
Also you'll miss leaks by using flame, the amount of gas can easily be less than enough to ignite, and you'll still smell it.

Didn't see where your from, if you live near the Twin Cites I might be able to help.

Al

[John Miliunas]

Lighter test????
Not exactly the most professional way to check for leaks.
Also you'll miss leaks by using flame, the amount of gas can easily be less than enough to ignite, and you'll still smell it.

Al

Al, guess I shoulda' qualified that remark a bit more. When he did the initial hookup, we smelled some gas and that's when he "clicked his Bic". Once he re-tightened joints up, he went back through with his fancy-dancy soap applicator. All was good! :) Oh, and I trust the guy and his work to the n'th degree. He's one of the "Top Guns" with the outfit he works with and they're highly regarded in the area. I was actually quite fortunate to catch him "in between" some of his "free time" to do that for me! :) :cool:

[Ben Grunow]

OT but I need clarification. Are the Hot Dawg units open flame heaters or sealed combustion (flame inside a heat exchanger that room air is passed over and thus heated)? Sorry but I cant find this info anywhere.

Thanks

Ben

[Steve Kohn]

I have a natural gas Hot Dawg also. I am now on my 3rd year. Absolutely no start up problems. I just turn up the thermostat and it fired right up. Heck, I haven't even bothered to blow the dust out. I leave it at 50 during the week and nudge up the thermostat to 60 when I want to work in my shop.

I probably shouldn't brag like this. Just my luck, the heater will fail tomorrow. I am the only one I know who had his sump pump fail last Friday when we were getting 11 inches of snow.

[John Miliunas]

OT but I need clarification. Are the Hot Dawg units open flame heaters or sealed combustion (flame inside a heat exchanger that room air is passed over and thus heated)? Sorry but I cant find this info anywhere.

Thanks

Ben

Ben, electronic ignition and no open flame! High efficiency, so you can even vent to an outside wall, rather than the roof. Nice units, IMHO. :) :cool:

[John Miliunas]

I have a natural gas Hot Dawg also. I am now on my 3rd year. Absolutely no start up problems. I just turn up the thermostat and it fired right up. Heck, I haven't even bothered to blow the dust out. I leave it at 50 during the week and nudge up the thermostat to 60 when I want to work in my shop.



Yup, 50° is where I keep mine during "off" hours but, I am routinely in my shop pretty "regular" after work & weekends. To that end, I installed a setback thermostat on mine. I leave work @ 2:30 and am home about an hour later. I set the time on it to kick on at 2:30 and by the time I get in there, everything is comfy, cozy! :) :cool:

[Peter Elliott]

My heater was just like all of yours. Full proof until this relay board went.

Then the hint of gas started.

I emailed the company, see if they can explain why.

Just wondering if the timing is still off?

Thanks for the input...

Peter

[Ron Coleman]

I have the small 30,000 BTU Hot Dawg in my shop and had to replace the timer board about 2 years ago. I think the original board lasted about 3 years. As far as I can tell the timer board doesn't control the gas firing sequence, the gas valve takes care of all that. The timer board only controls the air circulating fan. The fan will come on a set time after the thermostat call for heat even if the burner never starts. The fan runs on for a minute of so after the thermostat stops calling for heat.

I never detect any natural gas odor on startup old timer board or new. A constant problem I have is startup in the fall. Mine unit will try to start and then shut down because one of the burners didn't light. I found the burner with the hot surface igniter always starts but the second burner doesn't light until I blow out any dust with the air hose. There is a small gas passage between the two burners that allows the flame to move to the second burner and it must only take a small spec of dust to plug it. I never see any dust but have to use the air hose each fall to get it going.

One other problem I had with mine and it took me a while to figure out. I would find the thermostat calling for heat, the circulating fan running but the shop cold. The problem was low voltage from the thermostat. I had used an old Honeywell thermostat from the house and the silver contacts on the sub base were dirty. Switching the heat/off/cool lever several times would get the thing going but not for long. The timer board would start the fan but the gas valve and firing sequence would never start. The gas valve must be very sensitive to low voltage. I replaced the thermostat with a new one and everything worked as normal.

Ron

[John Lucas]

OT but I need clarification. Are the Hot Dawg units open flame heaters or sealed combustion (flame inside a heat exchanger that room air is passed over and thus heated)? Sorry but I cant find this info anywhere.

Thanks

Ben

They are suppose to be sealed units.

[Ron Coleman]

They are suppose to be sealed units.

From what I can tell there are two types of Hot Dawg units available today, open flame and sealed. The original units were open flame, as they burned inside air. Now there is a sealed unit available, for more money. I've got the original open flame type.

It's interesting that the Hot Dawg style heater is sold under several different brand names, not sure who really makes them.

Ron

[Al Willits]

John, whatever works for you I guess.
But where I work he'd at least get time off no pay for using a flame to find a gas leak.
Consider that you do not smell gas, you smell the odorant that's added to the gas, and relying on that to tell if there's gas or not is not a wise move.
This odorant can be filtered out of gas and the devices used to inject the odorant are not fool proof.

So, he may use a match and consider himself a top gun, but he's an accident waiting to happen.

PLEASE,anybody who reads this, do NOT use a match to detect a gas leak, after 35+ years in the gas industry, and now working on a Techinal Support desk, I feel quailified enough to say, don't do it...Please.

Just my personal opinion, fwiw.

Al

[Peter Elliott]

Thanks Ron,

My unit is sealed unit. Bought it that way for the wood shop.

I am waiting to hear from Modine...

Also, going to check for gas leaks.

PLEASE LISTEN TO AL WILLITS: NO OPEN FLAME.. I am not a gas expert but I do "clean up" after people who have done this. Not pretty site with skin hanging off your face or limbs.

AL- question, if I had a small leak wouldn't I smell it when the unit did not run, i.e. pressure in the gas pipe? If I had a leak, why only when it runs and not always. Thinking if I had a leak?

Thanks to all...
Peter

[Jim Murphy]

Gee, when I saw "Hot Dawg" on the Power Tool section, I expected to read another string about SawStop. My bad.:D :D

[Al Willits]

Pete, remember nat gas is lighter than air and it will rise, so if the leak is above you, the odor may not be present at your noses level untill the heater fires up and the blower comes on, that would circulate the air in the room and you'd probably smell it then.

Hope that helps.

Al

[Bill Lewis]

I wish I could bring home the detector but the fire chief would not be happy.

Would he be happier if you called up the fire department to report a leak, then have them dispatch trucks etc...? I don't quite understand why he would have a problem with using a piece of equipment to source a possible leak, after all isn't that what its all about?

I had a small propane leak on a direct vent FP unit. We could only smell it when it was lit. I did the bubble tests, and couldn't find it until I tried it with the unit fired up. Just a tweak on the fitting and that fixed it. However, the leak was on the burner side of the control valve, so it didn't leak when gas wasn't flowing.

BTW Just to be clear, Propane is heavier than air, NG is lighter than air.

[Peter Elliott]

Hi Bill.

Your comment makes sense, but I live in Frederick Co. and work as a fireman in Washington DC. Yes, I drive/operate one of those trucks who comes when you call for a gas leak emergency. In my department nothing is loaned out, cause we used it all the time. Very busy place, trust me... Prob. 95% of FD are this way, cause it's needed for emergency which this is not. Never know when the bell rings and you need "X" tool.

I tried the dish soap test and found nothing. Going to get the better stuff per Al reccomendation. I also tried on the other side of the gas valve, nothing.. Maybe the better soap will show something and good tip to check on the "other" side of the gas valve on the unit. Could explain why I never smell it off.

Thanks to everyone!
Peter
Tower Ladder 3, DCFD

[Bill Lewis]

You work in DC :eek: , 'nuff said.

Didn't know you were in the area, that explains alot. Where abouts are you in Fredneck Co.? As you can see, I'm youre neighbor in Monkey Co.

[Peter Elliott]

I live off the first exit in Fred. (RT.85) , Kingsbrook single family, nice area.

Washington DC - your right. Love the city, great job and people I work with. Crazy, you'd never believe!

[Ron Coleman]

After the discussion the other day about the Modine Hot Dawg garage heater I took a few pictures of mine to show what the innards look like. Mine is the HD30 which has the open flame and uses room air for combustion. You can see the timer circuit board that had to be replaced on the floor of the cabinet.

I use the Hot Dawg to heat about 450 sq ft with R19 insulation under the rafters and R13 in the walls, all on a concrete slab. The vent pipe is type B through the roof. Keeps the shop nice and toasty, even to -22f.:eek:

Just follow the link to a folder with the pictures.

Ron

http://mrcol.freeyellow.com/hot-dawg/

[Randy Johnson]

I work for a natural gas supplier and the leak calls we go on are free to the customer. I would think your supplier would be the same.
Soapy water or leak check are not 100% reliable. I can think of at least one code 7 I responded to where the oder was obvious but no leaks were detected with the fluid the company uses. Usually the bubbles are huge. In this case there were no bubbles of any size. The leak was found by using a gas track, the least sensitive of our electric testers.
If you think there is a problem you really need to get the utility company there. They have the toys that are needed to find the problem if there is one.
Regarding using a flame to check for leaks. When someone calls in an inside leak you tell them to leave the house and to not touch any light switches or even hang up the phone - you don't want ANYTHING that might cause a spark.
Then you get to the house and find the resident on the couch with the TV remote in hand smoking a cigarette because "it's in the basement by the water heater."

[Ben Grunow]

I was in a house that was flooded during "the perfect storm" noreaster in early 90s and nat gas was bubbling up from the kitchen range (yes it was underwater) and the lady who owned the house actually lit a cigarette. I am still here is all I can say.

Flame test is a nono