I did some real MacGyver **** here tonight

Jim K

Jim K

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Richard Digits
And none of my family can appreciate it. I spent the latter half of my day putting the new brains into my boiler. I was expecting it to be plug & play, but it wound up involving re-wiring the entire unit and cutting holes in the chassis for the new harnesses.

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And....it was still not firing. Clearly the bad board was not the only issue. These boilers sometimes have to be "choked" by putting your hand over the air intake if they haven't been run for a while. Helps suck the propane into the burner. I discovered I could keep it running if I constricted the air intake. Starting poking around the gas valve and discovered that the venturi is worn out for some reason. The gas valve uses a venturi to create negative pressure to keep the valve open, so if the airflow stops for any reason the valve shuts before the computer even senses a problem.

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The venturi eroded enough that it broke in two pieces and disrupted the airflow. After noodling on it for a while, I collected a Sprite can, some aluminum foil tape, and some scissors, and rebuilt the missing portion of the venturi. I was not convinced it was going to work, so I didn't take a picture, for which I'm really kicking myself now. It works prefectly. Boiler fired right up and we have hot water again.

So if you hear of a house explosion in central IL tonight, you'll know why. I'm debating whether to leave the thing on overnight, but it seems completely happy. I'll order a new venturi (which of course only comes as part of the gas valve assembly for $350), but at least I won't have to pay overnight shipping again.

Looking around on the internet, I don't find any discussion of these venturis failing like this. It's very sooty, in spite of being a long way from the burner. The actual combustion chamber is on the other side of the blower fan. Hard to believe it's backfiring that hard often enough to erode the venturi, but that's the only explanation I can come up with. Is there soot in propane? Odd that the blower is NOT sooty or eroded.

Knowing what I know now about the company that installed it, I doubt they ever adjusted it. I have the flame looking good in the window, but once I get it buttoned back up with a new gas valve, thinking I may call an HVAC guy who actually owns a combustion analyzer to get it dialed in correctly.

Anyway, I tried explaining to my family what I went through to get them hot water, but they have no idea what I'm talking about. Oh well.
 
You, sir, are awesome. Your family appreciates you, even if they do not tell you. Someday they will change your diaper, and you will remind them of this boiler escapade. Ending the reminder with "So, there!"
 
Anyway for the flame to "rollout" into the venturi? I wouldn't think it would be possible on that side of the valve, but I'm sure stranger things have happened.
 
Tell them you're a mechanical savant that gave them hot water when "the guy" couldn't....and you can just as easily turn the heat off mid shower. Just because. Then say your thirsty. First one to bring you a beer definitely gets a hot shower
 
Good on ya' for the quick fix, but I'd want to seriously find out why there is evidence of dirty burning that far back. When it lights off, is it a subtle light, or a big whomping WHOOSH sound? What do the burners look like?
 
Jim K said:
I'll order a new venturi (which of course only comes as part of the gas valve assembly for $350), but at least I won't have to pay overnight shipping again.
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See if someone made a 3D model for ut and 3D print it. Actually, it looks simple enough to design and 3D print.

Is that soot on it, or just plastic dust? I'm thinking the airflow made it vibrate and flex to failure?

Also, MacGyver got lazy
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aterry1067 said:
Good on ya' for the quick fix, but I'd want to seriously find out why there is evidence of dirty burning that far back. When it lights off, is it a subtle light, or a big whomping WHOOSH sound? What do the burners look like?
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Nope... nice & quiet. I can't find any fault with the thing. When I "choke" it, I get a little whomp and can feel it push air back a bit. As I said, it's a long way from the burner to the venturi:

IMG_20250204_201003467~2.jpg

And of course it shuts the gas off long before the fan. It'll be interesting to see what the aluminum can piece looks like after a couple days of running, because i know what it looked like going in. That venturi has seen a decade and 10s of thousands of cycles. The one pictured above actually is one my dad had replaced ten years ago with the exact same failure mode. He kept it, of course:rolleyes:

AV8R_87 said:
See if someone made a 3D model for ut and 3D print it. Actually, it looks simple enough to design and 3D print.

Is that soot on it, or just plastic dust? I'm thinking the airflow made it vibrate and flex to failure?

Also, MacGyver got lazy
View attachment 137846
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Printing one was my first thought. It's more complicated than it looks, as there's a gas passage on the back side. There's also the fact that it don't know what a new one looks like. My repair was based on my intimate knowledge of Bournoulli's Principle :biggrin:. I wish I had a scanner.

Never thought about plastic dust. Where it failed isn't actually touching anything though. Maybe it needs an air filter :dunno:
 

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Keep us updated.

The fact that the Venturi is so far away from the burner and still seeing a flame front is the concerning part. But…. It’s been flying that way for years, so it should be ok. :)
Check it out in a day or two and see what you find.
 
The problem is not only does your family know you can fix stuff, including stuff that the people who do it for a living can't (airplane engines, f’rinstance), they probably believe that you are physically, mentally, morally, and spiritually incapable of NOT fixing something.

You’ve dug yourself a deep hole there, my friend, and I’m afraid you’re never gonna dig yourself back out.

Good on ya! :D
 
I would buy the part quickly and get it installed. The problem with Macgyver fixes on a boiler is that if something goes wrong and your house burns down, your insurance may not cover the loss. I found out a while ago that propane is not as clean a fuel as natural gas. It burns dirty and equipment that burns it needs regular maintenance and cleaning. Good job on getting the thing running again.
 
It's all good and fun until flash vaporization ruins your whole day.
 
I’m not familiar with your particular unit, but similar ones I have worked on have a metal mesh “sock” over a perforated tube that goes into the burn chamber to act as a flame arrestor to keep the flame front from moving back up the intake pipe. It eventually wears out and lets the air/fuel mix in the intake ignite and have fire where it shouldn’t. I would not consider it fixed. Often when the flame arrestor fails it will start “chuffing” it sounds like somebody is shooting a suppressed gun as fast as they can.
 
I am not being cute. I don't think I understand how it heats your house.
I have a water heater so I get that part of it. I don't understand how it warms the house.
Reading about it, It says that it heats water to be used for cooking, baths, etc or water can be sent to the radiator for central heating.

I assume you have some sort of fan box in the attic that pushes air to the rooms but what is the thing that is hot for the air to pass through?
My attic has a gas heater connected to a fanbox with a web of ducts going to each room. Fire + Moving Air.... Come to think of it I am not sure what the fire actually heats.
It can't just be blowing carbon monoxide into the vents. My system must be heating something with the fire and blowing the air over what that hot thing is.

Basically what I just learned is the ceiling fan is the only thing that I know how works.

I will be in the attic.
 
Figured mine out. Fire / Gas travel through tubes. Air blows over the tubes. Gas goes out the roof.
 
SixPapaCharlie said:
I am not being cute. I don't think I understand how it heats your house.
I have a water heater so I get that part of it. I don't understand how it warms the house.
Reading about it, It says that it heats water to be used for cooking, baths, etc or water can be sent to the radiator for central heating.

I assume you have some sort of fan box in the attic that pushes air to the rooms but what is the thing that is hot for the air to pass through?
My attic has a gas heater connected to a fanbox with a web of ducts going to each room. Fire + Moving Air.... Come to think of it I am not sure what the fire actually heats.
It can't just be blowing carbon monoxide into the vents. My system must be heating something with the fire and blowing the air over what that hot thing is.

Basically what I just learned is the ceiling fan is the only thing that I know how works.

I will be in the attic.
Click to expand...
Oh...

Okay, so the boiler heats water in a closed system to 190 degrees. Pumps then pump this hot water through the house to baseboard radiators. Basically a copper tube with little fins crimped onto it. The radiators passively heat the air through convection...no fan involved.

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Since we already have a unit making hot water, it's pretty trivial to make another loop passing that hot water through a tank to heat up "domestic hot water" for bathing/cooking. There's 5 heat zones and one more for DHW.

IMG_20250205_151913126.jpgIMG_20250205_151924677_HDR.jpg

Now to make things even more needlessly complicated, the baseboard radiant heat is more of a backup. Most of the house is heated & cooled through forced air. The actual furnace though is a little different. It's a geothermal system. It's a heat pump, so an air conditioner that can pump heat into or out of the house. Instead of using an air conditioner coil outside (an "Air-Source Heat Pump"), it uses water passed through loops that are drilled 60' into the ground, taking advantage of the fact that the earth stays about 60 degrees year round, and making it more efficient than an ASHP in both heating and cooling. This is the pump that circulates the water through the loop, and the box on the right is the actual heat pump and air handler unit.

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The geothermal system was put in about 20 years after the house was built, so it doesn't reach all areas, necessitating the boiler to still be in service. Neither system reaches the room above the garage that wasn't intended to be living space originally, so that room has it's own traditional forced air furnace, like yours. Then this year we put a mini-split ASHP in that space as well for air conditioning and more efficient heating when it's not super cold. So I have 4 HVAC systems to look after :oops:
 
This is fascinating. I would never think in a million years a passive heat system like that could warm a house in such cold locations.

Also I bet your kids don't stand in the middle of the kitchen under the vent in the morning going "Ah this feels like being in a warm shower"

Question: If the room gets too hot, how do you turn it off? The pipe is full of hot water and going to continue warming for some time right?
 
Also I am jealous you have a basement. We dont have those in Texas and I always wanted one.
 
SixPapaCharlie said:
This is fascinating. I would never think in a million years a passive heat system like that could warm a house in such cold locations.

Also I bet your kids don't stand in the middle of the kitchen under the vent in the morning going "Ah this feels like being in a warm shower"

Question: If the room gets too hot, how do you turn it off? The pipe is full of hot water and going to continue warming for some time right?
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Pump shuts off.. They're each controlled by their own thermostat. Doesn't take long for the water to reach ambient temperature. One of the supposed benefits of "hydronic heating" is that it's more gentle and even. No hot air coming from vents, no fan noise. You can't tell if it's on unless it's really quiet. The pipes do sometimes pop when they expand & contract. I really need to insulate those loops that are in regular use.

If you go into old buildings and see those big cast iron radiators, it's the same idea. It was the predominate method of heating before air conditioning. Once central a/c became a thing, forced air heat made more sense as you were running ducting all over the house anyway.
 
SixPapaCharlie said:
Basically what I just learned is the ceiling fan is the only thing that I know how works.
Click to expand...
:rofl:

In addition to what @Jim K has with the hydronic baseboard heaters, some lucky folks instead have heated floors, where there are plastic tubes that zig-zag back and forth right underneath the floor surface. That's especially nice in the bathroom on winter mornings, as well as being a more efficient method of heating in some cases. For example, I have a living room with a vaulted ceiling, but at the peak of that ceiling on one end of the room it goes up even further because that's where the upstairs hallway is. To heat that room via forced air (which is how that room is heated), I have to heat the entire volume of this big room. If I had a heated floor in there, more of the space closer to the floor would be heated first, resulting in more heat where it matters (where the people are).

We did look at one house when we were shopping that was 100% heated by heated floors. During the open house someone else's kids were sprawled out on the floor in the entryway enjoying the warmth. :rofl:
Jim K said:
The geothermal system was put in about 20 years after the house was built, so it doesn't reach all areas, necessitating the boiler to still be in service. Neither system reaches the room above the garage that wasn't intended to be living space originally, so that room has it's own traditional forced air furnace, like yours. Then this year we put a mini-split ASHP in that space as well for air conditioning and more efficient heating when it's not super cold. So I have 4 HVAC systems to look after :oops:
Click to expand...
:o

I only have two - Forced air in most of the house, plus electric radiant baseboard heaters in the basement that I normally keep completely turned off at the breaker. However, if something happens to the main system it's nice to have that there as a backup. It does a nice job of heating the floors on the main floor too, 'cuz the thermostat doesn't really work and lets it get up to about 90 in the basement, which is why I keep it solely as a backup.
SixPapaCharlie said:
Also I am jealous you have a basement. We dont have those in Texas and I always wanted one.
Click to expand...
Where do you put all your stuff? I've heard Texas doesn't have basements - Something about puncturing the ceiling of hell or somesuch, right? :rofl:

As a lifelong resident of a state where EVERYTHING has a basement (a "ranch" here is one floor above ground, accompanied by a large basement which is usually at least partially finished with a nice game room/theater/bar), I don't know how I'd live without one. The finished half of our basement is split in half into a play area where the boys can be boys and throw things to their heart's content without risking damage to anything, and half into a hobby/relaxation area where I have the 3D printer and we can play music without disturbing anyone else in the house. Then there's the unfinished half which has all of the various holiday decorations, kid clothes that don't fit one and are too big for the other, various toys waiting to be handed down, ya know... Stuff! I'm hoping to build a bit of a shop down there eventually, more focused on electronics and 3D printing type stuff as opposed to woodworking and mechanical type (dirty) stuff that I do in the garage.

Without a basement, how do you do "dirty" stuff? :o
 
There was a guy down the road here that built a contraption in his barn that looked similar to the unit that @Jim K built.

Then one day the black suburbans showed up and arrested the guy, then went choppity chop on his contraption...
 
flyingcheesehead said:
:rofl:

In addition to what @Jim K has with the hydronic baseboard heaters, some lucky folks instead have heated floors, where there are plastic tubes that zig-zag back and forth right underneath the floor surface. That's especially nice in the bathroom on winter mornings, as well as being a more efficient method of heating in some cases. For example, I have a living room with a vaulted ceiling, but at the peak of that ceiling on one end of the room it goes up even further because that's where the upstairs hallway is. To heat that room via forced air (which is how that room is heated), I have to heat the entire volume of this big room. If I had a heated floor in there, more of the space closer to the floor would be heated first, resulting in more heat where it matters (where the people are).

We did look at one house when we were shopping that was 100% heated by heated floors. During the open house someone else's kids were sprawled out on the floor in the entryway enjoying the warmth. :rofl:

:o

I only have two - Forced air in most of the house, plus electric radiant baseboard heaters in the basement that I normally keep completely turned off at the breaker. However, if something happens to the main system it's nice to have that there as a backup. It does a nice job of heating the floors on the main floor too, 'cuz the thermostat doesn't really work and lets it get up to about 90 in the basement, which is why I keep it solely as a backup.

Where do you put all your stuff? I've heard Texas doesn't have basements - Something about puncturing the ceiling of hell or somesuch, right? :rofl:

As a lifelong resident of a state where EVERYTHING has a basement (a "ranch" here is one floor above ground, accompanied by a large basement which is usually at least partially finished with a nice game room/theater/bar), I don't know how I'd live without one. The finished half of our basement is split in half into a play area where the boys can be boys and throw things to their heart's content without risking damage to anything, and half into a hobby/relaxation area where I have the 3D printer and we can play music without disturbing anyone else in the house. Then there's the unfinished half which has all of the various holiday decorations, kid clothes that don't fit one and are too big for the other, various toys waiting to be handed down, ya know... Stuff! I'm hoping to build a bit of a shop down there eventually, more focused on electronics and 3D printing type stuff as opposed to woodworking and mechanical type (dirty) stuff that I do in the garage.

Without a basement, how do you do "dirty" stuff? :o
Click to expand...

I don't fully understand it. I think it has something to do with the clay and the soil. In Texas the saying is there are two types of houses those that have had their foundation repaired in those that are going to so I'm guessing whatever makes up our soil shifts and moves a lot and isn't conducive to basements.
 
SixPapaCharlie said:
I don't fully understand it. I think it has something to do with the clay and the soil. In Texas the saying is there are two types of houses those that have had their foundation repaired in those that are going to so I'm guessing whatever makes up our soil shifts and moves a lot and isn't conducive to basements.
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Sure are nice when there's tornados about. Our last house didn't have one. Just a hatch down to a dirt crawlspace, that was still above grade. We would open the hatch and pray we wouldn't have to go down there.

Now, we just go downstairs, pop some popcorn, and watch a movie on the big TV.

Most houses around here have basements, primarily for that reason. I would've thought Texas would too. Are you guys mostly on slabs down there then?

Dan Thomas said:
They look like the O-gauge Lionel stuff I had when I was a little kid.
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That's because they are... https://www.pilotsofamerica.com/community/threads/toy-train-dorks.149913/
 
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@SixPapaCharlie up north we don’t have the HVAC units or water heaters in the attic like some houses in Texas do. Some other differences are that older homes had/have heating oil (similar to diesel) to run the boilers. To see something wild, check out some YT vids of people in -40 deg climates that have to deal with town boilers that supply municipal hot water to heat homes and other buildings.
 
Jim K said:
Sure are nice when there's tornados about. Our last house didn't have one. Just a hatch down to a dirt crawlspace, that was still above grade. We would open the hatch and pray we wouldn't have to go down there.

Now, we just go downstairs, pop some popcorn, and watch a movie on the big TV.

Most houses around here have basements, primarily for that reason. I would've thought Texas would too. Are you guys mostly on slabs down there then?



That's because they are... https://www.pilotsofamerica.com/community/threads/toy-train-dorks.149913/
Click to expand...

All slabs here as far as i know.

In Texas when we get tornadoes our only option is to die like men.
 
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