PH

[Otterhound]

Originally Posted by Mr. Jelly

A neutral pH does not mean there is an absence of minerals in the water. Condensate has minerals in it. The minerals are what screw up a humidifier.

My research shows that condensate water is basically mineral free .
The presence of minerals is the very reason that I use distilled water since it is mineral free . Condensate is distilled water . The difference for myself is that mine is pumped into a holding tank instead of a drain . This makes available for other purposes . My system was not designed with this use in mind . It was designed this was so as to not need to plumb into old ductile iron drain piping .

[martingitdave]

Condensate from a condensing gas furnace should NOT be used for anything. It is corrosive. Condensate from a DX cooling coil can be used carefully. Tap water is fine to use for a humidifier. Just clean them out periodically.

Most whole house humidifiers (furnace mounted) that are installed in well insulated homes in moderate climates will not get above 30-40% RH in winter. Why? The heat doesn’t run often enough. Most humidifiers are interlocked with the burner to prevent wetting of the ductwork.

Some mister/power humidifiers can be interlocked to the fan. You can force the fan to run periodically,with the burner off, using a digital thermostat. This is what I do. You have to still be careful because you can wet the ductwork.

Lastly, moisture in the air “spreads.” This means that unless a specific room is sealed off from the rest, placing a humidifier in the vicinity of your guitars and leaving the doors open with allow the house generally reach the same level. So, keep humidifiers where the are convenient to maintain.

[Otterhound]

Originally Posted by martingitdave

Condensate from a condensing gas furnace should NOT be used for anything. It is corrosive. Condensate from a DX cooling coil can be used carefully. Tap water is fine to use for a humidifier. Just clean them out periodically.

Most whole house humidifiers (furnace mounted) that are installed in well insulated homes in moderate climates will not get above 30-40% RH in winter. Why? The heat doesn’t run often enough. Most humidifiers are interlocked with the burner to prevent wetting of the ductwork.

Some mister/power humidifiers can be interlocked to the fan. You can force the fan to run periodically,with the burner off, using a digital thermostat. This is what I do. You have to still be careful because you can wet the ductwork.

Lastly, moisture in the air “spreads.” This means that unless a specific room is sealed off from the rest, placing a humidifier in the vicinity of your guitars and leaving the doors open with allow the house generally reach the same level. So, keep humidifiers where the are convenient to maintain.

I measured the pH at 6.0 .
This is very mildly acidic .
What is the corrosive agent present ? HCL , H2SO4 ?

[martingitdave]

Originally Posted by Otterhound

I measured the pH at 6.0 .

This is very mildly acidic .

What is the corrosive agent present ? HCL , H2SO4 ?

Flue gas contains the byproducts of combustion. When that gas condenses in the secondary heat exchanger, it takes the corrosive elements with it in the condensate fluid. That’s why condensing furnaces are made of highly corrosion resistant materials. It’s not just the acid, but the other byproducts. I’m an engineer not a chemist, so I’d have to research to find the exact compounds, but it’s looks like Nitric Acid (NOX).

From WiKi:


Condensing Furnace

The fourth category of furnace is the high-efficiency, or condensing furnace. High-efficiency furnaces can achieve from 89% to 98% fuel efficiency. This style of furnace includes a sealed combustion area, combustion draft inducer and a secondary heat exchanger. Because the heat exchanger removes most of the heat from the exhaust gas, it actually condenses water vapor and other chemicals (which form a mild acid) as it operates. The vent pipes are normally installed with PVC pipe versus metal vent pipe to prevent corrosion. The draft inducer allows for the exhaust piping to be routed vertically or horizontally as it exits the structure. The most efficient arrangement for high-efficiency furnaces include PVC piping that brings fresh combustion air from the outside of the home directly to the furnace. Normally the combustion air (fresh air) PVC is routed alongside the exhaust PVC during installation and the pipes exit through a sidewall of the home in the same location. High efficiency furnaces typically deliver a 25% to 35% fuel savings over a 60% AFUE furnace.

Another good primer:

http://www.jlconline.com/how-to/hvac...ky-to-manage_o

[Otterhound]

Originally Posted by martingitdave

Flue gas contains the byproducts of combustion. When that gas condenses in the secondary heat exchanger, it takes the corrosive elements with it in the condensate fluid. That’s why condensing furnaces are made of highly corrosion resistant materials. It’s not just the acid, but the other byproducts. I’m an engineer not a chemist, so I’d have to research to find the exact compounds, but it’s looks like Nitric Acid (NOX).

From WiKi:


Condensing Furnace

The fourth category of furnace is the high-efficiency, or condensing furnace. High-efficiency furnaces can achieve from 89% to 98% fuel efficiency. This style of furnace includes a sealed combustion area, combustion draft inducer and a secondary heat exchanger. Because the heat exchanger removes most of the heat from the exhaust gas, it actually condenses water vapor and other chemicals (which form a mild acid) as it operates. The vent pipes are normally installed with PVC pipe versus metal vent pipe to prevent corrosion. The draft inducer allows for the exhaust piping to be routed vertically or horizontally as it exits the structure. The most efficient arrangement for high-efficiency furnaces include PVC piping that brings fresh combustion air from the outside of the home directly to the furnace. Normally the combustion air (fresh air) PVC is routed alongside the exhaust PVC during installation and the pipes exit through a sidewall of the home in the same location. High efficiency furnaces typically deliver a 25% to 35% fuel savings over a 60% AFUE furnace.

Another good primer:

http://www.jlconline.com/how-to/hvac...ky-to-manage_o

Conventional chimneys are also used with a stainless steel liner .
The main issue with the exhaust of a high efficiency gas furnace in the low temperature of the exhaust gases . Because of this low temp , conventional chimneys often do not warm enough to draft properly . This allows for 2 factors . A buildup of exhaust gases in the chimney that can then result in the condensing of exhaust vapors . These vapors are mildly acidic and will react with brick , but even more so , the mortar which is alkaline/base in nature because of limestone .
NOX is commonly know as nitrous oxide . Aside of it's commonly known use in dentistry , it makes a fine accelerant .
Thought you might like to know .
Nitric acid is used for etching and , of course , making a really cool green gas when mixed with copper/pennies in chem class . Yes , it also has other uses .

[martingitdave]

Originally Posted by Otterhound

Conventional chimneys are also used with a stainless steel liner .

The main issue with the exhaust of a high efficiency gas furnace in the low temperature of the exhaust gases . Because of this low temp , conventional chimneys often do not warm enough to draft properly . This allows for 2 factors . A buildup of exhaust gases in the chimney that can then result in the condensing of exhaust vapors . These vapors are mildly acidic and will react with brick , but even more so , the mortar which is alkaline/base in nature because of limestone .

NOX is commonly know as nitrous oxide . Aside of it's commonly known use in dentistry , it makes a fine accelerant .

Thought you might like to know .

Nitric acid is used for etching and , of course , making a really cool green gas when mixed with copper/pennies in chem class . Yes , it also has other uses .

Thanks. But I suspect that we agree it’s not great for use in humidifiers? :-)

[KevWind]

Originally Posted by martingitdave

Flue gas contains the byproducts of combustion. When that gas condenses in the secondary heat exchanger, it takes the corrosive elements with it in the condensate fluid. That’s why condensing furnaces are made of highly corrosion resistant materials. It’s not just the acid, but the other byproducts. I’m an engineer not a chemist, so I’d have to research to find the exact compounds, but it’s looks like Nitric Acid (NOX).

From WiKi:


Condensing Furnace

The fourth category of furnace is the high-efficiency, or condensing furnace. High-efficiency furnaces can achieve from 89% to 98% fuel efficiency. This style of furnace includes a sealed combustion area, combustion draft inducer and a secondary heat exchanger. Because the heat exchanger removes most of the heat from the exhaust gas, it actually condenses water vapor and other chemicals (which form a mild acid) as it operates. The vent pipes are normally installed with PVC pipe versus metal vent pipe to prevent corrosion. The draft inducer allows for the exhaust piping to be routed vertically or horizontally as it exits the structure. The most efficient arrangement for high-efficiency furnaces include PVC piping that brings fresh combustion air from the outside of the home directly to the furnace. Normally the combustion air (fresh air) PVC is routed alongside the exhaust PVC during installation and the pipes exit through a sidewall of the home in the same location. High efficiency furnaces typically deliver a 25% to 35% fuel savings over a 60% AFUE furnace.

Another good primer:

http://www.jlconline.com/how-to/hvac...ky-to-manage_o

Glad I read this thread, as I have a high efficiency gas hot water heater we use for domestic hot water and open direct radiant floor heating system . Which has the double wall PVC exhaust/outside combustion air gas vent system, (as in your post) . There is however also a little condensation drain PVC tube that comes out of the bottom of the exhaust system that goes directly into the house drain system (which is also all PVC ) and not really a problem But I may check the PH anway.

[Otterhound]

Originally Posted by martingitdave

Thanks. But I suspect that we agree it’s not great for use in humidifiers? :-)

I never said that .
By the way , I brain farted .
NOX is typically nitric oxide . Been a long time since High School chem class .
With a pH of 6.0 , the minimal acidity present is hardly a concern .
When the condensate starts to eat my holding tank , I will be concerned .
Rain water may actually be more acidic than this and likely is . Maybe I'll test some just for FSG .

[Otterhound]

Originally Posted by KevWind

Glad I read this thread, as I have a high efficiency gas hot water heater we use for domestic hot water and open direct radiant floor heating system . Which has the double wall PVC exhaust/outside combustion air gas vent system, (as in you post) . There is however also a little condensation drain PVC tube that comes out of the bottom of the exhaust system that goes directly into the house drain system (which is also all PVC ) and not really a problem But I may check the PH anway.

You'll likely find it to be 6.0 or very close .
Blueberries want more acidic soil than that .

[Swamp Yankee]

why not have the wastewater analyzed by a laboratory first?

[Otterhound]

Originally Posted by Swamp Yankee

why not have the wastewater analyzed by a laboratory first?

Likely not close to being cost effective .
Distilled water costs $4.56 / 6 gallons .
This is simply a casual convenience .
I'm not drinking this stuff .

[Mr. Jelly]

Originally Posted by Otterhound

My research shows that condensate water is basically mineral free

In a perfect world. I've worked with demineralization and deionizion processes of water. Waste water and systems that involve condensate. Given time and heat they are all a problem to systems.