# Old furnace removed , hole in chimney



## fitter1 (Nov 26, 2010)

Use a 7 inch flue cap and refractory cement, or brick and mortar.


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## Bondo (Dec 8, 2007)

Ayuh,... The quick, 'n easy way is the 7" flue cap/ plug noted above...

They can be found at most any hardware store...


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## yuriy128 (Nov 30, 2011)

so do i remove the netted piece from the bottom of the cap before cementing it in? or what is the proper way to attach it. Its just a round hole in chimney.


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## yuri (Nov 29, 2008)

post some pics of it and where the water heater enters etc.


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## yuriy128 (Nov 30, 2011)




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## yuri (Nov 29, 2008)

Ooooh that is ugly!! Not sure what material that is made of and how to seal it properly. Hang in here and maybe someone with masonry experience can help. Try post this in the Construction forum at the top of the page for better odds of running into one of them.


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## beenthere (Oct 11, 2008)

What size is the inside of that chimney? Your orphaned water heater may not be able to keep the chimney warm enough for it to draft. This will cause the water heaters flue gasses to condense in the chimney and and eat the mortar. Along with allowing CO to escape into your basement and house.

Probably need a liner dropped in the chimney to safely use the water heater.


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## yuriy128 (Nov 30, 2011)

seriously? i would guess it should be ok as long as i close off the hole since the furnace was being used only during cold months so the water heater was mostly used alone.


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## yuri (Nov 29, 2008)

Beenthere is correct. code won't allow an unlined chimney with a gas appliance where I am. now in your cold months the problem will occur. it can also ice up/plug the chimney and spill CO into your house. need a 4 inch liner if it is a 40 gal tank. where do you live. if it is in a very cold climate like mine you may need a B vent/insulated liner as a single wall type can still freezeup.


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## yuriy128 (Nov 30, 2011)

This is in Jersey, i will peek inside the chimney to see if anything is there...


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## joepierson (Oct 26, 2011)

yuriy128 said:


> seriously? i would guess it should be ok as long as i close off the hole since the furnace was being used only during cold months so the water heater was mostly used alone.


The old furnace kept the chimmey (and the air in it) warm in the winter, so the hot vented water heater gas did not cool down much and it rose out of the chimmey correctly. The water heater requires hot air to vent correctly, it's doesn't have a powered vent fan to push it out. 

Now the water heater gas is going to have to fight against a "cool air plug" in the chimmey and the combustion gas is just going to sit in the chimmey during cold days (depends on how much of the chimmey is exposed to the outside air). 

You most likely need a liner or replace the water heater with an electric water heater or direct vent gas type that doesn't need a chimmey. 

http://absolutehomeperformance.org/images/Orphaned_Water_Heaters.pdf


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## yuri (Nov 29, 2008)

electric water htr is the best bet where I am and we are steadily getting rid of NRG wasting chimneys and converting over to them. a chimney is essentially a 4-6" hole in your roof/house and 24 hrs/day heat and $$ rise out of it.


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## joepierson (Oct 26, 2011)

yuri said:


> electric water htr is the best bet where I am and we are steadily getting rid of NRG wasting chimneys and converting over to them. a chimney is essentially a 4-6" hole in your roof/house and 24 hrs/day heat and $$ rise out of it.


Agree, if is was me I would replace that water heater with a $300 electric and seal that bad boy completely up!


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## yuriy128 (Nov 30, 2011)

in terms of efficiency, isnt gas supposed to be cheaper? Also can anyone ballpark a electric heater installation will run me?


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## yuri (Nov 29, 2008)

depends on your local elec vs gas rates. call your utility co to find out, they should know which is cheaper to run. getting rid of the chimney saves NRG, makes your house more comfortable/less drafty and has other advantages. cost per BTU to run them is not the only REAL world cost. having to reheat the air infiltrated into your house by exhausting it up the chimney is expensive and those utility costs don't reflect that. in my experience elec tanks last longer as well. need to buy the tank and and have a 240 volt circuit run to it and have the panel space for it. best to get a quote from a local contractor or find a electrician and plumber to do it for beers or swap labor with what you can do for them.


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## joepierson (Oct 26, 2011)

yuriy128 said:


> in terms of efficiency, isnt gas supposed to be cheaper? Also can anyone ballpark a electric heater installation will run me?


Yes electric is more expensive, but it will take a long time to recover the cost of the liner.

Home depot charges $289 plus the cost of the heater ($300-$400), assuming you have the electric available.

A new insulated liner, professionally installed can cost $1500-$4000 to bring everything up to code, it can quite involved, that is why I recommend you close it off. Or at least get a couple quotes to determine where you stand.


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## yuriy128 (Nov 30, 2011)

Thanks for your advice guys, I have to take a look at the panel and see if i have an empty slot there for a 240 outlet. I cant believe the contractor that did the heating didnt mention anything and let this hole unplugged...


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## yuri (Nov 29, 2008)

need 2 slots for 240. stuff some fibreglass pink insulation in there temporarily or a 7 inch cap. if the chimney plugs or downdrafts and it will with an open hole you can get CO poisoning.


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## yuriy128 (Nov 30, 2011)

As long as i plug the hole, do you think this could last at least one winter? i dont have the budget to get a new heater this winter.

Also, after i do get the heater, how do i completely seal off the chimney? (i'm guessing from the roof)

Appreciate your help!


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## beenthere (Oct 11, 2008)

yuriy128 said:


> This is in Jersey, i will peek inside the chimney to see if anything is there...


Code in New Jersey is the same as the rest of the USA. IMC and NFGC both require it to be lined. It should have been done as part of the furnace change out, or at least you should have been informed that it needs to be done.

As others said, during the winter, the old furnace helped keep the chimney warm. Now with just the water heater, it won't be enough. 

Its more then possible it will fill your basement/house with CO. Or it m ay just deteriorate your chimney that the chimney falls in. or you may get a way with it for 1 winter. No one can say for sure.

We all realize that this close to Christmas no one has an abundance of money to spend. Of course, we also want everyone to still be alive and healthy to enjoy Christmas also.


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## beenthere (Oct 11, 2008)

yuriy128 said:


> As long as i plug the hole, do you think this could last at least one winter? i dont have the budget to get a new heater this winter.
> 
> Also, after i do get the heater, how do i completely seal off the chimney? (i'm guessing from the roof)
> 
> Appreciate your help!


A cap, or plate on top of it is best.


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## joepierson (Oct 26, 2011)

yuriy128 said:


> As long as i plug the hole, do you think this could last at least one winter?


you can get a CO monitor and see if goes off


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## yuriy128 (Nov 30, 2011)

yes i have one on first floor, should i get one for basement and second floor, im guessing its a good idea...


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