New high-efficiency gas furnace, old hot water tank - any issues?
 

I've replaced my 82% efficiency gas furnace to a new 93% efficiency
model. Prior to this my old gas furnace and my hot water tank were both
vented through the chimney. Now, only my hot water tank is vented out
the chimney, while my new furnace is vented out the side of the house
through PVC pipes.

Are there any issues with having the hot water tank still use the
chimney? I didn't think so until I saw this article. I'm not an HVAC
person so I don't fully understand what is the issue with "Now the hot
water tank has to heat up that big chimney all by itself".

I don't know the specs of the hot water tank but I believe its around
13 years old.


Here's the full paragraph:


"Another hot water tank issue is when you switch from a conventional
gas furnace and hot water tank to a new, high-efficiency sidewall
vented furnace. Now the hot water tank has to heat up that big chimney
all by itself, and you probably will have to pay for chimney relining.
It is often better, when choosing a chimneyless furnace, to switch your
hot water tank to sidewall venting at the same time and seal the old
chimney closed. However, sidewall vented hot water heaters are more
expensive than conventional hot water heaters and can be noisier."

http://www.cmhc-schl.gc.ca/en/burema...ose/ce_048.cfm

wrote in message
ups.com...
I've replaced my 82% efficiency gas furnace to a new 93% efficiency
model. Prior to this my old gas furnace and my hot water tank were both
vented through the chimney. Now, only my hot water tank is vented out
the chimney, while my new furnace is vented out the side of the house
through PVC pipes.

Are there any issues with having the hot water tank still use the
chimney? I didn't think so until I saw this article. I'm not an HVAC
person so I don't fully understand what is the issue with "Now the hot
water tank has to heat up that big chimney all by itself".

I don't know the specs of the hot water tank but I believe its around
13 years old.


Here's the full paragraph:


"Another hot water tank issue is when you switch from a conventional
gas furnace and hot water tank to a new, high-efficiency sidewall
vented furnace. Now the hot water tank has to heat up that big chimney
all by itself, and you probably will have to pay for chimney relining.
It is often better, when choosing a chimneyless furnace, to switch your
hot water tank to sidewall venting at the same time and seal the old
chimney closed. However, sidewall vented hot water heaters are more
expensive than conventional hot water heaters and can be noisier."

http://www.cmhc-schl.gc.ca/en/burema...ose/ce_048.cfm

It's been two years since I put in a high efficiency furnace and still have
just my hot water vented to the chimney. My initial concern was whether or
not the snow would clog the chimney cap resulting in a back flow of the
exhaust gas into the basement. Just hasn't happened--the chimney cap is
always free of snow and the chimney, at least to date, doesn't show any
signs of any problem.
MLD

On 8 Aug 2005 13:11:26 -0700, wrote:


Are there any issues with having the hot water tank still use the
chimney? I didn't think so until I saw this article. I'm not an HVAC
person so I don't fully understand what is the issue with "Now the hot
water tank has to heat up that big chimney all by itself".

yes there are issues., there is also a kit made for this purpose. your
installation contractor should have done this for you.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

"hvactech2" wrote in message
...
On 8 Aug 2005 13:11:26 -0700, wrote:


Are there any issues with having the hot water tank still use the
chimney? I didn't think so until I saw this article. I'm not an HVAC
person so I don't fully understand what is the issue with "Now the hot
water tank has to heat up that big chimney all by itself".

yes there are issues., there is also a kit made for this purpose. your
installation contractor should have done this for you.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

I heard the same thing from the house inspector, as well as a chimney
cleaning guy and the HVAC people I use. It makes sense. The liner's being
installed in September.

hvactech2 wrote:
On 8 Aug 2005 13:11:26 -0700, wrote:



Are there any issues with having the hot water tank still use the
chimney? I didn't think so until I saw this article. I'm not an HVAC
person so I don't fully understand what is the issue with "Now the hot
water tank has to heat up that big chimney all by itself".


yes there are issues., there is also a kit made for this purpose. your
installation contractor should have done this for you.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail
they put a sleeve inside the chimney for the water heater. that is what
they did to my chimney. cut the moisture down and saves the mortar.

Greetings,

a) don't worry about it unless there is an actual problem created
b) there probably won't be a problem
c) make sure you have a carbon-monoxide detector installed in your
basement

Hope this helps,
William