I'm installing a 35'x5" round aluminum chimney liner because my exterior chimney (terracotta inside block) is showing wet spots in the mortar joints. I have a 36,000 btu gas fired hot water heater that has a 3" gravity flue piped to my chimney and also a 100,000 btu input 80% power vented heater with a 3" flue that bumps up to 5" before it enters my chimney. I'm a pipe fitter by trade so I deal with installing these all the time but never deal with the flue side. My question is when I bring the 5" through my chimney and tie in a 5" wye, which appliance should go on the bull of the T? I've been told both ways, just curious what some thoughts are. Thanks.

On 02/06/2014 05:04 PM, wrote:
I'm installing a 35'x5" round aluminum chimney liner because my exterior chimney (terracotta inside block) is showing wet spots in the mortar joints. I have a 36,000 btu gas fired hot water heater that has a 3" gravity flue piped to my chimney and also a 100,000 btu input 80% power vented heater with a 3" flue that bumps up to 5" before it enters my chimney. I'm a pipe fitter by trade so I deal with installing these all the time but never deal with the flue side. My question is when I bring the 5" through my chimney and tie in a 5" wye, which appliance should go on the bull of the T? I've been told both ways, just curious what some thoughts are. Thanks.




I just posted a few days back that I'm going to have to put a liner in.

My days of going up on the roof are over so I'm going to contract it out...
but I had given it some thought.

Since I have a gas furnace and a gas water heater, the only thing that
would fit inside my chimney would be a reducing "Y".

Maybe your chimney is larger than mine but I don't see that a "T" would
fit very well.

I'm pulling the liner through an existing 5" hole in my basement and the wye will not be in the chimney

On 02/06/2014 07:05 PM, wrote:
I'm pulling the liner through an existing 5" hole in my basement and the wye will not be in the chimney




OK, I was just curious ... I'm not qualified to give advice.

On Thursday, February 6, 2014 8:21:20 PM UTC-5, philo* wrote:
On 02/06/2014 07:05 PM, wrote:

I'm pulling the liner through an existing 5" hole in my basement and the wye will not be in the chimney









OK, I was just curious ... I'm not qualified to give advice.

I'm not qualified either, but the ones I've seen, when
you have a furnace and gas water heater feeding into a chimney,
the furnace has always been the direct route, with the WH
coming off the side from T or wye. Kind of makes sense that
you'd want the higher capacity appliance to have the direct,
straight path. That's how my old furnace was routed, but
it also had a larger vent from the furnace than from the
WH. Now furnace is gone and WH goes straight into a liner.

philo* posted for all of us...

And I know how to SNIP


On 02/06/2014 07:05 PM, wrote:
I'm pulling the liner through an existing 5" hole in my basement and the wye will not be in the chimney




OK, I was just curious ... I'm not qualified to give advice.

Ding ding ding!! I believe this is the first time I have ever seen a post like this!
Qualifications never stopped anyone before. Like politicians, journalists, liberals.

--
Tekkie

On 02/07/2014 06:37 PM, Tekkie® wrote:
philo posted for all of us...

And I know how to SNIP


On 02/06/2014 07:05 PM, wrote:
I'm pulling the liner through an existing 5" hole in my basement and the wye will not be in the chimney




OK, I was just curious ... I'm not qualified to give advice.

Ding ding ding!! I believe this is the first time I have ever seen a post like this!
Qualifications never stopped anyone before. Like politicians, journalists, liberals.



I feel confident giving advice in several areas:

If I have first hand knowledge, I'll give advice.
You wan to know something about lead-acid batteries...
I did that for 38 years and will give all kinds of advice.


I'll also give advice in areas where I'm reasonably sure I'm right...but
if I'm wrong...no harm would be done.

"What's the best type of duct tape?"


In this situation, concerning the exhaust of waste gas containing carbon
monoxide...I'm not going to give advice. I even asked of friend of mine
who is a building inspector, but did not relay his information as for
some odd reason it did not sound quite correct to me.

On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:
I'm installing a 35'x5" round aluminum chimney liner because my exterior chimney (terracotta inside block) is showing wet spots in the mortar joints.. I have a 36,000 btu gas fired hot water heater that has a 3" gravity flue piped to my chimney and also a 100,000 btu input 80% power vented heater with a 3" flue that bumps up to 5" before it enters my chimney. I'm a pipe fitter by trade so I deal with installing these all the time but never deal with the flue side. My question is when I bring the 5" through my chimney and tie in a 5" wye, which appliance should go on the bull of the T? I've been told both ways, just curious what some thoughts are. Thanks.


I'm not an expert but I've owned homes with the gas hw heater and gas T'd together before myself. I've always wondered how the waste heat from the hw was enough to get out the vent without condensing when the furnace was not on.

One consideration is that your next gas furnace will probably be a condensing one. How old is your furnace and hw heater now?

On 02/08/2014 08:19 AM, jamesgang wrote:
On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:
I'm installing a 35'x5" round aluminum chimney liner because my exterior chimney (terracotta inside block) is showing wet spots in the mortar joints. I have a 36,000 btu gas fired hot water heater that has a 3" gravity flue piped to my chimney and also a 100,000 btu input 80% power vented heater with a 3" flue that bumps up to 5" before it enters my chimney. I'm a pipe fitter by trade so I deal with installing these all the time but never deal with the flue side. My question is when I bring the 5" through my chimney and tie in a 5" wye, which appliance should go on the bull of the T? I've been told both ways, just curious what some thoughts are. Thanks.


I'm not an expert but I've owned homes with the gas hw heater and gas T'd together before myself. I've always wondered how the waste heat from the hw was enough to get out the vent without condensing when the furnace was not on.

One consideration is that your next gas furnace will probably be a condensing one. How old is your furnace and hw heater now?




It's interesting that you mentioned that...because that was the very
thing I did not bring up before. The building inspector I talked to told
me that the water heater alone is /not/ sufficient without the furnace
also running.


The reason I did not mention that was because it did not seem right...
but then realized that in the summer, when the furnace is not
running...since it's warmer, there of course would not be a condensation
problem. In my situation it needs to get to -10F before there's a problem.

On Saturday, February 8, 2014 9:44:11 AM UTC-5, philo* wrote:
On 02/08/2014 08:19 AM, jamesgang wrote:

On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:

I'm installing a 35'x5" round aluminum chimney liner because my exterior chimney (terracotta inside block) is showing wet spots in the mortar joints. I have a 36,000 btu gas fired hot water heater that has a 3" gravity flue piped to my chimney and also a 100,000 btu input 80% power vented heater with a 3" flue that bumps up to 5" before it enters my chimney. I'm a pipe fitter by trade so I deal with installing these all the time but never deal with the flue side. My question is when I bring the 5" through my chimney and tie in a 5" wye, which appliance should go on the bull of the T? I've been told both ways, just curious what some thoughts are. Thanks.





I'm not an expert but I've owned homes with the gas hw heater and gas T'd together before myself. I've always wondered how the waste heat from the hw was enough to get out the vent without condensing when the furnace was not on.



One consideration is that your next gas furnace will probably be a condensing one. How old is your furnace and hw heater now?









It's interesting that you mentioned that...because that was the very

thing I did not bring up before. The building inspector I talked to told

me that the water heater alone is /not/ sufficient without the furnace

also running.





The reason I did not mention that was because it did not seem right...

but then realized that in the summer, when the furnace is not

running...since it's warmer, there of course would not be a condensation

problem. In my situation it needs to get to -10F before there's a problem..

That's the essence of the condensation issue. Condensation becomes
a problem when a chimney is sized for a furnace plus WH and then the
furnace is converted to direct vent. You then have a chimney that is
too large for just the water heater, making it very easy for condensation
to occur. With the large chimney and the furnace, when the weather was
cold enough for condensation to occur, the furnace was running enough
of the time to keep the chimney free of condensation. Also, with a
chimney that is too large, you won't get proper drafting. So, if you
go with a direct vent furnace and keep an existing WH,
you probably need a flue liner to reduce the
size. I guess at some point, if the run is long enough and the climate
cold enough, you're going to get condensation anyway, because the WH
doesn't generate enough heat. But with a liner, any condensation is
going to stay in the liner, not screw up the flue.

" wrote:
On Saturday, February 8, 2014 9:44:11 AM UTC-5, philo wrote:
On 02/08/2014 08:19 AM, jamesgang wrote:

On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:

I'm installing a 35'x5" round aluminum chimney liner because my
exterior chimney (terracotta inside block) is showing wet spots in the
mortar joints. I have a 36,000 btu gas fired hot water heater that has
a 3" gravity flue piped to my chimney and also a 100,000 btu input 80%
power vented heater with a 3" flue that bumps up to 5" before it
enters my chimney. I'm a pipe fitter by trade so I deal with
installing these all the time but never deal with the flue side. My
question is when I bring the 5" through my chimney and tie in a 5"
wye, which appliance should go on the bull of the T? I've been told
both ways, just curious what some thoughts are. Thanks.





I'm not an expert but I've owned homes with the gas hw heater and gas
T'd together before myself. I've always wondered how the waste heat
from the hw was enough to get out the vent without condensing when the
furnace was not on.



One consideration is that your next gas furnace will probably be a
condensing one. How old is your furnace and hw heater now?









It's interesting that you mentioned that...because that was the very

thing I did not bring up before. The building inspector I talked to told

me that the water heater alone is /not/ sufficient without the furnace

also running.





The reason I did not mention that was because it did not seem right...

but then realized that in the summer, when the furnace is not

running...since it's warmer, there of course would not be a condensation

problem. In my situation it needs to get to -10F before there's a problem.

That's the essence of the condensation issue. Condensation becomes
a problem when a chimney is sized for a furnace plus WH and then the
furnace is converted to direct vent. You then have a chimney that is
too large for just the water heater, making it very easy for condensation
to occur. With the large chimney and the furnace, when the weather was
cold enough for condensation to occur, the furnace was running enough
of the time to keep the chimney free of condensation. Also, with a
chimney that is too large, you won't get proper drafting. So, if you
go with a direct vent furnace and keep an existing WH,
you probably need a flue liner to reduce the
size. I guess at some point, if the run is long enough and the climate
cold enough, you're going to get condensation anyway, because the WH
doesn't generate enough heat. But with a liner, any condensation is
going to stay in the liner, not screw up the flue.

I don't think a normal furnace has enough exhaust heat to evaporate
condensation. I noticed a lo of water inside top of mine earlier in the
year. Even some moss. That's without liner.

On my living house, I got water heater up old chimney which is external.
HVAC installed it. It's probably ok except during a heavy storm, my
uncovered chimney leaked some water of of bottom clean out from old oil
burner furnace, which originally was coal.

Greg

On 02/08/2014 10:34 PM, gregz wrote:


snip
I don't think a normal furnace has enough exhaust heat to evaporate
condensation. I noticed a lo of water inside top of mine earlier in the
year. Even some moss. That's without liner.

On my living house, I got water heater up old chimney which is external.
HVAC installed it. It's probably ok except during a heavy storm, my
uncovered chimney leaked some water of of bottom clean out from old oil
burner furnace, which originally was coal.

Greg




My house originally was coal. When I bought it, it used an oil burner
which I replaced and went to gas. I installed it myself.

Eventually as I finally managed to start saving up some money I had
professionals put in a new one.

They made one small error. The exhaust pipe going into the chimney was
not cut and the lower portion jutted out and collected a small amount of
moisture when it rained. That was just enough to clog the air flow
sensor. Once I cut the pipe flush, I have had no more problems.

On Saturday, February 8, 2014 11:34:46 PM UTC-5, Gz wrote:
" wrote:

On Saturday, February 8, 2014 9:44:11 AM UTC-5, philo wrote:

On 02/08/2014 08:19 AM, jamesgang wrote:



On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:



I'm installing a 35'x5" round aluminum chimney liner because my

exterior chimney (terracotta inside block) is showing wet spots in the

mortar joints. I have a 36,000 btu gas fired hot water heater that has

a 3" gravity flue piped to my chimney and also a 100,000 btu input 80%

power vented heater with a 3" flue that bumps up to 5" before it

enters my chimney. I'm a pipe fitter by trade so I deal with

installing these all the time but never deal with the flue side. My

question is when I bring the 5" through my chimney and tie in a 5"

wye, which appliance should go on the bull of the T? I've been told

both ways, just curious what some thoughts are. Thanks.











I'm not an expert but I've owned homes with the gas hw heater and gas

T'd together before myself. I've always wondered how the waste heat

from the hw was enough to get out the vent without condensing when the

furnace was not on.







One consideration is that your next gas furnace will probably be a

condensing one. How old is your furnace and hw heater now?



















It's interesting that you mentioned that...because that was the very



thing I did not bring up before. The building inspector I talked to told



me that the water heater alone is /not/ sufficient without the furnace



also running.











The reason I did not mention that was because it did not seem right...



but then realized that in the summer, when the furnace is not



running...since it's warmer, there of course would not be a condensation



problem. In my situation it needs to get to -10F before there's a problem.



That's the essence of the condensation issue. Condensation becomes

a problem when a chimney is sized for a furnace plus WH and then the

furnace is converted to direct vent. You then have a chimney that is

too large for just the water heater, making it very easy for condensation

to occur. With the large chimney and the furnace, when the weather was

cold enough for condensation to occur, the furnace was running enough

of the time to keep the chimney free of condensation. Also, with a

chimney that is too large, you won't get proper drafting. So, if you

go with a direct vent furnace and keep an existing WH,

you probably need a flue liner to reduce the

size. I guess at some point, if the run is long enough and the climate

cold enough, you're going to get condensation anyway, because the WH

doesn't generate enough heat. But with a liner, any condensation is

going to stay in the liner, not screw up the flue.



I don't think a normal furnace has enough exhaust heat to evaporate

condensation.

For the most part the furnace doesn't have to evaporate the
condensation, the exhaust gases just never condense to begin with.
A conventional furnace is only 80% efficient. If you have a 100K BTU
furnace, you're putting 20K BTU up the chimney. If the chimney is
properly sized, it will keep it hot enough when it's cold out so that condensation is minimal.

If you take the chimney that was sized for a 100K BTU furnace and a
35K BTU water heater, ie 135K total and remove the furnace, then you
have a problem. The chimney is now oversized and the WH is typically
going to run a lot less
and for shorter periods than the furnace did. When it's 20F outside,
with the chimney not in a heated space, then you will get condensation.
And over time, with a gas furnace, it will deteriorate the mortar in
the flue joints because of the acidity. You might not see any evidence
of problems for a long time, but when you do, it will be too late.



I noticed a lo of water inside top of mine earlier in the

year. Even some moss. That's without liner.



Is the chimney properly sized?




On my living house, I got water heater up old chimney which is external.

HVAC installed it. It's probably ok except during a heavy storm, my

uncovered chimney leaked some water of of bottom clean out from old oil

burner furnace, which originally was coal.



Greg

" wrote:
On Saturday, February 8, 2014 11:34:46 PM UTC-5, Gz wrote:
" wrote:

On Saturday, February 8, 2014 9:44:11 AM UTC-5, philo wrote:

On 02/08/2014 08:19 AM, jamesgang wrote:



On Thursday, February 6, 2014 6:04:08 PM UTC-5, wrote:



I'm installing a 35'x5" round aluminum chimney liner because my

exterior chimney (terracotta inside block) is showing wet spots in the

mortar joints. I have a 36,000 btu gas fired hot water heater that has

a 3" gravity flue piped to my chimney and also a 100,000 btu input 80%

power vented heater with a 3" flue that bumps up to 5" before it

enters my chimney. I'm a pipe fitter by trade so I deal with

installing these all the time but never deal with the flue side. My

question is when I bring the 5" through my chimney and tie in a 5"

wye, which appliance should go on the bull of the T? I've been told

both ways, just curious what some thoughts are. Thanks.











I'm not an expert but I've owned homes with the gas hw heater and gas

T'd together before myself. I've always wondered how the waste heat

from the hw was enough to get out the vent without condensing when the

furnace was not on.







One consideration is that your next gas furnace will probably be a

condensing one. How old is your furnace and hw heater now?



















It's interesting that you mentioned that...because that was the very



thing I did not bring up before. The building inspector I talked to told



me that the water heater alone is /not/ sufficient without the furnace



also running.











The reason I did not mention that was because it did not seem right...



but then realized that in the summer, when the furnace is not



running...since it's warmer, there of course would not be a condensation



problem. In my situation it needs to get to -10F before there's a problem.



That's the essence of the condensation issue. Condensation becomes

a problem when a chimney is sized for a furnace plus WH and then the

furnace is converted to direct vent. You then have a chimney that is

too large for just the water heater, making it very easy for condensation

to occur. With the large chimney and the furnace, when the weather was

cold enough for condensation to occur, the furnace was running enough

of the time to keep the chimney free of condensation. Also, with a

chimney that is too large, you won't get proper drafting. So, if you

go with a direct vent furnace and keep an existing WH,

you probably need a flue liner to reduce the

size. I guess at some point, if the run is long enough and the climate

cold enough, you're going to get condensation anyway, because the WH

doesn't generate enough heat. But with a liner, any condensation is

going to stay in the liner, not screw up the flue.



I don't think a normal furnace has enough exhaust heat to evaporate

condensation.

For the most part the furnace doesn't have to evaporate the
condensation, the exhaust gases just never condense to begin with.
A conventional furnace is only 80% efficient. If you have a 100K BTU
furnace, you're putting 20K BTU up the chimney. If the chimney is
properly sized, it will keep it hot enough when it's cold out so that
condensation is minimal.

If you take the chimney that was sized for a 100K BTU furnace and a
35K BTU water heater, ie 135K total and remove the furnace, then you
have a problem. The chimney is now oversized and the WH is typically
going to run a lot less
and for shorter periods than the furnace did. When it's 20F outside,
with the chimney not in a heated space, then you will get condensation.
And over time, with a gas furnace, it will deteriorate the mortar in
the flue joints because of the acidity. You might not see any evidence
of problems for a long time, but when you do, it will be too late.



I noticed a lo of water inside top of mine earlier in the

year. Even some moss. That's without liner.



Is the chimney properly sized?



I think not. Like 10x10 at least. I noticed the moisture when outside temps
were 40-50 degrees. This is one shaft. Might have been 4 shaft with two
chimneys. 1900 house. I have not run the water heater yet. Its been off for
going on 3 years. There is also a trail of minerals on the bottom of the
flew to the furnace. I even think the minerals got on the exhaust fan
blades. Fun times.

The two chimney bottoms are also part of the support structure. All other
shafts are top sealed off.

Greg





On my living house, I got water heater up old chimney which is external.

HVAC installed it. It's probably ok except during a heavy storm, my

uncovered chimney leaked some water of of bottom clean out from old oil

burner furnace, which originally was coal.



Greg