HVAC question - Page 5

Posted by jamesgangnc on October 19, 2009, 1:39 pm

wrote:

> On Mon, 19 Oct 2009 05:47:04 -0700, trader4 wrote:

> >> >Hello,
> >> > =A0 =A0 =A0 =A0I have a 2600 sq ft 4 level split home in Canada. It =

was built in

> >> >1985. This past spring we replaced our very non-effecient furnace wit=

h a

> >> >Tempstar 95% effecient gas furnace. It really is wonderful as the old
> >> >furnace would cause the house to feel sort of drafty and basement was=

always

> >> >cold etc... Now I have this furnace that I love to bits BUT now since=

it has

> >> >gotten colder outside these past two weeks, we have kept the doors an=

> >> >windows closed and now have a high humidity problem inside the home I=

> >> >fogged up windows (triple pane)...air basically feels clammy...bought=

> >> >humidistat and the house is sitting at around 50% humidity....
> >> What did you change in addition to the furnace? =A0Windows? =A0insulat=

ion?

> >> Did the furnace come with a humidifier?
> >> The last would be my guess-- and it should have both an adjustment and
> >> an outside sensor.
> >> What does the installer say?
> >> Jim

> > It's possible the new furnace has a seperate intake where it pulls
> > outside air in for combustion.

> Hmm. Ours has an intake and outlet to the outside world - but it also has
> a small shoebox-sized pump beside it, which collects moisture and pumps
> it into the waste water system for the house. I'm not sure if that pump
> is for extracting moisture that's in the air, or from the gas supply -
> but given the way it's floor mounted beside the furnace it looks like
> optional extra equipment, as otherwise surely it'd be built into the
> furnace...
> If it *is* optional on furnaces and the OP doesn't have it, maybe they
> need it, whatever its exact function is...
> (just idle speculation, not based on any knowledge of how furnaces work! =

:-)

> cheers
> Jules- Hide quoted text -
> - Show quoted text -

That pump is to pump out the water byproduct of the gas burning. On
older lower effeciency furnaces the water would go out as vapor. On
newer furnaces the exhaust temp is too low so the water condenses.
It's optional because some people have a drain nearby in the floor tha
the pipe can be routed to. Yours maybe has to pump up to a sink drain
or something like that?

Posted by Jules on October 19, 2009, 2:52 pm

On Mon, 19 Oct 2009 10:39:29 -0700, jamesgangnc wrote:

> That pump is to pump out the water byproduct of the gas burning. On
> older lower effeciency furnaces the water would go out as vapor. On
> newer furnaces the exhaust temp is too low so the water condenses.
> It's optional because some people have a drain nearby in the floor tha
> the pipe can be routed to. Yours maybe has to pump up to a sink drain
> or something like that?

Yeah, that's it. We've got no drain in the basement floor, and the main
pipe to the septic runs at about chest height along the basement wall. The
pump raises it about 8' though, where it taps into one of the drain lines
running from a sink.

Sounds like it's irrelevant to the OP's problem, then...

cheers

Jules

Posted by Stormin Mormon on October 19, 2009, 5:55 pm

It's called a "condensate pump". One of the reasons 90
percenters are so efficient, they condense the steam out of
the exhaust gas, which puts more heat into the house.

In the summer, the AC drains humidity out of the air, which
also needs to be pumped out.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

in message

Hmm. Ours has an intake and outlet to the outside world -
but it also has
a small shoebox-sized pump beside it, which collects
moisture and pumps
it into the waste water system for the house. I'm not sure
if that pump
is for extracting moisture that's in the air, or from the
gas supply -
but given the way it's floor mounted beside the furnace it
looks like
optional extra equipment, as otherwise surely it'd be built
into the
furnace...

If it *is* optional on furnaces and the OP doesn't have it,
maybe they
need it, whatever its exact function is...

(just idle speculation, not based on any knowledge of how
furnaces work! :-)

cheers

Jules

Posted by TimR on October 20, 2009, 9:37 am

..air basically feels clammy...bought a

> humidistat and the house is sitting at around 50% humidity.... we use

50% doesn't feel clammy to me, but maybe it would to you.
Condensation on a triple pane window sounds unlikely at 50% too.

But "sitting at" makes me wonder if the humidistat is working.

Your furnace should be cycling. This early in the season it should be
off longer than it is on.

Can you watch your humidistat and see what happens when the furnace
comes on? Does the humidity raise or lower as the furnace runs? That
should tell you something about what is going on.

Posted by Tony on October 20, 2009, 12:26 pm

Jim wrote:

> Hello,
>
> I have a 2600 sq ft 4 level split home in Canada. It was built in
> 1985. This past spring we replaced our very non-effecient furnace with a
> Tempstar 95% effecient gas furnace. It really is wonderful as the old
> furnace would cause the house to feel sort of drafty and basement was always
> cold etc... Now I have this furnace that I love to bits BUT now since it has
> gotten colder outside these past two weeks, we have kept the doors and
> windows closed and now have a high humidity problem inside the home IE:
> fogged up windows (triple pane)...air basically feels clammy...bought a
> humidistat and the house is sitting at around 50% humidity.... we use
> bathroom fans in the shower, and have a fan over the stove when cooking that
> we use all the time...we keep lids on pots on the stove etc...We have no
> children and only the two of us in this home so no long lingering showers by
> kids or anyone else....
> I don't want to have to buy a dehumidifier over this new furnace..
> sort of defeats the idea of trying to be energy effecient... Thinking of
> trying to duct in an outside air source to feed the furnace?
> Thoughts? Thanks... Jim

In addition to all the other good advice and questions, do you have a
gas oven/range? Been cooking/baking a lot? Normally no one pays
attention to the warning that the exhaust fan should be on when cooking.
Besides using up oxygen, it puts LOTS of moisture in the air.

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