Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 04-10-2013, 02:56 PM   #46
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Share |
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
If your referring to secondary heat exchangers. Boilers don't use a secondary heat exchanger. But all cat III and IV have heat exchangers. other wie they would be direct fired, and not be vented.

All cat III and IV appliances are positive pressure vent systems. So they are power/direct vent systems.
Ok, what about direct vent fire places. Mine has a stainless steel flex line running up the chimney for intake and exhaust. Those don't have heat exchangers do they? Positive pressure just means they are fan assisted venting, right?

mmiller is offline   Reply With Quote
Old 04-10-2013, 03:25 PM   #47
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


The fireplace would be a Cat I. Is it a fireplace, or fireplace insert.


Quote:
Positive pressure just means they are fan assisted venting, right?
Fan/blower assisted. The fan is also responsible for creating the draft in the heat exchanger. It may be a negative or positive pressure heat exchanger.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 04:28 PM   #48
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
The fireplace would be a Cat I. Is it a fireplace, or fireplace insert.




Fan/blower assisted. The fan is also responsible for creating the draft in the heat exchanger. It may be a negative or positive pressure heat exchanger.
Its an insert. Its direct vent so how can it be Cat I?
mmiller is offline   Reply With Quote
Old 04-10-2013, 04:39 PM   #49
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
The fireplace would be a Cat I. Is it a fireplace, or fireplace insert.




Fan/blower assisted. The fan is also responsible for creating the draft in the heat exchanger. It may be a negative or positive pressure heat exchanger.
Here is another thing I get confused with. My furnace has an induced draft blower. Now that forces the byproducts of combustion out through the exhaust, right? What I don't understand is what is the difference between that and a forced draft blower?
mmiller is offline   Reply With Quote
Old 04-10-2013, 04:58 PM   #50
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


Quote:
Originally Posted by mmiller View Post
Its an insert. Its direct vent so how can it be Cat I?
Its vented in a chimney. The chimney liner is the chimney. It doesn't vent through a sidewall. It needs a natural draft chimney.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 05:00 PM   #51
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


Quote:
Originally Posted by mmiller View Post
Here is another thing I get confused with. My furnace has an induced draft blower. Now that forces the byproducts of combustion out through the exhaust, right? What I don't understand is what is the difference between that and a forced draft blower?
Your furnace, if an 80% unit. Has a draft inducer. It induces a draft in the heat exchanger. Its not actually a blower. As it requires a negative draft in the flue pipe.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 05:36 PM   #52
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
Its vented in a chimney. The chimney liner is the chimney. It doesn't vent through a sidewall. It needs a natural draft chimney.
Im confused. The liner that is being used is a double stainless steel flex line. With direct venting I thought that is cat IV and positive pressure in the vent. Is this not the case with fireplaces?
mmiller is offline   Reply With Quote
Old 04-10-2013, 05:38 PM   #53
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
Your furnace, if an 80% unit. Has a draft inducer. It induces a draft in the heat exchanger. Its not actually a blower. As it requires a negative draft in the flue pipe.
Ok, and what forces the exhaust into the vent pipe? Mine is a 93% unit. 2 pvc pipes for intake and exhaust. These are horizontal so it has to be positive pressure in the draft, right?
mmiller is offline   Reply With Quote
Old 04-10-2013, 05:50 PM   #54
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


Quote:
Originally Posted by mmiller View Post
Im confused. The liner that is being used is a double stainless steel flex line. With direct venting I thought that is cat IV and positive pressure in the vent. Is this not the case with fireplaces?
Its just a liner. The fireplace is till a negative pressure draft appliance.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 05:52 PM   #55
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


Quote:
Originally Posted by mmiller View Post
Ok, and what forces the exhaust into the vent pipe? Mine is a 93% unit. 2 pvc pipes for intake and exhaust. These are horizontal so it has to be positive pressure in the draft, right?
Your furnace is a condensing furnace. it is a positive pressure vent furnace. the inducer is a blower. It creates a draft in the heat exchanger, and also forces the exhaust fumes out the flue pipe.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 06:55 PM   #56
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
Your furnace is a condensing furnace. it is a positive pressure vent furnace. the inducer is a blower. It creates a draft in the heat exchanger, and also forces the exhaust fumes out the flue pipe.
I know you need air and fuel to create proper combustion and I thought that was done at the burners? Why does the heat exchanger need a draft? The pipe leading into my draft inducer is hot so if its creating draft from outside air how is it hot?
mmiller is offline   Reply With Quote
Old 04-10-2013, 07:01 PM   #57
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


The exhaust pipe of your 93% furnace shouldn't be real hot. Less then 140F. Thee is no negative dratf in it. Its under a positive pressure. What little draft would be created in it by the flue gasses being at 140 wouldn't be near enough draft.

The heat exchanger needs a draft through it to keep the gasses moving through it, and not rolling out toward the burners.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 07:56 PM   #58
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
The exhaust pipe of your 93% furnace shouldn't be real hot. Less then 140F. Thee is no negative dratf in it. Its under a positive pressure. What little draft would be created in it by the flue gasses being at 140 wouldn't be near enough draft.

The heat exchanger needs a draft through it to keep the gasses moving through it, and not rolling out toward the burners.
The draft inducer that sucks in combustion air is also the same blower that forces exhaust out of the second pvc pipe? I also noticed on my indoor coil there is the obvious incoming liquid line and outgoing suction line. I noticed a third port for another line. Do you think that is for a heat pump?
mmiller is offline   Reply With Quote
Old 04-10-2013, 08:01 PM   #59
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,542
Default

Humidity question


Quote:
Originally Posted by mmiller View Post
The draft inducer that sucks in combustion air is also the same blower that forces exhaust out of the second pvc pipe?

Yes, it does both functions.

I also noticed on my indoor coil there is the obvious incoming liquid line and outgoing suction line. I noticed a third port for another line. Do you think that is for a heat pump?
Probably not. Post a pic of it.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is offline   Reply With Quote
Old 04-10-2013, 08:22 PM   #60
Member
 
Join Date: Apr 2013
Location: Michigan
Posts: 92
Default

Humidity question


Quote:
Originally Posted by beenthere View Post
Probably not. Post a pic of it.
how do you post pictures on here?

mmiller is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
window condensation kmpittman Windows and Doors 4 11-29-2011 09:10 AM
sweating double pane windows etch Windows and Doors 6 10-31-2011 09:30 PM
Honeywell IAQ thermostat and humidity control GhostBuster HVAC 14 12-19-2008 12:28 AM
Need to reduce humidity in house creamaster HVAC 4 11-19-2008 04:03 AM
Basement Renovation Question KUIPORNG Remodeling 234 08-26-2008 08:19 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.