Pressure Switch Rating Question - HVAC - DIY Chatroom Home Improvement Forum


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

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

Reply
 
Thread Tools Display Modes
Old 11-04-2010, 09:00 PM   #1
Newbie
 
Join Date: Nov 2010
Posts: 4
Rewards Points: 10
Default

Pressure Switch Rating Question


I have a Criterion II with a bad pressure switch and bought a replacement at the end of winter last year. I didn't get around to even opening the package til today (didn't need it).

Looks like they sent me the wrong one. I bought it on eBay, so I am not going to bother trying to return it. I will either get another one or use this one. So, here is my question:

The switch my furnace uses is a .45 and the one I bought is a .35. I installed the "wrong" one and it worked, but took it back out and put the original back in becuase I don't know if the "wrong" one will cause damage.

Should I use the .35 or am I crazy?

Advertisement

danbeall is offline   Reply With Quote
Old 11-04-2010, 09:07 PM   #2
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,122
Rewards Points: 882
Default

Pressure Switch Rating Question


You need the higher rated original one or it will be UNSAFE to use. The pressure switch measures/proves the proper amount of safe draft thru the furnace and if it is not enough shuts it down. A lower pressure switch will fool it into thinking it is safe to use when it is not.

Advertisement

__________________
"Cut it twice and it is still too short".
yuri is offline   Reply With Quote
The Following User Says Thank You to yuri For This Useful Post:
danbeall (11-04-2010)
Old 11-04-2010, 09:13 PM   #3
Newbie
 
Join Date: Nov 2010
Posts: 4
Rewards Points: 10
Default

Pressure Switch Rating Question


On second look, I had the numbers backwards.

The "wrong" one is .45 and the original is .35. I am going to assume it is still unsafe to use the .45.
danbeall is offline   Reply With Quote
Old 11-04-2010, 09:19 PM   #4
GC/Master Plumber/Mech
 
Join Date: Feb 2009
Location: Hays, KS
Posts: 1,472
Rewards Points: 504
Default

Pressure Switch Rating Question


Going a little larger will be ok
__________________
John Wayne once said "Life is tough and it is even tougher if you are stupid"

Tempstar and Trane Dealer
Plumber101 is offline   Reply With Quote
Old 11-04-2010, 09:24 PM   #5
Newbie
 
Join Date: Nov 2010
Posts: 4
Rewards Points: 10
Default

Pressure Switch Rating Question


Huh.

Maybe that is why they sent it... because it is an "acceptable" replacement. I will probably use it, at least temporarily.

Thanks!
danbeall is offline   Reply With Quote
Old 11-04-2010, 09:29 PM   #6
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,122
Rewards Points: 882
Default

Pressure Switch Rating Question


Usually the exhaust fan can produce up to 1" WC suction so .45" will be okay .
.35" is the minimum suction but they usually produce 2X that when working properly or they would be tripping all the time. I would order a .35" from a reputable dealer and not necessarily from the "great unknown" market which could be used or whatever parts.
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 11-04-2010 at 09:34 PM.
yuri is offline   Reply With Quote
Old 11-04-2010, 09:32 PM   #7
Newbie
 
Join Date: Nov 2010
Posts: 4
Rewards Points: 10
Default

Pressure Switch Rating Question


That makes perfect sense to me. Thanks for the explanation.

Looking forward to sleeping through the night without waking up, feeling cold, then going to the basement to tap the switch

Advertisement

danbeall is offline   Reply With Quote
Reply


Thread Tools
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
Pressure switch stuck open? 2 areas im looking @ 1001miles HVAC 42 12-03-2012 04:51 AM
Well Pump pressure switch help needed. slabm7 Electrical 20 11-03-2010 06:56 PM
fan/light switch buzzing mjlocat Electrical 4 05-23-2010 03:44 PM
New pressure switch and inducer and still incorrect drafting kevintabb HVAC 5 01-19-2010 01:59 PM
Another 3-way switch question. perpetual98 Electrical 10 07-21-2009 12:16 PM




Top of Page | View New Posts