HVAC-Talk: Heating, Air & Refrigeration Discussion banner
Cancel
Create thread New Forums

limit switches

Jump to Latest
41 - 56 of 56 Posts
Discussion starter · #42 ·
pecmsg said:
After 3 + weeks of tripping maybe it's time to get someone out and solve the problem!
Click to expand...
Thanks for taking the time to reply but please READ!!!!

I replaced the capacitor and it has not tripped in 3+ weeks.

I was responding to the other person's questions about how I took the measurements.
 
#44 ·
7474 said:
Thanks for taking the time to reply but please READ!!!!

I replaced the capacitor and it has not tripped in 3+ weeks.

I was responding to the other person's questions about how I took the measurements.
Click to expand...
With 70+ D T it should trip or be right on the edge.

Yes you need someone to look at it. The cap was a bandaid.
 
Discussion starter · #45 ·
Where is the best place to take the supply temp? On the vertical or horizontal plenum? I am getting 2 different measurements.

I changed the blower speed to medium (increased from medium-low). Temperature at the plenum 18" above the coil case is 124*. Temperature right after where the vertical plenum turns horizontal temperature is 132*. Return air temp is 72*.

This gives me a range of 52-60* temp rise. Lennox plate states 40-70* range.

Additionally, TESP was .32 without filter and .42 with filter after I increased the blower speed.

Thanks again for the continued assistance.
 
#46 ·
I would go with the higher number. Best practice is to take readings at several places after the coil but before first takeoff.

TESP is taken from return side directly before unit in return plenum. Other side is taken directly after the blower but before evaporator coil. Same as temperature, best practice is to take several readings. Since you run your system with a filter you should test with a clean filter in place.

Even if your data plate says up to 70 if you are anywhere close to that you will end up with a shortened life for the furnace and components.

Also, you were rude Pecmsg. He could have just misread your text.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 
#47 ·
Also, when your testing your supply side static and you take the blower door off and your static goes up a bunch your return is way to restricted and is giving an artificially low static number. Just an FYI.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 
Discussion starter · #48 ·
Snaple4 said:
I would go with the higher number. Best practice is to take readings at several places after the coil but before first takeoff.

TESP is taken from return side directly before unit in return plenum. Other side is taken directly after the blower but before evaporator coil. Same as temperature, best practice is to take several readings. Since you run your system with a filter you should test with a clean filter in place.

Even if your data plate says up to 70 if you are anywhere close to that you will end up with a shortened life for the furnace and components.

Also, you were rude Pecmsg. He could have just misread your text.

Sent from my SAMSUNG-SM-G891A using Tapatalk
Click to expand...
Thanks for the reply.

I took the return static pressure by drilling a hole in the removable access panel of the blower compartment. I also took it several places along the return plenum, before the filter box, and directly after the filter box before the actual unit.

The supply static pressure I took by drilling a hole in the removable cover of the evaporator case and through the delta panel of the coil.

So, with a temp range of 40-70*, you would like to see the number as close to 40 as possible?
 
Discussion starter · #49 ·
Snaple4 said:
Also, when your testing your supply side static and you take the blower door off and your static goes up a bunch your return is way to restricted and is giving an artificially low static number. Just an FYI.

Sent from my SAMSUNG-SM-G891A using Tapatalk
Click to expand...
Sorry, I don't understand this statement's application to my situation? I have not tested my static supply with the blower door off. I have only tested the static pressure both with and without the filter. The manual from Lennox states static should be tested without the filter. However, as you stated the unit is run with a filter so I was curious as to the change it made.
 
#50 ·
Most situations I like it around 40 but some situations dictate other temperatures. I think you took the supply static after the coil. This will give you a number much lower than actual.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 
Discussion starter · #51 ·
Snaple4 said:
Most situations I like it around 40 but some situations dictate other temperatures. I think you took the supply static after the coil. This will give you a number much lower than actual.

Sent from my SAMSUNG-SM-G891A using Tapatalk
Click to expand...
I took the measurement with my probe directly between the A formed by the 2 coil panels.

I read the 2 coil panels form an "A" with a triangular sheet of metal called the delta plate between the 2 coils on each side. This is where I drilled a hole that is accessible with my straight probe through the panel/cover and the coil delta plate so that the probe is inside of the coil "A" structure.
 
#52 ·
A s long as your temp probe was not in line of sight of the heat exchanger you should be good, try going up to the next speed tap.
 
Save
Like Like
Discussion starter · #53 ·
buford said:
A s long as your temp probe was not in line of sight of the heat exchanger you should be good, try going up to the next speed tap.
Click to expand...
Thanks for the reply.

Interestingly, the temperature site 18" above the evap coil and in the line of sight of the HX was 8* cooler than the measurement I took on the horizontal plenum just after it changed from vertical. I would have thought the temperature would have been higher in the vertical plenum when in sight of the HX. This ~8* temp difference was consistent with both the medium-low setting and the medium setting.

Regarding the speed taps. I changed from medium-low (70* DT) to medium (60* DT). Are you suggesting to increase speed again to the medium-high setting? Would you like to see the temp rise as close to the low end of the 40-70* unit range as possible?
 
41 - 56 of 56 Posts
You have insufficient privileges to reply here.
About this Discussion
55 Replies
14 Participants
Last post:
buford
HVAC-Talk: Heating, Air & Refrigeration Discussion
posts
5M
members
275K
Since
2000
The #1 HVACR Community
Full Forum Listing
Explore Our Forums
AOP Residential HVAC/Refrigeration(Beenthere Zone) General Discussion Tech to Tech Chat - Residential Controls Refrigeration & Ice Making