ReplyCondenser motor change. Absolutely, I'll bet the condenser air discharge was unusally hat also.
Professional Member*
did a start-up today on furn' chg. out i did a couple months ago...it was 78 out,71 in,i had 300 psi head on this unit....i thought it was kind of high..would a condenser motor that had been changed out have something to do with this..22 super heat and delta t of 20 though?
Professional Member
Condenser motor change. Absolutely, I'll bet the condenser air discharge was unusally hat also.
God Speed, Jim. We'll miss you - 2-26-23
Its possible, check if its the right rotation.
Is there any chance you put a kink in the line while changing the furnace.
What was the suction pressue.
Professional Member*
67-68psi..discharge temp was 122, liq. line temp of 115...
Professional Member*
You never opened up the system? if you did not the system probably has been running these pressures before you touched it. What was the suction? if it was normal, the condenser may need a good bath, or check temp. on each side of the liquid drier. Just some thoughts.
__________________________________________________ _______________________
Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
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condenser was not plugged or anything....
Professional Member
Guess its that time of year again to dust off the old
air conditioning brain cells.
http://www.hvac-talk.com/vbb/showthr...threadid=55974
Extend to others the grace that God has given you.
Professional Member*
no dryer,no kinks,and i recovered refrig. took out coil cleaned it and pulled vacum recharge new refrig....by the way this is cap-tube coil..
Professional Member*
O I hate it when that happensOriginally posted by mo-flo
by the way this is cap-tube coil..
Any cap tubes freezing up? what was the suction pressure?
and the furnace is geared for the right amount of cfm's for the evap. coil? was it very humid inside the house when you started the system? this can cause a higher than normal head until some of the humidity is removed.
__________________________________________________ _______________________
Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member*
you sure you didnt over charge the system
some of the old cap tube coils ran low back arround 55 to 60. if the blower is not putting out enough cfms it will be lower. very easy to over charge a cap tube since we are used to today coils with 70 to 90 lb back
Regular Guest
clean the od coil. picking up heat may not be getting rid of it.
Professional Member*
I have run across them that looked pretty from the outside then I got out the water hose and it looked like a mud slide on the slab.Originally posted by mo-flo
condenser was not plugged or anything....
__________________________________________________ _______________________
Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member*
This is true! Tin, we are telling our age.Originally posted by tinknocker service tech
some of the old cap tube coils ran low back arround 55 to 60.
__________________________________________________ _______________________
Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member*
I was going to add for mo-flo to check if the coil is a double row job. But then I read about the evap having a cap tube so that made me wonder if the condenser is just as ancient (thereby unlikely to have double coils).I have run across them that looked pretty from the outside then I got out the water hose and it looked like a mud slide on the slab.
Last summer I split apart many of the condenser coils at my building. The amount of dirt between the two coil sets was astounding. Just washing the coil from the front or back without splitting it wasn't doing anything for all the crap in the middle.
Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.
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i was told 32 years ago get out while you can stil do something else heheheh man i should have listenedOriginally posted by mrbillpro
This is true! Tin, we are telling our age.Originally posted by tinknocker service tech
some of the old cap tube coils ran low back arround 55 to 60.
Professional Member
Condenser motor change. Check the HP rating, speed, and rotation also the fan position in the orfice is very important.
High head pressure is caused by not rejecting enough (quantity) of heat.
LL 115d, 78d Ambient, 37d approach too much.
Kinks would cause low pressures both sides.
High head pressures:
Dirty condenser
Overcharge (look for high subcooling)
Non condensibles
Low condenser airflow
Condenser air recirculation
High evap air flow and/or humidity causes elevated head
but not high head normally
Other causes also but rare.
Professional Member*
I'm with everyone else, clean the condenser first. Even if it looks clean.
Can you open the plenum's door and watch the coil. I've ran into some that were not feeding every circuit. Someone overcharged them to get suction pressure up.
Also, is the CU newer. Maybe the old coil will not work with a higher seer unit.
God Speed, Jim. We'll miss you - 2-26-23
Or is the CU a larger tonage then the cap tube indoor.Originally posted by lynn rodenmayer
Also, is the CU newer. Maybe the old coil will not work with a higher seer unit.
Professional Member*
the cu is about 15 years old....gonna give him a call and see if he wants me to clean it,but this will be added charge cause that don't come with a furn' changeout...i cleaned the indoor coil for him though,....also he said that the motor was bigger i'm assuming more hp....thanx for replies guys.
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also it is in modular home and the system is mismatched with evaporator made by someone else,...i would have to get file out....will take advice about watching tubes thanx.
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