heat pump contactor will not pull in. - http://www.hvacmechanic.com/ Forums
Original message
| olddog1017
 |  "heat pump contactor will not pull in."
, posted Fri 18 Feb 11:37  
i have a 7 yr. old goodman heat pump.contactor will not pull in to start compressor & fan when system is turned on.i can push contactor in manually & compressor/fan will kick on & run fine.system turns off properly when desired temp is reached & t-stat turns system off.contactor & run capacitor are only 3 mos. old.researching problem has lead me to probable low voltage problem causing coil not to be energized.i have a ohm meter & ck'd voltage going to contactor.it reads 240.here is where i'm stuck.i don't know where to ck for 24 volt reading to energize contactor coil.i am about ready to replace p.c. board only because it's the only part i have'nt replaced & don't know how to ck.i had service man ck & repair t-stat wiring 3 weeks ago to correct aux. heat inop. problem so i know wiring is correct. sorry this is so long,just trying to give all info available.any help greatly appreciated.
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Replies:
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| aircooled
| "Re(1):heat pump contactor will not pull in." , posted Sun 20 Feb 09:10
Might want to check high pressure switch,or maybe the defrost control board. If you call for heat does the yellow wire have voltage? Quick way to check is find the wire feeding the outdoor unit (y) and (c)common see if you have voltage to the unit....
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| | olddog1017
| "Re(2):heat pump contactor will not pull in." , posted Sun 20 Feb 12:49
thanks for your reply aircooled.i do not not know where pressure switches are to ck.as for voltage,when i call for heat i get reading of 5v that drops to 3.4v in several minutes.i am checking voltage by touching test leads to yellow wire on "y" terminal on p.c.board & blue wire on "c" terminal on p.c. board.both these wires go to contactor.i get same voltage reading when i test these wires where they connect to contactor.
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| olddog1017
| "Re(1):heat pump contactor will not pull in." , posted Sat 19 Feb 23:55
i finally got voltage ck'd at c & y terminals on p.c. board today.when heat is not on i get a 0 reading when touching test leads to c & y,when i raise t-stat temp enough to kick on system,blower turns on,compressor & fan do not come on because contactor does not pull in,i get a reading at c & y terminal on p.c. board & where those wires connect to contactor of 5 volts that drops to 3.4 volts after several minutes.system works fine when i manually push in contactor,i get a 0 reading at c & y like i should when aux. heat is on.can someone way smarter then me tell me what to do to repair this problem.thanks for all replys & help.
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| | Xenos
Webmaster 
| "Re(2):heat pump contactor will not pull in." , posted Sun 20 Feb 09:38
BTW, it extremely hard to follow these message when there not in order. Please reply to the proper message.
Is there a good refrigerant charge? Are the low and High pressure switches closed? These would be the next thing to verify.
Xenos.
The best way to escape a problem is to solve it.
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| | olddog1017
| "Re(3):heat pump contactor will not pull in." , posted Sun 20 Feb 13:12
thanks for your reply xenos.sorry about posting these messages out of order.i have never posted messages before.with your help maybe i can learn this & how to fix heat pump too.as for the refrigerant,service man that corrected wiring problem in t-stat to fix aux. heat inop. problem said refrigerant was fine.after he fixed wiring,system worked fine for two weeks.i did not notice compressor & fan were not kicking on until i called for cool air one warm day & system blew warm air.i ck'd & found that comp & fan not coming on.sorry this is so wordy,just trying to give you all info available.do not know where pressure switches are.can you tell me location & how to ck.thanks for your patience & help.
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| | Xenos
Webmaster
| "Re(4):heat pump contactor will not pull in." , posted Sun 20 Feb 15:32
Look for electric devices conected to copper pipes. these should be closed.
Xenos.
The best way to escape a problem is to solve it.
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| | olddog1017
| "Re(5):heat pump contactor will not pull in." , posted Sun 20 Feb 15:59
thanks for reply xenos.it is raining here at the moment so i can't ck outside unit.i do not recall seeing these on outside unit.would pressure switches be in air handler in attic? do i visually ck to see if they are closed or do if ck voltage.if i ck voltage what should it be.should ck be done when i am calling for heat? thanks for your help.
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| olddog1017
| "Re(1):heat pump contactor will not pull in." , posted Fri 18 Feb 23:51
thanks for reply xenos.notsure what you mean by safeties.will have to ck for voltage in morning.blue wire on c at p.c. board goes to contactor,yellow wire on y at p.c.board goes to contactor.these wires are in good shape & have good connections.next reply will be tomorrow after i ck voltage at c & y.thanks for walking me through this xenos.
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| olddog1017
| "Re(1):heat pump contactor will not pull in." , posted Fri 18 Feb 23:16
thanks for your reply xenos.first two terminals on p.c. board are c & y.are these the ones i should ck.do i touch one lead to c & one lead to y.if this is correct should i get a reading of 24v.if reading is 0 does it mean p.c. board is bad & i should replace it.sorry this is so juvenial(sic)but sometimes i need a picture drawn for me to understand.not sure what you mean about pressure switches.i do know that every thing works fine when i turn system on & manually push in contactor.should i ck for 24v at c & y with system running or off.thanks for helping me with this xenos.
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| | Xenos
Webmaster
| "Re(2):heat pump contactor will not pull in." , posted Fri 18 Feb 23:22
The question is where is the break in the power line. Odds are it's one of the safeties and not the board. If you have 24 vac on Y and C follow them on the diagram and see where the break is.
Xenos.
The best way to escape a problem is to solve it.
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| olddog1017
| "Re(1):heat pump contactor will not pull in." , posted Fri 18 Feb 15:19
thanks for your concern,i am very careful working around electicity.i still need to know where to ck for the 24 volts that is suppose to be energizing the contactor coil.again thanks for all help & suggestions.
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| | Xenos
Webmaster
| "Re(2):heat pump contactor will not pull in." , posted Fri 18 Feb 19:06
Start by checking for 24vac on Y and C. Are the pressure switches closed? that is where I would start.
Xenos.
The best way to escape a problem is to solve it.
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| tinner73
| "Re(1):heat pump contactor will not pull in." , posted Fri 18 Feb 14:38
i hope you're not pushing that 240v contactor in with your finger. call a contractor before you change more parts and waste more money.
union trained in Chicago
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