HVAC /heat pump not cycling

[Harold Tuttle]

well gee,

after a fun weekend camping at a local state park with the family,
we returned to a warm house

i turned on the AC and the thermostat switched on the fans and main blower but 15 minutes later

no cool air


the condensor unit is getting power

and i noticed that if i press in this contact:


i get the external units fan to switch on

do i have a bad starter relay?

it looks like there is a coil on the back side that must pull the contact shut...
the company that installed the unit can get someone out here tomorrow
but that will eat into my ammo fund



befuddled Tuttle

[280plus]

Unfortunately Harold it could be a number of different things. When you hold in the contactor for a couple minutes does the compressor run and the big line with the insulation get hot or cold? If so it may be in the controls. If not you may have the compressor not running for one reason or another. If I was there I'd have you an answer in just a couple minutes but I can't do it long distance. FWIW I don't SEE a starter relay or start capacitor in your control box. That shiny cylinder thing is a RUN capacitor for both the fan and the compressor. The fancy electronic board looks like a time delay / fan speed / defrost logic module. Sorry I can't help you much further.

[280plus]

Oh, that thing your pressing in on is refered to as a "contactor" is that what you mean by "starter relay" ? If everything runs when you press it in then

A. Yes, it could be the contactor

or

B. The contactor coil is not receiving a signal to pull in.

If you have a meter you could check for 24V across the contactor coil terminals while the thermostat is calling for cool. If you get a signal then the contactor is bad. If there's no 24 V then you have something else going on. Are there any red buttons to push? If pushing a red button gets it to work then the finned coil is dirty and needs a good but gentle hosing down.

Ah well, again, sorry I can't help you directly.

[Harold Tuttle]

while i wish the unit had a red button

no joy

i am about to head for home and attempt to multimeter out a solution

when i tested it this morning holding in the contactor did not seem to make the compressor run
but i did not engage it for longer than a minute...

[Harold Tuttle]

ok
i held the contactor in for over a minute
the compressor kicked on and started pumping

bad news
my install company can't get here till monday

time to go freelance

wheres my 27b/6 form?

[Leatherneck]

Harold, remember the mantra of the docs: "First, do no harm." Overriding automatic controls longer than a second or two to diagnose a system can burn out components that will run up the bill. Try a different company maybe?

TC

[Harold Tuttle]

well the way this switch works
when it receives 24 volts it clamps the contact shut and starts the cycle
when the thermostat sees the proper temp it drops the voltage and the contacts open

i'm gonna jumper the contacts and bring the system online while i figure out
why the 24 volts is not being sent

[Harold Tuttle]

and thus the cool air did again floweth forth from the ductwork

[280plus]

In the T'stat jump R to Y. I believe you'll also need to jump O to R to cycle the reversing valve for cool mode. That should call in the contactor in the outside unit. If it doesn't look for a signal across the contactor coil terminals. If you got 24V and the contactor is not pulling in it is bad, If not, something else is wrong.

I like how you called it a switch. Thats the hardest concept for people to get. A contactor or relay is nothing more than a remotely operated switch. Harold gets an "A"!  

[280plus]

What'd ya do?

[280plus]

FWIW the difference between a relay and a contactor is that a contactor is designed to take much heavier amperage than a relay.

[Harold Tuttle]

i jumpered the red wire to the white one and bypassed the contactor

[Harold Tuttle]

theres no 24 volts across the coil or as far as i can tell on the input side from the furnace

me thinks something in the basement is not sending, or getting 24 volts to send

[280plus]

THAT'S CHEATING!!  

It looks to me like the contactor is pulled in. Are you only able to push it in a little way when you do? See the black and yellow wiores on either side of the contactor? Those are the coil wires. With the T'stat calling take a reading acroos those and if you have 24V there the contactor is bad. I'm beginning to think the contacts are fried and partially welded together from what I see and what you are telling me. Still just a guess though.

You know you'll have to kill the main switch to the outdoor unit to shut off the cool the way you have it wired?

[cfabe]

I'm with 280, that contactor looks closed(mechanicall), but if it's open (electrically) contacts could be burnt up. If that's your problem, it's an easy, cheap fix.

[280plus]

OK, I'm one step behind you...  :p

You ARE getting indoor fan right? Did you try jumping R to Y at the t'stat?

Do you have a condensate pump in the basement? Sometimes they'll be wired to cut the signal to the outdoor unit if they start to overflow. Just a shot in the dark. Maybe it came unplugged or something?

[280plus]

Oh, don't be getting caught up in the time delays. Them time delays are a PITA! The transistor radio in the control panel probably has a time delay and if the t'stat is digital it probably does too. Turn the cool on, turn it down, wait ten minutes and THEN read across your contactor coil. That contactor does look pulled in from here.

[Harold Tuttle]

yep, i am the master switch now

i will let it run till the house cools down

the connector pushes in ~ a half an inch

heres the side view:



no volts are showing across the coil

[280plus]

OK, if it pushes in then it's not in already. It just looks like it is. Here's another test. Looking at the defrost logic, remove the plug on the left with the blue, red , yellow etc wires by GENTLY wiggling it back and forth. With the T'stat calling for cool read across or from Y to C ON THE NOW LOOSE PLUG and see if you have 24V there. If it's there the problem is in the logic if it is NOT there you're not getting a signal from the basement.

The logic board is marked so you can tell which terminal on the plug is which.

Also, you might try turning power to the indoor unit off for 5 minutes. It MIGHT be in some kind of lockout and that's how you would reset it.

[280plus]

Make sure there are no clips holding that plug in. Don't break it trying to get it apart. Be gentle...  

(same for putting it back on, don't press too hard, the board could break.)

[Harold Tuttle]

i snooped the wiring block for voltages and can't find any



these lead up to the defrost board

i also cleaned and inspected the condensing pump
it does have an overflow shutdown send wire but that seems to be working properly

i also opened the amana furnace and looked at the wiring & boards

when running, a red LED labeled manual slow speed fan is flashing

everything has been rebooted and the thermostat has been reset via the majic button

nada

i'm back to bypassing the connector

its dark out and i really dislike 240 AC in the dark



at least the humidity is dropping indoors

[Ron]

Post the model and serial number, maybe we can find a schematic on the Internet.

Actually your camera is pretty good. Take a pic of the schematic and we can talk you through troubleshooting it like a pro would.

[K Frame]

"its dark out and i really dislike 240 AC in the dark"

Don't make a wrong move or it will get bright REALLY fast....

[Ron]

I am a commercial HVAC guy so I don't know particulars about residential equipment. Give me an electrical schematic and I can offer suggestions of what to look at in a systematic way.

when running, a red LED labeled manual slow speed fan is flashing

Is the indoor fan coming on automatically or do you have it set on "fan on"?

[Harold Tuttle]

http://premium1.uploadit.org/docZox//schematic.jpg