# Is the blue thing a capacitor?



## erics37 (May 7, 2009)

A friend is having trouble with their HVAC unit - I'm distance troubleshooting. WTF is that blue thing? Is it the run cap? If so I haven't seen one like that before.


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## Introyble (Jul 10, 2010)

I'd say yes


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## jefft110 (Jul 7, 2010)

Strange looking hard start capacitor?


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## Introyble (Jul 10, 2010)

jefft110 said:


> Strange looking hard start capacitor?


No, sometimes they put dual capacitors in HVAC

Just thought of this, we know for sure where one capacitor is. If it is a dual it will be labeled with both of the farads. If the silver capacitor is only labeled with one uF rating then the Blue is for sure the Run


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## erics37 (May 7, 2009)

Introyble said:


> No, sometimes they put dual capacitors in HVAC
> 
> Just thought of this, we know for sure where one capacitor is. If it is a dual it will be labeled with both of the farads. If the silver capacitor is only labeled with one uF rating then the Blue is for sure the Run


Well I can't read the label and she is terrified of touching anything in there but I see that the silver cap has 4 terminal posts. Maybe it's 3.


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## Introyble (Jul 10, 2010)

Looks like it is marked with two uF ratings. Also looks like they passed in series from it though. Is there a uF on the Blue capacitor?


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## stuiec (Sep 25, 2010)

looks the silver says 5µF and 33µF....


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## erics37 (May 7, 2009)

Introyble said:


> Looks like it is marked with two uF ratings. Also looks like they passed in series from it though. Is there a uF on the Blue capacitor?


Trying to glean that info now :laughing:


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## Introyble (Jul 10, 2010)

erics37 said:


> Well I can't read the label and she is terrified of touching anything in there but I see that the silver cap has 4 terminal posts. Maybe it's 3.


Tell her to take a screw driver and short across the terminals before she touches them. This will discharge the stored energy. 

I can explode the image and see what looks like 2 ratings on the silver so it probably was dual. May of failed previously and some azz maybe passed through it


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## Introyble (Jul 10, 2010)

L2 is always on the run side in my mind I can follow the series to l2 from the picture. LOL ok sorry I'll stop. Do tell when you figure it out.


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## mgraw (Jan 14, 2011)

stec said:


> looks the silver says 5µF and 33µF....


The silver is a dual run capacitor. The 5uF is the condenser fan motor, the 33uF is the compressor. The blue is a start capacitor/relay.


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## JRaef (Mar 23, 2009)

I'm curiuos as to why it would have that quick snap-in holder if it is a run cap? That makes me wonder if it's an old school surge arrester of some sort and they (the company HVAC service techs) expect to have to change it often, so they made it easy, no tools required.


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## Introyble (Jul 10, 2010)

mgraw said:


> The silver is a dual run capacitor. The 5uF is the condenser fan motor, the 33uF is the compressor. The blue is a start capacitor/relay.


Where is the potential logic in that "relay"


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## erics37 (May 7, 2009)

Introyble said:


> Where is the potential logic in that "relay"


Yeah I can't imagine a 2 wire device being a relay for anything


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## erics37 (May 7, 2009)

Introyble said:


> L2 is always on the run side in my mind I can follow the series to l2 from the picture. LOL ok sorry I'll stop. Do tell when you figure it out.


Trying to get more info. Here's a blow-up of the blue thing. She's reluctant to take a new picture of the blue thing, partly because she already closed the unit back up and partly because I told her I would accept boob pictures as payment.


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## stuiec (Sep 25, 2010)

What is a PTC?

View attachment 24232


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## jefft110 (Jul 7, 2010)

Looks like one of these....http://www.midwesthvacparts.com/Products/2125-start-assist-amanagoodman-b1141670.aspx


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## bkmichael65 (Mar 25, 2013)

The silver one is a dual run cap for fan and compressor. The blue is definitely not a start cap since there is no potential relay in series with it. Most likely, one side of the dual cap failed and they replaced it with the blue one.


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## erics37 (May 7, 2009)

PTC relay! That's it! That must be what the blue thing is, that would make total sense.


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## stuiec (Sep 25, 2010)

oops. PTC = Start Thermistor.


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## mgraw (Jan 14, 2011)

erics37 said:


> Yeah I can't imagine a 2 wire device being a relay for anything


 The were used as a cheap replacement for hard start kits on units.


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## Introyble (Jul 10, 2010)

Actually its on the L1 

Here you go:

http://www.datasheetcatalog.com/datasheets_pdf/3/0/5/C/305C19.shtml


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## erics37 (May 7, 2009)

stuiec said:


> oops. PTC = Start Thermistor.


For the compressor


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## LARMGUY (Aug 22, 2010)

This says it's an axial start cap.

http://www.hvacpartsoutlet.com/Start-Assist-Capacitor-Goodman-B1141670.aspx


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## bkmichael65 (Mar 25, 2013)

Ok, that makes sense. I've never messed with one with a start thermistor


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## stuiec (Sep 25, 2010)

From Introyble's datasheet...

*"Positive Temperature Coefficient Resistors* ​​​​have been
used for many years in millions of HVAC applications to
provide starting torque assistance to Permanent Split​
Capacitor (PSC) single phase compressor motors"


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## mgraw (Jan 14, 2011)

mgraw said:


> The silver is a dual run capacitor. The 5uF is the condenser fan motor, the 33uF is the compressor. The blue is a start capacitor/relay.


 My bad should have said it replaces start capacitor/relay.


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## Introyble (Jul 10, 2010)

Ingenious device, I like it. RTD, Resistor and Capacitance. All packaged into one technology.


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## micromind (Aug 11, 2007)

Here's how a PTC start switch works; 

When power is applied, both the start and run windings are energized. The run winding stays energized until power is removed. The start winding is in series with the PTC. 

As current flows through the PTC, it heats up, as it is a semiconductor. The resistance of a PTC increases with rising temperature, therefore current to the start winding will decrease. 

A small amount of current is always present in the start windings, however it is of insufficient magnitude to interfere with normal operation. 

When power is removed, the PTC will cool off, and its resistance will decrease. 

It's important to note that enough time must be allowed from power off to the next start to allow the PTC to cool enough to engage the start winding. 

Almost every household refrigerator uses PTCs instead of potential relays these days, as do the majority of small A/C units. 

P.S. You've gotten some good advice here, Eric. It would seem reasonable that the 'payment' for this project should be shared via PM with each member who has responded.......

Lol.


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## guest (Feb 21, 2009)

Look closely at the silver capacitor....the top is domed (bulging) up. That means it has failed internally. Replace it and you'll be good to go. :thumbsup:

That will be two boobie pics please. :laughing:


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## ampman (Apr 2, 2009)

replace the romex too


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## erics37 (May 7, 2009)

micromind said:


> Here's how a PTC start switch works;
> 
> When power is applied, both the start and run windings are energized. The run winding stays energized until power is removed. The start winding is in series with the PTC.
> 
> ...





mxslick said:


> Look closely at the silver capacitor....the top is domed (bulging) up. That means it has failed internally. Replace it and you'll be good to go. :thumbsup:
> 
> That will be two boobie pics please. :laughing:


My final advice to her was to replace that dual capacitor, and pointed her off to Grainger's site to find the replacement.

I'll let y'all know if the boobie pic thing works out :thumbup:


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## Big John (May 23, 2010)

Don't mind me. Just responding for, uh, reasons.


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## frenchelectrican (Mar 15, 2007)

I was going to comment on the silver capaitour can which it was allready budged from the top., Oh well someone beat me on that. :whistling2:

The bleu can that something I learn with that.

At first I thought it was somekind of reactor for single phase motour but now I know what to look for. 

Eric., Tell her when she replace the combo capaitor make sure the conductors is in correct sequice otherwise it will not work ( either it will not run or pop the cap )

Merci,
Marc


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## John Valdes (May 17, 2007)

Is that a York condensing unit? Looks just like mine from the picture.
18 years old and I did not say anything!


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## BBQ (Nov 16, 2010)

John Valdes said:


> Looks just like mine from the picture.
> 18 years old and I did not say anything!




You are screwed, it will let the smoke out tomorrow because of the post. :laughing:


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## John Valdes (May 17, 2007)

BBQ said:


> You are screwed, it will let the smoke out tomorrow because of the post. :laughing:


Now you understand why I said nothing. :laughing:


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