AC troubles at home

[RoyBell]

Looking for some advice from the HVAC experts. After 3 days of over 90 degrees, I noticed my Fan was intermittent on my condenser unit yesterday.

The unit is about 28 years old now. I replaced the fan and cap once myself, about 5-6 years ago. I replaced the contractor about a year or 2 ago.

Is it safe to assume the fan has gone out again? The weird part is the house has remained pretty cool even @ 90 degrees outside (75 inside).

I did a little googling on intermittent fan issues and came to 3 possible issues.

1) the Fan is going out.
2) The low pressure switch isn't turning the fan on. I don't think my unit has this because I don't remember the fan ever not spinning when the compressor was running. Plus it was hot out which should call for the fan.
3) The compressor is going out, causing a higher draw than normal preventing the fan from starting.

#3 has me curious, mainly because it's an older unit. However, the compressor starts and runs. I would think if the compressor was going, it would take a couple trys to start. I noticed it did a couple times, but I imagine it was because the fan was not running. People say to add a hard-start kit for older units to help it along.

Any advice? I checked it this morning and the fan motor was hot to the touch and not running again. It spun pretty easy with no resistance which is a sign that motor is shot. I grabbed the info and ordered another one.

What about this hard-start kit? Is it needed? Good preventive part? I don't get any dimming of the lights in the house when it starts. I know the unit is old, but it still cools the house and is paid for. The furnace is a couple years older (I think pushing 30 now). I know I am on borrowed time, but why replace if it still works.

 

[Falcon67]

Not an HVA person but I tend to call BS on #3. If it pulls too much current it will trip the overcurrent device, not stop the fan from starting. I'd replace the fan+fan cap. 28 years - you are already about double normal life span IMHO.

However, basically they work until they are not worth saving.

 

[bazar01]

The condenser fan motor was replaced 5-6 years ago so it may still be good.
Check/replace the fan capacitor. Usually it is about 5uF. But check the specs anyway and just get a new one. Most times they are dual cap that connects to both the compressor and fan.
It is cheaper than the condenser fan motor.

 

[txst]

Is the compressor shutting off when the outdoor fan stops?
If not, it may be the capacitor. If you take the control box cover off, look at the capacitor and see if it is bulged out at the top (like a soda can that has been pressurized).
If the compressor also stops, it may be a high or low pressure switch de-energizing the contactor. High pressure trips could be due to the fan turning too slow (bad capacitor or dirty coil), low pressure trips could be due to a leak.

 

[Climatecreator]

Condenser Fan Motor capacitors are usually from 15mfd down to 3mfd never 35 that would be more for a compressor. If it has a dual capacitor replace for both don't just add on a new fan side cap, get another dual.

Replace the capacitor first, but it's most likely the motor.

Always put a new capacitor with a new motor.

It has nothing to do with the compressor.

Good luck

CC

 

[bazar01]

Condenser Fan Motor capacitors are usually from 15mfd down to 3mfd never 35 that would be more for a compressor. If it has a dual capacitor replace for both don't just add on a new fan side cap, get another dual.

Replace the capacitor first, but it's most likely the motor.

Always put a new capacitor with a new motor.

It has nothing to do with the compressor.

Good luck

CC

Must be my morning brain fart. Fan should be the lower microfarad on the dual cap.

 

[Trey T]

It's time to get a DMM with capacitor testing feature. W/o knowing the status of the capacitor, it's hard to figure out if it's a control or the induction motor issue.

 

[RoyBell]

I don't believe they are shared. The cap for the fan is only 5mfd. 1/5th hp motor. There is a second round looking thing that's in there as well. I assume that is the cap for the compressor. The compressor still runs, even when the fan isn't going. I put a box fan on top to draw some air through the coils. It kept up.

I did take the whole thing apart last year and cleaned the coils off. Since it's an old one, none of the coils are exposed so I basically had to take out like 50 screws and pull all the panels off. It was filthy. It made a big difference. I also had the attic blown last fall. It helped quite a bit in winter with the heat escaping. I imagine it will help with the AC too.

I ordered both parts from Grainger so they should be there today or tomorrow. I will try the cap first and see if that does anything. It's not likely based on how easy the fan spun with almost no resistance. It looked ok at first glance this morning, but it was before I had my coffee. The motor wasn't terribly expensive @ $135 If I get another couple years out of it, It's money well spent. I have also heard of techs changing out motors with the wrong fan speed for the blades and causing an overheat situation. I doubt that is the problem since it has been in place for quite some time without any issues. Hopefully the fan is a little out of balance which killed the motor a little early.

I did manually push the contactor in this morning and the compressor started, but no fan. Not sure if that means anything. It's a pretty simple machine. I don't think there's any boards inside.

 

[Trey T]

Check the fan when it failed to spin by manually spin the blade. If the fan works, then it's likely that your cap is weak. If there's power going to the fan and it's not working, then it's likely that the fan is out.

The point I was trying to make is this is justifiable to get the tool to diagnose the issue properly instead of throwing parts at it. If you're a part changer kinda guy, I recommend that you stock the Amrad Turbo 200 capacitor - it's a universal dual cap (made in USA). It's a cheap investment and many times, HVAC equipment tends to break down over the weekend and the stores are closed.

 

[RoyBell]

I don't think my multimeter has a capacitor feature since it's a clamp meter. Does basic volt stuff but that's about it. Grainger takes returns if the cap works.

 

[RoyBell]

well gents, the motor and cap came in. Grainger is awesome. Order and delivered the same day. Off to see if I can fix it.

 

[Climatecreator]

Check the fan when it failed to spin by manually spin the blade. If the fan works, then it's likely that your cap is weak. If there's power going to the fan and it's not working, then it's likely that the fan is out.

The point I was trying to make is this is justifiable to get the tool to diagnose the issue properly instead of throwing parts at it. If you're a part changer kinda guy, I recommend that you stock the Amrad Turbo 200 capacitor - it's a universal dual cap (made in USA). It's a cheap investment and many times, HVAC equipment tends to break down over the weekend and the stores are closed.

Yes these https://amzn.to/2JgDlOB are well worth carrying, AND they have a 5 year warranty to boot!

It's usually the motor if it doesn't spin start by hand when it first starts.

Doesn't matter how new things are. Nothing is made to last anymore.

CC

 

[Falcon67]

>Doesn't matter how new things are. Nothing is made to last anymore.

In the last 3 years on our old system, we replaced either the dual cap or the hard start every year. They install whatever the local supply house choses to carry here unless you want to pay $$$ and wait to have something special shipped in. These were "brand name" type caps so sometimes the quality is just not there.

 

[RoyBell]

Well, I went home yesterday and tried the capacitor first. Luckily that did not work I threw the new fan in and wala, she was back running.

However, my box fan burned up that I had running on it temporarily and the compressor was running when I got home. I hope that didn't hurt it.

I also realized I think I have a hard start kit installed already. I took some pictures, but of course I am locked out of my picture site. I see the capacity for the compressor, and the new one I just installed for the fan. Then there's a round looking canister thing that has 2 wires and it's label worn off. I am guessing that is the hard start capacitor and maybe why this thing is still living? I will upload picture when I get back into it.

 

[Fixin'Stuff]

... I took some pictures, but of course I am locked out of my picture site.

You don't need a "picture site". Just click "Go Advanced" under the reply box. Click either the little paper clip in the toolbar or scroll down and click the "Manage Attachments" button. Select the pictures you want to add to your post, click "Upload". Boom! Done!

 

[RoyBell]

I cant attach pictures because usually they are too large for what the site will allow. Then I have to figure out how to downsize them. Anyways, I am back online.

I have that black round thing under the new cap. You can't see it in the picture, but the cap for the compressor is actually mounted into the unit. It is located under the new one. I assume that black thing is a hard start kit based on pictures of what new ones look like? If it is, do they go bad? Should it be replaced?

My water heater also went out a couple times Friday. Very odd. Local ACE had the thermocoupler so I ran over there and bought it because that seemed to be common on water heaters. Now shes been running fine since my last restart. ACs been doing good too. But I haven't run it past couple days since its been in the 60s.

 

[LS6 Tommy]

Yes, that black thing is a hard start kit. They do go bad. Should be about $10.00. A Supco SPP6 is widely used:

https://www.amazon.com/dp/B00DZUAPQG/?tag=atomicindus08-20

If you think you're short cycling, I'd add a delay on break timer:

https://www.amazon.com/dp/B00GIOYTJ0/?tag=atomicindus08-20


Standard practice for me was to install both for units that frequently tripped breakers or seemed to have hard start issues.


Tommy

 

[RoyBell]

I know they make an SPP5 too. How do I know which size to get? $10 seems like cheap preventive maintenance to me. There have been no issues starting from what I can tell. I believe it's 2.5T.

 

[Climatecreator]

I like these a little better than the supco ones https://amzn.to/2Jveoiu check it out. Might be perfect for you, I'd also replace the capacitor to the compressor unless you're saying they removed it and installed the supco instead?

CC