Need some help with capacitors

[Chaotic42]

How do you do, my good nerds? My central AC unit's display has conked out and apparently it's because of some capacitors. A replacement system is on the order of $2,000, so I thought I'd try to get the caps replaced by a friend who will be visiting soon. He's unavailable right now and I need to order some parts. Unfortunately, the exact caps I need don't seem to exist online at places like Digikey, so I thought I'd ask you all about substitutes. The "how to read capacitor" guides I've found have left me a bit confused.

The caps I need to replace say: "220 HHB. J02", "E 294 47 10", and one that really seems busted where I can only read "5.5v/1.55". Looking at repair guides, it appears that "220 HFT. C72"s were used in place of my 220s. Can any of you tell me what you think suitable replacements for these will be? I'm assuming 220 means 220uF. I can't figure out the other letters in those codes. I've attached a picture and I'd appreciate any help you all could provide.

Danke.

 

[dullard]

220 means 22 * 10^0 pF = 22 pF. This is the usual marking. Looking it up it polymeric capacitors might be 22 uF with that marking.

J02 is the physical dimensions. The definition varies by manufacturer, but you want something physically the same size or smaller to fit. Just measure the height and diameter.

HHB I don't know -- probably manufacturer series name which is fairly meaningless. I think the first H is often used for surface mount. Might refer to lead spacing.

Then get the highest voltage rating you can fit into those parameters.

 

[sdifox]

Why do you care about your AC unit's display? You just use the thermostat to control HVAC no? The thermostat are cheap and easy to replace.

 

[Chaotic42]

Why do you care about your AC unit's display? You just use the thermostat to control HVAC no? The thermostat are cheap and easy to replace.

It's "smart" and everything is run through the screen. The touchscreen still works, but I can't see what it's doing. Because it's Lennox, it's a proprietary system and apparently rewiring it to take a standard thermostat is many thousands of dollars. Upgrading to a new screen generation is "only" $1500.

Found out that other cap is a 1.5F beast, not 1.55 *something*

Thanks for the replies, folks.

 

[NutBucket]

Sounds like a supercap to hold settings for a bit after power is removed.

For the other ones, 22uF sounds right for the size/type of cap. If you can, measure the voltage across it (if there is any). Otherwise, hard to say what voltage rating you need without further analysis of the circuit. Going big is fine too so long as it fits

 

[MtnMan]

It's "smart" and everything is run through the screen. The touchscreen still works, but I can't see what it's doing. Because it's Lennox, it's a proprietary system and apparently rewiring it to take a standard thermostat is many thousands of dollars. Upgrading to a new screen generation is "only" $1500.

Found out that other cap is a 1.5F beast, not 1.55 *something*

Thanks for the replies, folks.

And that is not very smart.

 

[VashHT]

Those are 220uF not 22, I have a board right next to me with a 470uF cap that's marked 470, plus those are way too big for a 22uF cap. If you're worried about the voltage you could always go higher, I'd just get the highest rated voltage 220uF cap you can in that package size.

Edit: After looking at a couple datasheets for caps I've used, these alum-electrolytic caps definitely mark with uF, and the HHB could acually be H for the voltage rating and HB for the series. Here's an example from a Panasonic one I use:

 

[dullard]

Those are 220uF not 22, I have a board right next to me with a 470uF cap that's marked 470, plus those are way too big for a 22uF cap. If you're worried about the voltage you could always go higher, I'd just get the highest rated voltage 220uF cap you can in that package size.

Edit: After looking at a couple datasheets for caps I've used, these alum-electrolytic caps definitely mark with uF, and the HHB could acually be H for the voltage rating and HB for the series. Here's an example from a Panasonic one I use:

You could be on to something. The 220 uF HB series Panasonic capacitor with 50 V (H) rating is here: https://www.mouser.com/ProductDetail/Panasonic/EEE-HBH221UAP?qs=d1CqaRUMZD/3EFp3r%2BrUSg==

Note: why don't companies follow capacitor conventions when marking them?

 

[VashHT]

That seems pretty common for the aluminum electrolytic caps, at least from the different companies I've used. Tantalum caps use an extra digit for the number of zeroes, like 225 for 22uF like you mentioned earlier. Annoyingly enough, aluminum electrolytic caps use that convention when looking at the part number, like 220uF would be 221 in the part number but 220 marking on the part, but that's probably so they can keep the part number the same length across the series.

 

[Chaotic42]

Awesome, thanks for the responses, guys. I ordered some of those Panasonics.