Replyit's done everyday, they certainly could have done a more professional application
so, how did you leave it?
Professional Member
I cannot believe that someone out there actually put a 5 and a 3 together to make a 7.5, wrapped it with duct tape, charged the customer and can sleep at night !
Professional Member*
it's done everyday, they certainly could have done a more professional application
so, how did you leave it?
It`s better to be silent and thought the fool; than speak and remove all doubt.
Professional Member
As long as it's wired in parallel, no problem. 8 mfd should be fine short term, but I would replace it with a 7.5. The duct tape is a nice touch.
I find electrical connections taped with duct tape.No wire nuts, just duct tape!
Professional Member*
I agree with the others, that this is done all over the country, everyday. There is nothing wrong with grouping capacitors to get out of a jam. We are in a very rural area, and can be an hour or more from a supply house, so sometimes it is your only choice.
That being said, it could have been done in a much more professional manner.
Regular Guest
Looks a bit like the Run Cap Bandit has been there, but he would have left the caps in the box, so maybe not.
Professional Member
I've been in this business a long time and have not seen this done before here in the So-Cal area. Went to visit some relatives in Tennessee and was checking their A/C when I was there and that's the first time I seen a set up like that.
So i think its like meplumber said its more in rural areas where the parts house is not close.
Professional Member
Yeah, I have put 2 together to get the customer by over a weekend or whatever the case may have been, but the tape had been on here so long it had started to deteriorate. Don't know if it really matters but the caps were upside down too, I like to put them in terminal side up. If nothing else it looks professional and that is what the customer is paying for.
Professional Member*
caps wired in parallel = total of cap values
caps wired in series = approximately 1/2 of each in series
will dredge formula out later
bottom line is: just because you've never sen it doesn't mean it's not allowed/permissable/accepted
that's why if you're not learning something new, you're probably dead
Professional Member*
There is nothing wrong with wiring capacitors in parallel to add up to the value needed, but there is a lot wrong with how those were mounted.
Member
Definately not my first choice for replacement caps, but I have done it many many times when the supply house is miles away. And I wouldn't mount them that way either, but the concept is very acceptable.
As a matter of fact, I believe it was demonstrated in some of my old traning manuals.
Professional Member
ok, now I know it is ok to wire caps like that. Would like to see the formula for series and parralel wiring. I had never seen or heard anyone ever say it was ok, so I ASSumed it was wrong, Thanks for lernin me something, ha ha.
Professional Member*
ugly hackery. Takes the professionalism right out of what we do, surprised he didn't have a 7.5 (I have at least 4) but did have a 3mfd.....I may have 1 or 2......anyway, what is embarrassing is opening up a panel like that and the homeowner asks you if that mounting was 'correct'. My answer is no. I have strap and drill tips in my toolbag and will secure those even on a maintenance. I want them to know that I am there to make sure their system is ok. I work for them, ultimately. Nice picture.
Regular Guest
Professionalism is not a word that is used very often in HVAC. Its hard to maintain a positive outlook on what we do when over half the industry are all hacks. They make the same money per call we do and the end result looks like this picture shown above. Most customers complain over price so they call they guys who do this level of work. If you do not posses a inner drive to do a good job this industry will often not inspire it. (Present readers excluded)
Member
So, you have four 7.5's on your truck at the beginning of the work day. By 3:00 you used all 4 of them, and on your last call, you need another one. Do you travel 60 miles to get one and return to put it in? And the customer is ok with paying an additional $150 to $200 for the same result? And you're ok charging the additional $150 to $200 even though paralleling 2 is acceptable?Originally Posted by JWB
Professional Member*
Wired in parallel, the value of the capacitors adds, so a 10µf + 10µf in parallel is 20µf.
This is how the Turbo capacitors from AmRad work.
Wired in series, the a reciprocal formula is used.
For 2 capacitors in series the easy formula is: Total µf= (µf1 x µf2)/(µf1 + µf2)
Two 10µf capacitors in series would be 5µf.
(10x10)/(10+10)
100/20 = 5
For more than 2 capacitors in series, you would need a different formula.
(1/µf1)+(1/µf2)+(1/µf3)=1/µfT
µf = 1/µfT
Three 10µf capacitors in series would be 3.33µf.
(1/10)+(1/10)+(1/10)=1/µfT
.1 + .1 + .1 = 1/.3
µf = 3.33
Typically there is not much, if any, use for capacitors in series in our industry.
Professional Member
Thanks !
Professional Member*
One thing does concern me about the 2 single caps in parallel: Are they 370V or 440V?
With a 120V blower motor, the working voltage (measure it while the motor is running) will not exceed 370... With a 240V fan motor, the working voltage may well exceed 370V, which means the caps may fail sooner.
Now if those single caps are 440V, well disregard what I just said...
GA-HVAC-Tech
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*Installation is more important than the brand of equipment
*The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
*The value of comfort, over the long term; leave economic choices behind!
Choose your contractor wisely!
Professional Member*
No, I would wire something together. My point was that the install is really unprofessional and just plain disappointing. I observe a lot of 5mf's on rheem/ruud/weatherking units in place of the manufacturer's recommended 3 mf. Which leads me to assume that guys would rather throw a 35+5 in cause they have it handy then wire together a 35 and a 3. Mostly I don't see a lot of 3's around so I assume they don't bother stocking them.
And also, if my truck is out of stock, that is my problem, the customer at my company doesn't pay EXTRA for something I failed to stock. We eat the additional cost.
Professional Member
If you have ever worked on old equipment manufacturers frequently used multiple capacitors. Of course they mounted them properly. As a refrigeration contractor I get the opportunity to replace capacitors frequently rarely are replacements the same physical size. Life is fun.
Professional Member
Turbo 2000 basically does the same thing... multiple caps in a single shell. However, professional mounting is a must. I too have joined capacitors in a pinch, but always mount them securely to the metal wall.
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