I need to replace two capacitors in our furnance, a Lennox Elite CH33-42B-2F.

The two capacitors are still working, but not within tolerance (so the repair man told me).

The specs are 5uF 370VAC for one, and 7.5uF 370VAC for the second (photo below)

My question is, do I need to source an exact match for each, or can I just purchase from the specification? Is there anything else I need to be aware of when purchasing? (based in Utah, USA, if that's relevant)


  • The specs are 5uF 370VAC for one, and 7.5uF 370VAC. That is all you need OVAL CAN capacitors. Some are polarized so pay attention to the leads when removing and installing. See my answer - because you might be the target of a money grab. – Ken May 5 '17 at 19:30

You can purchase them according to the specification.

5uF 370VAC for one, and 7.5uF 370VAC for the second.

Your repair man was there to fix something - they are working .. sounds like a suspicious charge to me. It is very unusual for a repair man to break out their capacitor checker and check UF of the Capacitors. The are +- 10% (so 4.5UF to 5.5UF ) is fine. On the 7.5 UF ( 6.75 to 8.25 UF is acceptable ranges) a meter that has a capacitance checker on it is what is needed to determine the capacitance - generally cheapo's do not have this function - although I have a cheapo (not really but cheaper than a fluke) I also have a fluke that measures this.

What reasoning is there that these are out of tolerance ?

This is the more relevant question

Is the unit experiencing any problems - what issues does it have .. ??

Because if they are working - what problem is there that he/she stated they were out of tolerance ?

Did he/she physically measure them and visually show you on his meter the reading?

If you are not experiencing any other problem - I would be suspect of the statement they are out of tolerance, especially if they did not show me the reading.

Typically you can buy these for $5 to $10 a piece - the repair guy will charge you $35 each or more plus labor. Another $150 - $200 . Ka' Ching and many people will be suckered to pay it.

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  • Thanks Ken. You're correct about the 'repair' guy; they wanted about $150 for doing it, and I know that they're pretty cheap. I have a capacitance test on my meter. I'm thinking of replacing them anyway, as the furnace is 10 years old, and keep any good ones as spares. – PeteCon May 5 '17 at 19:42
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    I had one of these "inspections" done a couple of week ago. The tech told me two of the capacitors in our condenser unit (88-108 µf and a 45 µf) were out of spec. They weren't; I am pissed. The 88-108 measured at 103.8 and the 45 at 43.9, both well within specs. – BillDOe May 5 '17 at 19:50
  • @BillOertell when they do a freon recharge on the AC - ask how on earth do they know how many pounds of Freon they put in ? The gauges do not have a meter - search on the web how on Earth they can know and you will find it is extremely difficult. If they measure the weight of their canister before and after use - they have at least TRIED to do you and themselves right. Typically these areas of repair are ripe for skimming unsuspecting consumers. – Ken May 5 '17 at 19:56
  • @PeteCon your meter is all you need to test them. Keeping the old hanging around is not a bad idea - I have one - sometimes it works and sometimes it does not work - that beats never works. However at the time I fixed mine I should have just bought 2 it was like $5 , oh well. – Ken May 5 '17 at 19:58
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    About a year after we moved into our new house in 2002 the blower run capacitor went bad. We didn't know whom to call, so we called the company that installed the unit. They charged us $350 to replace a 12-dollar capacitor. – BillDOe May 5 '17 at 20:00

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