Have been reading about the hard start caps, you can install in your A/C, but dont really know what it is all about.
Some years back, I had an old drink machine that I had a a/c tech guy to get back working again, & during the time he was working on it, we got off onto the subject of RV a/c units.
He was telling me, that a lot of roof top a/c units are being replaced just because the compression seams to be locked up & in reality all it need is an extra boost to get it going again.
Was a process he called "Hot Start" where a higher amps of voltage was used to get the compressor going & then would be fine after that.
That was all the info I got at that time, because I figured if I should ever have one stop running, then I would know what to do & just contact him.
I've lost contact with that tech guy, so I'm really lost on the whole deal now, but wondering if this Hard Start Cap is something to replace to Hot Start deal the tech guy was telling me about.
Thanks in advance if you know & can help out.
Neil
Those hard start caps are for piggy backing up the regular cap. They are for when comp is hard to start and for also low voltage situation. You can get those at the appliance parts store. Below is an example of where you are going to connect a piggy back to an existing cap. You need to know which one by looking at cheat sheet somewhere in that a/c unit. (diagram)
A Hard Start capacitor can be added in parallel with the compressor's existing run capacitior to assist with starting the air conditioner. Often used when running the AC with a generator or outher source that dosn't have very high surge capacity. Sometimes they help and sometimes they don't. Many folks use the Supco SPP6 which has a silicone switch in series with the capacitor that disconnects the capacitor (hopefully) after the compressor has started. The SPP6E does the same thing, but uses an electronic circuit to disconnect the start capacitor at just the right time. However, Supco dosn't recommond the E version for 120 volt applicances....though many people use it.
The SPP6 are easy to install and will make it easier for your compressor to start. There is also Kickstart units that use potential relay which are the best way to go,but there may not always be room to install this unit in a RV air conditioning where its out of the weather. Kickstar TO5 crosses over to SPP5 and SPP6.
Ok, thanks folks.
Looking at the Supco caps, the SPP4E might be lower than the cap I have.
Now I dont know how to read them, but on the label on the new cap I have that not installed yet, it says 165v.
Does that mean it will provide at least 165 volts starting cap to the compressor.
This cap does not have the small square relay on top, just the two hook up prongs & something looks like a small round car fuse, gray & different color lines on out sides of it.
I do have a cap with the small square relay on top, somewhere, but remembering where, God will need to help me cause I done forgot & just seen it the other day.
Neil
The voltage specification is the maximum operating voltage of the device.
Suggest you first start by removing the shroud from your AC, open up the control box, and determine if you already have a compressor start capacitor or not. You will likely have a run capacitor and a fan motor capacitor (frequently in the same device). If there is no compressor start capacitor, you "may" benifit by adding one. (never heard why you are considering this modification though) However, if you add a capacitor, it needs to have some sort of circuit to disconnect the it after your compressor starts. Don't just put in any old capacitor you may have laying around.
Before you do any of the above though, unplug your RV from power......
After you unplug and BEFORE you touch a capacitor short the capacitor terminals. A capacitor has the ability to stores electricity. The definition of a capacitor makes it sound like it's a storage battery.
The voltage specification is the maximum operating voltage of the device.
Suggest you first start by removing the shroud from your AC, open up the control box, and determine if you already have a compressor start capacitor or not. You will likely have a run capacitor and a fan motor capacitor (frequently in the same device). If there is no compressor start capacitor, you "may" benifit by adding one. (never heard why you are considering this modification though) However, if you add a capacitor, it needs to have some sort of circuit to disconnect the it after your compressor starts. Don't just put in any old capacitor you may have laying around.
Before you do any of the above though, unplug your RV from power......
Steve
Thanks Steve,
The A/C I'm working on is sitting in my shop, is fairly new & was removed from an RV because the repair shop thought the compressor was locked up.
I've had it running once, after replacing the blown cap with the normal one called for in that unit. It blew cold air for a few minutes & then popped that cap.
I have another new cap, one just a bit higher rating, but not messed with the a/c to see if that cap would be big enough or not.
Then, I read about the "hard Start" caps & now wondering if that is what is needed.
This a/c, has the fan motor cap, the big tall compressor run cap & then the start cap for the compressor, 3 caps, but the start cap normally called for in this unit, not the one with the small relay made on to the cap.
I guess this a/c, is an old type unit, but still new, if that makes any sense, but I've had it my shop for several years just in case if I was to need another unit.
Neil
Suggest you start HERE and get the Parts List for your exact model. Some have four parts in that area: Fan Run Cap, Compressor Run Cap, Compressor Start Cap, and Start Relay. I'm no guru on this, but from reading it's clear that a Start Cap has to Exit Stage when its job is done and various methods are used to accomplish that. The parts list will also give you the specs of the capacitors. At least the list I looked at did.
Compressor should be marked Run Amps, Locked Rotor Amps, and probably Start Amps. You may not be able to measure Start without a peak-reading meter. But if you see LRA, compressor is Either actually Locked (stuck) OR a capacitor failure.
I got this tip from an appliance shop: As a system ages, the starting/capacitor devices weaken, AND the compressor amperage requirement also increases. So I was able to get my daughter's 12-YOA fridge running with a new SUPCO start device, but it's very possible we really aren't home free compressor-wise.
In a home situation, at least we're usually working with a full 120VAC. In an RV situation, we rarely have full voltage, and that is going to make any bad case worse.
God Bless, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100
The start capacitor *must* have some sort of start device in the circuit to take it out of the circuit once the compressor is running. This can be done via a PTCR (solid state) device or via a relay. With no device inline you will blow the capacitor.
The Supco SPP6 is functionally identical to the stock Coleman start kit- an 88-108 mfd start capacitor and a PTCR start device. The SPP6E uses a potential relay.
It is fairly common for the old stock PTCR devices to burn up- they operate by conducting power until they heat up, which happens in a fraction of a second (and they stay hot).
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