Hard start capacitor and time delay relay to AC

Too Tall · 02-06-2016, 02:36 PM

Added hard start capacitor and time delay relay for better AC starting performance while on generator (or shore power). This is a popular upgrade for those of us with small generators.

https://youtu.be/NVkCjPh7Nd8

jgourlie · 02-06-2016, 11:33 PM

Thank you for the video....watched the whole thing...very informative!

DougP47 · 02-07-2016, 12:22 AM

Nicely done I have a domestic unit and I'm going to try the fan delay when it comes in. I already have the hard start cap installed. I found the timer on Jet.com for less than $6.00.

Too Tall · 02-07-2016, 12:32 AM

Thanks for the comments.

Witch Doctor · 02-07-2016, 05:38 AM

Quote:

Originally Posted by jgourlie

Thank you for the video....watched the whole thing...very informative!

That's a good video. You can see the difference those two little things can do and help. Even if your not on a ginny which is why most people do it, It is still a good idea to do even if your plugged in all the time. The Total cost is like 20.00 bucks or so and easy to do, and your compressor and power source will thank you. I would think it would almost be a must with a 30 amp unit.....Good Job Too Tall.....

itat · 02-07-2016, 02:51 PM

Quote:

Originally Posted by gljurczyk

That's a good video. You can see the difference those two little things can do and help. Even if your not on a ginny which is why most people do it, It is still a good idea to do even if your plugged in all the time. The Total cost is like 20.00 bucks or so and easy to do, and your compressor and power source will thank you. I would think it would almost be a must with a 30 amp unit.....Good Job Too Tall.....

Glen, I'm curious as to why you think this is a good idea if you are always on shore power?

doc73 · 02-07-2016, 02:53 PM

I would think the less high draw off the 30amp system will save the breaker from tripping under the right circumstances..

I have the hard start already but I am now thinking about this delay. I am still also debating the relay Turbs posted some time ago to make my AC run off the heater thermostat.... GOD I HATE THIS SITE!!!!!!

jgourlie · 02-07-2016, 03:23 PM

Now one thing that I kind of ignored was the delay because too tall has the coleman thermostat and I have the dometic digital thermostat which I automatically assumed meant it wouldn't work for me.

Does anyone see any reason why a delay would not work for my dometic... now having said that, when I fire up the a/c the fan runs first for probably 10 seconds and then the compressor kicks in....maybe dometic already has a delay built in.

Any help is appreciated,

Too Tall · 02-07-2016, 04:49 PM

Turbs has a Dometic with the time delay. It will work with either as it's 12 volts that energizes the fan relay. IMO, The relay doesn't know whether it's dometic, coleman or whatever. If your thermostat does start the fan first, you might want to get the 3 to 60 sec as opposed to the 0 to 10 second delay as you may need a little longer delay to overcome the built in delay. This is what I"m thinking, others can confirm.

Witch Doctor · 02-08-2016, 05:15 AM

Quote:

Originally Posted by itat

Glen, I'm curious as to why you think this is a good idea if you are always on shore power?

Doc 73, is correct that is why I still think it's a good idea. It doesn't take much to get to 30 amps if like your water heater decides to kick on at the same time. Also a hard start is used to kick your compressor into run faster from start-up amps. It's just a capacitor that stores power to assist in the start mode, then drops out. We use to install them on any unit that would cause what is called nuisance tripping. When I was an HVAC repair man. Many, Many years ago.....Cheap mod and insurance...

Witch Doctor · 02-08-2016, 05:29 AM

Quote:

Originally Posted by jgourlie

Now one thing that I kind of ignored was the delay because too tall has the coleman thermostat and I have the dometic digital thermostat which I automatically assumed meant it wouldn't work for me.

Does anyone see any reason why a delay would not work for my dometic... now having said that, when I fire up the a/c the fan runs first for probably 10 seconds and then the compressor kicks in....maybe dometic already has a delay built in.

Any help is appreciated,

I do not know about dometic, but it makes sense that if they designed there unit to bring the blower on for 10 sec. before the compressor kicks in then you really do not need one. You are the first that I read that said that. 10 sec. is long enough of a delay, it's just doing the opposite of a Coleman, when you install the fan delay. It always best for both not to start at the same time. Every amps counts as we all know who live on 30 amps, or even 50 amps....You can call dometic CS and I'm sure they will tell you why it was designed like that....

PS: if you call let us know there answer to you.

Too Tall · 02-08-2016, 09:56 AM

Quote:

Originally Posted by jgourlie

Now one thing that I kind of ignored was the delay because too tall has the coleman thermostat and I have the dometic digital thermostat which I automatically assumed meant it wouldn't work for me.

Does anyone see any reason why a delay would not work for my dometic... now having said that, when I fire up the a/c the fan runs first for probably 10 seconds and then the compressor kicks in....maybe dometic already has a delay built in.

Any help is appreciated,

Look at the schematic. There a thread where someone posted a picture of a domestic thermostat, it was Herk. If you are not trying to optimize your start up for use with a small genset, I wouldn't bother, but if you want minimal starting amps, delay the fan before the compressor.

TURBS · 02-08-2016, 10:14 AM

I don't see any kind of delay on current models.
That being said how could you tell when compressor kicks in if the fan is already running?
That fan is way to loud to be able to hear the compressor.

2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

Too Tall · 02-08-2016, 10:56 AM

This is the schematic for the roof unit. The relays will be on the other side of the connector. That's on the same schematic for the inside unit. It should show the thermostat wiring also.

jgourlie · 02-08-2016, 11:46 AM

I won't have my trailer in front of me to be able to take a closer look at it until late spring...so I will have to revisit this then...I do have a small generator that I would like to try and get to work with this trailer, so I should add this delay. We have a family reunion late August that I might not get hookups for, so I wouldn't mind trying to get my small genset to work with my rig.

I may be looking for help later this year

doc73 · 02-08-2016, 11:50 AM

My Dometic 13.5 on a 2014 does not have a delay build in.

jgourlie, not sure the size of your geni but I can run mine on a 2000 with just the hard start. Delay might help a bit more. Just make sure you have the fridge on propane only, and the converter off or it could be too much.

Witch Doctor · 02-08-2016, 11:52 AM

Quote:

Originally Posted by TURBS

I don't see any kind of delay on current models.
That being said how could you tell when compressor kicks in if the fan is already running?
That fan is way to loud to be able to hear the compressor.

2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

THere is no time delay in that, That's why I said that I have never heard of it before. Still as cheap as this mod cost ginny or not it is still good to install. Why not lower your start up amps, there is no down side to it, even plugged in...

Too Tall · 02-08-2016, 02:36 PM

You would need to have your model so you could find the right manual, some do have a time delay, see from Dometic manual below:

"In the COOL mode the system will cycle the compressor ON and OFF based on the room air temperature and the temperature set-point on the CCC 2. When the system calls for cooling there will be a delay of approximately two minutes. During this delay, the hour glass icon will be displayed in the LCD. In auto fan, the fan will turn ON first followed by the compressor in approximately 15 seconds. In this mode there are 4 fan speed selections:"

http://www.dometic.com/QBankFiles3/E...nual_17586.pdf

The time delay is done at the thermostat which is why you don't see it in the schematic above of the roof unit section.

TURBS · 02-08-2016, 04:57 PM

Quote:

Originally Posted by Too Tall

You would need to have your model so you could find the right manual, some do have a time delay, see from Dometic manual below:

"In the COOL mode the system will cycle the compressor ON and OFF based on the room air temperature and the temperature set-point on the CCC 2. When the system calls for cooling there will be a delay of approximately two minutes. During this delay, the hour glass icon will be displayed in the LCD. In auto fan, the fan will turn ON first followed by the compressor in approximately 15 seconds. In this mode there are 4 fan speed selections:"

http://www.dometic.com/QBankFiles3/E...nual_17586.pdf

The time delay is done at the thermostat which is why you don't see it in the schematic above of the roof unit section.

But that's only if fan is on auto correct?

2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

Witch Doctor · 02-08-2016, 06:23 PM

Quote:

Originally Posted by TURBS

But that's only if fan is on auto correct?

2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"

Turbs you are correct, The stat itself is what causes the time delay of 15 sec. The schematic which you showed is correct it is done by the stat itself not anything done in the A/C unit, and being it set to On in fan mode the the fan will stay on forever and the compressor will cycle at the set point only, So the delay has nothing to do with the A/C just the stat which controls it. That is also only for a 2 zone system not a single A/C that what this whole thread was about. If I had a duel system I would still add a hard start to both compressors......

PS: the main reason for that is they do not want both fans and compressors starting at one time. That is also why you can not use a Honeywell on a duel system because of the slave stat.

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