Hello, folks,I am preparing to install a Progressive Industries EMS-HW30C power supply protector in my trailer. In the manual, it states that if your air conditioner has a built-in restart delay you can use the short (15 or 20 second) factory setting on the protector, but if the AC does not have a built-in delay, you should remove a jumper "wire" inside to give the protector a 2-1/2 minute reset delay to protect the air conditioner from restarting too soon and damaging itself. According to Progressive Industry's documentation I am supposed to refer to the AC manual to figure this out. However, the AC is the one piece of equipment that did not have the owner's manual included in the document package when we bought the trailer new. This is a ducted, 13,500 Dometic unit installed on our trailer when it was built in early spring of 2003.Is there any way to tell if this particular unit has its own, built-in start-up delay so I can use the short factory setting on the power supply protector?Thanks,Regan

You may need to remove the shroud and take a peek. It should be a small plastic box perhaps 2"x3" with a dial on it to adjust the restart time. The technical term is a time delay relay. I had to install one on my home central air unit because of the frequent but momentary power outages here in FL. Having an AC restart immediately after an outage will cause short cycling which is the death of AC units.Another clue if you have a DTR is to momentarily cut power then turn it back on. If the AC doesn't restart immediately then you have a TDR.

IF you have a wall tstat for the AC unit, you have the time delay. IF you have an AC unit with ceiling mounted mechanical controls you do NOT have the time delay. Doug

Cycle the circuit breaker when the air is operating, if it restarts immediately you do not have time delay protection, if it does not restart immediately you do have time delay protection.I have seen adjustable time delay relays that can be set up to ten minutes delay.

Thanks for the prompt replies! I had thought about starting the AC up and cutting the power, but its only 20 degrees F here right now, so I doubt I can trick the AC into firing up right now anyway! I might pull the jumper wire just to be on the safe side until I figure it out...

Turn on the A/C.. if the blower starts, then 2 or 3 minutes later the COMPRESSOR starts, it has a delayThat simple. Or you can turn the A/C on and then trip it's breaker, wait 2 minutes and turn it back on.. Again if the compressor comes on IMMED, no delay. if it waits 2 or 3 minutues, delay.

How to tell if AC has a start-up delay? (EMS-HW30C Install)

15 Replies

rkentzel
Explorer
Feb 05, 2014
If you have changed to a digital stat you will have a delay on restart from a power interuption
time2roll
Nomad
Feb 05, 2014
+1 for just going with the extended delay. Never been an issue to wait.
aruba5er
Explorer
Feb 05, 2014
My Hunter replacement thermo has the time delay built into it. My HW30 didn't say anything about time delay, but it sounds like a good thing. There is a delay of a few seconds after it (HW30) shuts off before it kicks the power back on.
dougrainer
Nomad
Feb 05, 2014
rockhillmanor wrote:
shooted wrote:
Cycle the circuit breaker when the air is operating, if it restarts immediately you do not have time delay protection, if it does not restart immediately you do have time delay protection.
I have seen adjustable time delay relays that can be set up to ten minutes delay.

Well, thanks for that info!

Mine has a VERY long delay and many of mobile RV repair guys were convinced I had A/C problems when working on my coach.

Until I told them they had to wait, wait, wait for it. For it WILL come back on. All during that wait time they were telling me I was crazy that no delay could be that long!

The LONGEST delay on a RV Roof top system will be no more than 4 minutes. IF longer, your system is malfunctioning, OR you have a EMS system that is delaying the power to the AC. There are NO adjustable relay time delay's on a RV AC system. I believe he is talking about an aftermarket surge/monitor system. Doug
Woodtroll
Explorer
Feb 05, 2014
doughere wrote:
I think I'd leave the extra delay in no matter what. After a power interruption, the power is often pretty shakey for a while.

Doug

Mont G&J wrote:
Infrequent as power interruption occur, I see no down side in removing the wire, and having the 2-1/2 minute reset delay regardless if the air conditioner has a delay or not.

Good advice, friends, I believe you are right! I sure do appreciate everyone's help!
rockhillmanor
Explorer II
Feb 05, 2014
shooted wrote:
Cycle the circuit breaker when the air is operating, if it restarts immediately you do not have time delay protection, if it does not restart immediately you do have time delay protection.
I have seen adjustable time delay relays that can be set up to ten minutes delay.

Well, thanks for that info!

Mine has a VERY long delay and many of mobile RV repair guys were convinced I had A/C problems when working on my coach.

Until I told them they had to wait, wait, wait for it. For it WILL come back on. All during that wait time they were telling me I was crazy that no delay could be that long!
doughere
Explorer
Feb 05, 2014
I think I'd leave the extra delay in no matter what. After a power interruption, the power is often pretty shakey for a while.

Doug
Woodtroll
Explorer
Feb 04, 2014
Chris Bryant wrote:
Almost all of the delays are in the thermostat circuit- not the 120 volt line, so turning it off and on at the thermostat will cause a delay, but turning the 120 volt power off and on will not.

Thanks, Chris. To make sure that I am understanding you right: even most of the AC units with built-in delays won't be protected when the 120VAC power goes out and then immediately comes back on? Based on this, it certainly seems that to get the most protection for my AC, I should enable the longer delay.
Mont_G_J
Explorer
Feb 04, 2014
Infrequent as power interruption occur, I see no down side in removing the wire, and having the 2-1/2 minute reset delay regardless if the air conditioner has a delay or not.
Chris_Bryant
Explorer II
Feb 04, 2014
Almost all of the delays are in the thermostat circuit- not the 120 volt line, so turning it off and on at the thermostat will cause a delay, but turning the 120 volt power off and on will not.