Giving some serious thought to installing a hard-start kit on my 2012 Dometic 13,500 BTU Brisk Air a/c. Quite a few positive reviews on the Supco SPP6. Anybody have any experience using the Dometic Hard-Start Kit (#3310727.015)? Dometic claims their Hard-Start kit (or Starter Assist Kit) will dramatically reduce the LRA for their Brisk Air units. Thanks!

I installed the Supco SPP6E on my Coleman Mack (1350 BTU)last week. It was very easy to install. You can find a great video on Utube by searching for RV AC hard start kit. When talking to the company they suggested the E version as it re-sets faster and is electronic vs mechanical operation ???? it was only a few dollars more. As for operation I bought it so I can run my twin Yamaha 2000's in Eco mode. It is only 50 degrees here in Idaho but in testing the AC system after the install I noticed a huge difference in how much the generators had to work to get the AC unit running. The ultimate test will be in July/August.

My understanding is that the Supco unit is thermally operated and the Dometic is electronically operated. Translation, the Dometic unit will respond faster and is less strain on the compressor. I'm really happy with my Dometic unit.

Jayco23FB, really glad to hear the Supco SPP6E appears to be working for you. Noticed a bit of chatter online that the SPP6E (vs. SPP6) is supposedly designed for heavier-duty 220 volt applications. Not sure if there's any validity to this, but may be something to keep in mind if you have any issues with the SPP6E down the road.ernie1, I've heard the Supco/thermal vs. Dometic/electronic comparison before, too. Found some pretty good bargains on both the SPP6 and Dometic (3310727.015), so I've decided to order and try both. Although many folks install the hard-start kits to make an attempt to power their 13,500 BTU a/c's with their smaller generators, I think they're a worthwhile investment for everyone to just reduce the day-to-day strain on the compressor and generator during normal operation.I'm disappointed a/c manufacturers don't install these things in their OEM units as a matter of practice. Doubt it would cost more than a dollar for them to do so. Get the impression these things have the potential to reduce the LRA (inrush current) on many a/c units up to 50%--that's huge. It may not be much of an issue when powering a/c units with commercial power, but it's certainly a huge deal when using generator power.

There is virtually no difference between that Dometic part and the Supco SPP6- both are PTCR based start devices. Supco does not recommend the E series for RV applications- because if you shut the compressor and try to restart it right away, the E series will put the start cap in the circuit, a PTCR device will not. My response to that- doesn't short cycle the A/C (most new thermostats will not let you anyway).DuoTherm does make a couple of better options- p/n 3102903.006 , which is a true potential relay (unlike the Supco "E" series quasi potential relay), and a really good, though very expensive start kit, the SmartStart- unlike anything else on the market (at ~$370, it better be :) ).Another option I am looking at is the 5-2-1 compressor saver- a true 3 wire potential relay.Note that the benefit for the non-PTCR type kits is really only in running off an undersized genset- they keep the start capacitor in the circuit until the compressor comes up to 75% of speed, which takes a fraction of a second longer if the genset bogs down.

So which do you recommend I install to help an undersized genny set, Mr Bryant?TIA, Mike

Hard Start kits: Supco SPP6 vs. Dometic #3310727.015

otrfun
Explorer II
Mar 29, 2014
Jayco23FB, really glad to hear the Supco SPP6E appears to be working for you. Noticed a bit of chatter online that the SPP6E (vs. SPP6) is supposedly designed for heavier-duty 220 volt applications. Not sure if there's any validity to this, but may be something to keep in mind if you have any issues with the SPP6E down the road.

ernie1, I've heard the Supco/thermal vs. Dometic/electronic comparison before, too. Found some pretty good bargains on both the SPP6 and Dometic (3310727.015), so I've decided to order and try both. Although many folks install the hard-start kits to make an attempt to power their 13,500 BTU a/c's with their smaller generators, I think they're a worthwhile investment for everyone to just reduce the day-to-day strain on the compressor and generator during normal operation.

I'm disappointed a/c manufacturers don't install these things in their OEM units as a matter of practice. Doubt it would cost more than a dollar for them to do so. Get the impression these things have the potential to reduce the LRA (inrush current) on many a/c units up to 50%--that's huge. It may not be much of an issue when powering a/c units with commercial power, but it's certainly a huge deal when using generator power.
ernie1
Explorer
Mar 29, 2014
My understanding is that the Supco unit is thermally operated and the Dometic is electronically operated. Translation, the Dometic unit will respond faster and is less strain on the compressor. I'm really happy with my Dometic unit.
Jayco23FB
Explorer
Mar 28, 2014
I installed the Supco SPP6E on my Coleman Mack (1350 BTU)last week. It was very easy to install. You can find a great video on Utube by searching for RV AC hard start kit. When talking to the company they suggested the E version as it re-sets faster and is electronic vs mechanical operation ???? it was only a few dollars more. As for operation I bought it so I can run my twin Yamaha 2000's in Eco mode. It is only 50 degrees here in Idaho but in testing the AC system after the install I noticed a huge difference in how much the generators had to work to get the AC unit running. The ultimate test will be in July/August.

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Hard Start kits: Supco SPP6 vs. Dometic #3310727.015

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