AC - Intellitec ECC issue wth auto cool

[Servo]

HVAC Experts - or Anyone else who has HVAC knowledge who has the older Intellitec ECC thermostat (pic attached) that sheds power between the two units (2000 Pace Arrow Vision here - 34N)

We just had 2 new AC's installed but we're having a similar problem that we had before the old unit bedroom starter motor blew.

When the thermostat is set to "Auto Cool", once the desired temp is achieved, the compressor kicks off but the fan stays on, going from 40% humidity to 79% humidity over the course of a 6-7 hours being away from the rig, and the fan was still blowing when we got back.

Correct me if I'm wrong, but isn't the purpose of auto cool to get you to the desired temp and then kick off everything until the temp rises back up to an undesirable level?

To me, just getting a dehumidifier is treating the symptom and not the disease. I want to fix the problem and I can't imagine that this is operating as intended. My gut tells me there's a wiring issue somewhere but I'm far from an expert in HVAC so maybe I am missing something.

Note - I haven't tried it with these new ACs (since they were just installed this morning), but the same issue happened with the old units when placed on Hi Cool as well. That I can somewhat understand since you're placing it on a full-time ON setting.

[ret60sp]

Originally Posted by Servo

HVAC Experts - or Anyone else who has HVAC knowledge who has the older Intellitec ECC thermostat (pic attached) that sheds power between the two units (2000 Pace Arrow Vision here - 34N)

We just had 2 new AC's installed but we're having a similar problem that we had before the old unit bedroom starter motor blew.

When the thermostat is set to "Auto Cool", once the desired temp is achieved, the compressor kicks off but the fan stays on, going from 40% humidity to 79% humidity over the course of a 6-7 hours being away from the rig, and the fan was still blowing when we got back.

Correct me if I'm wrong, but isn't the purpose of auto cool to get you to the desired temp and then kick off everything until the temp rises back up to an undesirable level?

To me, just getting a dehumidifier is treating the symptom and not the disease. I want to fix the problem and I can't imagine that this is operating as intended. My gut tells me there's a wiring issue somewhere but I'm far from an expert in HVAC so maybe I am missing something.

Note - I haven't tried it with these new ACs (since they were just installed this morning), but the same issue happened with the old units when placed on Hi Cool as well. That I can somewhat understand since you're placing it on a full-time ON setting.

If your coach is 30 amp service, you'll have a constant shedding problem that might result in one or both AC compressors remaining off while the fan blowers are ON.



We had the same problem, and it only presented itself when the outdoor temperature was above 84 degrees. One AC unit would start, completing a surge well over 30 amps to get started, but not too much to trip the shoreline breaker. With one AC system on, the line load would settle in around 12 amps. Adding the second AC unit would cause the fan to bump the power consumption to about 18 amps, then the second AC compressor would attempt to start, bumping the line load over 24 amps, which would cause a magnetic field sensor in the electrical panel to force the first unit compressor into "shed". This shell game with one unit compressor in operation while the other was in "shed" mode continued until we decided to solve the problem and have our 2003 Fleetwood Expedition professionally converted to 50 amp service.



Now with 50 amps, we can operate both AC units at the same time with no problem.

[ret60sp]

Originally Posted by Servo

HVAC Experts - or Anyone else who has HVAC knowledge who has the older Intellitec ECC thermostat (pic attached) that sheds power between the two units (2000 Pace Arrow Vision here - 34N)

We just had 2 new AC's installed but we're having a similar problem that we had before the old unit bedroom starter motor blew.

When the thermostat is set to "Auto Cool", once the desired temp is achieved, the compressor kicks off but the fan stays on, going from 40% humidity to 79% humidity over the course of a 6-7 hours being away from the rig, and the fan was still blowing when we got back.

Correct me if I'm wrong, but isn't the purpose of auto cool to get you to the desired temp and then kick off everything until the temp rises back up to an undesirable level?

To me, just getting a dehumidifier is treating the symptom and not the disease. I want to fix the problem and I can't imagine that this is operating as intended. My gut tells me there's a wiring issue somewhere but I'm far from an expert in HVAC so maybe I am missing something.

Note - I haven't tried it with these new ACs (since they were just installed this morning), but the same issue happened with the old units when placed on Hi Cool as well. That I can somewhat understand since you're placing it on a full-time ON setting.

Prior to our decision to have ours converted to 50 amp service, we did install the AC Easy-Start systems on both HVAC systems. This system divides the start surge of the blower fan and compressor by about 1/2 second, which lowers the actual surge power demand by more than 50%. It actually improved our ability to operate both AC units up to but excluding outdoor temperatures over 95 degrees. The head pressure on a compressor that is attempting to short cycle by starting and stopping more frequently in higher temperatures meant we didn't have enough power to operate both AC units at the same time if the outdoor temperature was above 90 degrees. The easy start improved the dual use environment from what was a limit of 84 degrees to temperatures just over 90. So depending where you intend to camp, you might see a solution in the easy start system, but I can definitely tell you the real solution is found in a 50 amp conversion.

[RichKimball]

I put standard household thermostats in place of the remote thermistors to control the a/c.
The ECC had to be placed in AutoCool but the household thermostat then controlled the fan and compressor accordingly.

It was years ago and on a different coach..but did work well for us. This mod was for cooling only. The heat I left controlled by the ECC.

[phoneman01]

My system does the same thing. I had to have some contact clean-up done at M&M Electronics(Intellitec's support) and asked the tech about this. He said that it is normal operation for this ECC. The degree difference of fan and compressor seems to be extreme. The specifics are on page 4 of the service manual which I got online. The fan will actually run all the time except on a real cool evening. I would rather the fan and compressor shut of and came on simultaneously.
mevman: I would love to know a little more info about how you resolved this. What type of thermostats did you use to replace the thermistors? How did you keep the heating(works well) working without thermistors?

[RichKimball]

I did find posts and diagrams of others that had done this and followed their lead. Those pics and info are on another archived hard drive of which I don't have access to.

I know it worked and I used standard Honeywell or Hunter household thermostats that ran on battery power. It was great as the a/c fan turned off when it wasn't calling for cooling. It wasn't a difficult mod. Just put the thermostat where the remote thermistor was and tied the thermistor line into the thermostat.

In recall, I guess I did use the heater portion too of the household thermostat.

I'll do some searching and look around the internet a little and you might find some info as well here on iRV2.

[n5979u]

How big of a job to convert 30 amp to 50 amp and cost?

[spyderRV]

http://www.irv2.com/forums/f54/quest...ml#post2957373

http://www.irv2.com/forums/f107/cole...ml#post4040237

[garyre]

I have the two A/C Intellitec ECC control system and need to replace the front A/C.
The current unit is a Coleman #8632B6795 ducted unit.....installed on a 2007 TerraLX 30A service.



Do you know the replacement A/C's used on your rig and if they we a direct replacement without any modifications?


Plan to purchase and install myself and trying to locate a replacement for the outdated model. After searching around it seems the Coleman replacement model is 48257C969 but cannot confirm it is a direct fit.


I really do not want to convert to a 50A system, since the ECC Controllers, Surge protection, fuse panel busses, inline wire, plug, etc would need to be changed.

[ret60sp]

Originally Posted by n5979u

How big of a job to convert 30 amp to 50 amp and cost?

Q: How Big of a Job
A: The short answer: It depends on too many variables.
A: The Long Answer: We did it. Converted from 30 amp shoreline service to 50 amp shoreline service.

First understand that your existing system needs to be evaluated to determine how far into the electrical system will the existing wiring need to be replaced. You'll need to determine what role your existing generator can play.

Start with determining if the generator is priority over the shoreline. A 30 amp shoreline provides 3600 watts of power, whereas any generator over 3.6Kw (like an Onan 5K or 7.5K) is more than likely wired as the priority over the shoreline and can provide either 5,000 watts, 6,000 watts or up to 7,500 watts to the coach. This might explain why so many 30amp units have gensets with high hours. The generator in those units is in most cases able to operate just about everything at the same time.

Converting from 30 amps (=3600 watts) to 50 amps (12,000 watts) is, or can be, relatively simple. First you need to understand that you are converting from a 3 wire system that has only one primary conductor that is sized to carry 3600 watts of power, to a 4 wire system that is designed to carry 12,000 watts of power. Where the 30 amp only has one primary conductor, the 50 amp has two primary conductors. The 50 amp’s conductors are not 25 amps + 25 amps. They are actually 50 amps + 50 amps! So you cannot just add an extra primary wire. The wire size of your 3600 watt primary wire is probably 10AWG where the 50 amp will call for a 6AWG.

So your shoreline has to be completely replaced.

Whatever your shoreline connects to has to be replaced (line analyzer, shore disconnect, etc.)

Your transfer switch must be replaced. It senses the inlet power and switches between the shoreline and the generator. What you have now is most likely designed to set the priority to the generator and you’ll need to change that and have the shoreline become the priority.

Your AC (and possibly the DC electrical) panel will need to be replaced.

So lets recap: As a minimum, you’ll need a (1) new shoreline, (2) new transfer switch, (3) new AC electrical panel.

You might be able to keep your existing inverter/charger if you are in love with it and don’t need to invert much DC power into AC power. Now would be the time to upgrade that piece of equipment as well if you want to take advantage of more modern technology.

Q: Cost.
A: The parts (shoreline, transfer switch, some new larger wires internally, AC electrical panel, & new breakers) are the absolute minimum parts necessary, and they collectively cost less than $1,000.

It’s the labor cost that really makes this project stand out. I wouldn’t recommend taking this type of project to your local RV center. What you need, in my opinion, is a Marine (boat) specialist. That industry does high end yacht power conversions all day, taking the older yachts with 30 amp shoreline power systems to bring them up to code with 50 amp systems. That is what we did, and although it was more expensive on the labor side (per hour), they did it faster (less hours) and used top tier equipment (Victron Energy) to produce a system that is fantastic. The labor was $5,000. The added VE equipment another $2,000.

If you choose to upgrade your system to a Lithium Iron Phosphate (LIFEPO4) house battery bank ($3600), increase the inverter charger from a 1000/100 to a 3000/120 ($1400), making it possible to operate at one HVAC system on the battery system, upgrading the engine alternator from 130 amp to 300 amp ($785), making it possible to operate that one HVAC system while driving down the highway, things add up.

So there are many variables. We have sunk the better part of $15,000 in the upgrades to our Class A, and I’m not finished. My next upgrade is to take the unit to JC Refrigeration and have them convert our refrigerator compressor to one of their 88 watt DC high efficiency units. What we have now consumes 556 watts and doesn’t get cold enough to keep ice cream hard.

You could argue that “it would be cheaper to just buy a newer coach that is already 50 amp service”. That might be true theoretically, but you’ll still have a non modernization issue and a consolidation of cheap parts that will undoubtedly leave you stranded – most notably the engine alternator = one that most coach builders know is grossly insufficient to power the unit for nighttime driving.

So to answer your question “How much does it cost?” It all depends on if you are going to do it yourself and be minimalist = <$1,000.
You are going to hire it out to your local RV center who have NEVER actually performed such an upgrade = $10,000.
Take it to a Marine Electrical Center = $7,000

[spyderRV]

http://www.irv2.com/forums/f54/50-am...ml#post4159647