Any experience with a Havis Rear HVAC

[aarcaris]

Hey all,
I just went and looked at a E250 van that I am considering getting to start my own home brewed sportsmobile build and noticed something I haven't seen before.

It looked like it had a E-Series Van HVAC Rear Heat And Air Conditioning Unit By Havis. It didn't have any of the ducting, just the motor and the factory rear AC controls up front. When I was trying to get it to run it didn't seem to be blowing any air, but the from heat and AC worked great! Was wondering if any one on here had any experience/inputs on this system.

I don't know how much of a pain it will be to get it working or if its worth it to keep. Also if I do just take it out does any one know how much of a process that would be?

[arctictraveller]

Most interesting system, but the product listing pretty much gives zero information, just a couple photos of the ducting and evaporator. The Q and A section is blank and there are zero reviews. 23K BTU's would make this worth fixing if it were mine and since the Ford A/C is working and the rear evaporator is connected to the Ford system, it may just be a case of getting the rear evaporator fan running. I'm guessing it only works when the engine is running though.

[JWA]

Originally Posted by arctictraveller

Most interesting system, but the product listing pretty much gives zero information, just a couple photos of the ducting and evaporator. The Q and A section is blank and there are zero reviews. 23K BTU's would make this worth fixing if it were mine and since the Ford A/C is working and the rear evaporator is connected to the Ford system, it may just be a case of getting the rear evaporator fan running. I'm guessing it only works when the engine is running though.

Good advice and certainly worth spending a bit of money with a qualified vehicle A/C repair shop before scrapping the existing. Typically the weak link in rear A/C systems (aftermarket or OEM) is the refrigerant lines from the components up front. Arrcarris you don't mention if the front A/C is working? If not has it been checked for proper operating pressures?

Removal would depend how it was installed. If its tied into the front system you'll have to evacuate and re-claim any existing refrigerant and change some A/C lines in the front system, converting it from the rear A/C to a front-only system. That's not tremendously difficult, the existing compressor reused with the receiver-dryer and one or two of the flexible A/C hoses--I have part numbers etc when I completely deleted my own 2005's factory rear A/C system.

IF you go the delete route there are block off fittings where you can avoid replacing hoses etc (I have a set for E-Series I'll give you, a $79 value BUT they're NOT recommended as they can and do cause oil starvation to the A/C compressor.

Anyway PM is always available if you like---hit me up anytime!

HTH

[IanF]

It looks like a standard conversion van rear A/C system - just exposed for all to see. Yes, it's tied into the front A/C system and engine driven compressor.

Technically, you could disconnect it from the engine system, install a 12V compressor unit along with a separate condenser and receiver drier and run it off a battery/solar system if designed properly.

Something like one of these:
https://trumaheaters.com/collections...sor-7500btu-hr

[JWA]

^^^You'd most likely want a TXV or thermostatic expansion valve as part of such a system. If such a device is capable of 7500 BTU instead of the Havis's advertised 23 BTC cooling you might have performance issues, one being TOO much cooling in an insulated or otherwise built out van.

Double check the amp draws on the Truma unit---would be important if building for solar power whether as auxilary or primary/sole power source.

[IanF]

The TXV is typically on the evaporator. Might have to be replaced, might not. Too much goes into designing an A/C system to go into details here. This also doesn't even mention the heater core units like this usually have, which could be connected in numerous ways.

Yes, a 12V compressor draws a lot of amps. That goes without saying, hence the "designed properly" comment. These are the same compressors used in some of the newer RV's fitted with large battery systems and no generator. Which is also why they're 12V - so they can run directly from the battery system rather than through an inverter and incur additional efficiency losses. Even then, you aren't running something like this off a couple of deep cycle batteries. More like a bank of lithium batteries. Not cheap, but neither are generators than can fit under a small van.

If you want off-grid A/C, pick your poison. Living in the mid-Atlantic "land of oppressive humidity" this is a subject I've spent a fair amount of time researching.

[arctictraveller]

Originally Posted by JWA

you might have performance issues, one being TOO much cooling in an insulated or otherwise built out van.

That's a dream come true for me, I'm getting bids on a mini split for my house and have told the contractors I want to be able to see my breath when it's 100 degs out.

[JWA]

Originally Posted by IanF

The TXV is typically on the evaporator. Might have to be replaced, might not. Too much goes into designing an A/C system to go into details here.

I'm aware of that---I built and installed Liebert Corp A/C systems for 11+ years.

Originally Posted by arctictraveller

That's a dream come true for me, I'm getting bids on a mini split for my house and have told the contractors I want to be able to see my breath when it's 100 degs out.

I get that sentiment but don't install something over-sized---it might cool faster but it might leave too much humidity in the house if its "too big"

[aarcaris]

Thanks everyone for the inputs and information! I think I am going to go ahead get the van and then see if I can do some more in depth looking at it to see if it will be possible to get it running.

[arctictraveller]

Originally Posted by JWA

I get that sentiment but don't install something over-sized---it might cool faster but it might leave too much humidity in the house if its "too big"

That's very good advice, thanks. Fortunately, humidity isn't an issue where I live, but I suppose too large a unit might short cycle a bit more. Never the less, I'm VERY heat adverse, so some extra tonnage will be welcome.