replace original A/C unit

[Bob Robert]

I need to put a new air conditioner on my 1974 Overlander 27ft A/S. The one that is on there now is a Summer Air Conditioner model # TR21-12 by Armstrong Furnace Company. I believe this to be the original A/C unit. My question is what is the most compatible air conditioner to replace this one? I plan to replace it myself (with some family help) so also the easiest for the do it yourself er. I have read a number of threads and understand I will have to reenforce around the opening before putting the new unit in place but any other tips on instillation would be greatly appreciated as well.

Thanks for your help.

[TomW]

Check out what member Sneakinup did in his '72 Overlander:

1972 27

Tom

[lewster]

3 companies basically 'own' the RV roof air market. #1 is Dometic, which makes 2 flavors of units in the Brisk Air (taller and cheaper) and the Doutherm Penguin (sleeker, more aerodynamic and available as a heat pump also, in 3 sizes; 11K, 13.5K and 15K BTU). Then there is RVP (formerly known as Coleman) that makes a few units and sizes and finally Carrier, who make a couple of different units in different sizes.

Any of these are fairly easy to install, requiring 20 amps of 120VAC for the blower and compressor and 12VDC for the control voltage. You can get manual contols on the units, analog thermostats for the wall, electronic thermostats for the wall or now....portable wireless remote control.

Lots of choices! One thing you should consider is the warranty coverage and the availability of tech support should you have a problem. I would rank Dometic #1, RVP #2 and Carrier a far distant #3. I work on these units every day, and I see far more Dometics in use than any others, with RVP second. There are very few Carriers in use on the larger MoHos and trailers that I service, and I have had some major problems getting warranty support for these units!

Airstream uses Dometic Penguins on all of the newer units, but I just noticed that they went to Carrier for the new Safari Sport line.

Tough choice!

[Lumatic]

I put a Penguin on mine. No complaints except on one humid day I left it on full blast for a couple of hours and it froze up. Probably would not have with a more moderate setting.

A main concern with your usual ACs on Aistreams is what to do with the water condensate. SOBs usually just let it trickle down the outside. Airstreams have a drain pan with a drain tube that runs between the wallls.

I don't remember if its Sneakinup mentioned above, but there was a recent post about someone who put a regular house type AC mounted under the bed and ducted it out.

[Distantdrummer]

I thought that the 70 era Airstreams had to have a special drain pan, and that only one brand was either compatible with the drain pan or only one brand offered a drain pan that would work. I do not recall which brand. (assuming I am correct about any of this).
I seem to recall that Inland Andy was having some special drain pans made.
I've been absent from forums for a couple of years so I think this was discussed at least that long ago.
Anyone know anything about what I seem to recall?

Is the Carrier line actually made by Carrier (who make one of the finest residential unit lines) or is the name just licensed out?
Also do all of the various units have a special gasket for the slight curvature of the Airstream roofs?

[lewster]

Originally Posted by Distantdrummer

I thought that the 70 era Airstreams had to have a special drain pan, and that only one brand was either compatible with the drain pan or only one brand offered a drain pan that would work. I do not recall which brand. (assuming I am correct about any of this).
I seem to recall that Inland Andy was having some special drain pans made.
I've been absent from forums for a couple of years so I think this was discussed at least that long ago.
Anyone know anything about what I seem to recall?

Is the Carrier line actually made by Carrier (who make one of the finest residential unit lines) or is the name just licensed out?
Also do all of the various units have a special gasket for the slight curvature of the Airstream roofs?

DD,

It is Dometic that makes the drain pan that the factory uses beneath the roof units on the newer models. A special auxiliary drain kit is also available that catches the condensate into little cups at the drain holes and channels it into a special hose beneath the unit, and then into your drain hose in the walls of your AS.

This kit comes complete with the cups, tubing, fittings and an additional roof gasket that will allow the unit to be mounted with no pan. Let me know if you need me to look up the part #. Any Dometic dealer can order these or you. They do not sell direct to the consumer.

BTW, all 3 of the manufacturers that I mentioned above make their own units, although they may not necessarily be assembled in the US or use 100% US parts (what does anymore?)

[maccamper]

This is great information, thanks very much. Is there one brand/model that stands out as being the quietest?

We have not had our '74 very long, and it seems that when we ran the A/C last fall, the fan ran continuously and the compressor kicked on when the thermostat called for cool air. Do the new ones operate differently?

One last question, would you recommend that we keep the Armstrong running as long as possible rather than replace it? Thanks very much.

Laird

[lewster]

Originally Posted by maccamper

This is great information, thanks very much. Is there one brand/model that stands out as being the quietest?

We have not had our '74 very long, and it seems that when we ran the A/C last fall, the fan ran continuously and the compressor kicked on when the thermostat called for cool air. Do the new ones operate differently?

One last question, would you recommend that we keep the Armstrong running as long as possible rather than replace it? Thanks very much.

Laird

Laird,

The old Armstrongs are fully serviceable.....you can change components and have them re-charged....just like a domestic unit (provided you can find a qualified the to do the work). You can't do that to the new ones. When they go bad, you chuck them of the roof and replace them!

As for noise level....the new ones are all about the same. The normal mode of operation with a manual thermostat or on-unit manual controls are the same.....fan runs continuously and the compressr kicks in when needed. I you choose a unit with a digital or wireless t/stat configuration, you have the choice of 'auto' mode which will shut of the entire unit when the t/stat is satisfied.

[TomW]

Originally Posted by maccamper

... One last question, would you recommend that we keep the Armstrong running as long as possible rather than replace it? ...

Yes - That's what I'm doing; details are at my Overlander's website.

There is a valid argument for how cost effective my plan is. Yes, I spent more money getting the original Armstrong unit working again than the parts-cost of a modern-day replacement.

But my efforts resulted in a unit full of commercial-grade parts that can be replaced individually instead of collectively if one part should fail.

Most importantly, though, is that my rebuilt Armstrong keeps us cool in 90 degree-plus weather.

Tom

[overlander63]

If you get a unit with a remote thermostat, you can install a digital household type thermostat. It will turn off the fan when proper temp is reached. We have had ours set up like that for 8 months now (using it in Florida in winter is like Summer anywhere else), and it makes a huge difference in noise level when the proper temp is reached. It also helps save electricity because the fan isn't constantly running.

[mj81excella]

Originally Posted by lewster

3 companies basically 'own' the RV roof air market. #1 is Dometic, which makes 2 flavors of units in the Brisk Air (taller and cheaper) and the Doutherm Penguin (sleeker, more aerodynamic and available as a heat pump also, in 3 sizes; 11K, 13.5K and 15K BTU). Then there is RVP (formerly known as Coleman) that makes a few units and sizes and finally Carrier, who make a couple of different units in different sizes.

Any of these are fairly easy to install, requiring 20 amps of 120VAC for the blower and compressor and 12VDC for the control voltage. You can get manual contols on the units, analog thermostats for the wall, electronic thermostats for the wall or now....portable wireless remote control.

Lots of choices! One thing you should consider is the warranty coverage and the availability of tech support should you have a problem. I would rank Dometic #1, RVP #2 and Carrier a far distant #3. I work on these units every day, and I see far more Dometics in use than any others, with RVP second. There are very few Carriers in use on the larger MoHos and trailers that I service, and I have had some major problems getting warranty support for these units!

Airstream uses Dometic Penguins on all of the newer units, but I just noticed that they went to Carrier for the new Safari Sport line.

Tough choice!

would you make the same recomendation for an 81 31' excella? are the a/c's bolted on? How do you work in the roof without caving in? Have lots of questions for my new/old toy. thanks mj

[vswingfield]

Originally Posted by mj81excella

would you make the same recomendation for an 81 31' excella? are the a/c's bolted on? How do you work in the roof without caving in? Have lots of questions for my new/old toy. thanks mj

Here is a link to how I worked on my 83 34' Excella: http://www.airforums.com/forums/f427...ead-40795.html

[CJ of Okla]

Here is a great page on the ArmstrongBay Breeze air conditioner. Check out his info on rebuilding his AC. We have a 69 and use his info to rebuild ours last year. Worked great, we are hoping it last a few more years.

1967 Airstream Overlander

[lewster]

Originally Posted by mj81excella

would you make the same recomendation for an 81 31' excella? are the a/c's bolted on? How do you work in the roof without caving in? Have lots of questions for my new/old toy. thanks mj

I would use a 15K unit on a 31' for sure. These units are made to fit into a standard 14 X 14" opening in the roof and they bolt thru this opening, joining the upper unit to a retaining frame inside the trailer at the ceiling.

[vswingfield]

Originally Posted by lewster

I would use a 15K unit on a 31' for sure. These units are made to fit into a standard 14 X 14" opening in the roof and they bolt thru this opening, joining the upper unit to a retaining frame inside the trailer at the ceiling.

Ditto on the 15K unit!

[mj81excella]

Would it be best to use RVP as to match up with the existing hardware/opening since it has the coleman mach I on it?

[lewster]

Originally Posted by mj81excella

Would it be best to use RVP as to match up with the existing hardware/opening since it has the coleman mach I on it?

Probably easier, but given the existing wiring in place, a conversion to another brand should not be too difficult. All roof airs need 120VAC and a 12VDC feed, which you already have. The roof opening is a standard 14 X 14" size and unless you have a remote thermosat, you should be good to go with whatever you choose.

[pansy]

Lewster, we're changing out our Armstrong TR21-12 Baybreeze with a Duotherm Briskair 13.5. on our '71 23' Safari LY. Just dropped lower unit and pulled like 65 pop rivets on top. Now we have to gently remove from roof for cannabilisation. Rigging up the supports before we take it to Tyler RV near us for install next. Time and energy is running out. Any tips from this point would be greatly appreciated.
Charlie

[lewster]

Originally Posted by pansy

Lewster, we're changing out our Armstrong TR21-12 Baybreeze with a Duotherm Briskair 13.5. on our '71 23' Safari LY. Just dropped lower unit and pulled like 65 pop rivets on top. Now we have to gently remove from roof for cannabilisation. Rigging up the supports before we take it to Tyler RV near us for install next. Time and energy is running out. Any tips from this point would be greatly appreciated.
Charlie

Last time I took off a Bay Breeze, here was no charge left in it, so I cut into pieces (they ARE heavy!!) at the roof and gently removed them. If your unit still has refrigerant in it, it should be evacuated first before you start to dismantle the unit, as any release of CFC or HCFC containing refrigerants is a violation of federal EPA regulations.

Any properly equipped domestic A/C guy can do this for you. If you have a scaffold and can slide the entire unit on to it and get down, it will be much easier.

Be sure that the 14 X 14 opening at the roof is braced between the inner and outer skins with 2 X 2 aluminum 'U-channel'. You can rivet this onto the inner skin to provide a nice base for your new unit. This procedure has been discussed before in these Forums if you need more detail and a few photos.

[pansy]

Thanks Lewster. Getting her down is the problem. I'd like to keep it as one unit for others who may want to trade out parts for sumthin' or just give away locally to some members here.Think I'll try the ladder tec posted here by someone (sorry I've slept since then) can't remember who. My only thought is how to wrap, perhaps in blanket, then secure with ratchet straps, tie on lowering rope, turn on flattest side, and slide down laddie that is fully extended; with the help of a friend. Gotta have air by the 28th. That's our projected launch date for first short trip with our cutie Air.
Charlie