Different brands? Which are really better than others?

Unknown

I don't work on them... But was told by the guys do with with them, only time they happy when working on RTU is when the weather is perfect.... remember the quote....." The cheaper the equipment and installion, the more it will costs to run.."
Previous posts by others are correct...
Also was told to stay the h/// away from Trane brand....

andy kowalski

difference in brands - which are the better ones?

We are in the process of building our 1st commercial retail plaza for ourselves. Our engineer recommended a Trane system with all kinds of features,when we put the HVAC up for bid, every sub had a different recommended brand of choice (York, Bryant, Carrier)to name a few. Is there a brand that is actually better suited for a commercial exterior roof top unit? The approximate size of building is 16,000 SQ. FT. The retail spaces average 1,000 square foot units with some being larger at about 1,500 square foot. We are currently pricing out one 7.5 ton, nine 4 ton units and two 5 ton models. The 1,500 square foot unit is going to be a tanning salon with around 10 beds.(not sure of the load calculations at this time) Also concerned with the roof curbs if we need to install a larger unit for the space.

Brad White_112

WIthout intent to slam any of them, Andy

The ones we most often specify in our office are, in no particular order, Trane, Carrier, York, McQuay, Aaon.

We normally do not specify rooftop units unless we have to for budget reasons. I take it that is the case here. Generally such retail establishments are the one place where these are a common denominator. Any other means of cooling and ventilating such as split systems will set you apart, but I know the pressures of first-costs.

We find Aaon to be more flexible in meeting particular needs and features, especially if there is a lot of outside air or a higher "tonnage to cfm ratio". You may want to give them a shot. By and large though, most RTU's do not handle outside air above 25 percent very well, 30 percent at the outside. For your general applications the lesser outside air requirements may be fine. The tanning salon may have a lot of exhaust (heat extraction from the "ovens" so may have a higher OA quotient by virtue of that. Insidious loads, those. Sometimes you need a separate 100% OA unit for high-ventilation spaces supplement/make-up what the base unit cannot. Done all the time.

RTU's are a commodity item unfortunately.

Things I look for:

Reference to the ASTM Salt Spray test for corrosion resistance. Airside economizer (if your climate warrants it of course), well-staged DX cooling with hot gas bypass if low loads are expected. Packaged controls- big one. LonMark perhaps for a building of your size can allow economical networking. Packaged electrical components with phase loss protection if available. Price out extended compressor warranties. Select units across the board if possible to have common compressor sizes, dryers, filters, fan parts, circuit boards, etc. so you can stock spares.

Talk to the representatives re: curbs. You may consider semi-custom curbs of a fixed footprint (large enough to fit a variety of units for flexibility) then order adapter curbs for any unit that may change. ThyCurb, ConnMass (or is it MassConn?) and Novia Associates in NH have lines that may interest you.

Hope this helps.

Brad

Steamhead (in transit)

Andy, you might want to consider

not using rooftop units. On a hot summer day the temp on the roof is much higher than on the ground, so RTUs are more highly stressed and less efficient. They lose a lot of heat in the winter. Plus they're more difficult to service no matter what time of year. RTUs are fairly inexpensive, which is about the only thing in their favor. On the other hand, they're "cheap" and I don't mean that in a good way.

For an example of how inefficient these things can be, go here:

http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=260534&_#Message260534

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Christian Egli_2

Unbeatable advice... unbeatable value

What well thought out advice. Your firm, Brad, must do exceptional work. Go ask for a raise, surely you'll get a new title and a medal.

Thanks Frank, for reviving a thread where I went on and on, and good luck to you Andy.

I've had copper thieves climb roofs to vandalize the roof top units and cause great damage to the roof membrane. Heed the advice, stock the spare parts and keep the pail of roof repair handy.

Perry_2

Copper thieves are only one possibility

Within the last sevearl months it was reported that a group of people stole all the Rooftop AC units from a builing in the Milwaukee area (possibly a strip mall). People remember seeing the workman, and the crane, etc. Thought they were doing normal maintenance.

They're long gone and nobody was ever caught. Apparently, according to the newspaper article - this is becomming more common in the US as there is a good aftermarket for "used but good condition" Rooftop units.

The buiding owner was in total shock; and it took a couple of weeks to replace the units and make the building usable again.

Insurance may pay for the replacement units; but does insurance pay for the lost downtime....

Perry

Brad White_112

Forget copper

These guys have Big Brass Ones. Wonder if these are the units you see on E-Bay? Sounds like a good time to keep good O&M Manuals and document the serial numbers... Of course if your rooftop units show up at your local Pawn Shop, that is fair game in some parts and all bets are off....

Christian Egli_2

Play this number game

$5 worth of scrap value to the crook, $5000 repair and replacement costs to the owner, $50000 loss of value on heatless / AC-less property to the community. It is a sickening spiral. I wish $0.50 worth of lead would stop the cycle.

It isn't either a good deal for installers, this cost sucks away the owner's money that would ordinarily go for other work, other work that is more profitable than just swapping RTUs. The only ones making a steal are the metal recycling centers, they double (or so) their money with no risk.

Ken_40

One thing we saw all the time

was the defined area of each store being altered to meet the leassor's needs. Guy 'A' needs 1000 SF. Guy 'B' needs 500 SF. The walls/partitions get moved so the two tenants get what hey need, and the two 75 SF original spec.s get altered by simply moving a steel studde wall a few feet.

However, the HVAC guy put in ducts and registers for the original footprints! No one tells the HVAC guy about the change - which involves virtually everything he already has roughed in, and neither tenant has a system that works.

Beware of this accomodation for tenants. HVAC is a relatively cheap element of new commercial spaces. Removing and replacing it is a HUGE factor.

Been there. Done that.

John Mills_5

Ford vs Chevy

Everyone has their own opinion on brands. We just hoisted 3 up. 2 Lennox T class and one Rheem. The Rheem came with the wrong fan motor. The Lennox both have the blower compartment insulation falling off in 2 weeks. The Lennox design seems more servicer friendly. Don't get me started on Carrier products.

Most techs seem to say the Lennox L-series is about the best but salty in price.

Around here, seems like the chains use better stuff, AAON, L-series, York, Trane where the strip center builders who don't pay for their own repairs use Bryant & Carrier for lower first cost.

We service some strips with splits and condensers out back. They tend to get beat up more. Also no way to have an economizer. In applications with 5 ton and under, pretty easy to do. In 5+ tons, that means air handler with duct furnace or twin gas furnaces which is a lot of work. More metal with splits usually too.

joeoilman

nordyne makes good rooftops too. tappan,westinghouse,frigidaire. mammoth is the commercial/industrial line.

S Ebels

My favorite

I really like the Carrier PG series rooftops for efficiency (if you can call ANY rooftop efficient). Their economizer/enthalpy damper works great for blending in outside air, and you can order them with real live belt drive motors for high static applications andlong motor life. In addition, they have a nice control setup that will run the unit in a dehumidify mode (your tanning room comes to mind) and it's a 410A unit instead of R-22 so you don't have to worry about obsolete refrigerant in a few years. Available all the way down to 2 tons and I think you can get them in two stage heat and cool in the larger sizes. Excellent service access too.

If I had a gun held to my head and had to use rooftops on my own building, that would be the model I'd use.