decoding Johnson Controll RTU's

[indycar89]

A new twist from me. Thermoking reefer units brought me here back in 2011.

Now it's rooftop HVAC Johnson Control units . I'm told that these are 'proprietary'? I try to google a model number and come up with nothing. Is there a resource to decode model or serial numbers for these units?

Bought a property last Spring, and had a company out to do PM's on all the rooftop units. Turns out they PM'd only one unit and our building manager didn't catch that. Now we have 2 heat exchangers cracked - and the filters looks like mud.

Trying to get info on the units, and opinions on the value of replacing the heat exchangers vs unit replacements. We do have a couple of *other* HVAC companies coming up with estimates.

Are we married to using Johnson Control parts, etc with these units?

Lastly - generally is it possible to change out control system away from Johnson Controls with these units?

Thanks in advance.

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[frank]

It''s a York J10-ZF rooftop packaged unit https://docs.johnsoncontrols.com/duc...Package-Unit/B

The filters look like standard pleated panel

https://www.johnsoncontrols.com/hvac...SplitDXSystems

[indycar89]

Thanks so much, Frank! Just what I was looking for. Looks that that covers both our 2 larger units and our 4 smaller units.

Kind of laughable - as I said we recently purchased this property. It was built with grant money originally and wasn't managed well. Since we've had this issue - some suites getting 80 degrees and others being freezing, I've been up early to check temps. A tenant this morning said she was told (by previous management) that the RTU's were 'prototypes' (and discontinued and no parts) and that's why they always have these temp issues.

I find that a bit hard to swallow - that has to be a line from the previous folks to placate the temp swings? They went further and.... wait for it . . . supplied that suite with several space heaters!

QUESTIONs:

I get that with muti-suites and floors (we have 3 floors) that temperature issues are going to be a ongoing issue. Am I right about that - or are 'current' control systems better at eliminating these issues? The building where my wife works has the some kind of temp issues.

Suites have one or two "thermostats' that currently allow for a 5 degree swing. That seems like a lot of variance - especially if a suite has two stats and they are set opposite of each other. Would a better range be a 2 degree or so swing?

Am I right about that - or are 'current' control systems better at eliminating these issues? The building where my wife works has the some kind of temp issues.

Thanks again for any insight as I try to gain some foundational understanding.

[frank]

From what you describe, it sounds as though the units are providing heat/cool to multiple spaces via a ductwork distribution system.

This is always a difficult task, as most spaces have different heat gains/ heat losses, some situated on the side of the building where the sun impacts and others on the North facing elevation.

Also, different tennants will require different temperature settings.

How do you achieve this with a common ducted system? Without knowing how your system is installed and what control functions it has (assuming volume control dampers) it is difficult to offer advice on possible improvements.

It may be worthwhile asking a local HVAC consultant to have a look at the design and offer advice. The cost of this should repay in energy saving, as well as less earache from the tennants

[indycar89]

Yes, each RTU has 2 or more zones, with variable dampers. We did have Johnson Controls over today and they did some reprogramming. One crazy bit - these units have (had) been set to occupancy 25/7!!

But all tenants say the building always has had HVAC issues - which sounds like is the nature of the beast with this kind of system. I asked the JC tech if we would see much much improvement with a newer controller - he didn't think so due to our multiple zone system. Building was built in 2011 and the used a JC controller that came out in 2006 and I believe they stopped supporting in 2012.

We have a second company coming out Thursday to look at our system - both to give an estimate to replace the 2 heat exchangers vs replace the units.

If we were to replace the RTU's (2 of them) with a non Johnson Controls (york) units - would we run into even greater 'controlling' issues.

I'll check back after our meeting Thursday.

One other help? Any idea which unit this is? I should have checked before I left to see what area this small unit services - but didn't. I've changed out the filters in the other units, which all had twist knobs on the panels. This bad boy is all nuts and bolts on the panels. My guess is the filters are next to the power box like the others?

EDIT: Photos added to new post below.

Thanks again!

[frank]

Can't open your attachment

[indycar89]

[indycar89]

Sorry Frank! I was wanting to use higher res photos, I think I've got that settled now.

[indycar89]

I received two estimates for heat exchager replacements. One company wants to use a crane to hoist the exchangers. The other company does not see a need for a crane, that the exchangers will fit through our standard roof hatch on our 3 story (2 above ground) building.

Any insight on this one way or another?

These units were installed in 2011. In general, how many service years should we be figuring out of these RTU?

Thanks again. I have found manuals online, so I'm digging into those.

[frank]

Seems like you have had some 12 years service out of these units which seems about right if they have been in constant use during that time.

Bear in mind that technology has moved on in that time and opting for newer, more efficient units with warranty, instead of spending on repairs, will save you dollars in the long run.

I wouldn't worry about whether a crane is needed or not as once you contract someone to do the work, how they achieve it is up to them, and all costs should be included in the agreed job cost.

[indycar89]

Thanks again!