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Wow, can't believe this post is still going on. Have not read the last few pages but here is what I still know since 2005 when this post started.

I still have a lot of building with the original pneumatic controls in them and working just fine. Replacement parts are still easy to obtain in 99% of the cases. Air does not care what manufacture name is on them. It just wants to pass.....

Comparing Pneumatics to DDC is impossible because of the business frame work under which they are promoted...side stepping any technical talk. Pneumatics, once installed, take maintenance, some repair, some replacement. It's that simple.

DDC is promoted/sold as the elixir for all good in controls but things like misapplication (compared to pneumatics it's much more in my experience cause most of the designers/techs/sales people don't even know how the HVAC systems work), software glitches, misunderstanding of what the controls can actually do(as they are sold as being able to any & all things) AND the inevitable costly yearly or so software updates ~~~~ plus the fact that most of not all the time the purchasing customer purchases the hardware but does not & can not purchase the software, well the customer is in for a surprise when they realize that they just married this control manufacturer/contractor without knowing it.

I have a large expensive condo high rise switching over to DDC's now and the general manager/facilities manager asked me my opinion considering I have done work on this property for over 10 years...so I asked them to ask the DDC contractor for a future cost estimate AND a cost of future software upgrades along with some history of some of their other customers cost history.

Not a word yet. Silent. But the condo board, most being the new younger "high tech" folks in the "high tech field" are going forth with this conversion. Full steam ahead said the captain of the condo board that could be the Titanic is the way I see it. But something but find out the true costs first cause they are going to be "married" the is label for years to come.

They said they would, if they could, save all the pneumatics for me. If they don't scrap their compressors I'll probably put some of the machine room pneumatics back into work again.

My ex was direct acting with a narrow proportional band

yea the sqrt extractor, l o l , was likely the peak for pneum days, suckers were expensive to run tho, like 400 scim. !

my all time favorite was the pneumatic "Square Root Extractor"

I also started out on pneumatics controls and then into ddc controls. I still prefer pneumatic actuators because of their power and ease of replacement. I'm so glad I came from the era of pneumatics because I had a chance to actually see the components that are now software processes like low/high limits. averaging relays, reverse volume reset controllers etc... I do remember some of the control cabinets not be for the feint of heart. Nothing like a whole wall of receiver controllers, relays, adaptors, time clocks, day night set back, reversing relays, fire alarm override modes, shunts, etc.... Then of course the question was always just tell me which knob to turn to get it working again!!!!!!!!

Originally Posted by Control Man

Ran across some old HONEYWELL controllers you might remember

HONEYWELL MD7900 A1K3 Electric Control System big old grey box 8 knobs and vacumn tubes sharing an outdoor air sensor for 4 controllers controlling 4 large supply valves. It still WORKS but being 40 years old they want it updated.

Boss was cleaning up the attic here in our office, found this gem. It's headed to a children's museum.

They are right about the money. The property owner sees it like this:

Is my money better in the bank or for repairs/replace?
Am I better off (cash flow/payback/accounting advantage/energy) to replace or fix? (note replace may be more expensive than fix but it doesn't matter overall)
Make decision. Decision may be do nothing, fix, or replace.

....and it's different every time.

Anyway, what I'm saying is your sales staff may not be technically competant... but they may understand money really well. It's about the money.

But the field people in these branches support the office staff and thier dicisions.I think the function of a good salesman is to present all the options,then let the customer decide.These so called"specialists" and sales reps have little system knowledge compared to the experienced service fitter,but they will be the first to tell you that doesnt matter,money does.

Well, how about spending inordinate amounts of time going through pneumatics "putting it back" to original, or getting hung up replacing alot of components because of lack of care when at that time it may have been more beneficial to go DDC.

Works both ways. Just a matter of doing your job and using some discernment. Easy to get either the modernization bug on DDC or overly nostalgic about pneumatics. A wrong decision is simply wrong.

What amazes me,we had a new owner take over a large medical facility recently,and called my "controls" co to come take a look at it.Come to find out the original pneumatics,though somewhat neglected,was still in place and operational.First the co sends three office types to look at what they know nothing about,of course it includes lunch.The owner states he wants some options,so the next day no less than 8 people show up from our office to do a partial {ballpark}takeoff.Days later they end up quoting the poor guy just under a mill to rip out all his stuff and go ddc.They didnt get the bid,but youve got to ask how in the world mgt can not listen to a customer,not use the option of pneumatics they sell,paintbrush a bid then take the loss on maybe 100 or more hours of shop time by the sales and eng staff.Sound familiar?

This property manager has to go to bat again with the owner to shell out the money to fix the controls. I did the math for him and told him it's costing him about $300 a day until it's fixed so I expect that when they do approve it they'll want it done a month ago.

Twenty five years ago just about this month I had a call at a college campus in a very large and new building that was very cold everywhere.

Went to the machine room to find the boilers blasting away but a bank of OA dampers sitting 100% open. OA temp was in the 30's during the day and 20's at night. One of the local campus shop guys stuck a pop cicle stick in the mixed air receiver controller to keep the dampers open cause of a too hot office call he had gotten a week before.

Took about 3 days for the building to heat up again!

Originally posted by lma
pneumatic....the "ultimate" open protocol

lma

That's a good one. Quoted a property management company for some repairs last month. They had another contractor in there for a couple of months and they had bypassed all the summer/winter switches then they disconnected outdoor damper linkages when they still couldn't get the desired effect. Mixed air temps are all over the place on this hotdeck/colddeck system. Got a call Thursday saying that the gas bill was more than double a normal month. Any idea why!

AND, I just picked up my mail and in it was another school/church pneumatic control customer that I had done some work for about 7 years ago. And a few repairs about 2 months ago with some recommendations. The administrator has given me to go ahead on repairs and bringing the systems back up to par.....again.

I already did all this 7 years ago. Since then, they got another company that led them down a costly path. Things like all the unit vent air filters are plugged. Some belts are broken or falling off. The original thermostats were disconnected during a remodel and never hooked up again. The entire church/school was run off a time clock hooked up to the boiler, etc, etc, etc.

Two down and more to go.

pneumatic....the "ultimate" open protocol

lma

Guys
All is not lost this week. I just replaced a pneumatic air compressor on an old 3 story school that had been running wild for a year cause the other compressor had had it and had not been running. The previous company installed a 1/4 HP in place of a 3/4 HP and couldn't figure out why it wouldn't work.

The school administrators are extremely happy considering they have been bombarded with expert advice that all the controls need ripping out and replaced with DDC stuff.

Once the new compressor was installed I went quickly through all their controls and found only one leaking. The controls were installed in 1968. Finnally, maybe I won't get called to the principals office.

I literally saved them thousands and thousands of dollars.

One system at a time.

So VERY , VERY true, went through the DDC expert BS last week until the little DWEEB found out I had installed the DDC portion of the job 9 years ago and the PNEUMATIC 12 years ago. Building operator sort of let him know there was only 3 service calls in the past 11 years and 27 in the past 6 months. Funny part is the DDC expert started playing with everything about 6 months ago.

[Edited by Control Man on 02-28-2005 at 02:54 PM]

SO true,these guys also have a huge dose of arrogance and disrespect,and an anybody can do it attitude.In defense we clam up then they say we dont get along.Lets see,we studied and MASTERED most all systems and controls,and they come along and are given all the time in the world to add additional code to a screwed up sequence because no matter how long they spend ,the job is so fat it cant tank.The sales guys arrive in thier giant SUV,and work a territorial scheem that has them on a never ending spiral.

old fitter
You hit it right on. It's a skilled field that has been taken over mostly by gimmics to sell stuff and keep the customer dependent on them. But that's true almost in everything electronic these days. Just look at the computer industry, hardware and software.

I use to do A LOT of troubles shooting for a DDC guy who installed his crap on HVAC systems and had no idea what he was doing...although he had been in the business for over 10 years.

We had lunch once and he told me what he had made in his FIRST year of business, which was over twice as much as I had made that year. He just pushed systems without regard to the customer. I was working my butt off to help him make his sytems work, which I did most of the time. Other times it was just too hopeless so he sold the customer a new DDC control system.

It's pretty sick.

I have taught and calibrated pneumatics for over 25yrs.Show me a guy with a good understanding of all the different brands and you have a person that has a huge "system" knowledge,and can understand conrol of all mediums and the equipment that goes with it.It is a shame what the socalled control contractors have done with the pneumatic option.Because thier sales achievment is strictly numbers,they wont even present this still good method of control,even though thier company builds the product!The profit margi is not there with pneumatics and fitters as compared with circiut boars built in Mex and a 15/hr tech.They typically charge 120+/hr for their service calls.The one I work for now,at another branch had a phone center set up.They would receive your service call,pass that to an on line tech seated at a pc,they would bypass or correct your problem,and bill you 1hr.Imagine the cash rolling in as opposed to a fitter arriving in a van to calibrate a stat and controller.These days I am removing pneumatics more than servicing them,all because of corp greed.