A.O. Smith water heater. Big problems. No help. (JohnNY) **Updated 3/27/15, 11:30am**

EBEBRATT-Ed

when I started in the business I worked on a lot of "antique" oil burners. A lot of them had strange oem motors, Petro burners with step shafts, pumps were about the only thing that was standardized even then you needed 4 pumps (nozzle left, nozzle right), 2 clockwise and 2 counterclock. transformers were all different mounting with some weird universal bases, buss bars, ignition wire with crimp on ends. Blowers were all different but at 1725 rpm they seldom needed changing.

When Carlin came out with the 100crd and Beckett with the AF (late 60s?) we thought we had died and gone to heaven. Motors, pumps, transformers, and couplings were pretty much interchangeable. So we went from needing a lot of parts to fewer parts. Now it's going back the other way.

DanHolohan

More from Seth Godin on this topic. Note the sixth point he makes.

Shane_2

John,

Any update?

Did the AO field service rep come out and explain how the new version of the same heater (that worked for three years) was now undersized?

SWEI

Gordan said:

I have a spare MCBA and combustion blower "in stock" for my very own TT PS60. I was glad I did when a huge power surge during an ice storm blew up those, and a number of other things in my house (and others), in the middle of cold cold winter.

That same MCBA and blower will service multiple boilers, and with one more blower you can cover every size from 60 to 250. Smart people.

Hilly

It's too bad money wasn't a concern. It would be nice to get to the bottom of the mystery. I wonder if there is somebody stealing some water in there somewhere (like mentioned above) It really doesn't seem like there's a rhythm to when you lose hot water. Be nice to have a meter put on the hot water outlet pipe and setup a camera and clock. But I know this is the real world where time is money and witch hunts don't usually turn out to be efficient money making projects. I really cannot believe that wouldn't just give the replacement.

tim smith

Good modcon, braze plate heat x and good quality glass lined storage tank for high production hot water supply is what I really like. The high efficiency water heaters have a realistic life of 8-12 yrs. Not very good for quite expensive tank w/ flame in it! I know that is simplistic but really irks me. But if I put a 200 gals storage tank in, oversized braze plate to stay in condensing and a "qood" vertical firetube condensing boiler, I can produce hot water on and on. I stock the $$ parts for these boilers pretty well. Probably 10K + worth of parts just for the condensers I install. But they tend to run and run with annual maintenance. I have although had a slew of a certain mfrs blowers fail on the 399s and bolts popping off heads of heat exchangers of same. This may be leaning me towards another mfrs boiler that I install already 30% or so of the time. Time will tell on it as the prior mfr I mention has had there boiler out longer than most.

JohnNY

UPDATE:

A.O. Smith sent a technician from their Field Service Engineering team and it was like someone had opened a window. Having a knowledgeable technician there who was proficient and savvy in the language and design of where the Cyclone came from and how it functions today, was a breath of fresh air and all I really ever needed to put this thing into a state of reliable function for the application.

I’ll refrain from direct quotes because I wouldn’t want to wrongly convey the sequence of operation of this unit on this forum. There are a lot of non-industry people here that might misinterpret and then pass on inaccurate information.

In a nutshell, the Cyclone is a gas flame-modulating unit, a function that ultimately saves fuel and is a proven method of accurately meeting and maintaining a target temperature efficiently.

In this case, however, modulation takes several things into account such as two temperatures within the tank, time that it takes for those temperatures to change, and an algorithm to provide a run time at a specific flame intensity to meet the current demand.

The issue is that in this, or maybe any restaurant, that demand changes sometimes drastically and at unpredictable points in the recovery process.


When the tank temp drops quickly due to a large and sudden intermittent draw the integral logic is sometimes “caught looking” when it should be swinging for the fence.

In this particular case, modulating flame is not the best technology and that process is the only difference between the new water heater and the one that it replaced.
In A.O. Smith’s defense, the fact is that if my water heater were significantly larger, this almost certainly would be less of an issue or perhaps not an issue at all.

As a professional, I specify and install conservatively based on factors like proven math for the application, performance history, possible future changes in demand, and cost, without giving in to the common compulsion to grossly oversize.

I am set to receive two new replacement parts that will allow me to eliminate modulation and have the unit run in high-fire at any call for hot water. The potential disservice is that the water temperature in the tank will almost certainly overshoot at times by a few degrees. Our previously installed mixing valve will greatly minimize any scalding risk at the points of use, so I’m not concerned.

Clearly I’ve been very vocal about this whole episode and I’d like to take this opportunity to thank all of you in this wonderful and unique community of industry professionals and lay persons alike, Dan Holohan, my wholesalers at West Side Supply (Bill, Jeff, Jerry) and of, course, A. O. Smith (Thank you, Scott. Your professionalism is rarely seen these days) for all your support and for lending an ear.

When I get my new parts today or tomorrow, I’ll consider this whole issue resolved and closed.
My best to all,
John (JohnNY) Cataneo
New York

Steamhead

Thanks for the update, John. But by my reckoning there is still a huge problem here. The heater was installed in December. It is now late March. You've been dealing with this for over three months. That's way too long for you and your customer.

This should have been resolved in a couple weeks' time at the most. But it took over three months and this Wall thread for A.O. Smith to realize that this wasn't going to just go away and that they had to get off their tuchases and get it fixed. Fortunately your customer knows you well enough to realize this wasn't your fault, but the next time we might not be so lucky.

What we've seen is a reflection of A.O. Smith's corporate culture. Until we see that this culture has permanently changed, we can expect similar responses to problems with their equipment. And at least in my company, this will affect our position when customers own or ask about A.O. Smith equipment.

4Johnpipe

Hopefully this will all be water under the bridge...

NYplumber

Glad you got this resolved John. If you can, please post photos of the parts coming out, and going in, so one can see what hardware is necessary for the change and hopefully help a tech recognize this issue in the future.

Fred

Hopefully, at a minimum, AO will add a statement to their tech manuals, installation guide, and Supplyhouse/sales brochures, maybe even publish a technical bulletin that discusses high demand installations and modulating burners and any other tech issues they are aware of with there products and/or specific technologies in general. Sure would help the guys in the field.

Charlie from wmass

Sometimes being able to walk away with out expecting a call back is a great feeling. It is a terrible feeling doing things right and them still not work right. Glad you have a solution.

RobG

It's still hard to believe that tech support could not figure this out over the phone. I'm sure that if the new control logic was explained to you over the phone you would have just ordered the new parts AND PAID FOR THEM just to put the problem to bed. Instead, they had to drag it out and pay one of their own people to travel down and look at it just to say "you need some different parts". JMHO

hot_rod

And the rep should be in the loop and aware of any TB relating to upgrade or replacement.

Is the control logic explained anywhere in the I&O or tech sheets, or do you need to get a service rep out to clear it up?

Sounds more like a communication breakdown, is Scott or the service support person knew of the glitch others in the loop must, or should also.

icesailor

EBEBRATT-Ed said:

Don't know how true this is but I was told that if parts sit on the shelf at the supply house longer than 6 months without being sold that the supply houses have to pay tax on them and that is the reason they want to keep stock limited to things that move.

Don't know if it's true or just a Taxachusetts thing

It has NOTHING to do with Massachusetts. Its part of the FIFO )First In, First Out) and FILO (First In, Last Out) accounting of inventory. Anything left in inventory is considered profit, and you have to pay profit/taxes on it.

Its an accounting rules change made a few years ago that made it so bookstores no longer inventory any books. They let others do it and pull stock from other sources. It keeps cash flow mean and lean.

If you're wondering why wholesalers have no inventory, look no farther than the tradespeople that get all their bread and butter items from PEX Supply and other Internet "Wholesalers".

I traded with a family run supply chain that has grown to over 55 stores. They built a store where I lived and the owner told me that he wouldn't build the store unless he put $1,000,000 worth of inventory. And did. I could walk in on a Monday morning with a list of 25 items for a job. And walk out with all 25 items. I could go a few blocks away with the same list of 25 items and leave with 19. So I go to the first place to get the other 6. Why go anywhere else?

Look at Amazon.Com. Look at different items. They are being shipped from all over. They aren't inventoried by Amazon.

The need for next day air delivery isn't MY fault. Pay or wait.

JohnNY

@icesailor please stop commenting on this thread. Too many drift posts. Thanks.

icesailor

RobG said:

Some of the reps have stepped up to the plate and stock parts for the products they represent and sell direct to the contractor. The wholesalers could care less about losing the sale of a $300 fan, all they care about is the $5000 boiler sale.

Interesting point of view for the wholesaler.

A wholesaler is as relentless (more) to collect an outstanding debt of $50.00 as he is from so0meone that owes him $500. Because if 10 people owe him $50.00, it equals $500.00 And many just ignore a $50.00 bill. They find out that the $50.00 is just as important as the $500.00.

icesailor

EBEBRATT-Ed said:

All true. One of the hvac suppliers here they don't have the cheapest price in town, but they stock a lot and do a lot of business because they have the parts.

So, what is that worth to you?

To me, that's a lot and asks for my loyalty. I found that people pay their bills about as fast as you service their needs. The faster I could get in and out, and get the bill in the mail, the faster I got paid.

That CB that croaked that you have to get shipped in, next day or 2 day is stupid money with the USPS. Make someone wait a week with no hot water while waiting for a part because you didn't want to pay for overnight (which you are going to charge back anyway) and then demand a credit card for instant payment when you are done, and you have a conflicted customer. In AA, they call those "Resentments".

EBEBRATT-Ed

@JohnNY this will probably be your first good nights sleep. Glad you can put this behind you. Congrats for sticking it out.

Unfortunately, it shows inadequate testing by the mfg. (not intentionally I am sure) but lab conditions are not the same as a field installation. Sometimes it just takes the wrong mix of circumstances to bring out a design flaw.

Harvey Ramer

It seems their control logic is incomplete. It needs a flow meter to accurately asses the real time demand and adjust the burner output accordingly.

Sounds like your situation is finally getting resolved. That's good. Long overdue But still good. Sad that in today's world you don't get heard till you make a big noise.

unclejohn

Seems we are becoming a world of efficiency instead of comfort. That sucks.

SWEI

Modulating burners are controlled by algorithms. Algorithms with inputs and outputs. Measure the right things, do the right math, and change the correct outputs and it can look a lot like magic. Put one sensor in the wrong place, or choose the wrong equation to represent your intentions and it can all go to hell rather quickly. Tough room.

RobG

SWEI said:

Modulating burners are controlled by algorithms. Algorithms with inputs and outputs. Measure the right things, do the right math, and change the correct outputs and it can look a lot like magic. Put one sensor in the wrong place, or choose the wrong equation to represent your intentions and it can all go to hell rather quickly. Tough room.

Wouldn't it be nice if there was a dip switch or such to just put it in hi-fire if needed. You can do it on mod-cons for DHW priority, why not a water heater. For the price of a commercial heater you should have options and support. JMHO

SWEI

I'm not familiar with the controls, but most have some way to calibrate, diagnose, and test. Could very well be there in some kind of hidden menu or DIP switch setting, or perhaps a service tool.

RobG

SWEI said:

I'm not familiar with the controls, but most have some way to calibrate, diagnose, and test. Could very well be there in some kind of hidden menu or DIP switch setting, or perhaps a service tool.

Then why would John need parts to "fix it"?

A.J.

It seems pretty simple the only thing that has changed is the tank, the model you removed was the same one as the one you put back in so how could it be a capacity issue ? Sounds like they just don't want to deal with an intermittent problem that will take some time to figure out . They need to give you a new tank to fix this, to keep your business because lets face it, you are never going to buy another A.O. Smith tank again if they just leave you with this problem . Hang in there JohnNY you are not alone.

nicholas bonham-carter

Once again, I say that something so complicated, (and untested) should have been able to have been connected to the Internet for remote diagnosis by the AO Smith tech, with no waste of time for Gateway Plumbing, or the restaurant.
The Internet connection could even have sent a message automatically, not only to AO Smith, but also to John, as this fault reared its ugly head in the early days of its installation.
The true test of the manufacturer will be how quickly they can act to prevent this from happening to other unfortunate people, for as we know, bad news spreads like wildfire, (or you can smell the sewage works, from a greater distance than the rose garden!)--NBC

tim smith

I think it is an easy algorithm to write, when the lower tank sensor sees a drop of 1 or 2 degree in temp, it looks at coming on, if it sees another degree drop in less than a minute or some calculated rate, it would ramp to medium or high depending on what flow rate the calculation comes out to. I think pretty simple time/tempdrop/ flow rate computation. Just my simple mind thinking about it.

SWEI

https://en.wikipedia.org/wiki/PID_controller

Larry_52

I don't know anything about the control of this heater but if it incorporates a PID controller for water temp then it has to be accessible to be tuned to the process. Selling with generic Prop gain and Reset settings is not going to be successful, add in the derivative and forget it.

I have rarely seen a PID controller with preset proportion and reset settings work great with its application, without the ability to tune the process live. using a generic derivative setpoint can really screw it up. In fact based on my limited experience in PID tuning I would probably set the derivative to 0 for this process in the beginning.

ChrisJ

The only thing I think I'm misinterpreting is what exactly does "for nearly any commercial application" mean if it can't cope with a restaurant? They certainly have good advertisements, by the end of reading about them even I wanted to buy one.

To be honest, wouldn't any commercial application have the possibility of huge changes in demand? For example when everyone piles into an office building after rush hour and needs to hit the john.

JohnNY

Heavy restroom use isn't a big draw.
When restaurants need to fill large 3-compartment sinks with hot water through commercial faucets with their aerators removed and passing 8-12gpm each, or fill mop sinks/buckets with hot water, or both simultaneously, that's when the tank temps drop.

Charlie from wmass

To paraphrase. I think we are gonna need a bigger heater!

ChrisJ

JohnNY said:

Heavy restroom use isn't a big draw.
When restaurants need to fill large 3-compartment sinks with hot water through commercial faucets with their aerators removed and passing 8-12gpm each, or fill mop sinks/buckets with hot water, or both simultaneously, that's when the tank temps drop.

So basically It's just the wrong product for the job?

What does AO Smith recommend for this application?

Gordan

It is a common strategy for mod-cons to start at high output on a DHW call and modulate down if temp rise warrants it. Not a difficult strategy to implement. Sure, tank temps could still drop due to undersized burner capacity but that would not be a controls issue. If usage hasn't changed and burner capacity hasn't changed, seems like their control strategy isn't quite up to par with what's been common in the industry for decades.

SWEI

Convention hotels are another monster load. 100% occupancy with everyone showering at the same time for an 8:00 AM meeting. Throw in a big banquet operation with thousands of dishes all hitting the scullery at once and you can see some truly impressive loads.

You can almost always brute force it with capacity, but IME the best solution usually involves optimizing both controls and capacity.

ChrisJ

SWEI said:

Convention hotels are another monster load. 100% occupancy with everyone showering at the same time for an 8:00 AM meeting. Throw in a big banquet operation with thousands of dishes all hitting the scullery at once and you can see some truly impressive loads.

You can almost always brute force it with capacity, but IME the best solution usually involves optimizing both controls and capacity.

Reminds me of the early low-flow toilets that you needed to flush 6 times.

Abracadabra

ChrisJ said:

Chris, in their marketing, notice how their MBA grads put "nearly". That's their out. "Nearly" any commercial application.

Dennis Foley

Gas pressure delivery problems. We've had a lot of that this winter in the Boston area, both in NG and in a Propane system. And it can be intermittent depending on the time of day and use outside the building. There is something you can install to record this that the Field tech told me about, but I forgot what it was because I didn't get it.
If you could observe the pressure drop at the inlet when it fires, you might find the problem. But since it's about timing it might be hard to catch.

JohnNY

Gas pressure delivery problems on the coldest days of the year in NYC. That's when the city tells dual-fuel buildings they have, as they are contractually bound, to switch to oil.
I was at the restaurant yesterday measuring to fit them up for a new heater. I'm installing an HTP Phoenix on Wednesday.

I'll give the final details in a couple days and ask Dan to drop this thread from its perch on top of the forum. I've had my last sleepless night over this whole thing.