Control company wants to control firing of boiler. What do you think?

RayWohlfarth

I have been fighting this battle for the past few years and would like your opinion. We sell commercial boilers and the control companies seem to have the engineer's ear and want to use their controls to adjust the firing rate of the boilers. I do not think it is a good idea as they are not boiler experts and I feel the boiler manufacturer should control the firing rate of the burner. Thank you for your consideration of this.
Ray

ratio

The way our stuff (air mostly, not boilers) is that the controls push a DAT setpoint and the unit does what it can to make that happen, notwithstanding protecting itself from e.g. short cycling.

Any reason why the controls can't just give you a SWT, and you DTRT to make that happen?

I'd ask them how they feel about taking on the warranty of the equipment, & perhaps more scary the liability of operation.

STEVEusaPA

Sounds like a horrible idea. I guess the better question is Why?
Why do they want control?
How do they explain why this is good for you or the customer?
I'd maybe let them put a data logger on the controls if they want to crunch numbers to help make their product better, but even then, I wouldn't encourage unfettered access.

I envision phantom service calls for the unit 'not working', you show up, and it's working.
How about overriding when you want to test/troubleshoot components?
In light of what's going in with our power grid, and anything internet based, what happens if someone hacks in, and either makes the boiler run away to possible catastrophe, or locks it out in the dead of winter (or even puts some ransom ware on it).

Reminds me on a much lesser scale the annoying service calls about 'not enough cooling' or 'something is wrong with my AC' only to find out they allowed the utility company to put that device on their system that cycles it during peak load, you know to save the homeowner some money on their rate.

RayWohlfarth

Ratio That is what I think as well
Steve we are having issue with that already. We were having no heat calls every few days and when we arrived it started to work. We disabled their controls and have been heating for 10 days straight. No errors

SuperJ

I work for a controls company, and see it this way:
Like or not building mechanical systems are turning into something like a modern fighter jet. What I mean is that a modern fighter jet is said to not be able to fly without the aid of the flight computer system.
I'm seeing mechanical systems with highly variable flow, and hybridized with multiple heat sources (geo, weird valve arrangements, heat recovery chillers, high efficiency boilers, and maybe a dual fuel option as well).
In some cases the boiler just doesn't have the feedback it needs to run effectively in the complex system it operates.
That being said, as a controls guy I'm often frustrated that the boiler guys don't want to talk to me, they often only seem to care about playing with their combustion analyzers, and when the subject of controls comes up, they tell me to phone some product rep in another city. The start up guys need to get with the times, and start caring about the controls. The controls guys have been so used to fixing things that they don't trust the boiler guys anymore.

A proper design and handover meeting with the controls guys to discuss the details is crucial. Talk about the whole control strategy, staging, timings, modulation, and temp and flow limits etc. If you don't have a good feeling then I would resist giving them direct fire. But a good controls contractor will be able to make the plant sing, especially with direct modulation control.

Generally speaking I can make most systems work by set point control or direct modulation. And I've found the setup of the boiler controls to be lacking (not necessarily the capability, but just the effort taken by the boiler contractor). The other point is the boiler guy is usually in and out and never seen again, but the controls guy is their every week checking on things.

Setpoint control is a lot better than black box standalone control.
Usually when a standalone cascade control is done it isn't setup very well and the plant stages and cycles like crazy.

Here is an example of bad control: Two IBC boilers (40-400mbtu/hr each) running standalone (Control system just has a single relay to enable the plant, boiler controls everything). Probably 15+ cycles per hour. The IBC controls are actually quite capable, but it depends on someone who cares to set them up. The green and blue trend is the boiler entering and leaving temps.

RayWohlfarth

SuperJ I used to be a control guy and understand they have the responsibility for the owner. I would love talking with a control guy and discuss what can and cannot be done with the boilers. I am concerned when I see control companies trying to operate the boiler outside the design parameters. For example, A school district signed a performamnce contract with a control company and they installed an interface to the firing rate control. They were operating the non condensing boiler as a condensing one and did thousands of damage to the boiler, flue and chimney. I believe it was to get the energy savings they guaranteed.

Sam81

Agree with u ray if the heating contractor is communicating right with the control firm then it will workout beautiful otherwise it will do more damage to save

SuperJ

I agree, and will say that probably only 5-10% of controls guys should be touching central plants. Many are hacks just trying to get stuff to work, and are blissfully unaware that they're trashing the equipment.
I've seen boilers hauled out over 5 years totally destroyed by condensation. You could shovel the rust out of the bottom, and fill wheelbarrows full.
For school boards, it's often the board itself to blame in my experience. They come up with some wacky energy specs that ultimately destroy the boiler in the quest to lower system temps.

I'm a big fan of mechanical safeties for condensation control, on a variable primary system you often can't get your RWT up unless you have some sort of bypass to open. It's easier when you have a secondary loop with scheduling valves you can throttle to keep you primary temps up. This is something that's often missed in many designs.

Steamhead

SuperJ said:

I work for a controls company, and see it this way:
(snip)
as a controls guy I'm often frustrated that the boiler guys don't want to talk to me, they often only seem to care about playing with their combustion analyzers...

@SuperJ ,I think you have a LOT to learn from the boiler guys.

A combustion analyzer is not something we "play with", especially given how much one of these units costs. Rather, it is an essential tool that helps us make sure the boiler is running safely and efficiently. Carbon Monoxide is no laughing matter.

An analyzer can also help us avoid the situation @RayWohlfarth just described, where a control company was operating the boiler in such a way as to severely damage it. A simple stack temperature measurement with an analyzer would have been a red flag to a knowledgeable boiler guy. But if I'm reading this correctly, the control company didn't bother to check. This is the kind of thing liability lawyers salivate over, while the customer suffers.

So if you're trying to do something and the boiler guys say not to, they might just be doing you a favor.

SuperJ

Steamhead said:

SuperJ said:

I work for a controls company, and see it this way:
(snip)
as a controls guy I'm often frustrated that the boiler guys don't want to talk to me, they often only seem to care about playing with their combustion analyzers...

@SuperJ ,I think you have a LOT to learn from the boiler guys.

A combustion analyzer is not something we "play with", especially given how much one of these units costs. Rather, it is an essential tool that helps us make sure the boiler is running safely and efficiently. Carbon Monoxide is no laughing matter.

An analyzer can also help us avoid the situation @RayWohlfarth just described, where a control company was operating the boiler in such a way as to severely damage it. A simple stack temperature measurement with an analyzer would have been a red flag to a knowledgeable boiler guy. But if I'm reading this correctly, the control company didn't bother to check. This is the kind of thing liability lawyers salivate over, while the customer suffers.

So if you're trying to do something and the boiler guys say not to, they might just be doing you a favor.

What I'm saying is that having great combustion numbers isn't near as great if the boiler is going to be scrap metal in 5 years cause they don't give a rip about controls. You need a holistic solution.

What I'm saying is that boiler guys don't generally even care to have the conversation about what not to do/or to do. Generally, it seems like as long as they have a nice startup report to submit they could care less about what happens next. We actually go out of our way to dig up the specs and talk to the boiler manufacturer directly to ensure success. (I work in the controls division of a company that is probably 95% mechanical, 5% controls).

I also suspect that any boiler guy who's made the effort to join this website is probably decent one who would care enough to have a conversation the controls guy to ensure mutual success. (So don't take my boiler guy comments as a personal dig). My experience is also biased towards large scale commercial projects which might be different than smaller scale commercial/residential.

The other industry problem, is reps pushing equipment that's not suitable for the application. Many jobs get equipment that can't handle sustained heavy condensing, but the operational sequence requires it because of a heat recovery chiller that can't really handle entering condenser water temps to much above 110-120F.

Steamhead

SuperJ said:

What I'm saying is that having great combustion numbers isn't near as great if the boiler is going to be scrap metal in 5 years cause they don't give a rip about controls. You need a holistic solution.

What I'm saying is that boiler guys don't generally even care to have the conversation about what not to do/or to do. It seems like as long as they have a nice startup report to submit they could care less about what happens next. We actually go out of our way to dig up the specs and talk to the boiler manufacturer directly to ensure success.

In the case @RayWohlfarth cited, the boiler was damaged simply because the control company ran it too cool to prevent condensing. A "holistic solution" there would have kept the boiler warm enough that it didn't condense. The control company dropped the ball, and the boiler was damaged.

Boiler guys are required to submit startup reports to show that the boiler was running properly when commissioned. Otherwise they don't get paid, do they? And it also protects them from liability if someone else comes in and changes something that causes a problem.

SuperJ

Generally they stack the deck in their favor on startup, by requiring conditions that outside of the project design.
With high temps and flows to get great numbers. I'd like to see more real world setup and testing under marginally flows, and temperatures. Since the boiler was probably selected because of a min flow rate/temp capability.

If the SWT is spec'd to be at 140F, don't generate the startup report at 170F, with all the valves locked open. It leads to a false sense of everything's ok. If the startup report looks terrible running on the engineered sequence, then people will notice and be forced to consider reality, but if the numbers are fudged (because of unrealistic system conditions) then it obscures the problems (leading to trashed boilers).

I don't want to derail this thread anymore than it is, so I'll try and stay on topic. @Steamhead I think we are both saying the same thing but from our own perspectives.

It's a weird world contractually too. If the engineer spec'd a condensing temperature on a non-condensing boiler than it puts the controls people in a funny place. There may be financially penalties for not meeting energy targets, but no penalties for trashing the boiler in the process. I know it seems like black and white to not trash the equipment, but if the system is running at temperatures other than design, eyebrows are raised and fingers are pointed. I've been on jobs where I've tried to push the issue of damage to the boilers, and things take months/years to resolve all while doing more damage in the process. People seem to think that the condensation is a theoretically problem (since they are comfortable) until they actually get to see what a disgusting mess the inside of their brand new boiler is.

Zman

The onboard boiler controls have gotten so good that I don't see why the controls guys would want the liability. The building controls systems can simple request an output temp and monitor the boiler's operation.

I only know one controls guy that I would be comfortable controlling the boiler's firing rate. He will only do it if there is no on board option.

Sal Santamaura

There has been a long running 'discussion' in the engineering community over what seems on the surface to be a trivial nomenclature matter. Is one a "systems engineer" or a "system engineer."

I come down squarely for the singular version. What everyone in this thread is discussing underscores that, whether you prefer "heating" or "comfort," the combination of boiler, controls, distribution and emitters is one system. Unless and until some company starts manufacturing/selling/installing/maintaining all those things, the entity with authority (either one contractor who's given overall authority or, if none is, the customer) is the system engineer. If that entity permits a control sub to determine boiler firing rate, neither the boiler manufacturer nor the control manufacturer should be responsible for negative consequences. Those ought fall entirely on the shoulders of the entity with overall authority.

As someone who spent his career performing system engineering in the jet aviation industry, my opinion is that analogizing heating systems to fighters goes a bit far. The basic principles of integrated system design, however, apply to both. Unless a credible manufacturer decides to offer integrate boiler/control packages, I'd opt for leaving firing control to the boiler companies. Safety must always be first priority.

GBart

I would think most large boilers like schools would be piped in a primary secondary arrangement and they could simply control loop temperature and have the boiler on a outdoor reset with a minimum temp period.

From the sounds of it, trying to do what they are would destroy or crack a boiler. I'd say send the facilities management this thread and have them read it.

SuperJ

GBart said:

I would think most large boilers like schools would be piped in a primary secondary arrangement and they could simply control loop temperature and have the boiler on a outdoor reset with a minimum temp period.

From the sounds of it, trying to do what they are would destroy or crack a boiler. I'd say send the facilities management this thread and have them read it.

Retrofits are mostly primary secondary, but new construction (in my area ) is almost all variable primary only with a bunch of boilers in parallel (with isolation valves).
-Pumps are on drives maintaining differential pressure.
-Hopefully a flow meter and a bypass valve to maintain minimum flows and warm up the return a bit if necessary.
-A bypass alone is often not adequate to prevent condensing, with a building full 2 way valves zones sending back cold water.
-On a current 1yr old job they are in the process of adding belly pumps to all the boilers (basically pumping hot SWT into the RWT)

GBart

On most of the old systems especially schools I found the controls were shot so the boilers could get whammed by cold return water, having some company come in and promise huge savings by controlling the boilers remotely without going through and making repairs would be disastrous. Schools seem to be the worst I've seen just because of budgets and too many people unaware that you can't just let these things go, seen so many with the pneumatics all dead and boilers running wild, talk about a waste of taxpayer dollars and cracked sections galore and still no approval to repair the controls, replace the section yeah, repair what caused it no.

It's very interesting to find the original blueprints and read what the engineer's concept was and how the controls were originally set up....did I say interesting? ...it's imperative.

SuperJ

The old stuff works surprisingly well when kept in good repair. There are a couple schools in Toronto that are running ship boilers from WW1 surplus/scrap ships, that I've done work on. They run on coal, oil and now gas. Awesome to see those old beasts still alive, I wish I would've taken pictures.

Zman

@RayWohlfarth
This is an excellent conversation. It really is just the tip of the iceberg.
Very few mechanical folks really understand the control side of the system. Perhaps fewer controls guys understand the ins and outs the mechanical side.
In theory, the engineer of record should be writing a control narrative and overseeing the commissioning of the system. The 2 problems with that arrangement is that in reality, few engineers are cut out for the job and even fewer owners are willing to pay.

hot_rod

I think it would need to be a case by case basis. The boiler manufacturer would need to communicate with the boiler manufacturer and list the package together.

I suppose it is doable, most boiler controls are built by another manufacturer anyways, the boiler manufacturer just assembles the various components, test and certify the package.

Honeywell, Dungs, Siemens etc probably all work with the boiler manufacturers and develop the controls they need as it is now.

What is the reasoning behind the control folks wanting to take the control?

rbeck

After 20 years as a contractor and 19 years with a manufacturer both sides are actually correct. My boilers better than your controls, my controls do it better. The problem is after the installation is when the conversation starts. The guys that installed the boiler may or may not completely understand the boiler controls and how they interact with each other in multiples, then introduce the boiler controls to the systems controls. Do they play well together or not.
All this may even sound a bit confusing now add 80 parameters, pre-purge and post purge of fans and circulator, adjustable differentials above and below, over sized boilers with 100% redundancy to the mix.
Get byond all this and now add what the systems guy wants to happen and modulation of flow and input and we up with a hot mess.
It's all about communication between all parties. I have even seen drawings which were cut and paste. The original drawing was for cast iron boilers and now pasted in mod/cons with no piping changes.
I feel the systems guy should control setpoint if they want to control anything. I have seen too many problems trying to control modulation. One request controls guys on mod/cons please do not attempt to control our boiler pumps.

RayWohlfarth

wow so many great points! I don't have an issue with data logging to your heart's content. I like to have the control company enable or disable the call for heat and allow the boiler controls to ramp up and down to meet the call for heat. The argument for allowing the control company to control the firing rate is to reduce the cycling losses. I am concerned the boiler will suffer the consequences and the owner will believe my boiler was junk when it was like a Prius at the Indy 500. Thanks for allowing me the venue to vent. LOL

hot_rod

RayWohlfarth said:

wow so many great points! I don't have an issue with data logging to your heart's content. I like to have the control company enable or disable the call for heat and allow the boiler controls to ramp up and down to meet the call for heat. The argument for allowing the control company to control the firing rate is to reduce the cycling losses. I am concerned the boiler will suffer the consequences and the owner will believe my boiler was junk when it was like a Prius at the Indy 500. Thanks for allowing me the venue to vent. LOL

How would the control company be able to reduce cycling loss, different from the manufacturer? Wouldn't adjusting the firing rate be similar to adding an aftermarket ODR control like tekmar. It doesn't override boiler safeties or burner control per say, it just improves boiler control with another input. The control company could provide that add on.

Do most larger boilers you deal with include ODR in the boiler control?

RayWohlfarth

Bob
The boiler controls I see are usually designed to heat the water as soon as possible and will go to low fire once the loop or boiler temperature gets within a few degrees of the setpoint. I am seeing the control companies keeping the burner at low fire so it takes longer to heat the loop. It saves money for the owner but makes my boiler look like it cannot keep up. I was just at a job the other day and the OD temperature called for 150 degrees. The loop temperature was 120 degrees F and the boiler was at low fire. The customer asked if my boiler plant was too small. I smiled and showed the temps.
Some condensing boilers like the commercial Weil McLain have an integral reset control.

EBEBRATT-Ed

I have been fighting this battle for 45 yrs.

One of my issues with it is as a boiler service company going on a no heat call and finding it's a building control issue keeping the boiler off.......nothing wrong with the boiler.

To me it should be mandatory to have a bypass switch to bypass building automation and let the boiler run on it's own controls.

But it will never happen.

To me building automation should be able to enable/disable the boilers (with my emergency bypass switch of course) and monitor the boilers, pumps....whatever and that is all.

By doing this:
they can have their energy savings
they can shut the boilers down on a smoke, fire or other unsafe condition if they are monitoring those things.

My big issue is always with chillers. The chiller mfg. frequently ships a M/M flow switch to install in the chiller piping

The control people always want to use this to prove flow to there controller and have there controller signal the chiller to run because they want to control the chilled water pumps as well.

To me this is a no no. No one agrees with me but in my opinion that flow switch is a safety switch, just like a steam pressure control or a HW aqaustat.

When I get in that position I usually insist on (2) flow switches.
1. is mine and mine alone and gets wired directly to the chiller control panel.
2. The second one is the control companies.........they can do with it whatever they like

Solid_Fuel_Man

Many people don't understand boilers.

Control guys (me) and boiler people (also me) need to talk.

Engineers need real world expierence.

Control guys need to understand that their prints made by the engineering firm may not actually work or be safe.

I generally enable/disable or control low/high/ low with a DDC system. I always install a bypass switch, don't care what the print says.

Some burners accept a 4-20ma signal for total control, others I simply enable/disable.

@EBEBRATT-Ed chillers with one set of contacts on a flow switch get a relay DPDT hardwired, that way I can break the compressor enable with one set of contacts and the other can be used by the DDC as proof of flow. Also a good programmer will recognise if the flow switch fails when the pump is commended off and the switch still says flow.

That is a lot of assumptions, but if we just look at each other like knuckle draggers then things will never change and that chiller has the potential to freeze up.

RayWohlfarth

@EBEBRATT-Ed I love your idea. It is so hard tryig to figure how to get a call for heat on the preseason boiler check.
Solid Fuel Man, Thanks for thinking of us boiler techs

Mark Eatherton

Sure. First, they have to follow the factory's protocols as it pertains to protection of the boiler first, and system protection second. I'd also make them sign a release of liability to me for any damage that occurs due to improper operation outside of the factory specifications. The lawyer who writes that letter should refer to the factory for specifications.

RayWohlfarth

Thanks @Mark Eatherton

DZoro

This is like a nest thermostat on steroids

You pretty much can't have one without the other. We all need to work together, just like the controls and the system need to work together. Without that all you have is a mess, that's not going away nicely.
D

RayWohlfarth

@DZoro I agree. I was just curious why they would want the liability for that.

ratio

I'm sure that they're not taking liability, just control.

DZoro

I don't even want the liability for a nest

RayWohlfarth

@ratio good point
@DZoro me either. I am such a conspiracy nut and wonder if these smart controls listen to me LOL

lchmb

With all the smart controls..can you imagion what's coming down the road... Someone will install a system, notify the manufacturer and walk away..they will connect and verify start up and monitor the comfort in your home for you..;) wont even need an adjustable t-stat..they'll do it for you..

mikeg2015

It all needs to work together. Unfortunately, I’ve typically seen very, very poor boiler control. Even worse implementation of condensing boilers in terms of delta T and design temps.

At the last college I was working at as facilities engineer, only 1 out of 4 boiler system ran smoothly. The others had terrible loop tuning.

The factory I manage maintenance at now has poorly configured het recovery system and back up boiler configuration. Actually, every utility including air compressors, vacuum pumps and cooling towers are poorly staged and controlled. No feedback to the plant machinery when they go down. Everything else in the factory is state of the art communications and controls. But utilities aren’t important.... until they don’t work, and then nobody understands them.

In most every instance, the OEM controls work better and the controls get muddled because some engineer specs them and something gets lost on translation by the time it goes through a HVAC subcontractor then to the controls company.


... don’t get me started on out Johnson Metasys controls on the ventilation and HVAC.... apparently, +/- 3F and 0.5 cycles per hour is their target. The poorest, least responsive control system I’ve ever encountered. Might as well just use a bunch of $50 bimetallic switches and some relays. It would work better. Most of the problem is the York rooftop unit controllers themselves.

RayWohlfarth

@lchmb I think the industry will have plug and play for furnaces as well. I think you will pull one out and slide in the new one and walk away
@mikeg2015 LOL I agree about Metasys

lchmb

see that now..a bunch of metal tape and a flex connector and they are out the door!! But it was cheap!!