Complex System Needs a Simple Solution

gotgas

I recently purchased a commercial building. It is 18,000 sq feet and three stories. There is a basement that is another 6,000 square feet. Only 12,000 sq feet is conditioned, and only 6,000 needs to be.

Only two stories are heated. There are, primarily, two systems. For the first floor and part of the second floor there are two Weil-Mclain Ultra boilers that are run together in a loop. They are located in the basement. Basically this one: https://www.ecomfort.com/Weil-McLain-383500726/p49954.html?srsltid=AfmBOorsJMNcximrKrgp4Ucdxxt5sm-6lWVQR0QuZRsxXz4Jt8i8aBz4

In addition, also in the basement is a 3-phase air handling unit that runs HW loops and also handles the AC, although I have not yet located the compressor because I cannot yet access some of the building exterior. The boilers feed the loops that run to this unit. It heats the basement and part of the first floor with forced hot air.

The two boilers also supply a manifold that has seven circulators that pushes water all over the building to baseboard and hydronic radiators. They also supply another air handler on the second floor that does something we cannot yet determine, although it is new, expensive, and large.

All of this is run by a Distech control system that coordinates everything and controls all the air handlers, the boilers, and AC, and all the zone valves. This whole setup is about 17 years old. The controls are definitely out of date and need to be replaced, which would be about $50k.

That is all one system. The second system is two furnaces that run the 2nd floor heat and AC and are mounted on the outside of the building. That is separately thermostatically controlled and I am not going to touch that system at all.

Regarding the first system, there is no reason for me to have to high end control system. 4-6 programmable heat/AC thermostats would cover all the necessary zones. The man who installed these controls 15 years ago met me at the building to review and make recommendations. He recommended abandoning the control system and moving to simple thermostats.

Here is my question: what do I do? I have been trying to find a company with the necessary expertise to work on all parts of this system. So far, not much luck. I am in a large state with a small population and we do not have enough commercial HVAC people to cover all the needed work. Our idiot governor does everything in her power to make it difficult to do business in this state, so I do not see that changing soon.

Is it crazy to think that I could sit down with the manuals, Grok, and your advice and run the thermostats myself? I have done that on 5 houses, 2 with combis, one with Buderus boiler, 2 with Heat/AC furnaces. Nothing nearly this complex, though.

The heat is essentially unregulated now and runs all the time because the control system is reporting -200F temps in all zones. My NG bill last month was $1700. I reduced the operating temps of the boilers, set the zone as 110-140, turned the circulators from speed three to one, and that is helping.

I need to make a change but no one will even quote the job. Tell me if I am crazy.

P.S. I own a copy of Pumping Away. Does that help?…

Jamie Hall

You are not crazy. Nor, however, will what you want to do be obvious at first…

However, it is an engineering problem, and as such it can — and should — be approached that way.

First. Define, quite exactly, just what you want the system to be able to do. Not how. Not with what. Not referencing anything that's there at the moment. Just what it is that you want the system to be able to do.

Second, identify what basic conditions you have and, to a basic extent, what equipment you have.

Next identify ways in which the basic equipment — in this case your boilers and piping and radiation or air handlers might be used to accomplish the objectives (e.g. I want the west end of the second floor to be controlled at a constant temperature) and, taking that, assessing whether what basic stuff you have is possibly fit for the purpose.

Now you can begin to figure out how to connect the basic equipment bits together, possibly in groups — or identify places where what you have isn't going to do the job.

Note that I haven't said anything about controls or pumps or valves or manifolds of that sort of thing at this point!

Now you need to figure out how to hook the various equipment you have together to accomplish the goal — or to assess what you need to add.

Now, and only now, can you begin to decide just what controls, such as valve or pumps, you need to make it behave.

And, last of all, you can figure out what electrical controls — most likely thermostats and a few pump control boards at most and how to hook them together.

Take it step by step.

And don't be shy about coming back here with questions!

gotgas

Jamie Hall, thank you! Great outline for how to begin.

EBEBRATT-Ed

How about the guy that installed the original controls can't he help you out?

Best thing would be to draw out everything that needs to be controlled and figure out how to wire it on paper first.

gotgas

https://forum.heatinghelp.com/discussion/comment/1878870#Comment_1878870

I had the guy who installed the Distech system come out. It was 17 years ago and he does not have a complete database from the installation. He also was the one who told me it was overkill and convert to thermostats. I asked him it he would do the conversion. He said he could, but did not want to because he did not have the technicians to do it in any kind of timely manner.

Thank you for the advice about drawing it out. We are working now to create a system map.

Alan (California Radiant) Forbes

Jamie’s answers are often - and I actually mean always - spot on.