Should I Consider A Buffer Tank?

Eastman

Ok Justin, I will post the buffer design now in the radiant heat section with the title, The Trithermogulator.

Paul48

Well, I zoned primarily because I figured the upstairs doors could be closed off at times, primarily at night... my experience in my apartment where the single thermostat was in the living room was that the bedrooms got REALLY cold at night (like to the tune of 8-10 degrees colder) when the doors were closed...

I hated that and wanted to prevent that when we built our house...

Provided there is appropriate radiation in a room, and your reset curve is correct, you could wall it off with cinder blocks and it would still keep the room comfortably warm. I am not a fan of zoning mod/cons. You change conditions within the structure. Everything within the exterior walls becomes thermal mass. If you run adjacent zones at different temperatures, one affects the other. It just seems counter-productive to have a system that knows it needs to supply a certain amount of btus to the structure, based on the outdoor temperature. Then adding chaos to that by chopping the house into zones.

SWEI

As @Paul48‌ pointed out above, when you properly size emitters and balance flows, it can look like magic to the untrained eye. Side note: an unfortunate number of those untrained eyes belong to licensed architects, engineers, and contractors.

We zone almost exclusively for external influences and intermittent occupancies. If a space is subject to solar gain, has a woodstove, etc. you need a way to throttle back on the system supplied energy (temp or flow) to the area. An infrequently occupied bedroom, wing, or shop area dictates a zone.

Gordy

Define intermittent occupancy Kurt.

SWEI

OK, I'll take a stab at it: How does "occupied during 20% or less of the hours in a typical week." sound? Need long enough off periods to allow a tight ODR curve to recover from setback.

Paul48

I'm missing a post.

icesailor

Without me sounding argumentative, just how cold is it outside where you are now? If it isn't as cold as your design temperature, your boiler is oversized, and it's going to run and short cycle. If you lower the thermostats at night by manually turning thermostats down, or zoning off rooms, you have significantly reduced the amount of heat loss in the building and increased the boiler size.

You need to go look on City-Data and see when the lowest temperatures in your location occur. They are NOT on December 21. More like later in January. Then, see how many times the burner cycles per hour. Turn on all the zones and let the boiler do its thing. See how often it cycles under design conditions. Some people seem to have developed an obsession with their burners running. They don't differentiate the difference between their automatically downsized boiler and when it is running full sized because of outside conditions.

Maybe some of these fancy digital electronic thermostats need to have their CPH's changed. If steam is #1, and you're running at #3, maybe you need to try #2.

You sure never heard this from installations with T87 Honeywell's with properly set heat anticipators.

Whenever I ever lowered the high limit control, the burner ran less, the circulator ran longer. If I raised the temperature, the burner ran longer but the circulator ran less. Anyone who sits around in a snowmobile suit, waiting to count how long the burner ran, and the house gets cold in the process, needs to have a personal discussion with themselves. If my house got cold while I was waiting, my wife would be telling me to move to the garage if I wanted to be than cold. As she turns up the heat. And she spent 6 to 8 hours of every day OUTSIDE caring and riding her horse. Now she complains about it being too hot.

Paul48

Ice.....You should read up on mod/cons. They are a proven technology.

Gordy

SWEI said:

OK, I'll take a stab at it: How does "occupied during 20% or less of the hours in a typical week." sound? Need long enough off periods to allow a tight ODR curve to recover from setback.

That sounds good to me. Just wanted readers to understand when zoning could be logical. When it's not. Not being argumentive.

ced48

But in this guys case, he can't have zones with this boiler and not be subject to a lot of short cycling. He has to add a "buffer tank" of some configuration, or have that boiler cycle on and off way beyond any reasonable limits, lets say 6 per hour, which is way beyond what I would call reasonable for any modcon install. One per hour is my idea of a reasonable minimum.

icesailor

Paul48 said:

Ice.....You should read up on mod/cons. They are a proven technology.

Are you kidding???

I installed quite a few. I don't have a problem with them. I've been to quite a few classes on them. I love them. My personal opinion has been developing that some are trying to make them do things that are expensive and counterproductive.

They have become so complex that far too many installers are working way over their heads.

In the real world that I lived and worked in, if someone needed a new boiler, I would like to sell them the latest Mod/Con with all the bells and horns. Reality always set in when someone else came along with some ridiculous price to do something that wasn't even close to being right. I always gave multiple options choices. From bare basics to the grand poo-bah. They always picked something in the middle. I can't make someone spend money they don't want to spend. And because I took the time to do multiple work up's, I usually got the job.

If you want to be competitive, you have to be flexible.

Yu can't compete with competitors that think that overhead is a ceiling and profit is an obscene concept.

So, Paul48. Are you a rep or work for a supplier?

What do you say when some bonehead Hackaroo calls you about his problem install and can you help him fix it? I bought 99% of what I used from one supplier. If someone came in the store with a piece of equipment that they sold but wasn't bought from them, they would tell them to go back to where they bought it. If they had the cash/money, and a good attitude, I MIGHT look at it and possible fix it. If it could be fixed.

Maybe you'd like the name of this "Green Contractor" Carpenter who switched to building "Green" houses. He had a gang of shaggy heating experts that had a crash course in High Tech heating with Mod-Cons. Because this guy was so cheap (he squeaked when he walked), he used all non barrier PEX and Cast Iron fittings on all his in floor. All purchased from a Internet Heating Supplier. The whole house was like that. Less than two years later, the whole entire system was put away in the soiled bed. Someone paid for it. Someone is going to pay twice for it.

Paul48

I have no vested interest in either "old school" or "modern" technology. They just exist. You keep saying you couldn't sell mod/cons, but then you say a CI boiler with an I-series valve provides all the functions of a mod/con. No sale there! The first couple paragraphs of your posting above, apply to bang-bang boilers, not mod/cons. You take a boiler that is 2 or 3 times as big as what is needed, and you better zone it.

SWEI

Gordy said:

SWEI said:

OK, I'll take a stab at it: How does "occupied during 20% or less of the hours in a typical week." sound? Need long enough off periods to allow a tight ODR curve to recover from setback.

That sounds good to me. Just wanted readers to understand when zoning could be logical. When it's not. Not being argumentive.

No offense taken -- it was a good question; made me think a bit. Sometimes I "know" things but to paraphrase my grandfather: When you can teach someone else to do it, then you really know you know it.

I think we massively over-zone things here in the US. Partly to cover up poor design practices, partly because it's profitable for both suppliers and contractors, and partly because it's "cool" for certain wealthy owners to brag about. Coming up with good, scientific reasons for zoning (or the lack thereof) should lead to more comfortable systems being installed at more attractive price points, hopefully with less glitches.

icesailor

You must have a different client base than most of us out there deal with.

When you see 40+ YO oil boilers and people that can't afford to replace them, if you want to make some money, you provide them with what they can afford.

You must not sell to the bread and butter/lunch box crowd.

I want to see you sell a complete Mod/Con system, with all the bells and whistles to someone who could possibly afford one, but has a 10 year old working boiler. They might show you the outside of their house. In certain situations, the "I" series might be an easy sale. THAT WITH GOOD WILL, LEADS TO OTHER SALES!!!!!!

MANY jobs I've been on, venting a new Mod Con is next to impossible, let alone installing it to code and getting an inspection.

Not getting into pricing in any way, but another forum I read which also doesn't discuss pricing, has all these tales about "Commission Sales" where the installer is getting a commission on what he/she sells and/or installs. Often, a one time deal. Once done, they never come back. "Call somebody else". I was "Somebody Else". They called me because no one else could fix it. Or would fix it.

Maybe YOU enjoy being grilled by unhappy customers who have discovered a quirk in their new high tech water heater. Like the fact of that delay in instantaneous gas water heaters when you stop the flow and start it again. Some customers are really careful with their water use. They shut the water off while they brush their teeth or using soap in the shower. Then, they turn it back on, and it goes cold. Before I retired, I had a customer I had worked for, for years. I did his house new, He had an 80 gallon electric water heater. Years ago, I switched it to a Rudd PVP 50 direct vent. Last year that one died. He was considering a Instantaneous one. An easy install, A real Gravy Job. And he knew what he thought he wanted. A nice proud Swede Engineer from the Phone Company. I told him that I didn't much care what I installed, but I would have to run a 3/4"hard piped line to the new place because the old 1/2" line wouldn't be gig enough. And about the water getting cold and the need for a buffer tank. (more $) and removing all the shelves and the refrigerator where the Noritz would be going. Etc.

He went with a new PVP. He said that he had heard of this problem with the water getting cold and hot.

I worked for this guy for over 25 years. I should try to hide something from him? That he would be asking me why his water got cold when he turned it off and what could be done to fix it?

People will spend money on what they want. You can have ANYTHING you want. Just not everything you want.

All my customers, no matter how wealthy or poor, were more than willing to give me SOME of their money. But not ALL of their money.

BigRob

Good thing you caught it, you know? My crap install was set in motion before I arrived and I can't tell you how much was charged for the "work." I won't ever tell because it's that embarrassing. A lot of installers don't plan out the boiler room for the future, too. I like the idea of having a scalable go-to design. Maybe keep that in mind. I love the large diameter stainless flex lines you can get - so easy to make changes if you think it through. Using a Caleffi SolarCon or similar, sized for the need, with either a normal or high efficiency boiler, a DeltaT or DeltaP, and a bunch of zone valves is the way to go, in my opinion. Residential and light commercial buildings are just too simple to need much more. If you use a normal efficiency boiler, maybe a reverse indirect water heater for DHW and heating buffering is the way to go. I do think deltaT on high efficiency boiler pumps is useful. Anyway, I'm creating a plan to be implemented later down the road so we don't get hosed again. If the future installer doesn't like it and doesn't have reasonable reasons, on to the next.

icesailor

Somewhere here are photos I posted of a Veissman wall hung with all the circulators and controls, with a 60 gallon SuperStor under a set of stairs where the water tank is removable without having to move or drain any heat pipes. And there is still access to under the lower part of the stairs. Careful planning can lead to happy jobs.

BigRob

icesailor said:

Somewhere here are photos I posted of a Veissman wall hung with all the circulators and controls, with a 60 gallon SuperStor under a set of stairs where the water tank is removable without having to move or drain any heat pipes. And there is still access to under the lower part of the stairs. Careful planning can lead to happy jobs.

I'll look for it. Our boiler room is actually a closet.