Your opinion

Synway

Hello people. I’m having a plumber put in this combo boiler IBC 15-96 .
It’s a condensing high efficiency unit 96%. I’m curious why the plumber would choose to distribute the heat in this fashion illustrated in the photo. Isn’t the high efficiency lost by this method?

GroundUp

I'd be more concerned with the fact that he's charging you for bronze circs instead of cast iron and using those crappy little steel hanger things on copper pipe, but to answer your question depends largely on the type of heat emitters used. The way it's piped won't have much bearing on "efficiency", per se, but it may cause the first zone to have hotter water than the last if everything is calling for heat simultaneously. If all is low temp and each zone is properly balanced, the burner efficiency will still be the same as it would be if piped in another fashion and it should perform the same too- assuming proper balancing. Tell us a little more about your system here; how big is this home and what type of emitters are being used? How many bathrooms?

Synway

@GroundUp thanks for your input. We have a small 600 sq ft bungalow with a poured concrete unfinished basement built in 1949 in sudbury Ontario Canada. One bathroom. The plumber is installing 4 pumps . One for the basement that the emitter is undecided yet. The main floor is hardwood With 1/2 inch pex installed with emitter plates and fibreglass insulation . One thermostat for each bedroom mine is kept warm hers is kept cool and the last is for the kitchen living room. This home has all new doors and windows and 2 inches of rigid foam insulation. The basement is cool and the ground water fluctuates in the spring affecting the basement humidity.
So the steel hangers are not supposed to be used with copper?

Zman

The lat zone in line will get the coldest water when all three are calling. It will get the hotter water when it is the only zone calling. As for efficiency, if the boiler need to run hotter all the time to satisfy the needs of the third zone, that will cost you efficiency.

There is no reason to pipe it the way they have yours. I am sure the contractor will have a good reason. My guess is: "I have always done it that way" or "never had a complaint before" or even possibly "I've been doing this for 30 years".

I would suggest nicely requesting that they pipe it per manual.

Ironman

That's primary/secondary SERIES piping. If you want to get the same water temp supplied to each loop, it should be piped p/s PARALELL.

Like this:

Zman

I am also curious about header pipe sizing, bronze circulators and laying expansion tanks on the concrete.
You probably want to get the layout correct first.

hot_rod

Is it non barrier pex by chance? If so maybe that is why the bronze circulators. Are they bronze? based on the color?

Synway

@Zman thanks, I will address this Matt before he moves forward.
The expansion tank is suspended above the concrete. Darn 2D picture

Synway

@Ironman thanks , I will address this with the plumber cheers

Synway

Well this combo boiler has a great integrated monitor system that is being kyboshed by this loop. What good is the temperature monitor system if it is going to be done this way is my question. I’m not the best communicator here but this job is my dime grrr thanks for the input fellas cheers

Jellis

Wasting money on the Bronze circulators for sure.

I would have him pipe it like the manual says, what he has done will likely "work" however you will likely not see the same performance as if it were piped properly.

My advice is, be gentle when you approach the subject, a lot of these guys are easily offended when you question their methods (unfortunately)

Ironman

Look on the labeling of the PEX and see if it says "Oxygen or O2 barrier". I can't tell from the pic. If not, that may be the reason for the bronze circs, but you would also need an expansion tank that's rated for oxygenated water and I'm not sure if IBC approves of that boiler being connected directly to a non barrier PEX.

Synway

@Ironman yes that is the reason he is not using iron. I’m kinda uneasy about the return and supply mixing There will be a fluctuating temperature depending on the demand. That just doesn’t seem right.
I am hoping to have some hard information to make my request more palatable to the plumber to basically start over

Synway

@Jellis thanks. I will search within to be respectful , I was specifically talking to him about manifolds too goshdarnit lol

KC_Jones

Ironman said:

Look on the labeling of the PEX and see if it says "Oxygen or O2 barrier". I can't tell from the pic. If not, that may be the reason for the bronze circs, but you would also need an expansion tank that's rated for oxygenated water and I'm not sure if IBC approves of that boiler being connected directly to a non barrier PEX.

Quote from the IBC manual:
"DC modulating series boilers / water heaters can be connected directly to a floor of non-oxygen barrier polybutylene material (PB tubing). The internal boiler /water heater piping, and connections are all non-ferrous with the exception of the
corrosion resistant epoxy coated cast iron pump. For maintenance of warranty on such systems, we require evidence of a thorough flushing of all loops, plus installation of a dirt separator or side stream filter. A separator/filter maintenance
routine shall be carried out after the retrofit, with filter clearing after the 1st day, 1st week, month and annually thereafter. The installer must insure that all external piping components and pumps are non-ferrous when connecting the boiler / water heater to a system with non-oxygen barrier tubing."

So they allow for it, but are very specific about what needs to be done.

I'm scratching my head why the installer is doing this? My understanding is this is a completely new install so why not use oxygen barrier and save a bunch of money on the pumps?

Synway

@KC_Jones rats.... I hired this guy to do the right job and it seems he wasn’t confident with his plan. He encouraged me to run the pipe myself which I understand especially now why he did. But they are properly installed with plates and insulated. I lost the piece of paper that had all the lengths of the 3 loops but they were all under the length for a potable water heating system. I knew I would need all non Ferris parts but I was also wanting the best for a reasonable cost.
Yes that is what he said he was going to do for this job. He said All I needed was was that pipe I was willing to buy the 02 block pipe and called I’m to confirm at the suppliers grrr . I said great I’ll call you when I’m done. So then he goes to write up the work order and quote and says out of all options he recommends the combination boiler but the tanked unit was going to be a grand less. Well I thought I might as well Because my house was so small I was planning no tank option. Built a wall for it in fact lol. So down payment paid , this is what I have. I’ve installed my own outdoor wood boiler many years ago on an old farmhouse. I was looking forward to this job being well done.
I talked to him about wanting gauges to read and the premade manifolds but he said they were too expensive and he’d make them from scratch. Sorry for the off ramp rant.

Zman

Non-barrier tubing on a new job is ridiculous. He saved < $0.03 per foot and spent $100's extra on parts. As long as you are going down that road, you will need an expansion tank rated for potable water the one you have laying on the floor is for a closed system (make sure the pressure is reset before installing).

Synway

Zman said:

Non-barrier tubing on a new job is ridiculous. He saved < $0.03 per foot and spent $100's extra on parts. As long as you are going down that road, you will need an expansion tank rated for potable water the one you have laying on the floor is for a closed system (make sure the pressure is reset before installing).

@Zman he changed his mind with the water heater after his recommendation of making a potable water system. So this system is a closed system. Then he said the non barrier tubing would be fine then he said pumps were easier and cheaper to use instead of Flow control valves.
His plumber ran the fresh water line down the exterior uninsulated wall that didn’t look right to me and I’m not comfortable with this secondary loop method. Hopefully I can work something out .

Zman

Because the tubing has no barrier, everything in the system needs to be non-ferrous or it will rust.

Synway

Zman said:

Because the tubing has no barrier, everything in the system needs to be non-ferrous or it will rust.

Yes I understood that

Tomizai

You should consider an anti-bacterial for the water in the heating system. Think about it, it's warm, wet, dark and has plenty of oxygen. A great environment for algae to grow. It's happened before.

hot_rod

You can buy radiant specific expansion tanks, Amtrol and probably others. They are a bit more convenient compared to DHW tanks as the connection tapping is a hydronic common 1/2".

O2 ingress is directly related to the temperature of the water. If you are running low temperature distribution it is less of a concern.

O2 ingress is mostly about supporting corrosion, 120F and higher boiler temperature when in DHW mode will handle any potential bacteria in the boiler side.

While not ideal, it non barrier tube is not a deal breaker. Not like you can change it easily
Chemical, O2 scavangers, can also be used but it is an expensive, ongoing ritual. Non ferrous components is a one time cost.