Analyze the diagram (again)

SteamtoHotWater

Six weeks ago, I posted my first drawing of my combi and aluminum plate PEX install. You guys greatly helped in refining my ideas. Then I got busy with other things, but now I'm back - hopefully with a much improved plan.

This version actually fits on my wall. In my previous post, the diagram had grown beyond its physical limitations. The beige represents my plywood. Sorry if the labels make things a little busy. I have another version with just numbers that relate to parts on a spreadsheet. Previously, I had three zones. Now I'm just going for two, one for upstairs and one for down. I'll be sweating the 1 1/4" pipes. I'm pressing the 1", 3/4", and 1/2".

My main concerns:

1. The Laars manuals insists that the primary loop be 1.25", despite the CH inlet and outlet only being 1". I decided to go with 1" on my secondary. That's going to be okay, right?
   
2. Please make certain that all my valve and drain placements make sense.
   
3. I have one bedroom that needs to essentially have no heat. Can this be achieved using flow the meter on the Uponor manifold? If not, I might just run the loop, but leave it disconnected and cap it at the manifold.
   
4. I fear I'm missing something obvious and probably catastrophic. If you notice it, please let me know.
   
5. What are the pros using to fasten stuff to the plywood? Is there a particular product or system that people like?
   

Thanks again for your input.

GGross

1. Laars recommends that pipe size as that is the general recommended pipe size to deliver the BTU/hr that the Laars can produce. 1" to each manifold should be plenty I would imagine.

2. Valves look good, the drawing looks really good to my quick glance. I have been staring at prints all week though so maybe I miss something

3. I would hook it up and adjust with the flow meter. If you leave it unhooked and it gets too cold in there you would need to risk hooking up a new line during heating season and deal with all the purging associated.

4. Union for the gas line? I'm not a fan of using 2" PVC for a 140,000 BTU/hr appliance, even if the manufacturer says it will work. Personally I would be venting that in 3" unless there is a really good reason not to (which there may be!) You can use cell core PVC for the intake as well to save money, there is no harm in that, just make sure you have Schedule 40 for the exhaust, (or otherwise approved vent material)

SteamtoHotWater

GGross said:

I would hook it up and adjust with the flow meter.

So, using just the flow meter to the one loop, I can essentially have next to no heat going to the room?

GGross said:

Union for the gas line?

Whoops. I'll add one. Hopefully, I would have noticed at some point during the install - though you never know ; )

GGross said:

Personally I would be venting that in 3" unless there is a really good reason not to (which there may be!)

Where I'm planning to vent, space is tight on the outside of the house. Not impossible with 3", but more difficult. The manual reads that 2" is good for up to 50' in length. I thought I'd be fairly safe to use 2" with the 18' runs. What problem(s) am I likely to run into by using 2" instead of 3"?

GGross said:

You can use cell core PVC for the intake as well to save money, there is no harm in that, just make sure you have Schedule 40 for the exhaust, (or otherwise approved vent material)

That makes a lot of sense. Thanks.

GGross

I just worry about combustion issues with a smaller vent, it should be OK if the manual says you can do it, personally I would vent in 3" if possible. as for the loop you should be able to isolate individual loops on that manifold, just close them completely, they are designed to allow for actuators that will close flow off entirely to individual loops, you don't need the actuator to close off a loop though

Mad Dog_2

Thats a neat visual.  What program is that?  Mad Dog 🐕 

SteamtoHotWater

Mad Dog_2 said:

Thats a neat visual.  What program is that?  Mad Dog 🐕 

Illustrator and countless screenshots.

I've updated the drawing. Changed the label on the intake to use cheaper PVC. I now remember why there was no union on the natural gas connection to the boiler - does that union need to be dielectric? I'm finding conflicting info on the web. It's kinda pricey for a 3/4" FIP x FIP. Nonetheless, I'll leave it as dielectric until I get info that says otherwise.

Mad Dog_2

There's already a Union on gas spud from the unit.  In addition, the CSST flex has a "union" nut on it. Mad Dog 🐕 

HomerJSmith

Nice graphics. I guess that Laars has an internal pump.

SteamtoHotWater

Mad Dog_2 said:

There's already a Union on gas spud from the unit.  In addition, the CSST flex has a "union" nut on it.

You are correct. I had a male on both ends of the appliance connector. The drawing has been updated.

SteamtoHotWater

I thought of another question, added it as #5 in the original post:
What are the pros using to fasten stuff to the plywood? Is there a particular product or system that people like?

hot_rod

Exterior plywood would be fine and able to handle a bit of water should you leak at some point.
Stay away from particle or wafer board.

3/4" plywood holds screws better than 1/2", worth the extra $$.

If you want a cleaner look, cover the plywood with a galvanized or painted aluminum sheet.

The 1-1/4 between boiler and hydro sep is overkill and the 1-1/4 sep is more $$

SteamtoHotWater

hot_rod said:

The 1-1/4 between boiler and hydro sep is overkill and the 1-1/4 sep is more $$

That was my suspicion too, but the manual is really insistent:

Use at least the MINIMUM pipe size for the entire boiler loop piping (connecting boiler to and from the primary/secondary connection). Use only primary/secondary piping as shown. Failure to follow these guidelines could result in system problems.
CH pipe minimum size : 1 1/4 ̋

Is the manual just being overly cautious?

hot_rod

Looks like everything inside the boiler is 1" piping.
But if the manual asks for 1-1/4 may as well use 1-1/4 to avoid any warranty issues down the road.

SummitMechanic

The only things i would change are moving the fill/expansion the the secondary loop with air elimination and adding bypass between your feed and return on your manifolds. other than that, with the parts you are using you can reduce the flow on the zone you want to and let the thermostat do that rest. I would say it is over complicated for a two zone system, but what i see there will provide heat just fine with the small adjustments i mentioned.

Keep in mind there are many ways the build a boiler system and a lot of it comes down to preference. What you have there will work more than fine. it will only slightly frustrate the guy you goes to maintain it 5 years from now.

EdTheHeaterMan

The Water heater service valve kit should be carefully looked at. the idea is for you to be able to shut off the hot and cold water from the home to isolate the boiler heat exchanger for running a washing solution thru the heat exchanger. By the looks of the diagram, it appears that the isolation valves will connect the hose bib valves to the house hot and cold water lines and isolate the boiler heat exchanger from the service hose bib connections.

Think of it this way. when you shut off the hot and cold water to the boiler the hose bibs should be able to have a bucket of water with a pump force cleaning agent into the boiler heat exchanger. The idea being that you will operate the pump with a cleaning agent for about 30 minutes. The pump will take water from a bucket of cleaning agent and pump it into the cold water side, force it thru the heat exchange out the hot water side back into the bucket. This might be one option for maintenance https://s3.amazonaws.com/s3.supplyhouse.com/product_files/SpeedClean-SC-DS-5-Brochure.pdf

SteamtoHotWater

SummitMechanic said:

The only things i would change are moving the fill/expansion the the secondary loop with air elimination

You're suggesting that I move the fill/expansion (e.g. the Watts B9-11TM3 and Extrol EX-30) "to" the secondary? I think in a much earlier draft I had it on the secondary but this forum (EdTheHeaterMan) convinced me it belongs on the return side of the primary.

SummitMechanic said:

and adding bypass between your feed and return on your manifolds.

I don't understand what you mean.

SummitMechanic said:

other than that, with the parts you are using you can reduce the flow on the zone

Which parts that I'm using are reducing flow?

SummitMechanic said:

it will only slightly frustrate the guy you goes to maintain it 5 years from now.

That will probably be me. And I don't want to be frustrated.

EdTheHeaterMan

SteamtoHotWater said:

SummitMechanic said:

The only things i would change are moving the fill/expansion the the secondary loop with air elimination

You're suggesting that I move the fill/expansion (e.g. the Watts B9-11TM3 and Extrol EX-30) "to" the secondary? I think in a much earlier draft I had it on the secondary but this forum (EdTheHeaterMan) convinced me it belongs on the return side of the primary.

To be accurate, the primary loop is the loop that has the expansion tank on it. So changing the location from the boiler side of the SEP to the system side of the SEP actually changes the location of which is primary and which is secondary.

I just like the Expansion tank on the boiler side. But the System side is just as good as long as you have the hottest water in the loop and the lowest pressure of the loop in the same location by way of locating the circulator pump, on the supply (or hottest side) of the loop pumping away from the expansion tank. That is how you will get maximum air removal from your system. I believe the location you selected will be just fine. Especially if it fits so nicely. There is plenty of room for service and maintenance in your design.

SteamtoHotWater

EdTheHeaterMan said:

The Water heater service valve kit should be carefully looked at. the idea is for you to be able to shut off the hot and cold water from the home to isolate the boiler heat exchanger for running a washing solution thru the heat exchanger. By the looks of the diagram, it appears that the isolation valves will connect the hose bib valves to the house hot and cold water lines and isolate the boiler heat exchanger from the service hose bib connections.

I feel like I'm almost understanding you, but ultimately I'm confused.

EdTheHeaterMan said:

This might be one option for maintenance https://s3.amazonaws.com/s3.supplyhouse.com/product_files/SpeedClean-SC-DS-5-Brochure.pdf

That is a neat device. Is it not connecting to a very similar set of water heater service valves? Is the problem you're seeing with the location of my house side cold/hot isolation valves?

SummitMechanic

1. I always build my systems with expansion and fill on the secondary loop just before the supply pump. This way the expansion tank and fill valve have unrestricted access to all points of the heat system. However the fill valve itself will introduce microparticles of air to the system which is most likely why it was recommended to by installed where air could be eliminated easily. My suggestion was based on opinion and the way it is set up will perform just fine.

2. a bypass loop of some kind between the supply and return will prevent deadhead on your pump in the long run if you have an issue where zones are not opening for some unknown reason. it is essentially just a pipe connecting the two with a shutoff in the middle that stays off until a problem arises. Not necessary at all, just a nice feature.

3. The manifolds you will be using have an adjustable flow meter on the supply side. You can adjust them accordingly to make sure each zone is getting what it needs.

4. I looked at the picture for a little bit longer and the main thing i would add is a shutoff just after your fill valve as well. it will make it much easier to replace the fill valve in the future.

I want to reiterate that there are a whole lot of different ways to make boiler heat happen in a home. What you have here looks very good and i have been in countless rooms that i wished were that well designed.

SteamtoHotWater

SummitMechanic said:

1. I always build my systems with expansion and fill on the secondary loop just before the supply pump. This way the expansion tank and fill valve have unrestricted access to all points of the heat system.

Hmm. Something else for me to ponder.

SummitMechanic said:

2. a bypass loop of some kind between the supply and return will prevent deadhead on your pump in the long run if you have an issue where zones are not opening for some unknown reason. it is essentially just a pipe connecting the two with a shutoff in the middle that stays off until a problem arises. Not necessary at all, just a nice feature.

I will look into this. First I need to learn what, "deadhead on your pump" means.

SummitMechanic said:

I looked at the picture for a little bit longer and the main thing i would add is a shutoff just after your fill valve as well. it will make it much easier to replace the fill valve in the future.

I will add this.

SummitMechanic said:

I want to reiterate that there are a whole lot of different ways to make boiler heat happen in a home. What you have here looks very good and i have been in countless rooms that i wished were that well designed.

I think "designed" is the key word. We'll see how good looks once (if) it's actually built ; )

SummitMechanic

Because of the low loss header you are using i would just keep the fill and expansion as is. It is going to work fine, just not the way i would do it.

Deadhead is when a pump is trying to move fluid through nothing. So if the boiler has a call and turns the pump on, but there is no zone open it is essentially just hitting its head against a wall or "deadheading"

Add that ballvalve for sure, and consider a pressure bypass between the supple and return on your secondary piping. https://www.supplyhouse.com/Caleffi-519700A-1-1-4-NPT-Differential-Bypass-Valve?utm_source=google_ad&utm_medium=Shopping_tm&utm_campaign=Shopping_TM_New_users&gclid=CjwKCAjwxaanBhBQEiwA84TVXHfBhED83TNGIzpcbxXS9pYA4a5pGXuIRVggDgbJqTkDgcM5UXX6qRoCYuAQAvD_BwE . Something along those lines just for emergencies.

EdTheHeaterMan

SteamtoHotWater said:

EdTheHeaterMan said:

The Water heater service valve kit should be carefully looked at. the idea is for you to be able to shut off the hot and cold water from the home to isolate the boiler heat exchanger for running a washing solution thru the heat exchanger. By the looks of the diagram, it appears that the isolation valves will connect the hose bib valves to the house hot and cold water lines and isolate the boiler heat exchanger from the service hose bib connections.

I feel like I'm almost understanding you, but ultimately I'm confused.

EdTheHeaterMan said:

This might be one option for maintenance https://s3.amazonaws.com/s3.supplyhouse.com/product_files/SpeedClean-SC-DS-5-Brochure.pdf

That is a neat device. Is it not connecting to a very similar set of water heater service valves? Is the problem you're seeing with the location of my house side cold/hot isolation valves?

In looking at your diagram, the service valves appear to be installed in this configuration



All I'm sugesting is that you make sure that when installing the valves you can be sure to have this flow pattern, so the chemical will go into the water heater heat exchanger.




The instructions with the valve kit should be pretty clear on this.

SteamtoHotWater

EdTheHeaterMan said:

All I'm sugesting is that you make sure that when installing the valves you can be sure to have this flow pattern, so the chemical will go into the water heater heat exchanger.
The instructions with the valve kit should be pretty clear on this.

Got it. Thank you for the pictures. I'll double check the instructions.

hot_rod

If you run that Taco 0015 in delta p mode, which you should on a zoned system the dead head issue in never a concern. The pump will ramp down to virtually no flow if all valves close   No need for a bypass valve

The fill valve always connects at the expansion tank regardless if where you put the tank, as that is the point if no pressure change

Your proposed drawing is fine, at this point you are getting personal preferences that are not changing the basic operation or safety

SteamtoHotWater

hot_rod said:

Your proposed drawing is fine, at this point you are getting personal preferences that are not changing the basic operation or safety

This is reassuring. Thanks.