New Hydronic System - Much More Complex Than I Am Used To.

Redrum

Hi;

I have had a few boiler systems, most recently a Buderus with Indirect Water, and 5 zones, Taco valves and a single pump. I am a homeowner, not a pro, but have basic knowledge and have worked on my systems.

We just moved into a new house, very happy that we found one with hydronic heat. Then I looked at the mechanicals, and tried to fire up some zones and boy am I confused. I could really use some help.

I have attached a picture of the mechanicals and the Boiler/HW.

I should mention this is a Timber Frame house with SIP Panels and there is a lot of energy efficiency aspects. The home was built in 2001, but the new boiler installed in 2018. The boiler is a peerless, and there is a tekmar 363 reset controller.

There are 6 zones. The first 4 are controlled by the zone valves you see to the right - lower floor office - two rooms, two zones, both in floor radiant. Main bath - panel radiator, Master bath In floor radiant.

There are two other zones which pass through the two pumps to the right of the zone valves - main floor and master - both floor register. There are no zone valves that I can see.

Every zone is working (especially after fixing a mis-wired thermostat), except the one in floor radiant is working weird. I should also note it's a large area. When I turn the heat on with the stat, boiler comes on, the valve turns on, and the supply pipe to the field gets hot, then it cools to warm. The floor just never seems to come up to temperature. The other weird thing is the main floor feed (past it's pump) gets hot, yet, if I check the registers, they are cold.

I have two thoughts - It's say 65 degrees out when testing to try to heat floor, so perhaps the reset is just not allowing the water to heat enough, or, their is air or something trapped in the radiant field. I have never had in floor heat before.

The system confuses me because it seems like the supplies and returns connect with no check valves (except between boiler and hw), and I have not seen "zones" without using valves before. I test and test and though to see what's what, and put blue tape on my findings, but am still mystified.

I also don't know who the contractor was/is. I suppose I could just contact pearless dealers and ask if they have a record for my address, but I thought I would start here first

Any help is very much appreciated.

Jim

Boiler and HW.jpg

Mechanicals.jpg

Redrum

If it helps, I can make a markup photo of what I think is what.

DCContrarian

I think it's important to establish if you can whether it ever worked properly.

HVACNUT

I'm not too familiar with that boiler, but it's not piped Primary/Secondary, and there's a branch right off the boiler for the indirect. So that tells me the boiler is programmed for 2 circuits. High temperature for the indirect, and low temperature for the Central Heat.

The space heating is further controlled and tempered by the 363. The ODR should be for programmed for X boiler temperature at Y outdoor temperature. Set the radiant thermostats to your comfort, and leave it. Give it time. If after a few days it's not making temperature, or over shooting, then other things can be checked. Those checks should be in the 363 because the boiler only takes one Central Heat input. As long as the boiler is making the temperature of the demand from the 363, then look to the 363 if issues. The 363 must be programmed for at least 2 different temperature settings, otherwise it's not even needed. ODR and a one circuit Central Heat temperature setting is already in the boiler.

Redrum

I have read both responses and think I understand. With regard to @DCContrarian , I think that I would probably have to seek out who the previous owner was using for a contractor by calling contractors in the area. The house sale was a relocation, so I actually bought it from a corporation. I would have to think that it has worked, the mechanicals are not new that I know of, just the boiler was changed. This is in the north east so if it didn't work, there would have been bigger issues.

This house also has a HRV, the first for me, but I am less confused about that :)

Withe regard to @HVACNUT - I believe you are correct with the separate circuit for the indirect, but I have no experience with two circuit boilers? My previous Buderus had an outdoor reset, but the indirect used the same water.

So, what you are saying is do not expect an in floor radiant heat system to behave like a register or panel radiator? (bring the temp in in under an hour), I might need it to run for some time to bring those rooms up to temp?

One thing that still is confusing. I would like to understand how the system works, how it is piped, but I am not familiar with systems that don't have a simple supply/return/zones controlled by valves. This thing has pumps all over the place and unless I am not looking at it right, supply lines and return lines are connected without a check valve? If you look at the last four vertical pipes on the right, two with pumps are for two zones, and their returns are right to the right of them. Yet they both connect the the dual horizontal manifold at the bottom, which are connected together, one side to supply, and one to return, huh? I have attached this area of confusion.

confusion.png

I guess I could look at the pump lit, but will they pass water if they are not running? I sure wish there was an indicator on the pumps that they are running, like a zone valve.

I like a challenge, that's good.

I am going to go over there again tonight (I am in transition), I might need to map the piping. But maybe there are some "standard designs" that are doing something similar that I am not aware of? Remember, I understand hydronics, but only on a basic level.

Thanks for your comments.

Redrum

I found this video. Primary-Secondary and piping proximity. Now it's starting to make a lot more sense. I'll check it out closer tonight.

https://www.youtube.com/watch?v=0sA-b2vLU78&ab_channel=HeatingHelp

SuperTech

Thats a Peerless Purefire. It has a water tube heat exchanger and is similar to the HTP Munchkin boilers. I work on a few of them.

Unfortunately that is not installed correctly if it is not piped primary/secondary. The water tube heat exchanger is quite restrictive and must have its own dedicated circulator that has higher head requirements than the space heating and indirect zones. If I remember correctly the boiler circuit should have a Grundfos 26-99 or a Taco 009. Check the installation manual to make sure.

That's a decent boiler but it needs to be installed correctly and serviced properly every year. Proper combustion settings need to be made in minimum and maximum firing rates with a digital combustion analyzer. I see a lot of problems as a result of the combustion air intake pipe being too close to the exhaust pipe. I also don't recommend using concentric vents for the intake and exhaust.

EdTheHeaterMan

Did you select your handle based on a Stephen King Novel that was turned into a movie in 1980?

mattmia2

It looks like that loop under the circulators is a boiler loop and those are closely spaced tees connecting the heating loops to the boiler loop.

Most circulators can have a flow check valve installed in them, that is probably what is happening here.

The indirect uses the same water as the domestic heating but it has a separate heat call on the boiler so when the indirect calls, the boiler shuts off the domestic heating even if there is a call for it and only runs the dhw circulator and makes a temp for the DHW(i see a mixing valve at the boiler so it isn't necessarily a different temp and priority)

Radiant heat in masonry has a lot of mass so it will take hours to a day or 2 for the slab to reach temp. Hot water will go in to the slab but cold water will come out until the mass of the slab is heated. It is important the outdoor reset is set to match the load or it will overshoot.

Redrum

yes @EdTheHeaterMan . It was one of my favorite books when I was going to college in the late 70's. I was studying engineering and working and it was killing me (redrum), so I adopted that as my early handle/password, and almost 50 years later, it's still there!

Still love the movie to this day.

@SuperTech - thank you for your input. I'll have to hunt down the contractor that was servicing it for the previous owner. No disrespect to the people that love the high efficiency boilers, but I chose the Buderus I have (in the process of selling the house) because it had a relatively high efficiency, yet was still a cast iron boiler.

I'll look at it closer and get some details. I do believe it is piped primary/secondary (from what I leaned today). I'll check the pump(s) model/manufacturer and check the manual (I am not at that house right now).

But my main initiative is to find out who was servicing it.

SuperTech

I prefer cast iron boilers for everything except radiant floor heating. Those condensing boilers work best for those applications. Yes they are more complex and high maintenance and it's tougher to find a tech who has expertise with them, but the juice is worth the squeeze when everything is done right.

The cast iron Buderus boilers are great, I like them a lot too.

hot_rod

I think it is pipes as a “moose antler” primary secondary? Zone valves with a single pump

with zone valves, a delta p circ would be better

Also some higher temperature zones off the primary”boiler” loop

It is a clean piping arrangement with good components

IMG_8746.jpeg

mattmia2

https://forum.heatinghelp.com/discussion/comment/1813575#Comment_1813575

It looks like there is a circulator for the zone valved zones that does the circulation between that zone and the boiler loop then a second circulator in that section that does injection mixing to make a lower temp for the zone valve controlled zones.

Not sure what the thermostatic valve on the boiler loop is for, maybe return water temp protection.

EDIT:

Or maybe the other way around, the circulator between the manifolds move the water in a loop through the zone valve controlled zones and the circulator connected with closely spaced tees to both loops is modulated to control the temp of the zone valve controlled loop.

EBEBRATT-Ed

It' looks like primary secondary to me. Don't see a boiler pump but maybe it is there somewhere

hot_rod

https://forum.heatinghelp.com/discussion/comment/1813580#Comment_1813580

a large Taco just as above the boiler for boiler loop?

bburd

@Redrum I suggest you set the thermostats where you want them and wait to see how the system performs as the weather gets colder. The comments above about radiant floor heat being very different from radiators, with very slow response time, are correct. Radiant floors simply cannot heat and cool quickly. They are not good candidates for night setback.

I don't think you have a problem, you are just looking at something different from what you are used to. "If it ain't broke, don't fix it.".

Redrum

Thank you for all of your comments, and @bburd you are right, I really wasn't looking like I had an issue (other than does in floor take longer), I was trying to understand what I had. Up until yesterday I didn't know of primary/secondary piping.

I went back there last night (in the process of moving, not yet moved), and mapped it out, and with all your help and a couple you tube videos, I now understand what I am seeing. See the marked up photos.

Boiler and HW marked up.png

Mechanical marked up.png

So, it is primary/secondary with two secondary loops. The primary loop (light blue) pump is on the return just before the boiler (Taco 001-F3). One secondary loop (green) branches to two baseboard register zones, each zone is fed by a pump (no zone valve). The other loop (violet) runs through two pumps (see **) two the four zone valves that feed 3 radiant floor zones, and one panel radiator.

** The one thing that confuses me is why two pumps? The only reason I can think of is because of that ball valve in series with that faucet fixture on the left of the manifold, perhaps it's for draining/bleeding. Or, maybe the tech had an issue that he solved with the second pump. Maybe it's as @mattmia2 mentioned, but I don't quite understand what he is saying :)

As for the in floor, thanks for the heads up on the time it takes to heat the mass. It is going to get colder here soon (I think?) and I'll fire it up then.

One question - could someone explain simply the concept of primary secondary and how it relates to high efficiency boilers? From my simplistic view the water is always circulating in the primary and it returned to the boiler with very little heat and pressure loss, so the boiler maybe isn't firing as often? The secondary then "borrows" some of the heated water and returns it to the primary cooled to mix with the primary's hot water.

What I don't understand is I had thought to get the high efficiency the water needed to be returned cold

But maybe I'll just keep reading.

Oops, a second question - why would the designer/installer choose one pump and zone valves for the in floor, and separate pumps, no zone valves for the baseboard register runs?

Thanks again. I always enjoy my time talking with you guys.

Jim

HVACNUT

https://forum.heatinghelp.com/discussion/comment/1813638#Comment_1813638

Those are injection loops. The boiler itself is not piped P/S. Check the I&O manual. It MIGHT not be a concern if the Central Heat input on the boiler is programmed for Low Temperature, but the manual will either show it, or it won't.

hot_rod

primary secondary piping is a means to disconnect various circuits, hydraulically speaking

It is commonly used with boilers yhat have a high pressure drop. So the boiler has a pump sized to just flow itself

Then, vis closely spaced tees the secondary circuits are connected with the appropriate pump

You have injection pumping which pretty much requires primary secondary piping as the tekmar control varies the speed of the injection circulator. So the primary or boiler loop has a fixed speed pump to assure it gets adequate flow

Some boiler brands have a pump and primary loop built under the cover.

You are correct, boiler efficiency suffers a bit when the boiler temperature is higher.

Ideally the boiler return temperature stays below the fuel dewpoint, around 130f for gas fired, for 90% operations

mattmia2

You have let's call it a loop 1a in blue and 1b in red. The circulator in the blue loop brings hot water in to the red loop and I think is modulated by the Tekmar control based on a temp sensor somewhere so it makes the lower temp water it needs for the radiant.

I thought i saw a thermostatic mixing valve at the boiler but looking more closely it is just the PRV that fills the system.

The need to make lower temp water and not wanting to have 20 circulators in the system is probably why the low temp circuits are controlled by zone valves instead of circulators.

Redrum

@mattmia2 - ok, I see. I had just thought blue was part of red, but what do I know? It makes sense if the pump on blue is modulated, and the one in red is not. The blue modulate based on temp via the reset controller, the red just circulates, or modulates for another reason. That would explain "why two".

There is a wired outdoor sensor.

I have a simple outdoor reset on my buderus on my current, soon to be last home. I guess I should investigate the tekmar. Thee is a hand written list of parameters that I found in the manual that the a previous home owner (there were 2) left. From memory there was a couple dozen or so. However, you never know how current that it, another tech may have set something different up.

SuperTech

Looking at it again and seeing the variable speed injection setup I have to say that it appears to be a pretty nice setup. I'd probably be smiling if I saw that in person and everything was done correctly. Nice boiler, radiant floor heating, nice piping, injection pumping, outdoor reset. Kudos to the installer.

Redrum

https://forum.heatinghelp.com/discussion/comment/1813684#Comment_1813684

whoever he is….😉

We had been looking for about 9 months, saw this house and immediately realized "this is the one". I do remember walking into the boiler room, looking the setup over and smiling. For one thing I have lived in a hot water heated home all my life and it was going to stay that way. I also like when things appear thought out, and the routing is nice and neat, wire dress, etc.

The house also has a life breath HRV. I have learned what I need to know about them I think, but it's hard to take guidelines and apply them to practical purposes, where past experience would be best. For example, if the previous homeowner had just provided me with some notes "we set it to X and the humidistat to Y. I plan on doing that when the sale of our current home closes.

hot_rod

From my view you have an above average hydronic system. It was planned and executed well with brand name components.

While unusual to you, I suspect it works well, enjoy it.

Redrum

unusual to me only because I am used to boiler→pump→valves→runs→boiler

Thank for all the thoughts and insights to everyone, I learned a lot. But I will track down who has been servicing it. I have maintained my simple systems, but this is well above my capabilities/comfort.

Jim

mattmia2

If the injection for the radiant is run only on ODR and there isn't a temp sensor somewhere, it will take that loop a long time to get up to temp. It is injecting enough to keep it at steady state, not to heat it. It could be run off a floor temp sensor and ODR.

hot_rod

A few extra pumps, one with a tekmar brain.

The most complexity is under the hood of that boiler. Inducer fan, computers modules, ignition system, gas valve, lots of thermistors and safeties.

Redrum

@mattmia2 - thanks, makes sense. I'll look for a temp sensor in the ground floor radiants (2 of the 3), or at least look to see it a wire leads to a location in/near the floor. Would they be embedded or would they be in something that is serviceable? What would it look like, something like this? Would it bed fed, say in a conduit that leads into the slab?

mattmia2

Usually they are slid inside a sleeve in the slab so that they are serviceable.

Redrum

I believe I am all set. I am a receiver of your good information and experience, not knowledgeable to contribute much, so I just wanted to thank everyone for helping and supporting me and many like myself.

I participate in other boards, mostly audio and electronics, and I am much more useful there. I know from that experience it's fun and satisfying to help others, but still, you all should be appreciated and thanked.

What did we all do before the internet? 😏.

Cheers;

Jim