problems with Triangle tube piping

t300

This spring I bought a house that was built last fall, so it had 1 Canadian winter on the heating system. I will probably get terminology wrong but it is a natural gas Triangle Tube Instinct Combi boiler. DHW and the other side heats multiple zones in the house for heat. Basement floor, garage floor, garage radiant heater, household furnace and a zone for outside front steps (never used). They stubbed some glycol pipes for a future sunroom heating as well.

Problem I discovered in spring is the house kept heating to 22-23c. I disabled the glycol heating side of the boiler but the tube manifold in my furnace kept heating up (zone for household heat). I then disabled the DHW as well, and the problem went away. Had a couple different companies come out and they indicated that the system is not properly setup as primary/secondary piping, and what is happening even when the system is not calling for heat, is that the boiler heat needs to go somewhere so pressure is pushing past one of the zone valves (happens to be for the household head) and heating up that zone. Logically this all makes sense.

company1 was onsite for 2 hours to review. their T&M estimate to fix is 3 days onsite and 'some' parts. Waiting on another company to come out to ensure company1 has properly diagnosed and scoped the amount of work. My small pea brain that knows nothing about this says why can't you simply add a piping loop for the sole purpose of heat evacuation or wild loop or what have you, but i'm sure there is more than that.

Looking to this group to validate the diagnosis or at least that company1 is on the right track. I realize I don't know what I'm talking about and will ultimately leave it to the pros, but 3 or more days of labor plus parts is a lot of cash and want to ensure I have a few sets of eyes on it. Pictures coming right away!

t300

tim smith

Someone likes iron pipe. Its a bit of a semi organized mess. Little hard for me to see in photo but does not look like its piped primary secondary, 1st mistake. If you did not want to spend the $$ to to some semi substantial repipe. They could just tie system supply and return piping together with some closely spaced tees or a low loss header and then pipe the boiler supply and return to either the closely spaced tees or LL header and add a pump it looks like. I can't see how the dhw coil is tied into boiler but that might have some influence on how its done also. It would be nice to see it cleaned up a fair amount but $$$ are not always available. Just a thought.

t300

t300

tim smith said:

Someone likes iron pipe. Its a bit of a semi organized mess. Little hard for me to see in photo but does not look like its piped primary secondary, 1st mistake. If you did not want to spend the $$ to to some semi substantial repipe. They could just tie system supply and return piping together with some closely spaced tees or a low loss header and then pipe the boiler supply and return to either the closely spaced tees or LL header and add a pump it looks like. I can't see how the dhw coil is tied into boiler but that might have some influence on how its done also. It would be nice to see it cleaned up a fair amount but $$$ are not always available. Just a thought.

Thank you! A question I forgot to ask is, since during winter / heating season the system will be running heat for the house (unlike in summer when its just DHW required and when I discovered this issue), is there any potential equipment early failure concerns or safety issues running it over the winter in this existing configuration? It did run from Nov to May without issues that I know of.

GGross

The external pump is an issue in this case as well, being that your boiler is a combi it has an internal pump and diverter valve, when you call for DHW the diverting valve closes off flow to the heating side, with that external pump still running it can fight the diverting valve and cause issues, it must be primary secondary piped. The installing company should come and fix it, it is not an acceptable install

I agree with Tim that it is an organized mess though, fairly neat layout, but unacceptable piping strategy

psb75

Agree with the above commenters. An "organized mess". Strange looking. Visually...well laid out.
Hydronically...notsomuch. Black iron is a strange medium to express one's self. The wiring is "veryfine" too. I gotta walk-away from this one. Creepy.

Ironman

Is that O2 barrier pex that’s installed?

psb75

It is just...OCD-strange. Opaque white, crimp pex. ??? Odd AF.

hot_rod

Basically the boilers own pump, and the one below the boiler are in series. So the pressure they develop could push past the zone valves
Proper piping would solve that

I always wanted to try putting a delta P pump in series for these fixes to see how the two would get along, since this comes up often

here is a fairly simple repipe to primary secondary

t300

thanks all, learning a lot from your posts. Different company coming today to give their assessment.

t300

Realized another issue I had forgot about but most likely related somehow. The boiler is used for DHW, piped to a electric HWT which is used as storage, electrical element turned off via the breaker. With the boiler used for DHW, I get pipe hammering in the ceiling in the room next to the boiler. It starts loud, every 5 or so seconds, then over the next minute gets quieter until it stops. Doesn't happen for another hour or 2 or so. I'm guessing this is when the boiler is heating DHW. The company that came to look at the furnance zone heating issue just shrugged and said some water pipes may not be properly fastened in the ceiling, but I'm wondering if the DHW piping is also causing some flow contention with the pumps? I assume the DHW side also has an internal circulator? When I disable boiler DHW and flip to electric.(unplug the boiler DHW external pump and flip the HWT breaker ON), thats the setup where I hear pipe hammering. When I run electric only, there is no pipe hammering.

t300

note I have had both sides of the boiler OFF since spring, been running the HWT on electric.

Teemok

There was an attempt. Lots of wisdom already stated above. Someone can make this work but there's defiantly re-piping needed. There's no simple, change this one thing fix. Combi DHW to storage tank is a thing I've seen piped wrong many times. Fixing one existing fault at a time can be a woeful chain of discovery. Have a pro go over the whole thing and fix it all at once. Finding someone who is both competent and willing can be a challenge.

t300

Update for those interested, Company who looked today said it’s physically feasible (but tight!) to add a primary loop by moving around the zone valve that’s circled in first pic to make some room, and around that spot adding a piping loop to go up and around the boiler then tie it back in below the boiler.  Not sure why the original installer put the pump at the bottom that essentially is hitting all the zones but they talked about moving that pump on top of the circled zone valve which is the furnace zone.   The basement floor, garage floor and garage air heater zones all have their own pumps.  My job this weekend is to turn things on one by one so at least identify and label all the zone supply and returns. 

They also did say if they reprogrammed the boiler to on demand instead of “constant”, that the original issue may go away, although then still stuck with no primary/secondary loop as recommended as best practice and by manufacturer.   Note this was not their recommendation but more of a “it’s technically possible”

appreciate all the posts, will still obviously leave this to the pros and want to do it right but I feel a lot better now that I have a general understanding of how this is supposed to work 

GGross

I believe that what your contractor said about "constant" is correct. In the programming on that boiler there is an option to run the heating all the time or only when there is a call for heat, it gets by many newer installers who do not know what the boiler is asking them to program. Unless the system was designed for constant circulation, which it does not appear to be as it is not piped correctly, you will want them to reprogram it to only run for space heating when there is a demand for it. that is in addition to re-piping the boiler as primary/secondary, this is especially needed considering there are other pumps involved which I did not originally see

Teemok

There's constant heating demand, covered above and a "stay hot" setting for fast DHW production. Given you have a storage tank you don't want it programed for DHW stay hot mode.