pic of antique b&g mono t

Alan(OnVacationInOregon)Forbes

the 1" spring check is not closing the whole way; perhaps some debris or an off-center spring?

Why is the boiler on when there are no zones calling for heat? How many zones are there? Zoning by zone valves or pumps?

Jim_64

pic of antique b&g mono t, and.........

the continuing saga of the inhereted problem child. and as of today's search, no one has an answer for this; 3 cu returns into the same header, 1-1/4"/2", 1", 3/4". the boiler is in low mod, no zones calling. and if i follow by touch, each circuit's return from the boiler toward their supply, the 1-1/4 and the 3/4's very hot temps drop rather quickly, but the 1" stays very hot for a longer distance, and the convectors supplies on the second floor are very warm with a very warm air flow. all three circuits have had spring checks installed on the returns in an effort to prevent gravity migration
why is that 1" circuit behaving that way?

Jim_64

pic of antique b&g mono t, and.........

the continuing saga of the inhereted problem child

as of today's search, no one has an answer for this;
3 cu returns into the same header, 1-1/4"/2", 1", 3/4". the boiler is in low mod, no zones calling. and if i follow by touch, each circuit's return from the boiler toward their supply, the 1-1/4 and the 3/4's very hot temps drop rather quickly, but the 1" stays very hot for a longer distance, and the convector's supplies on the second floor are very warm with a very warm air flow. all three circuits have had spring checks installed on the returns in an effort to prevent gravity migration.
why is that 1" circuit behaving that way? conduction?

Jim_64

well, i know it don't always count for much,

but the checks are brand spankin new

3 pumped zones, and the boiler pump was programmed to be on 24/7 before my inheritance. but it's about to be changed to on-call when the other changes take place

bruce_21

Nice old monoflo tee. My old house's basement was full of them. Be careful around that insulation its asbestos laden. I'd wrap it up in tape to keep the dusty fibers from migrating.

Unknown

Monoflo's

Why are you considering replacing the monoflo tees? If some were installed in the wrong direction, why not just reverse them. From the drawing you made in your other posting, it looks like a typical split monoflo loop.What problem are you having with the radiators on the monoflo circuit?

I thought the main problem was the overheating on the 1" circuit. Stopping the boiler pump will most likely reduce or eliminate that problem. Really don't understand why the boiler pump was left running 24/7 ??

Does this system incorporate outdoor reset and if not, have you considered adding it?

Jim_64

the asbestos

is the customer's responsibility and i don't touch it

Jim_64

why not just reverse them?

while going that far, i'll just replace them

with the checks in place, the pump shouldn't have any effect, as it doesn't on the other two circuits. and, it's programming is about to be changed

yes, it does have an outdoor reset, and that was reprogrammed

Unknown

Antique Mono`s ?

My house is full of those too,, supplying the rad(cone pointing towards flow on main), if you have Dan`s book "How Come?" he describes some minor negative issues that may apply with this, but it will still work OK in any case.
I wish I could find some CI Mono`s as I have many customers who want to add-on to a main.
Don`t think replacing them will get you anywhere unless they are installed on the wrong riser, pointing in the wrong direction, especially if 2 (per loop)were used.
Then just turn them around.

Dave

Unknown

I still dont understand what the monoflos have to do with the stated problem of overheating of the 2nd floor zone. If I understand it correctly, the second floor is supplied by the 1" monoflow loop. How would a few backward monoflos in this circuit cause overheating and undesired flow with the zone not calling for heat? If some of the second floor radiators are not heating properly, that would be another story.

Unknown

I totally agree Mike K,

just think the OP has a problem understanding the positioning of Monoflo tees.
It sounds like a gravity-flow problem he has.

Dave

Big Ed_4

Are they backward

They should be installed on the return riser for up feed and two are used on the down feed systems.

Teflon tape in the system will get caught in spring checks and keep them open. Pull them and clean them out.

Watch the returns on a parrell system. Make sure all the returns connect to a single return before joining to the return manifold. If haphazard plugged in you will create a Ghost Flow..

Mark Eatherton

You may THINK you're not disturbing it....

but every time you bang a pipe, it cuts loose with a snoot full of deadly dust. Seal that joint with spray on glue and then tape it off. And do the same with any other joints in the vicinity. Friable asbestos can't be seen to the human eye under normal lighting conditions.

Proceed with caution...

ME

Jim_64

i'm with ya big e

installed on the return riser for up feed
exactly, and some are and some aren't. and yet some also installed counter to the flow arrows. not that that isn't acceptable in some situations, but with such a mixed up combination........

and......sorta can't pull the spring checks bec they were pro-pressed

Jim_64

monoflos have to do with the stated problem of overheating

that's only a part of the problem('confused' pressure difference in what was reacting as a gravity system) and todays re-inspection clarified two other larger parts of the problem, one solved today, but too lenghty to get into here

Mark Eatherton

Explanation of B&G tees.

In the case of the radiator/convector being above the main, ideally, the MF tee should be in the return, with the arrow facing down stream. This creates a true "venturi effect", which essentially is a situation whereby the water velocity INCREASES across the entering side branch of the tee, and creates a low pressure zone to induce side branch flow. It is typically connected to the return, because that is where the heaviest, denser water will be. The hotter water will have a tendency to want to RISE UP in the supply main, further enhancing flow. However, and this is a big however, alternately, the MF tee can be placed on the supply riser IF the MF tee is installed backwards.

MF emitters, MUST be bottom filled, and top bled if they are above the main. You can NOT force water through the side branch at a high enough velocity (in most cases) to completely and adequately purge the air out of the branch circuit. If the emitter is below the main, it should self purge due to bubbles rising. I will caution you, purging these systems is a royal P.I.T.A.

The check valve on the 3/4" return should be on the 3/4" branch, and not the common header, and there should also be a check valve on the MF common return to avoid movement when any of the other zones are running, and that one is not.

If you don't already have three thermostats, you could use a Honeywell wireless thermostat station with multiple thermostats, and use their outputs to fire replays to the pumps. If you have three stats, then once you move the checks to where they are supposed to be, then you shouldn't have any more ghost flow issues.

Essentially what happens here is that it creates a partial blockage between the supply and return tees, which causes the water, which is wet lazy and stupid to take the path of least resistance, which is UP the side, supply branch,

IF the side branch has a significant pressure drop, OR if the side branch is serving emitters that are below the main, it may require the use of TWO MF tees. One on the supply, acting as a diverter, and one on the return, acting as an inducer.

In general, there really doesn't seem to be a consensus as to exactly which loop is consider the "primary" loop. Some writers consider it where the heat source is, some where the PONPC is. Personally, I prefer to consider it where the PONPC is, because in most cases, there is only one PONPC, but you can have numerous thermal input loops.

That's my story, and I'm stickin' to it.

ME

Jim_64

yeah, three stats

already existed, so they stayed

and yep, the check on the header was a good idea in regards to killing two birds with one stone, but i'd've rather seen it on the 1" line to have the ghosts busted

where the PONPC is; uh-huh. and it's obvious to me that that's why weil calls it the boiler pump and boiler loop vs the primary pump and primary loop

and again, thanks for the input