GV 90 Boiler calling all zones

Bill Julian

I installed a GV 90 with 5 HW zone on circs. Used flow checks and what is happening is no matter what zone calls all he zone get hot. I've never seen this in all my days.
Everything is wire correctly and no zones are calling (except the one) but all feeds and returns are getting hot along with the baseboard. I can't figure it. I'm ready to just install zone valves but I'd like to know what is going on anyway. How can all zones get hot when only one (anyone) calls?

hot_rod

Got a pic of the flow checks?

  I’ve had several hydronic service guys tell me the plastic checks in the circulators can fail in 3-5 years. If so, any one circ could induce flow in other circs.

The white colored checks are rated at 150F continuous, the black are 189F or higher.

If you have weighted checks, it’s rare, but possible for multiple ones to fail, or stick partially open.

Weighted swing checks, not a great check for Hydronics, they need a delta P to seal 

Jamie Hall

How is it piped? Sounds like a particularly evil case of ghost flow or a subtle piping error.

Bill Julian

Thanks for all the replies here are a few pictures Flow checks in ceiling not shown.

Bill Julian

Also I have installed the plastic circ flow checks in circs so I have double flow checks and still have flow to all zones when ONLY ONE zone calls. We have to shut system down up strs its too hot. Confused on this one!

Bill Julian

The flow checks above the boiler are taco swet checks 219

HVACNUT

Not sure about the 219, but the 221 comes shipped with a piece of cardboard between the weight and body. It must be removed before installation. 
You also have flow checks in the circulators? Why?
Circulators are on the return? Again, why?

kcopp

Can we get a better pix further back and w/ better lighting? makes me wonder about piping....is it piped with a boiler loop and a system loop? AKA... Primary/ secondary.

Bill Julian

Hi Ya the 219 cardboard is removed, of course. The reason the flow checks are in the circs is b/c I did not removed them after having installed the 219's on the supply. Just didn't bother to remove them yet until I know what is causing this issue. No I did not pipe typically using system loop the boiler has its own loop internally. I have piped this way many time with no issues. I think however what I might do is pump away. Install circs on the supply.

Bill Julian

What might be happening is any circ that is "On" is pumping the rest of the zones as well for some unknown reason it must be a piping issue. Thanks for helping me get there with your insights.

hot_rod

Does that boiler have a circ built inside of it?

Bill934

Yes it does

Tom_133

the internal circ is flowing to all. You need to install 2 closely spaced tees. That will fix it

Tom_133

like this

Bill Julian

I thought of that. What about moving the circs to the supply?

Tom_133

it won't help. the internal pump will push right through them. You could swap the pumps for zone valves (if you are sure your boilers internal pump can handle the head of the system), or do the two closely spaced tees. I would suggest the tees it fixes everything. If I was doing it, I would put the pumps on the supply as well. Just simpler and ensures you are pumping away from the expansion tank.

Bill Julian

Its a GV90-5. There is not much BB. Zone 1 26' CI BB, Zone 2 10' CI BB, Zone 3 8' CI BB, Zone 4 small space heater (tiny), Zone 5 30' Cop BB. Its a restaurant. BTU's I'm figuring the 44 feet of CI BB @ 25-28,000 BTUs and so the entire heating is probably under 50,000. So the load is certainly not excessive. Ya I think I will install the TEES. and maybe move the circs.

Tom_133

Ok. Seems reasonable. I looked at it a little and thought if it was me I would pull that first 90 off the supply and put a tee there vertically. Then a short nipple below it and the other tee aiming the branch toward the lower return on the boiler, and pipe that boiler return to the branch. Then off the top and the bottom of the tees I pipe to the corresponding manifolds, in fact if the direction of flow doesn't matter to your system, flip the pumps in place and pipe to the new supply and return manifolds.

Bill Julian

Sounds right. Didn't know the internal pumps would cause so an issue I mean Ive done these before without an issue but as I recall I used the spaced Tees but not always...strange. The book also calls for 11/4, I used 1" supply and return but have such little btus??? Thanks for the help much appreciated

Bill Julian

O If you have to time send me a sketch of what you mean with the words you sent....if you can, if not I'll figure it anyway.

Bill Julian

I repiped today seems to function normally with the TEES.