Goast Flow

kevin

i have had a similar problem before. I added flow checks, traps,yelled at it and the only way I was able to stop it was a zone valve. A bit overkill but it worked...just my 2 cents if it gets to that. (i would do the Sparco mixer, on the domestic side 1st) kpc

Jamie_6

Goast Flow

When the primary pumps A & B are running we are getting water through pump C and the flow check! If I where to put a flow check on the return of the hotwater maker would this stop the goast flow?

Thanks ,
Jamie

KCA_2

Well.. It looks


like the S&R for the HW should be taken off of the supply from the boiler with two tees no more than 6" apart.

Also consider a heat trap.. Drop the piping to the HW maker 18" or so below the supply piping. The pressure differential is feeding the HW maker now. The heat trap will keep a ghost flow from occuring later after you've repiped the system.

Is that a radiant system on pump A?
Is the HW maker on a priority?


My thoughts..

Hope they help

:-) Kca

Boilerpro

Follow the flow and you'll discover that....

The boiler loop pump and the hot water maker pump are piped in series. Water coming out of the boiler will get to the tee going to the water maker and the system and will go both ways because it is easiest to go that way. An additional flow control may stop it, it depends on the head pressure drop on the piping going to the system loop. Also most flow checks do not seal tightly, so you can still get leakage....something I learned recently. Depending on your controls, you may want to connect that water maker P/S to the boiler loop. It all depends.

Boilerpro

Jamie_6

Kca, Thanks for the fast reply!

The radiant comes off of the main loop via. injection. I also have a flat plate heat exchanger for back up,& the hot water is on priority.

The Hot-water maker is coming off of the supply and into the return, was this the right thing to do?

KCA_2

I just happen to be

online with nothin to do.. Installed 2500sqft slab system this mornin so..

Anyway.. Seems to me that it's a matter of piping the HW maker like I posted earlier. Minimize the head across the S&R to the HW maker and use a trap and there shouldn't be any more issues. Now.. I have seen where the primary pump is oversized and there still is some flow & that would be where some sort of flow device could be used.

What's the plate exchanger for & where is it?

You could also pipe the HW maker in series with the boiler & use it as a BTU dump but that requires a Temp valve for the domestic and a domestic recirc is best.

Are you a HO or a Contractor?

:-) Kca

Art Pittaway

Hey, BP

if it's a true B&G flo control the weighted check could be raised up with the lever on the top. You need to make sure it's turned all the way down. In this case it probably is driven open by the boiler pump because it's installed wrong.
Art

Jamie Pompetti

Here is a picture of how it is piped. The goast flow is going straight into that hot-water maker

Jamie Pompetti

So taking it off from the bottom and move it to the main primary is my only alternative huh? This will suck if I have to do that, not to mention I followed the directions in my CDAM.

Frank_3

The short answer ...

... is no. If the boiler circulator (B) is able to pull water through the one existing flo-check it'll most likely be able to lift up a second one just as easily.

Quick fix: See the tee where the DHW return comes into the boiler return? Move that tee to the discharge side of the boiler circulator. The existing flo-check on the DHW supply will prevent the boiler circulator from reverse-flowing through the DHW tank.

However, you're still at risk of having the DHW circulator pull water out of the primary loop, whether or not you move that tee. You'd do well to put a flo-check in the boiler supply, between the DHW supply tee and the primary loop tee.

Frank_3

The short answer ...

... is no. If the boiler circulator (B) is able to pull water through the one existing flo-check it'll most likely be able to lift up a second one just as easily.

Quick fix: See the tee where the DHW return comes into the boiler return? Move that tee to the discharge side of the boiler circulator. The existing flo-check on the DHW supply will prevent the boiler circulator from reverse-flowing through the DHW tank and the boiler circulator's intake sees only the primary loop.

However, you're still at risk of having the DHW circulator pull water out of the primary loop, whether or not you move that tee. You'd do well to put a flo-check in the boiler supply, between the DHW supply tee and the primary loop tee.

Tom M.

a suggestion

You could move the boiler pump (B) back to the other side of the tee where the hot water maker return comes in. This way, the pump is still in the same direction in it's intended loop but the pressure difference it creates will be in the opposite direction of the hot water maker loop, flowing against the flowcheck rather than opening it.

Dan_8

Probably not very helpful...

but could you just move the return tee for the DHW from the boiler return to just downstream of the DHW supply tee on the boiler supply? That would make it a true secondary circuit on the boiler supply line and should virtually eliminate the pressure difference across the DHW supply and return.

You'll have to run the boiler circ and the DHW circ to get heat to the DHW but there would be no need to run the primary loop during the non-heating season.

Dan H shows a similar setup in the 'boiler room' chapter of his Hyrdronic Radiant Heating book if that helps at all.

I'm just a lowly HO but I've been doing way too much thinking about a similar setup for my house lately...

Dan

PS - If anybody can tell me why this is a bad idea I'd really like to hear about it. I'm close to putting this one to paper for my upcoming re-design.