what's wrong with piping diagram

helgy_2

I was called out to a job that anothere contractor had installed. The system was not heating corectly. This is what I found. I know it is wrong, but need a little direction on corecting it. Any help you can give would be great. Sorry for the crude drawing.

Thanks, Helgy

Floyd_5

Just move the pump...

to the other side of the mix valve, and you should be all set.

helgy_2

might be missing some info.

the two lines that run horizontal end they do not conect to gethere is this going to be a problem.

Floyd_5

Shouldn't be...

IF... the piping is sized correctly.
What size are the pumps,mixingvalve, the piping, and the loops of the radiant?

Floyd

Paul Rohrs

I would also consider

moving the boiler pump to the inlet side of the boiler. It helps with the pressure drop on the PinnacleMunchkin.

Not illustrated is the air-separator and expansion tank. (?)

Regards,

PR

jwade55_3

Typical diagram

that I use. Just another take on it. With the short secondary piping associated with this layout, I find pump on supply or return of boiler works fine.

J

Kal Row

Mark Eatherton answered

the why in a thread called "mixing valves"


http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=14482&mc=5

hr

Why the mix valve

if this is a one temperature application. Could you run the Munchkin at desired temperature and delta t?

And no reason to run the horizontal pipes past the take offs and cap. Just use 90's to prevent a dead leg?

hot rod

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Kal Row

he didnt indicate

which muntchkin he has - if it's the cast iron one - he needs to keep the primary temp above 140F - anti-condensing, but if it's the stainless steel condensing one , your right - the boiler can take anything (cold water, hot to cold shock - etc) - then i agree - why not simplify the piping - and let the boiler stabalize the temp unless he intends to grow the system to other branches

- mixing valves - as do many spring and bi-metal control valves, get stuck or chatter, i have a braukman d146 differentiall pressure bypass that sings at one point in it's control range, am probably going to have to put a globe valve downstream of it, to give it some back pressure to push against - now i'm into weird science

Einsiedler_2

pump

move the pump closer to the header(s) and past the mix valve.

think of the pump as the floor circ , not the mix valve circ.

EIN

Weezbo

simple. put ball valve where pump is located ahead of the mixer,move pump to mixed side of the mixing valve stick check valve on return past mix on return side Cold to allow water a choise as which direction it wants to go easiest. to mix or to boiler. amen. done deal

Arthur

Circuit problem

The secondary pump Should be after the 3y valve.Otherwise the 3y valve will just act as a diverting valve not a mixing valve .When the 3y valve is open to bypass there is nothing to induce the water to circulate though the heating zone, unless the 3y valve is closed to bypass there will be no pressure differential on the zone circuit to cause the water to circulate.
The Primary pump should just pump in a complete loop back to the boiler return. The primary pump function should be to just circulate the water around the loop. Without affecting the zone circuit.

Arthur

Circuit problem

The secondary pump Should be after the 3y valve.Otherwise the 3y valve will just act as a diverting valve not a mixing valve .When the 3y valve is open to bypass there is nothing to induce the water to circulate though the heating zone, unless the 3y valve is closed to bypass there will be no pressure differential on the zone circuit to cause the water to circulate.
The Primary pump should just pump in a complete loop back to the boiler return. The primary pump function should be to just circulate the water around the loop. Without affecting the zone circuit.