Weil WM 97 piping ?

hot_rod

Which of the two options would you use, single boiler piped into the distribution loop via closely spaced tees?

The installation manual shows using it with valve 5 closed ONLY with multiple boilers??

I helped a local plumber do a start up on this system 3 years ago, I checked combustion, helped him with settings. All low temperature radiant.

Been working just fine for the last 3 years.
Owner called yesterday, could not get ahold of the installing plumber. He told me another plumber came out and told him the #5 valve must be open and cannot believe it ever worked with it closed, factory rep confirmed?

EBEBRATT-Ed

I agree with you.

If the boiler is piped into a system with closely spaced tees the the primary/secondary connections are remote from the boiler and valve 5 is shut. I am assuming a system pump exists.

If the boiler is connected to a system's supply and return connections and a system pump exists then valve 5 is open and the primary secondary connections are at the internal boiler piping.

Least that's what I see.

EdTheHeaterMan

That’s Weil-McLain for ya

hot_rod

seems like an overly complicated piping assembly under the hood, for a fire tube mod con?

Tinman

Next thing you know they’ll be putting a heat exchanger on the outside of the boiler jacket. 😎

Ironman

It looks similar to the arrangement that ECR uses on their laser tube. You either open or close the valve depending on whether you're direct pumping or using p/s.

rick in Alaska

That setup in the 97+ is basically a primary secondary that is built in. You can leave the valve open if you want to do it that way, but if you want to just pipe direct to the emitters, then leave the valve closed. Either way, they already have most of it piped for you.
Rick

Solid_Fuel_Man

Seems pretty straight forward.

Valve open: boiler has the primary/secondary all taken care of.

Valve closed: boiler is direct piped, and you set it up as an injection loop. Primary/secondary is still accomplished. 

Edit: I like piping direct with fire tube mod/con with a large radiant if it's all one zone like a shop etc. 

Otherwise if its zoned and minimum flow cant be achieved then pri/sec it is. Seems like you could do it either way, but pipe size would be limited by the factory connections. So an injection loop would have to be used if the system has large flows. 

But with W-M throwing their choice of circulator in there, you really cant pipe it direct. Unless the system matches the curve of their circ. If not, pipe it like you did. 

hot_rod

My question why is Fig 51, valve closed only for multiple boilers? If I pipe a single boiler primary secondary, it seems this is what I want.

If you use the internal P/S, fig 50, you are mixing up the return, lowering the boiler efficiency, according to the purple color.

Danscrew

Yes its a Primary/ Secondary in stand alone mode. I piped mine like this for my one pipe system. Runs great I also added Taco Delta T pumps and running those in 2nd speed mode. The pic is old I got rid of the condensate pump and made it a gravity system.

Tinman

You may want to add a condensate neutralizer to the drain. The condensate is very acidic and most codes require it.

Ironman

I think that the wording isn’t as clear as it could be. In figure 51, the boiler HX is being pumped directly and p/s is taking place at the header. 

In figure 50, p/s is taking place within the boiler and the amount of mixing will be dependent upon the flow rate of each loop. Not too different than closely spaced Tess?

Danscrew

Yes of course Steve I have a neutralizer Thanks

Solid_Fuel_Man

Why? 

Who knows......

It would be nice if some W-M guys were on here. Eneegy Kinetics sure answers our questions!