Weil Mclain Easy Up manifold question

jakethomas

Hello all!
Im currently replacing my munchkin boiler. Im putting in an AquaBalance heat only boiler to replace it. The question I have is with the new plumbing. The old plumbing was simple, but this easy up manifold makes me think I need a check valve in the system. Please let me know if Im wrong.
Here is how the current plumbing sits. Exit boiler-plumbing goes up to T fill valve. After that the circulation pump, then expansion tank, after that all the zone valves. Pump would only come on when the zone valve was triggered. In this scenario all the flow makes sense. Water has only one way to go based on the pump setup. Now with the easy up manifold the return and supply are connected within 12" of a T. I have attached pictures. Can someone help fill me in on how to set this new system up. Not sure if I need a check valve installed..
Thanks
Jake

Ironman

That’s a primary/secondary manifold that allows hydraulic separation between the boiler and the system.
You need to supply the pump for the manifold and also a correctly sized one in the system loop.
Forget the check valve, you don’t use those with zone valves.

hot_rod

The installation manual shows some piping options

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Weil-Mclain-383-100-050-User-Guide.pdf

jakethomas

Ironman said:

That’s a primary/secondary manifold that allows hydraulic separation between the boiler and the system.
You need to supply the pump for the manifold and also a correctly sized one in the system loop.
Forget the check valve, you don’t use those with zone valves.

My old system didn't have this. I did see the manual on different ways to route everything. Is it wise to stick with this? Or should I ditch this manifold and just have the pump mounted outside the boiler supply and route it back through with a return?
I might down the road install an indirect water heater.
Thanks for the replies

hot_rod

While the manual doesn’t prohibit direct piping, they don’t show any piping that way?

With a zoned system like yours you may not get adequate flow when only one zone operates. Do you know the flow rate of the smallest zone?

jakethomas

hot_rod said:

While the manual doesn’t prohibit direct piping, they don’t show any piping that way? With a zoned system like yours you may not get adequate flow when only one zone operates. Do you know the flow rate of the smallest zone?

I don’t know the flow rate. I know I did have a flash in temp with the last boiler because there wasn’t enough water moving at one time.(only one zone in the house would do this)I thought about combining two zones to eliminate this. I got a laundry room that I could run with one of the bathrooms. I had a few quotes done before buying. One guy said he would install a small water tank in line because of this 

EBEBRATT-Ed

I would strongly stick with the primary secondary manifold

jakethomas

EBEBRATT-Ed said:

I would strongly stick with the primary secondary manifold

Why do you say that?

Hot_rod they didnt have any diagrams showing direct in the manual.

hot_rod

In some cases you can buy a hydraulic separator for the same $$ as that manifold.
Then you get air, dirt, magnetic, separation plus the primary secondary feature.

Jamie Hall

Did you say that your expansion tank was on the output side of the circulator? I'd strongly recommend repiping that -- whatever else you do -- so it is on the input side.

GGross

That Munchkin was very likely supposed to be piped primary/secondary like the new one, that is likely why you had the overheating scenario with low flow conditions. Primary/secondary is there to separate the boiler flow from system flow, in other words to guarantee flow through the heat exchanger. There was less education around water tube condensing boilers back then and a whole lot were direct piped when they shouldn't have been. Looks like you got your moneys worth out of the first one though.