Caleffi Manifold Choice

Mudaero

I am looking at using a manifold as a main branch for my cast iron radiators. There are 2 Caleffi manifolds I am looking at and am trying to determine which one would be better, the 663 series or the 668 series. My concern with the 668 series is that it lists the maximum temperature as 180F degrees, which is the estimated supply temperature in my system. The 663 says 210F degrees is the maximum temperature, but that model doesn't have the flow meters.

So, should I be concerned about the max temp of the 668 if it were to be used in my system? Do the flow meters help or should I just not worry about them (the CI radiators vary in size). I will need the balancing valves in the manifold as I have removed some of the non-working balancing valves that were connected to the radiator. Any suggestions are appreciated.

hot_rod

Correct with the composite flow indicators, the temperature rating is lower.

The 668 has a 180° continuous, 200° peak if that helps. It's rare to see a system run up to 200 these days and if it is remotely mounted it may not see boiler temperature.

The balancing valve and indicator make it possible to dial in the exact flow requirement and fine tune your system. With various loop lengths and radiator sizes I think you want a balance device.

Mudaero

Thanks Hot Rod. I initially wanted to go with the 668 but was just a little concerned when I saw the temp limit. But I do like the idea of being able to see the exact flow per loop, so I will definitely go with the 668. It's a nice looking unit.

Mudaero

One more question if you have time. The 668 has air vents on both supply and return. My boiler also has an air vent coming off the top. Would you still recommend adding a Discal air separator on the supply line?

hot_rod

Yes add the Discal at the boiler. The Discal pulls the smallest of bubbles at the best (hottest) spot in the system.
The manifold vents are really high point vents catching air that rises up to the manifold. Manifolds are often the highest point in the radiant systems.

If you plan on any ECM circulators, now of in the future, I highly recommend a magnetic function. The DiscalDirtMag
will pull air, dirt down to a 5 micron size and any magnetite type of corrosion. Well worth the investment as the pump manufacturers are clamping down on warranty if the pump is full of crap when it fails, same with the boiler.

Mudaero

Excellent information. That is exactly the unit I was planning on using. And yes, I will be using an ECM circulator (grundfos alpha). Thanks for the help, much appreciated.