5 zone home

Snowmelt

5 zones, going with zone valves & a Weil McLain 155,000 ultra.
Would you go with the delta t or delta p pump?

EBEBRATT-Ed

P. As zones close down the pump will back down

Snowmelt

would you go with taco or grundfos

Zman

Taco or Grundfos is kind of a Ford or Chevy question. They both good brands.
I do like the support Taco has offered on this site and would select Taco for that reason.

Snowmelt

if i go with taco shouldn't i just go with a delta T, especially if i use the outdoor reset that comes with the ultra.

hot_rod

Snowmelt said:

if i go with taco shouldn't i just go with a delta T, especially if i use the outdoor reset that comes with the ultra.

Why? ODR and constrained delta T operation may not get along.

Here are some thoughts and explanation.

Tinman

Last winter alone on 6 Ultras, I replaced either the blocks under warranty or the entire boiler for those just out of warranty. I'd be much less concerned on the choice between Taco or Grundfos pumps. Both are rock solid.

Snowmelt

Ok hot rod, what if I don’t go with outdoor reset, and use the delta t pump

hot_rod

If the system meets these requirements, see below, the ∆T circulator will work. Personally I don't see any advantage to holding a constant ∆. If the delta wanders above or below the design a few degrees on low load, or high load conditions what's the harm?

I've yet to find any heat emitter that must work at a specific ∆˙under all conditions? The ∆ in a system changes as a result of heat output.

Probably more ∆T value in chilled water applications where tight ∆ is critical to prevent condensation.

Opinions may vary