Lochinvar Knight WHB085 + Taco VR3452-FC1A01 (0-10v input) Boiler Pump

tuffcalc

Hi everyone,

Installing a Lochinvar WHB085. All the literature states that it comes with a variable speed ECM boiler pump with 0-10v input (so the Lochinvar can control it's speed) for the primary loop. Unfortunately when the WHB085 arrived it had a standard non-ecm grundfos pump in the box. Called Lochinvar and they told us only the euro versions come with the ECM pump. Anyway, here we are.

I went on a mission to find an ECM pump with 0-10v control input. Looks like the smallest ecm pump I could find that supports 0-10v input from a boiler is a mid-sized Taco VR3452-HB1-FC1A01. The submittal sheet shows a pump curve that needs at least 2 feet of head to pump 1 GPM (https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Taco-VR3452-HB1-FC1A01-Submittal.pdf)

Called Taco to see if the pump would work at those low rates. They said they didn't know.

My alternative is using a standard variable voltage pump like the Taco 007-VVF5, but again, no guarantees from Taco that it will pump at super low GPMs.

Anyone have any suggestions or experience in a similar situation? Should I try the VR3452, or return it and go with the 007-VVF5?

Zman

The Lochinvar 399's come with a 0-10 vdc circ. It is a Grundfos, I don't remember the model number.
2 ft of head is not very much. You could put in a balancing valve after the circ to give it a little extra resistance.

Rich_49

These are smaller than VR3452 . 008 is used in many 1-10v applications .

http://www.tacocomfort.com/products/water_circulation_pumps__circulators/wet_rotor_circulators/_variable_speed_variable_voltage_00_circulator/index.html

tuffcalc

> @Rich_49 said:
> These are smaller than VR3452 . 008 is used in many 1-10v applications .
>
> http://www.tacocomfort.com/products/water_circulation_pumps__circulators/wet_rotor_circulators/_variable_speed_variable_voltage_00_circulator/index.html



Yes, but these aren’t ECM.

Gordy

I know it doesn’t answer your initial question, but what is it you are trying to achieve with the 2’ of head @1 gpm?
Sounds like you are trying to meet the minimum flow rate requirement for that boiler. That’s a tough nut to crack.

tuffcalc

Gordy said:

I know it doesn’t answer your initial question, but what is it you are trying to achieve with the 2’ of head @1 gpm?
Sounds like you are trying to meet the minimum flow rate requirement for that boiler. That’s a tough nut to crack.

Yes, just trying to make sure I can meet minimum flow rates - so that the boiler can take advantage of its entire range of modulation for both the pump and burner.

Rich_49

tuffcalc said:

> @Rich_49 said:

> These are smaller than VR3452 . 008 is used in many 1-10v applications .

>

> http://www.tacocomfort.com/products/water_circulation_pumps__circulators/wet_rotor_circulators/_variable_speed_variable_voltage_00_circulator/index.html







Yes, but these aren’t ECM.

I apologize for the recommendation . I was unde the impression that you'd be maintaining min flow through boiler . Did not realize you just wanted to save 2.50 year on electric .

tuffcalc

Rich_49 said:

tuffcalc said:

> @Rich_49 said:

> These are smaller than VR3452 . 008 is used in many 1-10v applications .

>

> http://www.tacocomfort.com/products/water_circulation_pumps__circulators/wet_rotor_circulators/_variable_speed_variable_voltage_00_circulator/index.html







Yes, but these aren’t ECM.

I apologize for the recommendation . I was unde the impression that you'd be maintaining min flow through boiler . Did not realize you just wanted to save 2.50 year on electric .

All good. If you read my original post you will see that I already considered the 007-VVF. Like I said, Taco would not confirm of any of their VVF pumps would also pump very low flow (like 1 GPM/min).

Gordy

tuffcalc said:

Gordy said:

I know it doesn’t answer your initial question, but what is it you are trying to achieve with the 2’ of head @1 gpm?
Sounds like you are trying to meet the minimum flow rate requirement for that boiler. That’s a tough nut to crack.

Yes, just trying to make sure I can meet minimum flow rates - so that the boiler can take advantage of its entire range of modulation for both the pump and burner.

The boiler will take advantage of its full modulation range. As far as getting in the weeds with a 1gpm flow rate you will need a stable load at that 8.5k low end. So hopefully you are not micro zoning.

AlexZavgorodni

@tuffcalc Did you end up getting answers for Taco VR3452-HB1-FC1A01? Assuming you installed this unit - how is it working for you?

BigRob

Check out the Armstrong Compass H 20-20. It claims a 0-10VDC input.

https://armstrongfluidtechnology.com/~/media/documents/sales-and-marketing/solution-outlines/10-192-compass-h-solutionoutline.pdf?la=en&display=1

tuffcalc

AlexZavgorodni said:

@tuffcalc Did you end up getting answers for Taco VR3452-HB1-FC1A01? Assuming you installed this unit - how is it working for you?

I installed it but it was too big a pump for my needs. I installed an Armstrong Compass instead. No issues with it.

After using the WHB/WHN boiler for about a year, I've learnt it runs best with about 20degree delta T pumping about 10gpm through the boiler. Higher delta Ts work but the boiler sometimes makes funny noises - so I backed it off.