Is the circulator sized properly?

**alexb** · 03-20-2005, 08:26 AM

Back in 1999, my circulator was replaced along with the furnace. The old unit was a Taco model where the motor rested in a C-Frame with a spring-loaded couple to the impeller shaft, the whole thing was about 1.5 feet long. I now have a Taco 007, 0-20GPM and head-range=0-11ft. What's the difference between the old model, and this newer model? What are the symptoms of a pump that's under-specd? Over-specd? Is 'head-range' the number of feet the pump must be able to lift the water given the piping structure of the house? No DIY, just wondering if this affects efficiency at all...

**beenthere** · 03-20-2005, 08:53 AM

Ft.hd. is the amount or total restrict the pump can move x-gpm.
The 007 has a low rate ate 11 foot of head, alittle less then the taco 110 you use to have.

If it isn't moving enough water then your base board of what ever you have will not give off enough heat.
If too much it could cause condenstion in the boiler combustion area.

What is wrong that you are only asking 6 years after the change out.

**alexb** · 03-20-2005, 11:27 AM

If it isn't moving enough water then your base board of what ever you have will not give off enough heat.
If too much it could cause condenstion in the boiler combustion area.

In trying to determine if I have enough GPM flow, is there a way to determine proper GPM, given I have ~318ft. of 3/4in. copper line? (all loops, upstairs & down). Does Boiler BTU play a role too? Changing the circulator is a cheap way to gain efficiency.

**beenthere** · 03-20-2005, 11:39 AM

Baseboard is rated at 4gpm.
The circ is sized to the highest head loop.
the boiler is just one part of a system, all parts must be considered.

What size is the boiler.
Does it have a thermol loop.
Where is the circ, before or after the boiler.
How is the thermol loop piped, system bypass, or boiler bypass.

Your upstairs may have 170' copper and element, plus normal fittings that equal 12' of head. That would give you about 1gpm.
1gpm brings 600btu per foot baseboard down to 500btu.

Is your system heating the house to stat set point, or is it falling behind when its below 20 degrees ouotside.
Or are you trying to save fuel.

**sweet** · 03-20-2005, 01:47 PM

Taco 007 cannot move 20 gpm at any head. Not sure of performance curve for Taco 3-piece pump you have, But most 3-piece pumps have a fairly flat curve moving more gpm at less head press. At 318 ft of pipe is this total system or longest run?

**condenseddave** · 03-20-2005, 02:26 PM

Originally posted by sweet
Taco 007 cannot move 20 gpm at any head. Not sure of performance curve for Taco 3-piece pump you have, But most 3-piece pumps have a fairly flat curve moving more gpm at less head press. At 318 ft of pipe is this total system or longest run?

The 007 most certainly CAN move 20 GPM, at 3' of head.

Check the curve. It's the MAX, but it is 100% capable of doing that.

**beenthere** · 03-20-2005, 02:33 PM

LOL...

Dave, when your right your right.

I wasn't going to argue the point, since the OP doesn't have a zone short enough to only have 3 ft of head.

**sweet** · 03-20-2005, 02:54 PM

Your right I was looking at 007 ifc. However depending on loop lengths, 007 at design day temps might be a tad undersized. At this point we know very little of application usage.

**tinknocker service tech** · 03-20-2005, 03:11 PM

to aanswer you question without getting to technical
there is little difference between to two pumps and the taco007 is a strong and reliable pump. all it does is move the water in a closed loop. if the boleir is an 80% it is still 80%

**alexb** · 03-20-2005, 05:37 PM

At 318 ft of pipe is this total system or longest run?

318ft is the total for the entire system. The longest runs would be the upstairs at about 120' (upstairs has two of them) Also, another member wanted to know if the pump was before, or after the boiler - The pump is ~2ft. before the return runs into the boiler. Also, the boiler doesn't have a large storage capacity, nor does it have an aux. storage tank; the water from the boiler directly feeds the house.

**sweet** · 03-20-2005, 06:02 PM

Like beenthere asked does the system keep up? Any heating issues other than difference in pump performance?

**alexb** · 03-20-2005, 07:31 PM

Like beenthere asked does the system keep up? Any heating issues other than difference in pump performance?

I'd say that the furnace runs significantly more during very cold weather (below 30degrees), so I'd be safe to say that the system definitly has trouble maintaining a setpoint in cold weather. Also in the mix, is the heat-loss in my house; I think the exterior walls are poorly insulated; R30 in attic though. It's not scientific, but I think the house used to be a bit warmer with the Taco 110 circulator. Now would be a good time to mention that the boiler that was installed in 1999 may have been 20,000BTU smaller than the old 1963 National US that came out; I don't remember what the rating was on the old furnace; too long ago...

**tinknocker service tech** · 03-20-2005, 07:53 PM

is the house staying warn and the tstat reaching its set point. are the rooms comfortable in the cold below 30degrees. back in the 60 fuel was cheap and no one worried about btu. as fuel costs more people found a lot of systems were way oversized. in the colder wheather any unit will run longer as more heat is needed to warm the house.just like ac on cool days it turns on and off and on hot days it seems to never turn off till the sun goes down
so please tell us is it keeping up with the stat

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