Too much flow?

[mark115]

My system has 1 circulator (TACO 007-F5) on the return, pushing into the boiler.

If FT.HD. = loop length * 0.06 and GPM=HPx2178/FTHD, here are GPM in each of my loops using TACO 007-F5, 1/25hp, 3250rpm vs TACO 0011-F4, 1/8hp, 3250rpm:

ZoneX: FTHD, gpm(1/25hp), gpm(1/8hp)

Zone1: 10.8, 8.1, 25.2
Zone2: 9.0, 9.7, 30.3
Zone3: 6.6, 13.2, 41.3
Zone4: 7.2, 12.1, 37.8
Zone5: 6.0, 14.2, 45.4

Recommended flow thru the new boiler is 10gpm.
Are those flows with the 0011 simply TOO high?
Most everyone suggests 1 circ/loop. Since it's rare that more than 2 zones call at one time, and zone 1 is easily the most active, what do you think of just adding another 007 on zone1?

[beenthere]

Yes, the 0011 would be too much.

Did you allow for fittings in the loop.

Just adding another 007 for zone 1 may work, but I don't remmember the original problem to give a better answer.

You got too many threads going.

[hydronicsman]

What kind of radiation do you have Mark?

[mark115]

beenthere: Original problem was the BANGing boiler. You may have seen that the mfr has agreed to replace it. During all of that, we discussed the possibility of low flow being the culprit. Don't know if low flow was the cause for the BANG, but after looking at it, most everyone agrees that flow thru the system is not adequate.

hydronicsman: all baseboard, plus 2 undercabinet radiotor+fan units. Original bb is 1.25" cast iron. Zones 4&5 are new with 3/4" copper.

Here are the details per zone:

Installed radiation:
Zone1, 60’ of bb (x600BTUH max radiated capacity = 36000), 120’ of pipe excluding bb, serving 850sqft to be heated
Zone2, 60’ bb (36000 max radiated), 90’ pipe, 600sqft
Zone3, 60’ bb (36000 max radiated), 50’ pipe, 400sqft
Zone4, 30’ bb (18000 max radiated), 90’ pipe, 300sqft
Zone5, 30’ bb (18000 max radiated), 50’ pipe, 220sqft

House Totals: 240’bb (144000 max radiated), 400’ pipe, 2400sqft, approx 23 gal in pipe & radiators plus 6 gal in boiler.

[beenthere]

Cograts on the replacement boiler.

Ok, now you are using the wrong flow rate for the 007, I think your using theroretic.

Taco chart says.
007 at 10 ft hd. is 3.5 gpm
007 at 9 ft hd. is 5 gpm
007 at 6 ft hd. is 13.5 gpm
007 at 7 ft hd. is 12 gpm

A 008 would be a better choice for your first and second zones, at 8 gpm or 0010 at 10 gpm.

[mark115]

The 008! I can't tell you how many times I looked at that chart, but the 008 didn't jump out at me.

It sounds like the 1 circ/zone is the "best" solution. I think I'll go that route.

Thanks for the help.

[mark115]

OK...
just to be sure...
now that I'm using the charts correctly...

If I stick with 1 circ, here are the gpm generated by a TACO 0011 on each zone:

Zone1: 10.8 FTHD, 22gpm
Zone2: 9.0, 23
Zone3: 6.6, 24.5
Zone4: 7.2, 24
Zone5: 6.0, 25

(Remember, typically, only 1 zone calls at a time, but it's rare that more than 2 call at a time. Zone1 is easily the most active. Recommended flow thru G124/25 is 10gpm.)

Are these flow rates simply too high?

[beenthere]

Yep, you'll get noise, might not pick up heat from the boiler, or get enough out of the baseboard.

You might get condensation in the boiler also.


Over sizing a circ is just about as bad as under sizing.

Use a 008, or 0010, even a 0010 is alittle high, but ok.

[mark115]

008 it is.