Finally got my heat running: Got some questions.

newtonkid88

Finally got my heat running for a test: Got some questions.

Boiler: Buderus G115
Pump: Grundfos 15-58fc SPEED LOW
Hydrostat
2 Heating zones Taco Sentry Valves
2 Caleffi manifolds
1" Pex A from boiler to manifolds.
1/2" Pex from manifolds to HWBB

1) Upon first startup, I dont hear air bleeding from the Caleffi manifolds (the auto bleeders are on, not the test caps) or from my Spirovents. I need to manually bleed at the HWBB and from the high point vent in the basement in order to get flow to the HWBB. Is this normal?

2) I'm not getting a 20 degree differene between the supply and return. Maybe 10 degrees. Is it because the ambient temperature is mid 80s? House is under renovation so no AC.

3) I have to manually adjust the Caleffi knobs to get equal flow. Is this normal?

4) Should Economy Mode be used on my Hydrostat? The boiler temperature only got to 140 with Economy Mode set to 2. I shut it off to get to 190 degrees.

5) My indirect water heater has 1" copper pipe from the boiler. Will it be okay with my cir pump on Low Speed 1?

6) What are these flow meters reading? The indicator is kind of thick. It looks to be just under 1.5 GPM. Is that okay?




Some more pictures

hot_rod

You need to manually bleed until flow is moving through the air vents to be able to have them work. Since the flow meter are reading about 1.5 gpm, you must have flow now? With translucent pexc you can usually see air bubbles if any are still circulating.

If the loops are different lengths by even a few feet the flow rate in the meters will; be different until you dial them in. That's why they are adjustable Do you know what gpm you are looking for? A load design and calculation would give you the desired, designed flow rate. If not it will be a bit of trial and error. Start with them wide open.

If you need more flow, bump the circ up a speed.

Same with the indirect, the faster the flow rate the faster the heat transfer. If it recovers to you expectations leave it where it is. If you want faster recovery, increase pump speed.

Two things increase heat transfer, higher SWT and faster flow rate.

The delta T will move around and close to near nothing as the load satisfied. But you really don't have any load, unless you are trying to get the space to 90 or 100.

newtonkid88

I assumed 1 - 1.5 GPM is my goal beacause that's what I read what 1/2" pipe should be flowing.
I started all of the loops wide open and they varied wildly. I played with the knobs and they pretty much all settled at about 1.5 gpm as seen in the picture.
Is 190 SWT good in terms of health of my boiler and heating system? With Economy Mode on, it does not go above ~140.

hot_rod said:

You need to manually bleed until flow is moving through the air vents to be able to have them work. Since the flow meter are reading about 1.5 gpm, you must have flow now? With translucent pexc you can usually see air bubbles if any are still circulating.

If the loops are different lengths by even a few feet the flow rate in the meters will; be different until you dial them in. That's why they are adjustable Do you know what gpm you are looking for? A load design and calculation would give you the desired, designed flow rate. If not it will be a bit of trial and error. Start with them wide open.

If you need more flow, bump the circ up a speed.

Same with the indirect, the faster the flow rate the faster the heat transfer. If it recovers to you expectations leave it where it is. If you want faster recovery, increase pump speed.

Two things increase heat transfer, higher SWT and faster flow rate.

The delta T will move around and close to near nothing as the load satisfied. But you really don't have any load, unless you are trying to get the space to 90 or 100.

hot_rod

As you can see, 2 gpm is about max for the ports of that manifold.
If you had a 250- 300' 1/2 radiant loop, .65 is typically a design flow rate.

The indicators will read wild, variable flows until all the air is purged out. Is the pump running quietly? That is another indicator of an air free system.

newtonkid88

The pump is not silent. I can hear it if I am nearby in the basement. I can't hear it if I'm on the floor above.
Even when I got all the flows to equal out, I can hear dripping sounds in the HWBB like it's slowly being poured or the water is exiting out and falling down through the return riser pipe. No leaks though.
The longest loop is ~100'. The shortest loop is ~35'
If typical design flow rate is .65 gpm, why does SlantFin's specs give flow rates of 1 gpm and 4 gpm? I assumed that 1 gpm is for 1/2" pipe and 4 gpm is for 3/4".

hot_rod said:

As you can see, 2 gpm is about max for the ports of that manifold.
If you had a 250- 300' 1/2 radiant loop, .65 is typically a design flow rate.

The indicators will read wild, variable flows until all the air is purged out. Is the pump running quietly? That is another indicator of an air free system.

mattmia2

You might want to increase the circulator speed and open the balancing valves all the way and open the zone valves one loop at a time (or use the balancing valves to open one loop at a time) and run each loop separately for a couple minutes to help get the big pockets of air to the air separator. You can also temporarily increase the pressure to close to the relief valve pressure to make more of the air dissolve and find its way to the air separator.

The flow @hot_rod was talking about was for radiant loops. In fin tube it is specified for more, but as long as the whole loop is near the supply temp you have about as much heat as it is going to give off. you notice the output doesn't change much between 1gpm and 4 gpm.

Jamie Hall

To go back to the boiler and temperatures -- that boiler is not a condensing boiler, so the return water temperature should be kept above about 150 or so except when it is starting up. The supply temperature should be set at what is needed to provide the heat you want in the space, then you can dial the flow up or down to the various zones so they balance the way you want them. In most baseboard systems one wants a 15 to 20 degree drop from supply to return; the drop will increase with less flow, and decrease with more flow.

hot_rod

500 X flow X delta t
So if you are seeing a 1 gpm flow 15 delta
500.1.15= 7500 btu/hr of heat being delivered, somewhere

If you designed for a 20delta which you will see under a load condition 500.1.20= 10,000 btu/hr

Did you do a fast fill or power purge at a higher pressure, say 27 psi? Or with a hose?

The big, noisey air should come out with the initial purge. Within hours of all loops open the air should be completely gone

Assuming components are in the best location and working properly

Higher temperature in addition to higher pressure as @mattmia2 mentioned, will speed up rouge air removal. Run it up to 180 or so for an hour at 20 psi. Keep an eye on pressure, if it approaches 30, bleed some off 

Return to 12 psi when finished

newtonkid88

hot_rod said:

500 X flow X delta t
So if you are seeing a 1 gpm flow 15 delta
500.1.15= 7500 btu/hr of heat being delivered, somewhere

If you designed for a 20delta which you will see under a load condition 500.1.20= 10,000 btu/hr

Did you do a fast fill or power purge at a higher pressure, say 27 psi? Or with a hose?

The big, noisey air should come out with the initial purge. Within hours of all loops open the air should be completely gone

Assuming components are in the best location and working properly

Higher temperature in addition to higher pressure as @mattmia2 mentioned, will speed up rouge air removal. Run it up to 180 or so for an hour at 20 psi. Keep an eye on pressure, if it approaches 30, bleed some off 

Return to 12 psi when finished

What does 500 represent in that equation? Is that a constant?

I filled the system via the make-up water valve. I believe it’s regulated to 15 psi. 

I do not have a pressure gauge on the manifold setup.

From what I gather here, as long as i can get the flows between 1-1.5 gpm, the air should eventually work its way out?

Jamie Hall

The 500 is a constant, derived from several other constants -- the density of water and the heat capacity of water.

Eventually may be a very long time. Purging through the makeup water valve usually doesn't work all that well -- they don't allow enough flow.

hot_rod

newtonkid88 said:

hot_rod said:

500 X flow X delta t
So if you are seeing a 1 gpm flow 15 delta
500.1.15= 7500 btu/hr of heat being delivered, somewhere

If you designed for a 20delta which you will see under a load condition 500.1.20= 10,000 btu/hr

Did you do a fast fill or power purge at a higher pressure, say 27 psi? Or with a hose?

The big, noisey air should come out with the initial purge. Within hours of all loops open the air should be completely gone

Assuming components are in the best location and working properly

Higher temperature in addition to higher pressure as @mattmia2 mentioned, will speed up rouge air removal. Run it up to 180 or so for an hour at 20 psi. Keep an eye on pressure, if it approaches 30, bleed some off 

Return to 12 psi when finished

What does 500 represent in that equation? Is that a constant?

I filled the system via the make-up water valve. I believe it’s regulated to 15 psi. 

I do not have a pressure gauge on the manifold setup.

From what I gather here, as long as i can get the flows between 1-1.5 gpm, the air should eventually work its way out?

Yes the 500is a constant, derived from a gallon of water at a temperature of 60F, 8.33 lbs X 60 minutes. You could tighten up the 500, knowing the actual AWT.
Density of water as a function of temperature. Water at 160F would be 61 lbs per cubic foot, 508.13. So the temperature doesn't change the result much. 500 is an easy number to use in the formula, huh?

Is the fill valve open, is it a fast fill valve? Pressure maintaining at 15 psi? As air leaves water needs to replace it. I'm surprised that it isn't air free in several hours.

newtonkid88

All I did was turn on the make up water valve. When i stopped hearing water flowing, i called for heat via thermostat to get the circ pump going. I assumed any air that I bleed out would be replaced via the make up water.

Can I better fill up the system using the drain valve on the caleffi manifold? Using house water pressure

hot_rod

Got a pic of the makeup water fill; valve. Some brands have the ability to be put in fastfill mode. If the valve you have just trickles water in, it will not be adequate to get a good purge. them purge needs a good flow especially on first fill to flush out any debris that was left in the piping during assemble. Like, too much solder

Yes you could turn the red and blue valves off on the manifolds, hook a garden hose on one, purge from the other valve. A small submersible garden hose pump from HD or a garden hose from a faucet nearby. Get a couple 5' wash machine hoses to connect to the manifold purge valves.

Be sure to flow the proper direction, flow or pump into the red manifold, purge from blue one.

To do one loop at a time, close off all the flow meters. Pop the white cap off, flip it over it is a wrench. Or the white caps on the return could be closed. Open one at a time until they flow bubble free.

You still want to purge the piping from boiler to manifolds. Depends on where you put purge valves to facilitate that.

With a couple critically placed valves everything could be purged right at the boiler, even the manifolds and loops.

A valve like below, placed at the boiler or system piping could be a central purge point for a system like yours.

newtonkid88

hot_rod

That brass lever is what you lift to put it in fast fill mode. The directions should show how to drive it

You will need to keep an eye on the pressure gauge when you use it to prevent over pressurizing and causing the 30 lb relief valve from discharging

 Next time try a Caleffi 573, it is a fast fill valve that doesn’t need and levers or knobs turned. Set the pressure you want and it fills at 5 gpm up to the setpoint. Very easy to fill and purge with the Caleffi AutoFill valves

Tom_133

Can you take a few photos from 5-6' back so we can see a bit more of the boiler and piping?

rick in Alaska

I don't know how much it matters as far as purging goes, but most manifolds do not like to be installed upside down like that.
Like the others have said, you will need to "power purge" the system to at least get most of the air out.
Rick