Taco 007e Installation

hobbit

After replacing a Taco 007 f5 circulator with the 007e, boiler pressure increases and pump shows air purging after zones were bled. The pump is on the return side of boiler with two zone valves on the supply side. I contacted Taco support as this orientation is not listed in the preferred or alternate installation methods. There is no external flow check and unsure if the IFC would be required.

hot_rod

Does that pump go into a high speed mode for air removal? The Alpha stays in that air removal mode for I think 10 minutes then drops back to selected speed

Is it causing the relief valve to pop? Do you have a good air separator in the system?

Where is the expansion tank connection? If you are pumping at the tank you could be pulling air in at a high point vent? Esoecially at the higher pump flow in air removal mode.

hobbit

Thanks for the response hot_rod. The pump is normally in the orange led run mode and I can occasionally hear air noise at pump. I bled both zones several times and also replaced the expansion tank and air vent for general maintenance. The tank and vent are installed in the Watts air scoop just before the Taco zone valves. I lowered the Watts water pressure regulator but it doesn't reduce the fluctuating pressure. The psi will increase from 12-15 to 20-30. The relief valve popped once. I've cleaned the pressure regulator in the past so I was going to remove the strainer and check the seat. The well water here is hard and also has some impurities. Was thinking of installing the old 007 f5 to see if the water psi stabilizes. The old pump is in working order.

hot_rod

Try turning the fill valve off if you can and drain a small amount of water from the boiler drain to get to 12 psi.

If the expansion tank is waterlogged you will see a pressure increase that could pop the relief. Remove the cap at the bottom and push in the air stem for a second. Should be air, not water coming out.

The tank also needs to be set to 12 psi when the system pressure is lowered below that.

Sounds like the pump is on the return to the boiler, zone valves on the supply after the air scoop?

Make sure the air vent on the scoop is working also to get the air out.

I don't know what triggers the pump to go into the "white" mode? Maybe Taco will shed some light on that mode. How, when, and for how long.

Does it go into that mode only at first start, or anytime it detects air?

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hobbit

I replaced the tank and it was set at factory 12 psi. I raised it to 15. I also replaced the old vent since it wasn't seating properly. I closed the fill and the pressure stabilized but went low since the boiler is running regularly at 180 high temp. If the tankless coil had a leak, it could also cause a fill problem. Not sure if the 007e pumps increased head and rpm's is magnifying an existing problem? It looked like the pressure fluctuation was occurring only on one of the zones. I'm going to isolate the zones and monitor the pressure and air. In this setup would you think the pump requires the IFC? The Taco 007e install document doesn't show this particular installation setup. Taco states to use the IFC if your not using zone valves but this pump is on the return side with zone valves on the supply side

hot_rod

https://forum.heatinghelp.com/discussion/comment/1838248#Comment_1838248

In some cases you can get heat going up the return side, so ZVs on supply, check on the return gives you 100% flow stopage. A gauge at the discharge of the circulator would show you how much ∆P is being added to the boiler. I sometimes tap a gauge into the flanges on these small circs.

It depends on the head of the circuit the pump is connected into. Typically 6- 8 psi is what these small circ add.

Thermal expansion, if the tank is sized properly, maybe 5- 8 or 10 psi from 70 to 180°?

But if all was fine with the previous 007??

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Dave H_2

The 007e is not going to raise the system pressure, all it can do is create a pressure differential. It sounds like you still have air in the system, every time you purge, you are still introducing air into the system. Incoming water can contain up to 10% air.

What I do now is get the boiler hot and let the system circulate, hotter water lets the air out of solution easier. Turn the water pressure up to help constrict those air bubbles.

To determine if your indirect has a leak, turn off the automatic fill valve for the boiler and monitor the pressure then.

If the pressure keeps rising, then yes, your indirect has a leak.

hot_rod

some good reading in Idronics 16 about circulators and circulation

https://www.caleffi.com/sites/default/files/media/external-file/Idronics_16_NA_Circulation%20in%20hydronic%20systems.pdf

A demo on my shop wall to show the effect of a circulator spinning adding head energy which the gauge shows connected in this small circuit static pressure of 7 psi goes to 12 psi when the circ is powered. The pressure increase is “evidence” that head energy has been added

The demo also allows me to move the PONPC to either side if the circ

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hot_rod

I asked @hobbit about the expansion tank connection point. This graphic demonstrates how them pump head can show up in the system depending on that tank/ pump relationship.

Pumping away from the tank add that pressure developed by the circ to the system, static fill of 10 psi goes to 18 psi at the discharge of the circ when pumping away./

When you pump at the expansion tank, which is common in cast iron packaged boilers, the pressure differential the circ establishes is deducted on the inlet side of the circuit. In this example you see that static fill of 10 psi is actually 2 psi at the circ.

In some cases that can lead to cavitation if you drop below the vapor pressure. Systems running high temperature, low pressure are prone to cavitation. A system running 190° needs to have 4 psi at the inlet of the circ to stay out of cavitation potential. So figure 12-16 shows a circ that is a prime candidate for cavitation at high operating temperatures.

Cavitation is often dismissed as an air problem. But it never goes away.

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hobbit

Thanks for all the information guys. I decided to shut off the water supply again to the fill valve and monitor the pressure. I removed some water and the pressure has been stable so far at 12-15 psi. It has been approximately 24 hours so it doesn't appear to be receiving water from the tankless coil feed. I'll continue to monitor and if the pressure remains stable, i'll turn on the water to the feed valve. If the pressure increases, the valve must not be seating properly.

Dave H_2

Excellent, you are on the right track. When was the feed valve installed or replaced last?

hobbit

Day two and the pressure is normal with the cold water feed valve off. Good to know the tankless coil isn't leaking water. I installed this boiler around 2007 and only cleaned the fill valve 5-7 years later. Back in those days the valves were cheap and they sold repair kits. Now the valves are three times the cost and the repair kits are discontinued…throw away world. I'll see if i can remove the strainer again, if not I'll replace the valve.