Replace air separator new location?

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G

goosegunner

Minister of Fire
Oct 15, 2009
1,469
WI
I really believe that my Taco 4900 is not working properly. I am thinking I should just replace the darn thing with a Spirovent or Caleffi.

Here are some pictures of the current set up and measurements.

With my current set up it will be difficult to get it in the same spot as the Taco. I am thinking about moving it to a new spot which is also upstream from the circulator in a 12" section of straight pipe.


This is the new location I am considering. Will it be too close to the 90 on left and T on right?

airsepspace2.jpg




I have 1-1/2" pipe is this 8.5 inches too short between the air sep and start of pump flange valve?

airsepspace1.jpg
 
Lower pump was installed in parallel for overheat and redundancy for overheat or failure of top pump.
 
Isn't that a Spirovent after the gauge and before the T on the top loop?????

Are you pumping away from the boiler or back in to the boiler sump??

Where is your bladder tank in relation to the circulators?

Question about the automatic air vent on the elbow attached to the header pipes near the ceiling; is it working properly and do you really need it?




Can you show more pictures of your plumbing when you have time? it is a bit confusing.as I would like to see near boiler piping at the rear of the boiler where the copper pipe enters the tappings on the boiler.
 
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Pumping away from boiler, water moves from left to right on supply.

The bladder tanks are connected to the half inch copper pipe at bottom of taco 4900.

It is a Taco 4900. At times I can hear what sounds like small bubbles whoosh right through and through the circulator when boiler is heating.

The small vent is in the no power dump loop. It is closed off from the main loop unless the power goes out.
 
Here are a few more pictures as request by Leon.

Picture of piping with bypass.
piping1.jpg



Pictures of back of boiler.
piping2.jpg



One more of supply
piping3.jpg


Risers and vents I added near tank incase air rises from tank into piping.
piping4.jpg
 
Piping look fine, nice and straight. The Taco is in the best spot, too bad it is not more user serviceable.

Those two small float style vents won't do much good, no means for air to rise up there. Typically they go at the top of a tee on the vertical to catch air that rises to a high spot. Or at the top of a tank, radiator, air handler, etc. a high point vent. the Taco should do the heavy lifting.
 
Thanks Bob, not really sure what the problem is with the 4900 other than poor design for air removal. I have read of others with unsatisfactory results.

They have no documentation on service.

It is not going to be fun putting a different one in that same spot....
 
Bob,

Would it be ok to put a new Separator up stream in the 12" section in first picture and put a piece of straight pipe where 4900 is (concern there is the 90 and T so close)?

I could probably get it exactly where the 4900 is but I think I might have to put unions right on both sides of new one. Unless I can find some slip couplings.
 
I would likely put a new one in the 12" spot and just leave the Taco where it is.

Thinking the new one should be closer to the T than the El? I think it is a longer downstream straight stretch that is needed rather than upstream?

Or - could you go back towards the boiler from there to the second El, replace the El with a T and put the new vent on the new riser you just created?
 
I'd remove the one that is in there, I have seen them sludge up like this. Ideally you would have a cleaner system fluid:)

The Caleffi Discal is very easy to disassemble and clean, no metal mesh inside so aggressive or dirty water will not harm it.

I opened this with a small channel lock. The top is serviceable and also replaceable, fine thread and o-ring seal so you just hand tighten it.

If you cut one side, you may be able to remove the top and thread the current one off.

If not a couple 1-1/4" copper sweat repair couplings would be an easy fix. The repair couplings do not have a stop inside, so slide it over the pipe, lift the new one into place, slide the coupling centered and solder away.
 

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Bob,

That sludge looks bad! I should take a look inside mine just to see if the float plate is blocked.

When taking the Taco apart does it just screw back together or does it need some type of sealant?
 
I am sorry to see that you are going through this.

Perhaps a parallel set of fine mesh wye strainers with ball valves on the drain tappings and 2 ball valves on each strainer to empty the strainer while the other is still in use would work better using a spirovent mounted on an air scoop would suit your system better?

If it were me I would eliminate the bladder tanks, remove and plug the tappings for the air vents or close the automatic air vents completely and install a fine wye strainer with a ball valve on the drain tapping in front of an air scoop with a 3/4" tapping to feed a steel expansion tank with 30 gallons of capacity and an airtrol valve to have a better and larger air cushion and in the end it will let you operate at a much lower pressure too. the 30 gallon tank would give you a 10 gallon air cushion,
 
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goosegunner said:
Bob,

That sludge looks bad! I should take a look inside mine just to see if the float plate is blocked.

When taking the Taco apart does it just screw back together or does it need some type of sealant?
Click to expand...


I don't know how the Taco is assembled, possible an o-ring like Caleffi? If so juct clean the ring and surfaces, lubricate the O-ring.

I believe that is actually made by Flamco in Sweden for Taco. Not much info at that site either, just how to use the shut off screw?

If you decide to upgrade this Caleffi DiscalDirtMag product does an excellent job of air, dirt, and magnetic particle removal. Easily disassembled for service and cleaning.
 

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leon said:
I am sorry to see that you are going through this.

Perhaps a parallel set of fine mesh wye strainers with ball valves on the drain tappings and 2 ball valves on each strainer to empty the strainer while the other is still in use would work better using a spirovent mounted on an air scoop would suit your system better?

If it were me I would eliminate the bladder tanks, remove and plug the tappings for the air vents or close the automatic air vents completely and install a fine wye strainer with a ball valve on the drain tapping in front of an air scoop with a 3/4" tapping to feed a steel expansion tank with 30 gallons of capacity and an airtrol valve to have a better and larger air cushion and in the end it will let you operate at a much lower pressure too. the 30 gallon tank would give you a 10 gallon air cushion,
Click to expand...


I initially had a 110 gallon vertical propane tank for an expansion tank. It seemed like the Taco has never been good at removing air. It would allow bubbles through back then too. I switched to bladder to try and eliminate reabsorption of from the tank.
 
Bob Rohr said:
I don't know how the Taco is assembled, possible an o-ring like Caleffi? If so juct clean the ring and surfaces, lubricate the O-ring.

I believe that is actually made by Flamco in Sweden for Taco. Not much info at that site either, just how to use the shut off screw?

If you decide to upgrade this Caleffi DiscalDirtMag product does an excellent job of air, dirt, and magnetic particle removal. Easily disassembled for service and cleaning.
Click to expand...



I have a sprirovent dirt trap on the return from the tank before the thermal valve. I also had a Wye before the valve but removed it. I thought Dirt trap then wye was overkill.
 
After the system sits I get clatter at the top of the Bypass T when I run the circulator.

I think air collects there and when the return for the tank is closed because of the thermal valve The air bubble just sits at the top of the T and the circulator can't push it down the pipe. If I choke down the valve in the bypass it goes away. open it and it clatters.


Either that or there is something wrong with the thermovar 823 that I just put in.....
 
As to capturing crud in the boiler water, I used a hot water filter with a replaceable filter element, much like a home water filter. Mine is stainless steel, high temperature plastic ones are available also. This one has only 3/4" ports and is rated at 7gpm (don't know pressure drop at this gpm rate). I have it installed on the tank to system supply side, only demand is in-floor radiant with flow well under 7gpm. After about 6-12 filter changes, the filter no longer was catching any crud, and I removed the filter element so the housing is merely a pass-through device at this time.
https://www.amazon.com/dp/B004C3XG6G/?tag=hearthamazon-20
 
goosegunner said:
After the system sits I get clatter at the top of the Bypass T when I run the circulator.

I think air collects there and when the return for the tank is closed because of the thermal valve The air bubble just sits at the top of the T and the circulator can't push it down the pipe. If I choke down the valve in the bypass it goes away. open it and it clatters.


Either that or there is something wrong with the thermovar 823 that I just put in.....
Click to expand...


Possibly you have a cavitation issue, sounds and presents itself like air, buy it is actually vapor pockets collapsing. It can be caused by small restrictions in throttled valves, and high temperature, low pressure makes it worse.

It could be the cause of the sound you are hearing also.

Cavitation from the root word cavity. I make the analogy that a cavity could be a hole in your tooth, cavitation is a hole in the water or fluid :)
 
If you still have that 110 gallon tank I would use it for more water storage in your system and
I would still remove the bladder tanks and install a 30 gallon steel expansion tank in the ceiling with an airtrol valve.
I have no trapped air problems with my system.
 
1000 gallons of system would need a lot more than 30 gallons of steel expansion tank.

As one who has done both, I see no reason to remove the bladder tanks that are already there. Once the Taco is replaced with something that would work better there should be no more issues - not sure about the cavitation thing though, but thinking once the air bits are all scrubbed out that might go away?
 
Bob Rohr said:
Possibly you have a cavitation issue, sounds and presents itself like air, buy it is actually vapor pockets collapsing. It can be caused by small restrictions in throttled valves, and high temperature, low pressure makes it worse.

It could be the cause of the sound you are hearing also.

Cavitation from the root word cavity. I make the analogy that a cavity could be a hole in your tooth, cavitation is a hole in the water or fluid :)
Click to expand...

That was a concern I had with my Danfoss. I had to choke down the bypass T. When the return from storage was below 150 I thought I could have some cavitation with the reduced flow due to choked down bypass.

Switched to new style valve, Thermovar 823 and I still have same issues.

Maybe the Taco 4900 is restricted causing cavitation?

Or maybe my piping scheme is causing it.

Doesn’t matter though a 26-99 on high or 15-58 on low still has the same noise. On 1-1/2” copper pipe.
 
Also checked the pump impeller for pitting or wear from cavitation. It was smooth with no visible defects.
 
I have flushed it and the flush is clear. It is also between the tank and thermovar so I think it would see minimal flow when tank return is cool. It still makes noise then.

My water samples have been very clear water when sent in for testing.

This thing is really starting to frustrate me. I think it could be related to Thermovar. Strange thing with that though is it makes noise on just about all different flow amounts.
 
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