Hard Time Getting Air Out Of Indirect Water Heater Conveyor

Docfletcher

My Grundfos circulator 15-42fr is making more noise than ever. Seems like my efforts to burp it have only made matters worse. One option I'm considering is adding a Spirotherm Spirotop air release valve. Please share your experience with these. Do you know if it is connected directly in the conveyor piping or if it needs a air scoop or other device under it ?

Zman

You seem to have a number of posts that are all symptoms of the same problem.
Do you have a picture or drawing that shows the overall layout of your system?

icesailor

Something that was done or is being done is wrong. I have never ever seen anything like what you have and are dealing with. I've seen things that if we had a wall of shame here, it would be the standout first prize. They still pumped and there wasn't any air. I've seen things pitched every which war but right, and they still worked.

O promise you that in the last 5 to 10 years I was working, I never once opened a coin vent to vent air. Unless it was a cast iron radiator that I was filling for the season. Once I got water, that was the end of it. If the system pressure was high enough to cause water to squirt out of the highest vent, once flow was established, that was it. It went YEARS without any venting. I used to change things "on the fly" and never go back and vent things. If something didn't work, I gave it a good solid purge. And not 20 minutes either. I'm starting to think that your stuck thermostat is causing steam flashing.

Docfletcher

I will start with a photo of the system with the old Bock indirect and the circulator on the return side mounted vertical. All was quiet.

http://screencast.com/t/AhmznjCGoVn0

Then I installed the Superstor changing the circulator to the supply (HOT) side mounted horizontal. All was quite for a week or so. Then the noise started.

http://screencast.com/t/mD97dAYiHZ57

http://screencast.com/t/tM7Ej0ksOUB

Noise sounds very much like this... Please note this demo of the noise is not with my Grundfos circ, it is just something I got off you tube.

https://www.youtube.com/watch?v=_0p_6I6C8lc

Here are some other shots of the system. Including the replaced boiler circulator which I recently put in and is quiet.

http://screencast.com/t/bbqRb0xRucE7

http://screencast.com/t/apY1KZ6ChmX

Ice, I ask this... If it had to do with the mixing valve causing a steam flash would it not do the same to one or more of the other 3 circulators? Or would it not affect the heat in the house in some negative fashion?

I have a new pump ready to install, but I don't want to end up destroying it. That's why I'm thinking of the Spirotop.

If you need more photos please tell me and I will be sure to get them posted.

icesailor

I doubt that a Spirotop will make that noise go away. That sound sounds like something rubbing on the impellor vanes.

Something must be pumping because I hear the sounds of expanding pipes in the background.

Did any of those pumps you replaced have a red rubber wrong gasket in it? They get as hard as a tar road and fall apart when you try to remove them completely. If they fall into the piping, and end up in front of the circulator, they can make a sound like that until either the vanes on the pump are worn down, or the red rubber wrong piece gets chewed up. Or else it is just a bad circulator. It sounds more like a B&G Series 100 with a bad coupler. A broken spring.

Docfletcher

Well like I said the pump in the video is Taco 007 and not my pump. My pump is a Grundfos 15 42FR And just like you say mine is also pumping something cause we always have hot water and have speedy recovery.

I'm wondering if the matter is simply that after 20 years the grundfos simply did not take well to moving from vertical to horizontal position. Although it was quiet for the 1st week or so. When I moved it fresh grundfos gaskets were used.

I was kind of hoping some of the guys had used them in the past or perhaps still using them. I'd like to know more about them and how to install one.

Here for grins is a photo of the old zone valves which I swapped out in the fall of 2013. Don't laugh too hard

http://screencast.com/t/S7i0dSSpM

Here are the new Taco valves with ball valves so I can drop the manifold easily.

http://screencast.com/t/SSVg4FGMdk

I'l be sure to take the old Grundfos apart to find out what's wrong.

icesailor

There's a queeb in the pump. Nothing more.

Docfletcher

If you mean "queeb" is air I'm not so sure. I rotated it 45 degree so air would rise out thus quieting the circ. But their was no change so I placed it back to level.

Docfletcher

So today the weather was pretty good so I swapped out the the noisy Grundfos with a new one. The noise is the same with the new one. That is to say it sounds like the Taco in the video above. Furthermore when I applied power to the old removed Grundfos it was whisper quiet. So I don't know. My next best guess is the 3/4" in amd 1" out of the circulator is causing turbulence , either causing a bearing rattle in the pump itself or water resonating weirdly in the piping itself.

I'm thinking about relocating the pump back to the return side where is was originally located. I'd appreciate some thoughts from a few of the pros here.

Steamhead

Maybe it's cavitating? Where is the flow-check for the indirect zone now?

Docfletcher

This photo shows the old circ with check valve location. It is currently set up the same with the new ciculator. Thanks.

http://screencast.com/t/tM7Ej0ksOUB

jonny88

That airscoop needs 18inches pipe diameter for before it to give air a chance to rise and release it.Switch it with a spirovent or equivalent.Idronics latest magazine are asking for 12 diameters of straight piping between outlet of circ and any downstream check valve.I usually at a minimum go 10 inches either side of circ to keep turbulence noise down.I have found circs with internal checks can be noisy and have started to put dirtmag before circ.Good luck.All comes to worst beat it with a hammer works every time. (joking)

Docfletcher

Which air scoop are you talking about. There is no scoop in the photo. Just the check valve.

8" is all I have between it and the circulator. No checks in this pump. I did install a spiro top in the return line.

Air in the line is not, and probably never was the problem.

Docfletcher

Do you think moving the check valve to the return side would help?

jonny88

Sorry was looking at a different pic with air scoop after expansion tank which you repiped in 2013.

Docfletcher

So what about moving the check valve to the return side? I mean since the check is only 8" away from the circulator outlet perhaps the check is causing cavitation.

Otherwise I still wonder about the 3/4 in and 1" out of the circulator.

hot_rod

Did you ever have the check out to inspect it? Perhaps something is lodged in it preventing it from opening fully?

Other than that,I'd guess you still have air in then loop. An additional air purger, not an air vent, may be needed in the line to the indirect. If that is a high point in the piping, it can be tough to get the air out and keep it out.

The piping size should not be a problem.

Docfletcher

I'll pull the check valve just for grins. I think the Spirotop might be defective. It's dripping water out of the vent hole.

kcopp

pump about a cup of Dawn dishwashing detergent into the system.... it will get out any last remaining air.

jonny88

Funny Doc,I have to fix a spirovent today cause its spitting water.Please keep us up to date

hot_rod

kcopp said:

pump about a cup of Dawn dishwashing detergent into the system.... it will get out any last remaining air.

Don't over do the soap, depending on the system capacity a few spoonfuls might be enough. An entire cup may cause foaming. Also soap does change the ph.

Ideally you want a very thin film on the inside of all the components. This protects the entire system from further corrosion. Too much soap and you will scour all the piping clean.

Most of the hydronic additives have a film provider as part of the package.

It's best to remove air with the correct air removal device. The micro-bubble type air eliminators will remove air small than you can see, micro-bubbles. Hense the name of the device.

hot_rod

jonny88 said:

Funny Doc,I have to fix a spirovent today cause its spitting water.Please keep us up to date

Consider adding a small check under float type air vents. Some brands can be easily dis-assembled and cleaned. It doesn't tank much more than a spec of dirt or debris to cause them to drip.

Look for a brand of vent that can be easily dis-assembled and cleaned out. They rarely "wear out" they just need service from time to time.

Docfletcher

Jonny88, I have a ball valve under it so I can close it off for now. I'll call spirovent and see if they will send me another.

If soap were used what quantity for 22 gallon system?
I have several bottles of Cryo-Tek inhibitor. They've been stored in a cabinet for around 13 years now. Not sure of the shelf life?

I have a Spirovent Jr 3/4" which I could install at the 3/4" supply to circulator. I would move the check valve to the return side. Space is tight so I won't get 10" of pipe on either side.

I think the easiest thing to do is move the circulator back to the return side. I never had any cavitation issues there.

hot_rod

If it worked properly on the return, it could indicate the new location that is trapping air. The circ should work fine on S or R.

An air vent is intended to be mounted at a high point, to trap air that migrates up to it. They are not intended to be an air purger, there is no mechanism to pull air from a passing fluid stream with a float type vent.

Occasionally systems work best with several air purgers if the piping does not allow all the flow to pass through one location. or you cannot get a "clean" fill and purge.

What temperature and pressure are you running. Higher temperature/ lower pressures encourage cavitation. The eye of the circa impeller is a low pressure zone and can cause cavitation if you are right on the line.

Sometimes a few additional psi solve a rouge air problem.

Docfletcher

Right now I'm running at 28 psi to help drive air out. Running 180F.

I'm going to try and get a recording of the noise. I'm starting to think it's in the tank itself.

Docfletcher

So here is a video with my cavitation. Notice as I move down to the in and out of the tank the noise gets louder. When it fades to black it is more behind the tank and foundation wall.

This is shot at 100F boiler and 28 psi. Luke warm water in tank. When water and boiler are hot the noise becomes a slightly faster rattle.

https://www.youtube.com/watch?v=XWLVbOhkjZY

hot_rod

Kind of sounds like the check is rattling. Did you ever look inside to make sure it is clean?

Also, when checks are oversized the flow from the circ may not be enough to push them completely open and they can rattle.

That check may have a Cv of 11, and you probably have 1/2 of that actual flow. Ideally that type of check is sized to flow rate, not pipe size.

Yeah, that vent is of little or no use in that position. Installed on a tee at the top of the tank and they can collect air that migrates up when the circ is not running.

If you are up for some mods, move the air vent, eliminate the check and use the one Grundfos provides for the installation in the pump.
The checks supplied with the circ pumps have a .35 psi pop, and flow wide open, even at low pump speeds.

Docfletcher

Just looked the check up. It's a Apollo 61-100 Series Bronze Check Valve, Ball Cone, 1" it's looking for 6 gpm to open it fully.
I'll have to see if I can purchase checks separately for the Grundfos 15-42?

Jonny88 the Spirotop stoped leaking. I don't know why. Except perhaps the float took a while to seat correctly.

Thanks to Hot Rod & the rest of the guys who helped see me through this.

hot_rod

Depending on the vintage of the circ, they used two different size checks. Make sure the discharge side of the volute has a machined surface to accept the check.

I have a whole box of the 20 and 25 mm checks, be glad to send a few your way. Give me a mailing address if you want a few.

Docfletcher

It does not have a machined surface. I called Grundfos, they said I need one of PN 596630 for just the discharge side. So if I can get that I think I'm good to go. Otherwise I may need to do a 3/4" inline check which only needs 3.53 GPM .