Secondary pump size and head pressure problems

djm895

So I am having trouble with not getting really any flow at the manafold, the mixing valve is a taco 5004 
the first pump I had on the secondary loop was a 0015 , but couldn’t get any flow on manafold flow meters. So the local plumbing  place had a equivalent to a 0011 and put it on and about the same, if i shut off all loops except one , I would get like .5 gpm.

I have a 009 on my wood stove that feeds my house, so I took it off to try bc it’s low flow high head but I realized the propeller was junk so waiting on new cartridge. 

This is all new , not it’s plumbed right or what my problem is, thanks for any help

GroundUp

Sounds to me like it's airbound. The 0015 should have been moving easily .5 GPM per loop, despite that piece of crap mixing valve. How did you purge the loops?

djm895

Well!!! The guy that was helping me that I thought kinda knew how to fill the system, did not. So we took a union apart by the plate exchanger that feeds boiler and got about 9 gallon of glycol in and then he just turned water on to expansion tank and turned pumps on,  well I soon realized that wasn’t going to work, so next day I shut off valves at manafold and fill them loops one buy one with garden hose. 

Then cut pex today to try different pump and had to re plum a little bc this pump said only to mount vertical.

I not sure how to check or to get more air out

HVACNUT

Your drawing doesn't show any purge stations or where the feeder is.
And the radiant loop is sharing the same return as the plate HX loop. Meaning the return water from the radiant passes through the circulator for the plate HX?

GroundUp

Yeah, you need to actually purge the loops not just fill them. If you have some real manifolds, there should be some hose drains on each one. Get yourself a pump, a bucket, and 3 hoses. Suck from the bucket into the pump with one hose. Push from the pump into one manifold with the second. Drain from the other manifold back into the bucket with the third. This way, any air will float to the top of the bucket and be gone.

djm895

I will take a few pictures when I get home 

I thought that’s what I was doing with the hose letting the water run trough manafold and  each loop till it was steady coming back out . 

djm895

Robert_25

I just went through this last week in my own house.  I ended up isolating the radiant system from the boiler and hooking a garden hose on the manifold, then flushing to drain.  It takes a while to get all of the air out, even with 50 psi.  When you have that done, remove the garden hose and purge from the boiler through each manifold.  That should get the air out of the circulator and the return.  

Rich_49

9 gallons of Glycol huh ? What is the total volume of that system ? Boiler , HX , tubing ?

EBEBRATT-Ed

Why not calculate the actual head and buy the right pump instead of guessing

GroundUp

Well first of all it's piped backwards at the HX. Literally any circ on the market is adequate for such a system. If you poured in glycol and then finished off with water, either you still have air in it or your glycol is all down the drain. For a proper purge, each loop would have needed to flow at least a few gallons after being filled to eliminate air there and then the purge switched to the rest of the system. The circ and mixing valve are always tough to get air out of, and the air traps above and below your mixing valve are likely a part of the issue. If you want to keep the glycol, you need to use a pump and not domestic water. Also, why the heat exchanger?

djm895

Thanks, the HX is for my out door wood boiler that will heat the garage most of the winter but won’t keep up when gets real cold 

djm895

EBEBRATT-Ed said:

Why not calculate the actual head and buy the right pump instead of guessing

Right or wrong I don’t know how to calculate it 

Zman

To be perfectly honest, what you have is a typical DIY OWB hot mess:

• The circulators are not located correctly in relation to the PONPC.
  
• The piping is incorrectly sized.
  
• The mixing valve has too high a resistance for a radiant system
  
• The piping is supported with twine
  
• The wiring is Romex.
  
• The heat exchanger is high resistance.
  
• The OWB tubing and circulator sizing is likely incorrect and has cavitated the impeller.
  

It would be very difficult to accurately size the circulator given all these issues, most of the pros on this site would take a sawzall to all of it and start over.

That being said, if someone had a purge pump and some know-how, they could probably get the air out and glycol in and the system would probably heat the house. As you are finding, cutting open the pipes and pouring in glycol is not going to accomplish this.

GroundUp

Zman said:

To be perfectly honest, what you have is a typical DIY OWB hot mess:

• The piping is incorrectly sized. *false
  
• The mixing valve has too high a resistance for a radiant system *false
  
• The heat exchanger is high resistance. *mostly false
  
• The OWB tubing and circulator sizing is likely incorrect and has cavitated the impeller. *most likely false
  

Zman

GroundUp said:

Zman said:

To be perfectly honest, what you have is a typical DIY OWB hot mess:

• The piping is incorrectly sized. *false
  
• The mixing valve has too high a resistance for a radiant system *false
  
• The heat exchanger is high resistance. *mostly false
  
• The OWB tubing and circulator sizing is likely incorrect and has cavitated the impeller. *most likely false
  

@GroundUp
4 different pipe sizes in one loop. They are all correct?
A CV of 2.3 for 8 loops seems about right to you?
1/2" pipe size on HX in series with 1" piping looks correct to you?
Judging by the rest of the system, how do you figure the impeller on a 009 was destroyed?

My experience has been that the OWB folks provide bad design advice and systems like this are the norm unless someone knowledgeable is involved.

djm895

The 009 pump was on my owb that feeds my house and has nothing to do with my garage in the pictures and had been on owb for 12 years now, I wanted to try it in my garage on the radiant floor loop.

lots of what I have tried to say or ask has been misunderstood. 

Jamie Hall

We do the best we can. It is not always easy without a full schematic of a system to be able to figure out exactly what is doing what. The problem with verbal descriptions -- particularly with slightly unusual systems -- is that sometimes various people use various words slightly differently, and it's easy to get confused.

I don't think anyone is trying to be difficult -- but it is clear that no one has a really clear idea of what is actually happening, or what is wanted.

Zman

djm895 said:

The 009 pump was on my owb that feeds my house and has nothing to do with my garage in the pictures and had been on owb for 12 years now, I wanted to try it in my garage on the radiant floor loop.

lots of what I have tried to say or ask has been misunderstood. 

That was what I understood. Because there is very little head pressure on that loop and folks tend to install undersized tubing and oversized circs to compensate, my bet is that is cavitated.

Zman

I think you would learn alot by picking up a copy of "Pumping Away" which is available on this website. There is a combination of little design mistakes in your system that are causing you headaches.

Jersey2

Did a professional install that? That strikes the fear of God into me that I might get an installer that does this to my house.

pecmsg

Jersey2 said:

Did a professional install that? That strikes the fear of God into me that I might get an installer that does this to my house.

Once money is charged then there professionals. 

I prefer Qualified at a minimum. 

GroundUp

@GroundUp
4 different pipe sizes in one loop. They are all correct?
A CV of 2.3 for 8 loops seems about right to you?
1/2" pipe size on HX in series with 1" piping looks correct to you?
Judging by the rest of the system, how do you figure the impeller on a 009 was destroyed?

My experience has been that the OWB folks provide bad design advice and systems like this are the norm unless someone knowledgeable is involved.

By "4" I assume you mean 2? Because it's only 2 different pipe sizes, and no it doesn't matter.

A cV of 2.3 will yield roughly 4ft of head in this system. Big deal.

There is no 1/2" pipe anywhere in the loop, much less on the HX. It's 1" and 1-1/4".

The impeller was destroyed because it's an 009 on an OWB; wrong tool for the job. Also, it's pushing the loop and running 1" pex- there is literally no way (aside from low water) to cavitate an 009 unless there's a throttled valve on the inlet side.

I will wholeheartedly agree that OWB folks provide bad design advice, but then again there are a lot of "pros" who don't get it either. Atmospheric systems are very different animals from pressurized systems

Jamie Hall

If that 009 had atmospheric pressure on the suction side when it was turned off, I might agree that it wouldn't cavitate.

But... if it was drawing through any length of pipe, or was dealing (even for a few minutes) with near boiling point water, it can and will cavitate unless the whole system was under significant pressure -- any centrifugal pump will -- and it only takes a few minutes of that to destroy an impeller.

GroundUp

Any factory made OWB will have at least 1 psi at the supply outlet of the water jacket, most closer to 2. An 009 doesn't move enough water to suck that into a vacuum unless there is some sort of restriction such as a throttled valve on the inlet side. Several hundred of these OWB systems have had my hands on them, I'm quite familiar with what works and what doesn't. 12 years on an 009 was a gift from God; beyond 2-3 years is often borrowed time.

Jamie Hall

Good to know. Thank you @GroundUp .

hot_rod

2.3 Cv with a 4 gpm flow, closer to 7',head, plus the hx and all those insert pex fittings. Certainly you can pump your way out of most any bad design. First off get a good purge going on.

As for open OWB, it depends on the relationship to the system, most certainly you can see sub-atmospheric conditions with distribution, or the HX above the water level. Here is the calculation for that.

JakeCK

I say this not to be mean or to criticize you in anyway... But if the wiring in the rest of your house looks like this in anyway make sure your insurance is caught up. And for the love of god please make sure you have fire escapes in all rooms and everyone knows how to use em.


Is that 10-2 mixed with 12-2? and what's going on with that ground?