Danfoss flow direction?

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goosegunner

Minister of Fire
Oct 15, 2009
1,469
WI
So just to make sure about flow direction, Take a look at these pictures of the Danfoss I purchased. Sticker is wrong orientation.

I believe label should be 1/4 turn counter clockwise?

Anyone verify for certain?



gg
 

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It's possible! Mine came without any label attached but had two or three labels in a plastic bag that I could apply any way I chose. It's been so long since I looked at the inside of one, I can't tell by looking at your photo. You know which is the recirc. connection, right? Just make sure the sensing side of the automobile thermostat is on the boiler side. Stop and think about it for a second and you will make sense of it.

When the circulator is powered up (which is between the danfoss and the boiler inlet) hot water from the recirc. line will flow on to the sensor and cause it to activate when the water reaches 140* which will cause the thermostat to start opening when the system water starts coming through the thermostat will start closing or only be open a crack, mixing system water with recirc. water if the system water is too cold (below 140). If is hot enough (140 or above) the thermostat will continue to stay open and even open to full flow.

If the sensing side of the thermostat were on the return water side there would never be any flow so the sensing side would never see any hot water.
 
Mine came from the factory labelled wrong as well - it took me about a week and some help from people on here to figure it out. I had to remove the internal element and reverse it - after that no problems.
 
I just talked to a Tech at Danfoss. He said just make sure the small stainless spring on thermostat is facing the boiler.

He said with every system being different it has to be changed some of the time.


I also asked about pump location, supply or return?

He said the Danfoss does not care, You do not have to draw through the Danfoss. He also said the pump on the supply would work better with air elimination.

gg
 
Whether the pump is on the supply or return, you are drawing through the Danfoss.
I also had to turn the thermostat around.
 
Fred61 said:
Whether the pump is on the supply or return, you are drawing through the Danfoss.
I also had to turn the thermostat around.

That makes sense now when I look at the way the bypass and spring are configured.

gg
 
The sticker was Wrong on mine to. If I Knew you could pump to it I would have put my pump on the supply. Oh well It's already plumbed now.
 
I like pumps on the return, it is much cooler there which should improve the life of the pump. Just my opinion though. Mark at Ahona recommened drilling a small (1/8 to 1/4") hole in the stainless disk to allow some bleed through water whenever the circulator is running. He learned this from experience. I followed his advice and have no problems. I think it helps to slowly warm up the main loop and also offers some freeze protection.
 
I am also having an issue with my Danfoss valve. (See the valve as shown in the pic.) The thermostat is in the center leg of the valve. Even if the decals were flipped, there are stampings in the casting that indicate direction, so I don't THINK it's installed wrong. Regardless, it ain't working! It seemed like it was when I first fired the boiler, then when it was up to operating temp it's not opening to allow return flow. I have the pump located just off the boiler supply, and the Danfoss is close to the boiler return. The odd thing is that if I turn the pump off, then turn it back on, the return temp drops to about 140, as if the valve is opening and working, but then after 5 or 10 seconds, it closes again and the temp goes back up at the return. I'm about ready to remove the thermostat and control it manually. I went with this mechanical valve instead of an electronic valve to eliminate electrical issues. So much for that thinking.

It seems like move are using the "other" Danfoss valve. Does anyone out there have this one, and using it successfully??

Thanks
 

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Looking at my previous post, I see that the picture I snagged from a Danfoss PDF is opposite of my valve decals too. Also, the details in the PDF are conflicting. No wonder there are problems. They can't even get their documentation right.
 
I have a couple of the style pictured at start of post, mine work well. Not sure I understand your problem, but these are sensitive to pressure drop. did you play with the balance valve on the bypass? Can the T-sat be removed from this style, for inspection. The other style has a t-sat that looks like one one in first car. [red 66 mustang] Those were the days!! PS try operating it in manual, does the problem go away??
 
[quote author="jdkinohio" date="1292696043"]I am also having an issue with my Danfoss valve. (See the valve as shown in the pic.) The thermostat is in the center leg of the valve. Even if the decals were flipped, there are stampings in the casting that indicate direction, so I don't THINK it's installed wrong. Regardless, it ain't working! It seemed like it was when I first fired the boiler, then when it was up to operating temp it's not opening to allow return flow. I have the pump located just off the boiler supply, and the Danfoss is close to the boiler return. The odd thing is that if I turn the pump off, then turn it back on, the return temp drops to about 140, as if the valve is opening and working, but then after 5 or 10 seconds, it closes again and the temp goes back up at the return. I'm about ready to remove the thermostat and control it manually. I went with this mechanical valve instead of an electronic valve to eliminate electrical issues. So much for that thinking.

It seems like move are using the "other" Danfoss valve. Does anyone out there have this one, and using it successfully??

Thanks[/quot

I've never seen that model but how much different can it be than the other? What you describe leads me to believe that you're restricting the recirculating water. Try opening your ball valve a little more.
 
You can get to a PDF from here:

http://www.houseneeds.com/shop/danfoss/danfoss-thermostatic-by-pass-valve-buy.asp

I've tried every combination. I've opened/closed the ball valve on the return from the storage tank that goes into valve, and have played with the bypass ball valve. Nothing seems to make any difference. I've even swapped out pumps to eliminate a faulty pump problem. As I mentioned, the strangest thing is that if I have the pump shut off for a bit, turn back on, the return water temp drops significantly, then creeps back to normal. This must indicate something, but my pea-brain can't come up with the answer!

thanks
 
Are you in the process of trying to charge a large (colder) thermal mass such as a slab or storage tank?
 
bigburner...I missed your reply at first.

I have a tendency to not explain things well (or so my wife says).

Pressure was a question. Do you think there's a minimum pressure to maintain to make this work? I didn't think pressure would be an issue, but maybe. I'm just firing things up, and only running about 10psi at the moment. Plan to be a little higher once things get working...I hope. Yes the thermostat can be removed, which was probably the main reason I bought this version, so I could use a different temp thermostat, if needed.


thanks
 
Fred61 said:
Are you in the process of trying to charge a large (colder) thermal mass such as a slab or storage tank?


Yes, sort of. I have a Woodgun, and doing the initial "small" fires that they say you need to do to cure the refractory. I have 500 gallons of storage water.

But would that really make a difference? The valve should still mix to the correct temp, regardless of volume. It would just take a lot longer to get the storage up to temp for more storage. Right?

I don't even think the water is being circulated in the boiler loop. If I shut the storage return off, open the valve in the bypass all the way, it should just circulate through, with supply and return temps fairly close. The return temp never reaches the supply temp. Even sitting there right now, not fired. That seems to indicate no flow.? (which was one reason to swap circulators).
 
Is your recirc loop tapped into the pressure side of the circulator (outflow)?
 
This image from Danfoss's PDF pretty much depicts my setup. I don't have the optional return pump as they show.

I do have an expansion tank connected on the low side between the boiler and pump.
 

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Piped wrong or bad t-sat. I would remove t-sat and operate it by hand first isolate the boiler & watch the temp. if that goes up at a descent rate then you can start throttling it to the system. Once this gets hot the bypass doesn't do anything any way. Until you miss a fill up, then it protects the boiler. @ this point if it still don't work there is a piping issue. pictures are always useful or a sketch.
 
Thanks. Sort of what I concluded. Really hate to take it apart, but I guess I don't have much choice.

I'll post back after I see the results.

Thanks to all for such quick responses.
 
I guess I would go with Bigburner's suggestion but first take note of the orientation of the thermostat. It must be installed with the sensing bulb in the flow of the recirc loop.
 
I assumed that you have isolation valves on the three sides, if not that is just good practice. I meant to just remove the cartridge and use the hand valves.
 
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