Radiant heat valve actuation excitement


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Old 10-11-09, 12:54 PM
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Radiant heat valve actuation excitement

Hi everybody,

First, thank you for reading my post. I really appreciate it.

I'm a total radiant heating novice, but I'm only a partial doofus, so let me see if I can describe my problem. You'll probably have to ask me questions to clarify the things I am not being specific enough on.

I have a 6-year-old house built by the former homeowner. He often chose to implement "novel" technologies and features in the house along the way, some of which have turned out nicely and some of which were maybe not so great in retrospect.

For the heat, we have a Polaris stainless, propane-driven boiler. It connects via a decent-sized red pump to an 8-way plastic output manifold mounted on a board. There is an identical 8-way return manifold. There are five thermostats in the house, and I see five pairs of return wires connected to what look like 5 relays or step-up transformers or something. It appears, then, that a few of the thermostats control multiple loops.

The problem I am having is that of my loops is getting stuck on. This actually started last winter, and we had a nice HVAC person come out and take a look at it. At the time, he explained a little bit to me about how it works... these actuators (I'm still not sure the right term... zone valve? zone valve actuator? end cap actuator? valve actuator?) are normally-closed and are slowly driven open when the thermostat demands heat. Easy enough, right?

I guess the problem is that one of the 4-wire actuators died. He replaced it with a new one, but apparently the fitting between the manifold valve and the actuator is not QUITE right, and he wasn't sure if it would really work long-term or not. He said that our manifold was made by a company that apparently went bankrupt (something about lawsuits for their leaking tubing?) a while back. So, he says he cannot find an exact replacement for the actuator.

It is possible I am mangling some of the fine details of what he described. He also left me with a little plastic cap that I guess is a manual alternative to the electric actuator -- presumably, there is some way for me to take the substitute, not-working-so-well new actuator off and use this cap to set the valve manually. I have not been able to figure out how to remove the actuator (safely).

I guess my first few questions are:

1. How can I remove the actuator?
2. Is it really going to be impossible to find a new one that fits correctly? He implied that we might have to replace the whole manifold instead.
3. I noticed another weird thing that makes me question my feeble understanding of how the system works: in most cases, there is a one-to-one correspondence between the temperature of any specific outbound supply line and the return line at the return manifold. In other words, presumably the actuator is closed/off and there is no liquid flowing. The output line, then, is cool to the touch, and the return line is the same. Likewise, when a zone is on, both lines are warm. What I have noticed is that several of my loops, however, are warm on the output side and cool on the return. Could that be simply because the thermostat switched off recently, or might it signal some more nefarious problem? (I was imagining that perhaps some of the other actuators are not closing fully and are slowly leaking hot supply into the loop. Does that even make sense?)

Thank you for any thoughts! Sorry for my poor descriptions of the problem(s).

Ben
 
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Old 10-11-09, 02:48 PM
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Ben, actually, your descriptions are quite good...

I'd like you to post pictures if you can though, you can do so by uploading your pics to a free account at Image hosting, free photo sharing & video sharing at Photobucket and dropping a link to your album here.

Look closely at all the equipment and see if you can identify manufacturers... even part numbers may be 'traceable'...

I believe that some of the actuators are 'adjustable' for flow regulation in the loops, and that cap you have may be for that purpose. In other words, it will set a 'limit' to how far open the valve can go... I might be wrong about this, cuz I'm no radiant guru.

Depending on the length of the loops in the floor, and the flow rate in those loops, more or less heat could be getting drawn out of the water by the time it returns to the boiler. It is possible that the differences in temps you are feeling is due to this fact. On the other hand, you could be right about it slowly leaking...

Are these heating loops in a slab?
or stapled to the bottom of the floor with insulation below them?
 
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Old 10-14-09, 09:20 PM
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Sorry for the delay in getting back to you! Here are some pictures, one thing I do know a little about being in the software industry.

The first shot is an overview of the board, and you'll see the return manifold on the left and the outgoing one on the right. Notice the one, exceptional actuator on the bottom there, and the five relays (or transformers, can't quite see) on the right.



Here's a shot of the top portion of the board with the power supply and presumably the controller that figures out when to turn on the feed pump. I've tried reaching that "radiantdirect.com" phone number, but no one answers and there is no voice mail, so I fear that company might be out of business: (?)



Finally, the money shot. This is a close-up of two of the original actuators and the new one that only "sort of" fits and also seemingly also gets "stuck:"



So, can I take these guys off safely? If so, do I just put a wrench to the knurled ring (metal for the old ones, white plastic for the new one) and loosen it and then pull the thing off? (I don't want to try it until I know it won't launch heating fluid all over my basement.)

I am concerned long-term about ALL 8 of these actuators failing, and so I need to make a decision pretty soon: should I try alternative actuators that will fit correctly, or should I just bail on the entire manifold and replace it with a new one? The latter will be fairly expensive, I believe, and require draining the whole system.

More near-term, that stuck valve is on the coldest room in the house and the one we're in during the cold nights: the master bedroom. Moreover, we have a huge fluffy dog that gets hot easily, and she normally sleeps on the cool tile, but the tile stays hot all night if the actuator is stuck on. If I didn't have her to contend with, I'd just leave the heat on and crack the window, but the fact is right now we just have it off and, well, it gets chilly up here in the mountains.

Thanks for your response, in advance!
 
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Old 12-06-09, 07:51 AM
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Any more thoughts, anyone?
 
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Old 12-07-09, 06:20 PM
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Im not a pro, but I do tinker with my own radiant system..

That replacement sorta looks like a Wirsbo thermal actuator. Is there any kind of brand name on it ?
AFAIK, actuator systems have screw-on actuators that push the actual valve inside of the manifold open/closed. You should be able to unscrew the actuator without loosing fluid. Do you recall if the system was drained to swap out that actuator last time ?
Obviously, you're getting full-time heat to that zone.. but did you check for the lack of (no call) 24v a/c on the yellow wires ? If 24 exists, then theres some kind of wiring or t-stat problem.

Also, on a Wirsbo actuator, you have to screw it down to a fairly precise position. Having it not screwed down correctly can actually mechanically force the valve open. If the actuators havent been touched, and they used to work and now dont.. thats probably not the problem.

Is it possible that the valve itself is getting stuck ? IM not sure if you can pull the valves out of that manifold, but for sure it would require draining the system. If you cant get parts for that, you might end up having to swap out the whole manifold and actuators ($)
 
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Old 12-08-09, 01:58 AM
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Dave,

Thanks for your comments!

Originally Posted by DaveC72 View Post
That replacement sorta looks like a Wirsbo thermal actuator. Is there any kind of brand name on it ?
It's an Upunor, which the internet tells me is the same as a Wirsbo. Good call!

AFAIK, actuator systems have screw-on actuators that push the actual valve inside of the manifold open/closed. You should be able to unscrew the actuator without loosing fluid. Do you recall if the system was drained to swap out that actuator last time ?
You're right, this one works the same way. No leak.

Is it possible that the valve itself is getting stuck ? IM not sure if you can pull the valves out of that manifold, but for sure it would require draining the system. If you cant get parts for that, you might end up having to swap out the whole manifold and actuators ($)
Yep, you nailed it. I took the actuator off and the valve was stuck in the down position (closed? on my return manifold, the positions definitely mean the opposite -- but I know this loop has been stuck open for months). After I pressed it in a bit, it popped back out to the normal position.

I wonder how I figure out whether I can find a replacement valve?

Is it hard to drain and refill a loop?

Ben
 
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Old 12-08-09, 04:06 AM
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The manifold is like a common bus, but that being said, I suppose its possible to manually close off all the other loops .. leave that one manually open and drain the system down somehow. DOnt forget to close the fill valve (probably tied to the dhw lines). On refill, you're going to have to bleed the air out.. if you have properly placed air separators it will help.
The pros on here might be able to advise more on the proper refill way.
Not sure if a Upunor valve would fit (one wouldnt think, patents and all that)..
 
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Old 12-08-09, 08:43 PM
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I forgot to post about your question on the various return line temps..

Generally, you should have a reasonable difference between the supply and return lines on a loop. I forget what the 'ideal' is.. 30f ? Closer temps (lower delta) means the fluid is racing thru a short loop too quick and not giving off enough heat. Large delta (ie, cold return lines) means the fluid is moving too slow.. probably on a long loop. If you disconnect (or lower the tstats) for all zones except for that long loop.. and let it run for a while.. and still get cold returns, then you might need a higher output circulator pump. If its only while multiple zones are calling, then thats just the fluid exhibiting the path of least resistance.. and you might try to balance the zones with the caps on the other manifold (throttle back the short loops to allow more flow into the long loops).
 
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Old 12-09-09, 10:46 AM
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Well, the plot thickens. Sadly!

Yesterday I took the Uponor actuator off that bottom valve and left it off all night. The valve pin was sticking out, which I believe should be "off." Unfortunately, the lines are still hot and I believe the valve is not in any way closed.

Today, all of my house is overheated. Every thermostat is set to 65, the whole house is closer to 73 or 74, and none of the thermostats show they are asking for heat. And, every line is feeling hot to the touch down at both the output and return manifolds.

I'm now even more confused about what's happening with my system. It's quite possible I just thought I understood it, but really didn't, before.

???
 
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Old 12-12-09, 12:36 PM
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Hmm.. posted a reply this morning.. didnt stick for some reason..

Anyhow, I was hoping some of the vets might have chimed in.. but maybe nobody is familiar with that brand to have more specific details.

Have you made any progress ?

On my Wirsbo valves, the pin is up when open. When you screw an actuator onto it, the spring in the actuator push the valve closed. When the tstat calls for heat, the motor in the actuator releases the spring tension and the pin comes up (open). Because of the relation between the spring neutral position and the valve itself, you can see that it matters how far down the actuator is screwed down. On Wirsbo units, there is a little bar in a window that you have to center to an indicator. The actuator isnt fully screwed down.
 
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Old 12-12-09, 12:46 PM
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I have made some progress, indeed.

I took all of the actuators off and found a whole bunch of stuck valve pins. I pushed on all of them until they were properly springing back out, and then I put some WD40 on all of them and pushed and pulled some more. Then, I replaced all the actuators as firmly as I could (I had not yet read your advice about needing to set the exact point more precisely).

Next, I had my poor wife go around and engage and disengage every thermostat while I measured the voltage on the 5 transformers. I made a diagram to map them through to the 8 heating loops. It turns out that the thermostats are almost certainly not wired correctly -- one on my third floor is controlling a bunch of zones on the second floor, and one on the second floor is controlling a zone in sealed-off room on the bottom floor. !!

Finally, I did some baseline testing. I shut off all the thermostats and waited for the pump to stop and all the loops to cool back to nominal. I then engaged a single thermostat driving a single loop -- it happens to be the third loop from the bottom in the source manifold.

What I found surprised me, initially. Not only was the third loop running warm, like it should, but the bottom two loops were also engaging! It was only after I started feeling the return loops that I realized this was a red herring: the lower loops were warm just because of conduction, not because fluid was actually being allowed to flow.

I also learned that the return lines are not matched up 1:1 with the source manifold's lines -- something I would not have guessed. They seem to be haphazardly plumbed into the return manifold.

At this point, however, I believe I have sufficiently updated my characterization of the system to at least understand what it is doing. I do believe some of those sticky valve pins were the original culprit. Then, mixing in some incorrect wiring, conductive heat transfer in the manifold, and crazy plumbing on the returns... and it's easier to see how I got so confused.

I'm hoping those valves will keep working. The moment I have a failure, I'm probably just going to tear out the whole thing and put in a new one that I can get parts for.

Thanks again for your help!

Ben
 
 

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