Help w/old radiant system

Slowhand63

Thanks to everyone for reading - and especially those that are offering advice. Apologies in advance for the length of the post. 

My wife’s sister called and said her radiant is not working. She paid a plumber $ cash today (yikes!). He replaced an actuator on her system, but said it was old and outdated and should be replaced. He quoted her $ additional to do that. Thankfully she declined. Her husband is a cop and not technically inclined. I’m trying to be a good brother in law by helping her. 

I went over and took a look at her system. She has a single thermostat, and 3 radiant loops. One loop supplies the bathroom, and the other two supply the den. One zone in the den is hot (not as hot as I would expect - more like very warm). The other loops are ice cold. 

The replace actuator is the one on the right in the photo - actuator 3 in my drawing - and it’s the one that’s warm. Based on the cost to replace the actuator, I don’t trust the company she called. 

I made a rudimentary wiring diagram of what I found - and took a couple of photos. I’m looking for comment and some general guidance on what’s there and how I might proceed with troubleshooting. I don’t know if he simply wired the new actuator or if he did anything else - so a review of the wiring diagram is where I’d start. Does everything look right based on the diagram I drew up?

Beyond that I’m thinking:

1. Is the flow control on the manifold open?

2. Is the relay working? I can check for 110v at the relay and at the circulator. I can also swap out the relay with one of the others since only one is in use. 

3. Are the actuators wired correctly? #1 and #3 appear powered but not open (plunger on top up slightly). #2 is flush? Although they don’t look identical, I’d expect them to visually look the same since they are all wired together. Something doesn’t seem right here. 

4. The new actuator instructions indicate it’s manufactured by ?Antieb? What would be an equivalent replacement? My radiant system has an uponor manifold and wirsbo actuators that look very similar. 

4. Is the circulator running? Can I hear/feel it? If I have power at the circulator, but no flow - maybe it’s not working?

5. Why isn’t the white wire from the 24v power supply connected to anything?

I’m sure I’ll have more questions once I get into it - but that’s plenty to get started. 

Thanks again. 

hot_rod

If you only have one thermostat, you shouldn't need actuators? Or just one to trigger the pump on. Leave the one that is open on the manifold and unscrew them other two. That will allow flow through those two loops.
Actuator styles do tend to vary from brand to brand. Threads match, but the pin stroke may be different.

Slowhand63

hot_rod - thanks for your response.  You may be right about not needing the actuators, but the system has worked for 20+ years and I don’t want to change the design (I’ll panic the homeowners if I start removing things!).  I want to get it back operational as it was.  

Good comment about the pin on the actuator.  I hadn’t thought about that.  

I am looking at the wiring of the Taco SR503 in the lower left hand corner.  It doesn’t match the Taco literature I posted. I would have expected the terminals labeled X1 and X2 to be wired. What am I missing?

The fact that the service tech charged my SIL $1000 to replace an actuator, insisted on cash, and tried to talk her into replacing her system for $3000 makes me think he could have messed with the wiring to get her to move forward.  It has me questioning everything.  

I’ve looked closely at the 24v wiring for the actuators.  All 3 actuators are wired to the T-stat, and the zone controller.  They are also then wired to each other.  

I would appreciate additional comments/advice/suggestions.  

Thanks in advance - 

hot_rod

The relay box you show is for switching 120V loads like pumps. It doesn't have a large enough transformer to power thermal actuators, typically. But from what I see they are grabbing 24V from the T-stat connections? One pump being switched?

Removing the actuator, without removing any wiring just allows that port to open. Another way to prove an actuator has failed.

So either a work around, or find a compatible actuator.

Slowhand63

If I removed the other two actuators - would that allow the valves for those 2 loops to always be open?  I assumed (perhaps incorrectly) that the manifold valves would be normally closed and would require the actuator pin to open them?  Following your logic - the valves would then be always open - but there would be no flow unless the T-stat calls for heat and kicks on the circulator.  Correct?

And just to ensure I don’t damage anything - I shouldn’t need to unscrew the actuators.  I can just pull them off, correct?

Slowhand63

So…. My brother in law just called.  He had the owner of the company come by.  The owner popped off the actuators and showed my BIL a little water that was sitting on top of the actuator bodies.  He said the manifold is shot and should be replaced - otherwise it will continue to leak onto the actuators and they will continue to fail.  He also suggested eliminating the actuators - but said he still needed to replace the manifold. He said there might be caps that could be installed to depress the manifold pin - but since the manifold is leaking and the caps aren’t pressure rated (if you can find them) then he’s setting himself up for a catastrophic failure and flood when the pressure builds up between the cap and leaking manifold.  

What do you think? 

hot_rod

Yes, leaks around the pins are a common failure on old manifolds. Several posters here have disassembled the pins and found tiny replacement o- rings. If you have the time and patience.
Some of those plastic manifolds would develop leaks between all the segments also.

If actuators are not needed or desired, some basic copper manifolds, valves on one manifold, just pex connections on the other.

Then wire the thermostat and circulator to the Taco box.

Slowhand63

Sounds easy enough, but with the manifolds mounted on the wall I don’t think there’s enough room to rotate the new manifolds to screw them onto the existing pipe work.  I’ll have to go over and take a look this weekend.  

What are your thoughts on simply installing caps where the actuators are?  I found some in my basement from my uponor manifold, but unfortunately they are male and I believe I’d need female threaded caps.  I haven’t checked supply house but I’m thinking I might find what I need there - or elsewhere.  

Do you think that’s a viable solution?

If yes - can you provide me a little guidance on how to wire the T-stat directly to the Taco board?

hot_rod

The plastic caps that typically ship with manifolds are to push the pin closed, if you want to not use some branches, you tighten them onto the pins. I don't think they would seal a leak from the seal around the pin, it just a plastic straight thread.

I'll bet that manifold has a union nut on the end that connects to the copper piping. So you would just match that fitting and solder it onto the copper.

Brass or stainless manifolds are another option, they would have union options also.

The Taco sheet you posted shows how to wire that control.

Two wires to the thermostat on the top connections. Looks like the pump is already wired on the bottom black and white?

Slowhand63

Oh - I see.  I had it backwards.  I thought the pin in the manifold needed to be pushed in to allow flow.  What you’re saying is that the flow will occur without the pin being pressed in.  I do have brass caps that I could put in place of the actuators - that should work - correct?

And yes, the circulator is wired to the Taco board at the bottom (blk/white wires). I’d then remove all of the actuator wires and simply wire the red/white thermostat wires to the Zone 1 terminals on the top right hand side of the board.  

Since the cape are brass, I shouldn’t have to worry about the pressure and a catastrophic  failure.  

Is that right?

hot_rod

The cap cannot push the pin down or that zone will be shut off. I think you need a taller cap

Pin down= valve off
Pin up = valve open, this is the position the pin is in with actuator removed

So basically when you screw an actuator on, it closes the valve. When power is applied to the actuator it retracts inside and opens to flow. It takes a few minutes to open.

Slowhand63

hot_rod - many thanks for your help.  The owner of the company that sent the first tech Came by and was able to resolve the issue. He implemented what you outlined in your very first post - he removed two of the actuators and is running the system off of the third. As per my SIL this seems to have resolved the issue and all 3 loops are now hot.  Thank you for following this thread and answering my questions.  Although I didn’t get a chance to resolve the issue for them, I learned some things which I always enjoy.  

I didn’t ask them anything about how they resolved the financial end of it - I figured it was none of my business.  In hindsight a tech knowledgeable about their system could have removed two actuators (and perhaps swapping one that wasn’t working with one of the working ones) and been done.  10-15 minutes or work max.  I hope they didn’t pay $1000 for that