Pump controlled by zone valve control or actuator

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Old 12-18-18, 03:40 PM
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Pump controlled by zone valve control or actuator

I am trying to figure out why the person that wired our heating system did things two different ways. We have a four zone system, and it seems the zones are wired differently. The first way was to wire directly off the valve control system (Taco ZVC404) to open the valve and also to trigger the end switch to the circulator pump to immediately start. The second way is to just send a signal to open the actuators (Watts 22C - 4 wire) and then use the 3&4 wires that come back to turn on the pumps once the valve is open (usually takes 20s to 30s for the pump to kick on this way). I'm wondering why they would do this, or why one way would be better than the other? I'm a fan of the more explicit turn on / off from the valve control system, as opposed to using the actuators to indicate when they are open before firing the pump. Thoughts? Either way, I want to change the wiring so they are all the same.
 
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Old 12-18-18, 03:59 PM
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Possible unnecessary relay

I am trying to figure out why the person that wired our heating system added a transformer and two relays on our secondary panel. We have a radiant heat system and it has a primary and secondary panel (about 40ft away in the middle of the house). We have a Taco ZVC404 and the lines (standard 18 gauge 24VAC) run out to the secondary panel. On the secondary panel we have 3 zones coming off a Watts manifold controlled by Watts 22C actuators. One of the zones, nothing strange, line comes right in and goes back to the relay on the primary panel to switch the circulator pump. The other two zone control wires come in (24VAC) to a relay. The relay has coming into it 24VAC from a transformer. So, I'm staring at this going...I have 24VAC that when powered connects a 24VAC line on the other side of the relay. This seems unnecessary, but I don't know. Is this for code reasons, power draw to boost power local at the panel? I can't figure out why someone would use one line of identical purpose and voltage to throw a switch where the other side is exactly the same thing. Thoughts?
 
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Old 12-18-18, 04:01 PM
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Welcome to the forums.

Two like threads combined.
How many zones (zone valves) total ?
Very hard to picture what was done. I'm a pictures guy. I troubleshoot from pictures.
Diagrams are good too....... How-to-insert-pictures (or diagrams)
 
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Old 12-18-18, 04:14 PM
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Thanks, yes, two questions. I put them as different posts to try to avoid confusion on my questions, but they are definitely related. I'll go grab some pictures.
 
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Old 12-18-18, 05:00 PM
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I don't think these pictures will really help much here without full traces on the wires, but I'm including them. 3 zones, 3 actuators on one, 1 on another and 4 on the last one. Basically my questions are this:

1. Why would you put a relay on a secondary panel when all it's doing is having 24VAC coming in turn on 24VAC to open the actuators?
2. Is it better to have your zone control system turn on the pump, or have the actuators turn on the pump after they are open?
 
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Old 12-27-18, 04:34 PM
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Thanks for the offer to help here, and sorry that my pictures were so terrible. Without actually tracing it all out and drawing it, it would be hard to see what's going on here. I got my answers though I think. First, the reason for the transformer on the second panel was in fact to boost power. The TACO ZVC404 only has 40VA output, and the total potential draw from my valves if they were all open could be up to 48. They put in the transformer to make sure there was enough power. The reason for the different valve control to circular pump configuration was just confusion I think the best way (for safety) is to make sure the pump only activates once the valve is open. It can technically be done both ways, as I have found, but I'm favoring using the 3/4 wires on the valve to indicate it is open, and fire the pump. I do have another question now, but it's on a different topic, so I will create a new thread. Thanks.
 
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Old 12-28-18, 07:54 PM
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Dgoepp's system could be simplified and performance improved with an auto sensing, variable speed pump wired constantly on.

As thermostats activate zone valves, when they open and close the Grundfos Alpha “auto adapt” automatically adjust flow. The pump adjusts volume/pressure on several parallel zones as valves open and close.

There is no need for valve end switches or thermostat direct activation of pump. Welcome to modern technology. It also uses 50% less electricity. Here is a best buy:

https://www.supplyhouse.com/Grundfos...mp-w-Line-Cord
 
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Old 12-31-18, 04:41 AM
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That is the pump that I already have, and the way you describe it, is how it is configured for our bathrooms. You bring up an interesting point then, why was it not configured this way for the three other zones? So you are saying it is perfectly safe to have all valves closed, and this thing in auto? When I have it like that, it always reads around 7W I think, but that's not a lot just to sit there. Also, these strange thing about these pumps is they always show 0 GPM, never have figured that one out. Other than that, they work will.
 
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Old 12-31-18, 12:06 PM
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The Grundfos Alpha has 7 modes: Auto adapt, 3 constant pressure and 3 constant volume. Bought Grundfos Alpha because was $120 cheaper than Bell & Gossett Series 100 that failed.

I questioned Grundfos tech support about “constant on” who said it is OK.
Grundfos Pumps Corporation 630- 719-7456 http://ca.grundfos.com

For my 60 year old system with diverter tee's they recommended constant pressure mode. Pump is activated by zone valve end switches

On diverter tee systems a minimum flow is important.

Cannot explain the 0 GGPM. My GPM varies with zone changes.
 

Last edited by doughess; 12-31-18 at 12:57 PM.
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