Maybe I'm misunderstanding the EXP(ansion) ability of the Taco ZVC 406 and the SR501 both of the expandable models.

What I want to achieve is the boiler and pumps being turned on by the SR501 1 zone and the zones from the ZVC 406. As of yet I am unable to do it, even though they are both wired on the three terminals that is suppose to connect them. When the 501 1 zone calls for heat all is as expected but when the 406 calls for heat there is no action at the 501 so the boiler does not heat.

 

Is the SR-501 doing a domestic hot water zone? The ZVC normally will not energize the SR501.

 

Grumpy, I'm not real clear on what you are doing...

You have SEVEN zones so are using the 501 to add an extra zone to the system?

Can you explain exactly what's wired to what?

Or maybe post a diagram?

 

It would seem your post suggests you have zones and a circ for the HW?


If so I believe you dont need the sr501 to control the HWH.

The 406 has an endswitch to control the circ of the HWH. You just need to look in the notes under priority zone 6 below in the diagram.

Installation of Optional System

and/or DHW Circulator

http://www.taco-hvac.com/uploads/Fil...ry/102-108.pdf

Here is all of tacos complete wiring diagrams.

http://www.taco-hvac.com/uploads/Fil...ry/100-9.0.pdf

Mike NJ

 

Not doing hot water, it was two boilers and now it is one. One boiler was zoned with the zvc406-exp and 5 zone valves while the other boiler is just on or off at the pump.

I have been posting over the last year about connecting the two systems together and using one boiler to heat two buildings. (actually there is three, 1 block deep all attached)

I have an engineer drawing for replacing all the equipment but I'm not there yet, but the piping is done, and the small boiler is off line. The large boiler has two pumps, the orginal for the large building and a smaller one for the old boiler load in the other building.

The real question is doesn't taco exp mean expandable, which would allow the sr501 or the zvc 406 to control the end switch to the boiler depending on who is the MASTER. The zvc is slave and the srv501 is master, but the srv501 doesn't recognize the call from the zvc.

I'm pretty sure I could make it work if I used the 406 to control everything but it is at the extreme end of the other building. (and it goes against my understanding of taco exp, otherwise there is no need for the extra expense of the exp.)

one other quick note all the wiring diagrams show four connections for the expansion when in real life it is three.

 

Hello Grumpy,
I think you might need a SR502.
Would it be possible to post up a drawing of how everything is currently connected.


Peter

 

Set the expansion switch to MASTER on the

switching relay that has the designated priority zone or is utilizing thePowerPort options. Set all other daisy chained controls to SLAVE.Connect thermostat wire (18-22 gauge) between terminals 1, 2, 3, 4 onthe master control to the corresponding 1, 2, 3, 4 on the SLAVE control(s). Controls may be daisy chained up to 20 zones using any combination

of -EXP controls.

Quote:

one other quick note all the wiring diagrams show four connections for the expansion when in real life it is three.

What do you mean? Dont you need to wire both modules to each other using 1,2,3,4 ????



http://www.taco-hvac.com/uploads/Fil...ry/102-204.pdf

Mike NJ

 

Yes you wire both expansion 123 to each other, but that does not work. As for the 502, yea it may work but I still do not know why one exp does not talk to the other. The 501 is suppose to support 2 pumps one for the zone the other for circulation (boiler I think) I will take pictures later of my temp mess

 

I think I found the answer, hopefully not.

Q:
Is the SR EXP switching relay control and the ZVC EXP control for zonevalves compatible; or used together?

Answer: No, on like controls can be used together.

 

Probly woulda been best to have added this onto the existing thread... I may merge the two together if I can find the other one... to get some continuity of the issue.

Grumpy, I'm still only half understanding the setup.

I know that you have one boiler and you are heating two buildings.

I am picturing a manifold on the boiler that has two pumps on it.

One pump for the building with the 5 zone valves, the original setup.

One pump to run boiler water to the other building. The 501 relay is in this other building and triggered by the thermostat in that building... is that correct?

Or, are you running the 501 and 406 right next to each other and using long lines to get the thermostat signal over to the boiler from the other building?

In any case though, you've got the thermostat from the far building operating the 501 relay... right?


more...

 

Helllo Grupmy,
I believe if you have a SR 502 you can connect the end switch ffrom the ZVC406 to the unused thermostat input and then when the 406 calls the 502 would act just like a thermostat called and fire the boiler and the approiate pump.

I still think it would be best to taake the time and draw out exactly how thing are connected, now.
Perhaps there might be a way to make it work with the current equipment.



Peter

 

Questions:

To where is the pump for the zone valve system wired?

To where is the ENDSWITCH on the 406 panel wired?

........................................................................

On the 501, you have the thermostat wired to the T T ( R W ) terminals, correct?

And the pump for the far building is running off of the "H" terminal for "CIRC OUTPUT", correct? And that pump starts and runs properly?

Why not just forget the 'expansion' feature and simply wire the XX Endswitch in the 501 in parallel with the ENDSWITCH on the 406 ?

Isn't it that easy? Or am I still missing something?

 

1) sr501
2) is not
3)yes
4)false
5)yes

might try that, I know I could wire it just like another zone and get rid of the 501. but I bought it under the belief it would tidy up and ease installation. (I was Wrong)

http://i1239.photobucket.com/albums/...201_152600.jpg
http://i1239.photobucket.com/albums/...201_152612.jpg
http://i1239.photobucket.com/albums/...201_152625.jpg
http://i1239.photobucket.com/albums/...201_152638.jpg
http://i1239.photobucket.com/albums/...201_152649.jpg
http://i1239.photobucket.com/albums/...201_152706.jpg
http://i1239.photobucket.com/albums/...201_152720.jpg
http://i1239.photobucket.com/albums/...201_152726.jpg
http://i1239.photobucket.com/albums/...201_152737.jpg
http://i1239.photobucket.com/albums/...201_152750.jpg
http://i1239.photobucket.com/albums/...201_165045.jpg

pictures of install so far, yes it is all temp until I decide on an end game

 

All right Grumpy, now ya got me completely confuzzled...

Let's try this another way.

I believe that if the pump for the zone valve system should be wired to run from one of the endswitches on the 406 panel. The other endswitch on the 406 should be wired to the boiler T T terminals.

The thermostat from the far building should be wired to the 501 thermostat terminals.

The endswitch on the 501 should be wired to the boiler T T terminals, in parallel with the endswitch on the 406.

This way, EITHER panel will fire the boiler.

The pump for the far building should be running off the 501 relay box.

Scenario

Thermostat from far building calls for heat.

501 relay is energized and turns on far building pump.

Endswitch in 501 closes and calls the boiler to fire if needed.

OR

Thermostat from zone building calls for heat...

Valve opens, endswitch closes, triggers 406 panel to start pump for zone building.

Endswitch on 406 closes and calls the boiler to fire if needed.

OR

BOTH at the same time...

is this anything close to what you have wired?

 

This is the way the zone panel should be...

 

And this is the way the 501 should be:



The T T here goes in parallel with the 406 to the boiler.

 

No!

What hampers this experiment is winter The apartments need to be heated while I try different scenarios.

But after saying that I'm a lot closer to your page then I was yesterday...

I'm going to wire the 406 thermostat to the Honeywell pump relay(small back building pump), and wire the 501 to the front building where the pumps are.(boiler located in front building basement)

I need to change how the boiler fires as someone had set it up with the flow switch firing the boiler not the thermostat.(turn pump on get heat) Small pump does not currently have enough flow, though I can change that at the flow switch as it is identical to the back boiler so easing it off should do the trick I hope. (pump came from back boiler)

So I need to continue the thermostat from the relays to the wiring in the boiler, probably between the aqua-stat and the gas switch. Or just leave it so the safety device (flow switch) is the control device.

Of course I do that I want to see if the 501 can control two pumps, just don't know how and Taco never bothered to reply.

 

I think there is some basic misunderstanding...

Why do you want the 501 to control two pumps?

I've really tried to 'get' what you are trying to pass on, but something is missing in the equation. As I understand it, your wiring seems rather easy... but then, there must be something you aren't conveying to us that makes it more difficult.

 

Maybe I just don't understand which building is which?

So let's define some terms and use them consistently so we can communicate properly.

Let's call the two buildings the FRONT and BACK buildings, as you have done above.

Which building has the ZONE VALVES, controlled by the 406 ?

 

It's me, I'm probably complicating the process, but my understanding was the SR501 could control two pumps 1 as the zone pump the other as a circulator. Because I have a ZVC 406 EXP I figured the SR 501 EXP would be able to communicate. Not so!

Front building is the larger boiler, with more residents and commercial areas. This zone has been and still is controlled by 1 thermostat and 1 pump.

Back building is 1 resident and 1 commercial, there are 4 zone valves and 4 thermostats and a small boiler. (200,000 btu)

My goal is to replace the boilers but just not at this point in time, so the next best thing is to upgrade the boiler piping which needs to be done when I upgrade the boilers anyway. Now that the front building and the back building are connected I have disabled the small boiler and I'm using the larger boiler for both buildings. (600,000btu)

The problem is that the front building pump cannot run constantly or we will really overheat the tenants in the front building, but the back building is zoned and running the pump constantly is no issue. There are check valves in the system to stop cross over.

So my solution currently is to re-use the Honeywell pump relay (and separate thermostat not hooked into the ZVC406, well not yet but it will) and use the 501 to control individual pumps, but I still have an issue as the boiler fires on flow switch and the smaller pump does not activate it, guess I will be getting a low flow next week as the current one was already totally backed out to the point the adjuster screw spring was sitting in its case.