Correct Thermostat for Taco 571-2

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  #1  
Old 10-17-07, 08:05 PM
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Correct Thermostat for Taco 571-2

Ok the idiot question of the day is....

I have gas hot water base board heat that has a taco 571-2
zone valve connected to it. Which it doesn't appear to be working because upstairs only gets heat if it is in the OPEN position and not when on automatic. So if I set the temp downstairs to 70 upstairs (as we all learned in science heat rises) gets to be 80.

On the top of the zone valve power head (taken from Taco's website not that I know what I'm talking about) there are three screws labeled 1 2 3, but the thermostat, honeywell (can't find any indication of model, square programable) there are only two wires.

Do I need a special thermostate or hook up the two wires to specific numbers on the valve head? I saw a few wiring diagrams but my eyes cross trying to follow the lines as I have no idea what I'm looking at

Does Home Depot sell the valve power head if that needs to be replaced? If so do I need to get another thermostat that allows 3 wires?

Sorry but I am so confused all I know is the heat works downstairs ok and works upstairs if the valve is set to open but it's a shame because 90% of the day everyone is downstairs not upstairs.

Anybody? anything you can give me I appreciate.

Thank you
 
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Old 10-18-07, 05:17 AM
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On your current set up, is all 3 screws being used for your zone, or just two?

If you used all 3, you can use ANY t-stat, the #2 and #3 is used to turn on the pump at the primary control, and #1 goes to the t-stat's W, and R is getting power from the transformer.
 
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Old 10-18-07, 06:37 AM
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Jay11j, First, thank you for your reply.

I know the frustrtation level with me will start to peak because I don't know what I'm doing and the previous owners of the house were the ones who set it up and it hasn't worked from day one.

On the valve head only two (red & white) are being used the red is going to #3 & the white is going to #2. #1 is not being used at all.

The other end of the wires connect to the thermostat upstairs White on top left and Red bottom left.

So it seems there is something missing in the set up or my whole idea of how this should work is wrong. If I put the temp to 85 upstairs and t'stat is showing 50 shouldn't the heat kick on?
 
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Old 10-18-07, 07:36 AM
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One more thought....

Should something connect from the valve head to where the other thermostat is connected to the furnace?

The current setup is the valve head is attached to one of the pipes and then connected to a thermostat in that zone and that's it.
 
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Old 10-18-07, 03:57 PM
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From what I pulled up, if you only got two wires, the wire should be on 1 and 2.... But then I am not a wet head.. I'll get Grady over here and see what he can say about it.
 
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Old 10-18-07, 05:44 PM
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Taco Zone Valve

Ok, so I'm a wethead. And proud of it, I might add.

Let's start with some pictures of the boiler & neaby piping if you can. It makes things so much easier to explain if I can see what I'm trying to explain. The best way to post pictures is to post them on photobucket or similar photo hosting/sharing site & provide a link to the pics here.

Some digital thermostats have a problem with Taco or other "heat motor" zone valves. A model number of the stat would also be helpful.

As long as I'm being a pest about things; the numbers off the aquastat (main control on the boiler) would also be helpful. If the control is a Honeywell, the number could be something like L8148E (gas boiler). If it is oil fired, L8184A,
R8124, or R8182 would be possibilities.
 
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Old 10-18-07, 07:20 PM
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Grady, Before you laugh please understand we are in our early 30's, with two children, and this is our first house, so please keep that in mind when you see this dinosaur furnace. Hope these are OK because the furnace takes up the whole closet off the kitchen (would love to paint inside but you can barely get your hands in there.)

http://i217.photobucket.com/albums/c...t/HPIM0188.jpg

http://i217.photobucket.com/albums/c...t/HPIM0192.jpg

http://i217.photobucket.com/albums/c...t/HPIM0193.jpg

The furnace is a "SLANTFIN" for natural gas hot water based board heat(thank you for providing the example numbers made it easier to find) the control is a honeywell L8148E1273 120V 60HZ .2A Therm Current.

The zone valve is for upstairs and only works on the OPEN position not automatic. I'm not necessarily looking to "spark" or turn on the furnace with the upstairs thermostat but rather prevent the heat from going upstairs if it is already above the desired temperature. There is such a drastic temp difference between upstairs and downstairs because of the size difference as a result of the previous two additions downstairs

Currently the zone valve power head is connected from t'stat upstairs to#1(RED) and #2(WHITE) a little different than what I typed in other post from work earlier.

I have read that the digital thermostats have a problem so tonight I went to HD and bought Honeywell round manual thermostat model #CT87N. I also was able to purchase the replacement zone valve power head.

Sorry for the long winded response I was trying to cover everything so I don't hog your time with multiple post.
 
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Old 10-18-07, 08:01 PM
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Laugh? No Way

Robert, most of us have been in your or similar shoes. We're here to help if we can. Don't worry about hogging my, or anyone else's time here. We all do this because we enjoy it.

Before I get to the zone valve there is one thing which caught my eye as a possible safety hazzard. The vent pipe going into the chimney looks awfully close to the sheet rock. I suggest trimming the sheet rock back so there is an inch or two all the way around the vent pipe. If you wish to cover the hole, there are trim rings available at most home centers. Also make sure the pipe is well sealed into the chimney. Home centers have small containers of furnace cement which will work fine for this purpose.

I will try to make this as simple as I can but if you have ANY questions, please don't hesitate to ask.

You need a transformer (120 volts in, 24 volts out, and at least a 30 vA capacity) because you have no power going to the zone valve to operate it. Should be available at a home center.

Disconnect the wires from the zone valve. Connect one 24v terminals of the transformer to the wire going to the "R" terminal of the thermostat.

Connect a wire from the "W" terminal on the thermostat to terminal #1 on the zone valve.

Connect a wire from the other 24v terminal on the transformer to terminal #2 on the zone valve.

If the thermostat has an adjustable heat anticipator, set it to 1.0.

The thermostat will now control the zone valve but not the boiler or circulator.
 
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Old 10-19-07, 07:12 AM
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Grady, I will take you up on your offer regarding the questions.

1. So I'm facing not an easy solution with the transformer situation, I would imagine I need to get an electrician in to provide a power line to the transformer?

2. I read about the heat anticipator somewhere online, but I'm not sure what it is, the manual mentions nothing about it, just that I have to move one switch inside from the factory pre set of off to On.

I will certainly take measures regarding the safety issues and thank you for pointing that out. I wonder how this house past the home inspection or CO.
 
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Old 10-19-07, 08:07 AM
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The t-stat you got has the sub base to use with A/C , and fan.. those will not be used... You can use it. but the CT87k is heat only.
 
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Old 10-19-07, 08:15 AM
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Originally Posted by Jay11J View Post
The t-stat you got has the sub base to use with A/C , and fan.. those will not be used... You can use it. but the CT87k is heat only.
Jay11J - The above resolves the heat anticipator question, correct?
 
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Old 10-19-07, 01:38 PM
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Originally Posted by njrobert View Post
Jay11J - The above resolves the heat anticipator question, correct?
No, Older style t-stat had the anticipator, since the mercury style has gone away and uses electronic.

So if you do keep this t-stat, or get the heat only stat, set up is the same.

on the dip switch settings, you want to turn off switch 1, and turn on switch 2 on.
 
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Old 10-19-07, 02:51 PM
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Transformer

A transformer is very easy to install if you have any electrical skills at all. Even if you don't, we can talk you thru it if you are not electophobic.
 
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Old 10-19-07, 03:29 PM
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Good about the thermostat,

OK I'm up for it, I'm heading out to HD with the transformer specs.

Here is one other pic of the only place I see electric coming in.


http://i217.photobucket.com/albums/c...t/HPIM0194.jpg
 
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Old 10-19-07, 03:35 PM
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Transformer

Don't leave yet.
That device next to the switch is a transformer. If you don't have a multi-meter, you can get an inexpensive one at HD (probably <$20).
With the switch on, set the meter for AC volts & put one probe on each of the two screws. If you get 24-28 volts, use that transformer.
 
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Old 10-19-07, 03:58 PM
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Something told me to check before I left..

So these knuckle heads had the transformer there hooked up to nothing?

I can't tell you what I have been through in the house - everyone (even me who knows jack) shakes their heads.

One more thing - using the instructions before - I have to buy more wire too right? Because there are no wires on that transformer, I pick up more thermostat wire?
 
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Old 10-19-07, 04:10 PM
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Transformer

It is possible that transformer is no good, disconnected, or the wrong voltage (maybe 12 volts for a door bell?).

Yes you will need a little bit of t-stat wire. 18-2 is fine. They often sell it by the foot.
 
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Old 10-19-07, 04:11 PM
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Not sure it matters but the more info the better I guess

THe transformer says LOAD Class 2 not wet class 3 wet

Top Screw has R
Bottom Screw has C
 
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Old 10-19-07, 04:15 PM
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Transformer

Normal markings. R= hot C=common In this application it really makes no difference. Are there any voltage markings?
 
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Old 10-19-07, 06:14 PM
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There are no voltage markings on the current transformer.

I bought multi meter and with the switch to VOLT the screen says AUTO - I put one prong to each screw on that transformer in the picture and the reading (multi times) is 26.55V.

I picked up another transformer just in case (can always return it but i hate running back 10X).
 
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Old 10-19-07, 06:23 PM
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Transformer

Originally Posted by njrobert View Post
I bought multi meter and with the switch to VOLT the screen says AUTO - I put one prong to each screw on that transformer in the picture and the reading (multi times) is 26.55V.
As long as that voltage is AC, it sounds like you are ready to go. Just follow the wiring instructions I gave you earlier.

One caution: Don't allow the wires from each side of the transformer to touch each other. It's ok if the insulation of the wires touch, just not the ends or any spot where the insulation is missing. To do so, can fry the transformer.

Let me know how it goes.
 
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Old 10-19-07, 06:36 PM
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[QUOTE=Grady;1245017]As long as that voltage is AC, it sounds like you are ready to go. Just follow the wiring instructions I gave you earlier.

When I hit the select switch (AC/DC) the screen only shows V if I hit it again it says mv and that reading is almost 60.
I keep reading the instructions with the multimeter but I can't tell which one is ac and which one is dc. Both are above the 24V. I thought the digital would be easier, I got scared with the needle one and all those dials.

Ok here we go, Starting upstairs connecting new thermostat, May have to finish later because my wife gets nervous, and trust me rightfuly so, I sawed through a water supply pipe trying to take out a vanity sink and flooded the kitchen ceiling. and there are PLENTY more of those stories.

The color of the wires don't matter do they? just as long as I follow the instructions on the connections? In other words does it matter if the red or the white wire goes to the "24v terminals of the transformer to the wire going to the "R" terminal of the thermostat."


I will keep you posted. Have to do this as a covert operation.
 
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Old 10-19-07, 06:47 PM
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Wire Color

Wire color to which terminal makes absolutely no difference. The colors are just there to make tracing easier. One major equipment manufacturer used to use all black wires with tiny numbers on each wire. Talk about a pain to try to trace any given wire.
 
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Old 10-19-07, 09:01 PM
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GRADY & JAY

YOU TWO ROCK !!!! - it worked perfectly, the correct set up is no where near the way it was - No clue why it was done that way.

Grady, Thanks for the easy step by step instructions and all the right on answers, I was actually able to walk into HD like I knew what I was doing.

Jay, Thanks for bringing Grady to my post and the t'stat help.

I can't believe it and I definitely couldn't have done it without you two.

Take care guys and thanks again.
 
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Old 10-20-07, 05:46 AM
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Thanks for the update.. Glad to hear you did it!

Now that is out of the way, what is your boiler pressure?
 
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Old 10-20-07, 08:42 AM
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Thumbs up Way to Go

Congratulations

Well done. Glad it's working as it should. Hang on to that multimeter. You'll find many uses for it.

As Jay asked, what is the pressure on the boiler? For a two story house it should be in the 12-17 psi range.

If you have any other questions about the heater or almost anything around the house, please don't hesitate to post.
Here at doityourself.com, we have dozens of people with expertise in all kinds of fields & all are glad to help when & where they can.
 
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Old 10-26-07, 04:31 PM
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Sorry for the delay in response, had d.i.f, the psi looks like it's the 14 range.

So we're all set for the winter (watch it be a mild one this year now that it's working)

Again, I am truly grateful for your help.
 
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Old 12-19-08, 08:38 AM
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Can I use Honeywll RTH7500 with taco 571-2 zone valve ?

does anyone know if can I use Honeywell RTH7500 with taco 571-2 zone valve ?

I am planning to buy it but not sure if rth7500 will work with my 3-wire zone valve(taco 571-2)


I came across another forum and following link which says use only 2 and 3 wires of zone-valve and ignore the 1st. which did not make a lot of sense base on the discussion on current thread

Prog. Thermostat w/ 3 wire zone valve - Self Help Forums

please help..
 

Last edited by diy50; 12-19-08 at 08:53 AM.
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Old 12-19-08, 09:27 AM
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3 wire zone valves

Even though the 571-2 has three terminals it is not what is normally refered to as a "3 wire valve". A true three wire valve is powered to open and to close. The 571-2 and two wire valves are powered to open & when the power is removed they close on their own. Some thermostats require either an adjustment or a resistor when used with heat motor zone valves. I don't know if this is the case with the RTH7500 or not & Honeywell's site doesn't say, at least not that I could find. Jay is our resident thermostat expert. I'll ask him to take a look at your question.
 

Last edited by Grady; 12-19-08 at 09:45 AM.
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Old 12-19-08, 11:30 AM
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Thanks for your fast reply, I will wait for Jay's comment before buying it.

currently I have 2-zone system (both are 571-2 valves), water-base board heat. with burnham gas waterheater

for 2 values I have one programmable thermostat and one non-programmable mercury t'stat which I want to change.
 
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Old 12-19-08, 12:44 PM
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I got a msg from Grady asking for help. I am going to look into it more tonight after work..

My guts say no, You may have to go with RiteTemp t-stat.. but again, I'll post back for sure tonight when I am done shoveling snow.
 
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Old 12-19-08, 01:01 PM
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3 options...

Thanks for your reply....

I am looking at two options...

Honeywell RTH7500

or

rietemp 6080

or

ritetemp 6035
 
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Old 12-20-08, 04:41 AM
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sorry for not catching up with you last night. I had to work late, and got too busy playing catch up on my t-stat board, and humidifier.

On your current t-stats, what wire is hooked up to it, and what are they hooked up to at the boiler and valve?
 
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Old 12-20-08, 09:26 AM
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here are the pics ,

the valve connections

<a href="http://img151.imagevenue.com/img.php?image=94188_IMG_1925_122_748lo.JPG" target=_blank><img src="http://img151.imagevenue.com/loc748/th_94188_IMG_1925_122_748lo.JPG" border="0"></a>

and t'stat....

<a href="http://img258.imagevenue.com/img.php?image=99285_IMG_0316_122_550lo.jpg" target=_blank><img src="http://img258.imagevenue.com/loc550/th_99285_IMG_0316_122_550lo.jpg" border="0"></a>

<a href="http://img156.imagevenue.com/img.php?image=99287_IMG_0313_122_944lo.jpg" target=_blank><img src="http://img156.imagevenue.com/loc944/th_99287_IMG_0313_122_944lo.jpg" border="0"></a>
 

Last edited by diy50; 12-20-08 at 10:56 AM.
  #35  
Old 12-20-08, 10:15 AM
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571-2

That valve does not look like it is wired correctly. Usually there are 2 wires on terminal #2 & one each on terminals 1 & 3.
 
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Old 12-20-08, 10:57 AM
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thanks Grady.

this is zone valve #2, I think this is the one which is connected to the thermostat. by mistake I put the zone valve#1 in previous post sorry about that.


<a href="http://img44.imagevenue.com/img.php?image=02370_IMG_0331_122_918lo.jpg" target=_blank><img src="http://img44.imagevenue.com/loc918/th_02370_IMG_0331_122_918lo.jpg" border="0"></a>

<a href="http://img222.imagevenue.com/img.php?image=02376_IMG_0332_122_96lo.jpg" target=_blank><img src="http://img222.imagevenue.com/loc96/th_02376_IMG_0332_122_96lo.jpg" border="0"></a>
 

Last edited by diy50; 12-20-08 at 11:49 AM.
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Old 12-20-08, 03:52 PM
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Wiring

It would appear as if it too is wired incorrectly. Differently, but still incorrectly.
 
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Old 12-20-08, 06:11 PM
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The t-stat you got is a basic two wire set up. R and W.

So any of the t-stats will work with your manaul stat replacement. You are just going to have the fan switch, and the heat/cool/off switch, that will only be using the heat and off for your system.
 
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Old 12-21-08, 06:27 AM
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Thanks

Thanks Jay. From your advice I understand that any thermostat (programmable t'stat ) with R and W wries will work.

thanks that solves my problem. I think ritetemp 6080 has those options so it will work.
 
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Old 12-21-08, 06:54 PM
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Yes, RiteTemp and Honeywell had R and W on the hook up.. R and W is a standard wire hook up for heat on any t-stat.

I know some zone system needs to have more than one wire at the t-stat, but yours did not need that.

If you find that you are starting to feel "cool" before the system comes on, set the "swing" temp tighter like .5 vs 1 that may be a default setting.
 
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