zone heating for boiler


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Old 12-31-12, 06:50 PM
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zone heating for boiler

I have a mcneil boiler that doesnt seem to be getting a signal from any of the 4 tstats in the house. It was just working could it be the relay and how do you change it
 

Last edited by bigelu; 12-31-12 at 06:59 PM. Reason: spelling
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Old 01-01-13, 09:46 AM
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Hi big,

No, don't jump to conclusions. Doing so almost always results in spending more money than you need to.

You have electric zone valves, is that correct?

If ALL FOUR of the thermostats are not working, it could be that your 24VAC transformer had bit the dust, or yes, it COULD be a relay in the boiler, but without a means of testing, we can't say for sure.

I don't know your skill set, does it include doing minor electrical testing and do you own and know how to use a multimeter?
 
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Old 01-01-13, 02:17 PM
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Just had it checked out and it seems to be the transformer. Thanks for your help, should have it fixed tomorrow. Will let u know
 

Last edited by NJT; 01-06-13 at 09:12 AM.
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Old 01-05-13, 08:16 AM
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zone heating for boiler

what would make one zone out of four to stay on continuesly, i did change t'stat and zone valve, rest of zones work fine. pete
 

Last edited by NJT; 01-06-13 at 09:13 AM.
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Old 01-05-13, 10:18 AM
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did change tsta and zone valve
I take it that's..... t'stat and zone valve ?


What happens if you leave zone valve motor off ?
 
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Old 01-05-13, 11:52 AM
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what wire would that be on the zone valve to take off its a taco with 3 terminals white-red-yellow
 

Last edited by bigelu; 01-05-13 at 12:32 PM. Reason: spelling
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Old 01-05-13, 12:51 PM
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zones

could it be a ignition control problem, i changed the transformer and relay the other day and have no idea what can be causing the boiler to ignite with all the tstat's turned down
 
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Old 01-05-13, 02:37 PM
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If you have a stuck Taco zone valve....the zone will keep heating and the boiler will be getting the call for heat.

You said you changed the zone valve Is that correct ?
If you did change it.....did you wire it the same way it was ?
 
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Old 01-05-13, 02:52 PM
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changed transformer, relay, and zone valve, put all tstat's off and boiler is still lighting and sending heat to one zone, what could be the reason
 
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Old 01-05-13, 03:28 PM
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My guess is that it got wired back up wrong.

What kind of zone valves do you have?
 
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Old 01-05-13, 03:33 PM
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could it be a ignition control problem, i changed the transformer and relay the other day and have no idea what can be causing the boiler to ignite with all the tstat's turned down
Quit throwing parts at it, especially ones that logically shouldn't be the problem. What is called for is systematic troubleshooting with a multimeter. If this seems above your experience level, call a serviceperson.

PjMax could be correct - a zone valve. A voltmeter will tell the story.
 
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Old 01-05-13, 03:36 PM
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yes it was wired the same way, i also switched the wires with the valve next to it and the same thing happened with that valve
 
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Old 01-05-13, 03:42 PM
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It seems like we have at least three threads going from bigilu, one of which at least is hijacked. This particular thread seems to answer a response several hours ago, even though there are intemediate responses.

Bigelu, please designate one thead as the prime and delete all the others - and don't start any new ones.
 
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Old 01-05-13, 05:04 PM
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Nice job Troop...I thought I was seeing things.

You told us that you have one zone that is staying hot. Which zone is it ?
Is that zone still staying hot now ?
If it is still hot.....take Taco motor unit off of valve and tie it to something so it's hanging.
See if that zone cools off now.
 
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Old 01-05-13, 07:43 PM
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it cools down just cant figure out why 3 zones are fine and one isnt, it seems to be a short because when i had transformer replaced a couple of days ago the first one shorted out and we had to fuse the second one, but then it started workihg except for the one zone for my den. my son just came and made the whole unit work off of the kitchen tstat seems to be working fine now but still wouyld like all zones to work
 
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Old 01-05-13, 08:38 PM
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The pic below is a representation of your system.

When a zone calls for heat .....that valve opens and creates a short on terminals 2 and 3..... which calls for heat and circulator pump.

[NJT editor note: Do NOT run four Taco valves on a single 40VA transformer. It will overload the transformer and cause premature failure]
 
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Last edited by NJT; 01-06-13 at 09:28 AM.
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Old 01-06-13, 08:53 AM
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good morning, what are the "T" terminals, and where are they if you can show a picture, the one about the 4 zones was very helpful
 

Last edited by bigelu; 01-06-13 at 09:57 AM.
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Old 01-06-13, 09:17 AM
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Pete, let's back up a bit...

What MAKE AND MODEL boiler do you have?

changed transformer, relay, and zone valve,
Please tell us what "relay" you changed.

i also switched the wires with the valve next to it and the same thing happened with that valve
If when you switched the wires from one valve to another and the problem moved to the other valve, it is clear evidence that the wiring is wrong.
 
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Old 01-06-13, 09:27 AM
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There may be another issue here...

If the transformer fried and was the ORIGINAL problem, it is likely because it was OVERLOADED.

You can only run THREE valves on one 40 VA rated transformer.

When you get the problem with the burner firing fixed, you need to install a larger transformer (at LEAST a 50 VA part) or install a SECOND 40 VA transformer to power all the valves.

If all four zones call for heat at the same time you will very likely fry the new transformer, and this might be what caused the problem in the first place.
 
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Old 01-06-13, 09:57 AM
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I edited the schematic that PJ posted to clarify a bit:

Name:  taco four valves.jpg
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Old 01-06-13, 10:01 AM
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its a weil mcclain-mod. cgm-4-pi. comes together with the transformer it plugs in next to the trans. on the same plate.
 
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Old 01-06-13, 10:24 AM
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Oh... so what you are saying is that your zone valves are being powered by the transformer inside the boiler? Well... that's just wrong...

You WILL have the same problem again.

You MUST install a separate transformer to power the zone valves.
 
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Old 01-06-13, 11:37 AM
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why did it seem to work fine for 20 yrs. with the way it was
 
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Old 01-06-13, 11:58 AM
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why did it seem to work fine for 20 yrs. with the way it was
I'm a little lost with this statement.

Originally you told us you had a single zone staying on and three others working fine.
Then you tell us you were swapping wiring around
Then you told us none of the four zones were working.
Then you tell us the transformer is defective.
The transformer more than likely got shorted while you were working recently on the wiring.

Transformers from many years ago were rated much more conservatively then the parts of today.
You could just change the transformer with a new 40 watt unit. Will it work....maybe....for how long....who knows.



----------------------------------------------------------------------------------

Troop......thanks for adding the note in my post about the transformer size. I had just modified that diagram from 3 to 4 zones and completely forgot to change transformer size.
 

Last edited by NJT; 01-06-13 at 02:52 PM.
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Old 01-06-13, 02:48 PM
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PJ, I think the order was a little different...

First, nothing was working.

Replaced transformer, relay (I'm thinking the R8285 control inside the boiler, and a zone valve.

Then, it was working but one zone kept calling, probably the one that was replaced...

why did it seem to work fine for 20 yrs. with the way it was
I'm thinking it's because the zone valves are NOT being powered by the transformer inside the boiler and that there is in fact another transformer mounted somewhere externally that is powering the zone valves.
 
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Old 01-06-13, 03:27 PM
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pretty sure there is only one transformer, usally keep basement tstat all the way down. everything was fine 2 weeks ago
 
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Old 01-06-13, 08:14 PM
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When you said you moved the wires on the zone valve from the 'hot' zone to another.. but then the 'new' zone got hot...
So, that says the zone valve is driving open via the t-stat responsible for the 'hot' zone. Check wiring feeding the tstat from the transformer area. Swap t-stat with another to verify if it's a bad stat or the wiring..
I agree with upgrading the transformer.. I switched out a 40va transformer that was acting oddly due to load over to a 100va one.. no more worries about overdriving that sucker.
 
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Old 01-07-13, 05:18 AM
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still would like to what and where t terminals are a little confused, be back latter going to work
 
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Old 01-07-13, 06:02 AM
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The "T" terminals on your boiler are the " G " and " Y " terminals on the R8285 relay/transformer inside the boiler.
 
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Old 01-07-13, 10:10 AM
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I have three wires going into the boiler that come out to the valve white yellow red what goes to the "G" - "Y" and where does the other color go
 
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Old 01-07-13, 10:29 AM
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It may not go anywhere. Sometimes they use cables that have three wires and only use two.

Follow the cable and look at the other end to see if all three are used.
 
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Old 01-07-13, 01:12 PM
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yes all three are used white on terminal 1. red-2. yellow-3 on the valve
 

Last edited by bigelu; 01-07-13 at 02:02 PM.
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Old 01-07-13, 02:39 PM
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Wires from terminal 1 of the zone valve should not go to the boiler. They should go to the thermostats.

Can you understand the schematic diagram that was posted?
 
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Old 01-07-13, 03:20 PM
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yes I see that,my son is out of town till the weekend he is a electrician when he gets here I will show him these post and have him check it out. So I'll let you know what happens when he gets here. Until then, thanks for everyone who has helped I really learned alot. BIGELU
 
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Old 01-07-13, 03:22 PM
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Yes, please do let us know! I'm sure the youngun can work out the problem.
 
 

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