Taco Zone Valves


  #1  
Old 03-07-05, 02:09 AM
David M.
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Taco Zone Valves

Hi!
I'm a newbie with boiler controls, so I hope you can bear with me as I explain my problem.
I decided to help a friend of mine re-pipe her home boiler. She had a new unit installed about 4 months ago by a very shady contractor who has since disappeared who was actually recommended to her by a realtor (another story in itself). She already shelled out over 2 grand to have the job done, and did'nt have anymore to redo it (estimates of a re-install by several different contractors ranged from 1400$ to over 2,000$). I decided to help redo it at no charge until she can take the bozo to court and get her $$ back since he refuses to come back and do it right. The Municipal inspectors wrote up a sheet on it, and told us it's OK for me to redo it as long as I'm not charging her and it's done right. Long story short, incredibly, he did everything backwards....and I mean everything. I'm rather new to boilers, but I do have alot of plumbing experience and coupled with what I do know about them it was obvious the boiler was not plumbed correctly. The pump was on the supply side, the main water feed was dumping into the top vent tap instead of teed into at the return tap on bottom, the purge valves were on the supply side as well, on and on, and the pipes were all running at odd angles, etc. Part of the problems this system was experiencing was a strange lack of temp control over the loops...it was either fire or ice. You had to set the t-stat up to about 90 for the loop to get hot, and if you set it below that you better get the blankets out. I assumed this was due to the piping and the pump being on supply side, etc. Anyway, I ripped it all out, being careful NOT to mess up the wiring anywhere. I did'nt actually un-wire a thing except of course the zone valve heads. I re-used the bodies by un-sweating them and inserting them back where I wanted them in my new supply manifold.

Anyway after I got the re-pipe done with a bypass and the high limit re-attached to the 1" main supply riser, I wired in the Taco's exactly the way they were. I lit the pilot set to on and flicked the main switch....nothing. No burner at all, just a pilot. Since this was a fairly new system I assumed it was'nt the gas valve, or the thermocouple etc. But on examining the relay/transformer I could'nt make much sense out of it. It's a GWA gas fired boiler, supposedly made by Frigidaire, so I never heard of it. I'm looking at the spill switch, the auto vent damper (which I turned to manual and opened to no avail), the relay seemed OK since when i crossed the C and Y connections on the trans the burners came on. Totally perplexed and with a very frigid night approaching I decided to actually do away with ALL of it and experiment re-wiring it my way to get the thing to at least cycle. What I found worked was this, (sorry for my amateurish explanation) I took a new 24v trans and wired it to the source 110, hard wired the pump into the source as well, ran a wire from the hi-limit on the 1" riser to the TH terminal on the gas valve, and ran the other to C on my trans. Ran a wire from TR on the gas valve to the (hi-temp cutoff? high limit control?) in the boiler, ran the other wire from the hi limit to R on the trans. Ran a 3 wire stat cable from the trans up to where the zones are, white in R and red in C, green cut, and tied the white one into the wires on the second screw of both the Taco heads. This brings my 24v up. The red one from the trans I tied both whites from the two t-stats into. I separately tied the wires from the top lugs of both power heads to the red wires of both t-stats.

Whew. Sorry for the long-winded oap opera, trying to explain best I can. I have pics of this getup if needed. My question is, I know I should get the original controls back in there again, but is it ok to leave the boiler like this for awhile? The zones seem to open and close upon t-stat demand, albeit rather slowly (I don't know if this is a Taco trait or not). I did end up replacing one entire zone valve body after it started leaking after initial start-up, with brand new head. I already have some $$ in this and would just like to see it pace along until it can be properly done. Is my wiring appropriate and safe? Is it ok to hard wire the boiler like that as long as I have a bypass open?
Thank you bunches in advance for any information.
 
  #2  
Old 03-07-05, 07:32 AM
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Taco valves open slowly. The heat anticipator on the thermostat needs to be set to .9 in order to work with the zone valve. The pump on the supply is not a bad thing but I'm sure some of the other stuff was. Picture it thisway. Terminals 2 and 3 of the zone valve become the thermostat wires that would normally run the heating system if you only had one zone. If you have the zone valves wired in such a way that they open with the thermostat, you are half way there. I PM'd you with my email in case you still want that diagram.

Ken
 
  #3  
Old 03-07-05, 02:05 PM
David M.
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Red face

Thank you sir for your fast reply.

I am using a White Rodgers heating t-stat. It does'nt seem to have a .9 setting on the anticipator, just goes from .8 to 1.0. Would it be ok to set it at 1.0A? Thank you for this advice by the way, I had'nt checked that as I was'nt aware of that requirement.

I am using the #1 and #2 terminals on the power heads. Do I need to be using 2 and 3 instead? I am starting to have problems now, such as too much heat on second floor, not enough on first, but hopefully the anticipator adjustment will help with that.

Thank you for the diagram offer, I will PM/e-mail you back, I'm sure it will be a life-saver as this job is starting to make me nuts.

I did just one other boiler job like this before, and I used Honeywell zones on that one...as I recall they were alot easier to wire and work with....I think I'll stick to them from now on!
Anyway, thank you again for your time and help.
 
  #4  
Old 03-07-05, 02:23 PM
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As you will see, you need all 3 terminals on the zone valves. The power to open them needs to be kept apart from the power supply in the boiler control or you will have heat where you don't want it when the transformers buck. They will surely buck to the death of one. If it is the one in the aquastat, it will cost a few BUCKS. That's not why they call it bucking but you don't want it to happen regardless. The anticipator setting is fine at 1.0. It just shouldn't be below .9. It sounds like the wiring is not quite right. The thermostat should open the zone valve using the power from the added transformer and when the valve is open the boiler should see the call for heat and respond. It isn't any more complicated than that.

Ken
 
  #5  
Old 03-07-05, 05:20 PM
David M.
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Thanks again much for your responses Ken.

I just want to clarify one point, which pertains to the transformer (or lack thereof)

"It sounds like the wiring is not quite right. The thermostat should open the zone valve using the power from the added transformer"

That's just it. I am only using one transformer. No heating control (aquastat). It's all run off just one 24V PS wired into the source AC.
 
 

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