zone valves

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Old 01-21-08, 06:29 AM
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zone valves

I have 3 honeywell zone valves on my boiler. It seems that every year or ever other at least one goes bad. My upstairs is call for heat but I'm getting nothing from the boiler. It was working fine 2 days ago. Why do these keep going bad and is there a way to fix them without replacing the entire thing? Is there a place to veiw a diagram of the machanics/parts of a zone valve to check how they work? I'm getting tired of paying a furnace guy!

Thanks
 
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Old 01-21-08, 06:43 AM
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zone valves

On my Honeywell zone valves, the motors are what has gone bad and they are easy to replace, and not too expensive. Search and you'll find detailed instructions. Steve
 
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Old 01-21-08, 06:52 AM
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Yes they are a pain in the neck!!! I just manualy opened it and it was like it was stuck. It made a bang sound it the pipe but then the furnace kicked on. Do they get stuck?
 
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Old 01-21-08, 09:35 AM
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Yes, sometimes they are a pain in the neck, but they should not need replacement every couple of years!

WHY are they being replaced?

1)Is it because the 'clock motor' does not operate them any more?
2)Is it because they operate but the micro switch does not get activated any more?
3)Is it because they are 'sluggish' and move very slowly?
4)Is it because the gear (or rack) stripped a tooth?

We need to find out why they need to be replaced so often (or maybe they don't)

Charlie
 
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Old 01-21-08, 03:31 PM
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Zone Valves

Tell ya what to do about the zone valve problems. Come spring cut 'em all out & replace with circulators with internal flow checks. Then put all the zone valves in a box with a dollar & set the box out by the curb. At least when somebody finds the box they'll have a dollar.
 
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Old 01-21-08, 08:20 PM
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Hey Grady: Throw them out? Are you nuts? I can use those old 'clock motors' for some 'invention' or 'hobby project' or something, then throw the rest of the valve out!

I hate them too, BUT, someone is gonna start a whole thing now about how GOOD they are!

Charlie
 
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Old 01-26-08, 09:25 PM
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Honeywell Zone Valves

Greetings, I've been trolling this forum for a while and I am impressed with the expertise. I've learned a bunch so far and am planning to learn much more. I'm willing to share whatever limited knowledge I have.
Concerning Honeywell zone valves, I've had them in my old house for almost 30 years. I now have Erie valves in my newer place and haven't had any issues with them for 10 years.
Coming back to the Honeywells. I found that the limit switches in them died and had to be replaced almost annually, which proved to be a real PIA even though I was able to use some switches scrounged from work. After a while though I got tired of it and built a little circuit that fixed the problem once and for all.
Rather than operating the aquastat relay directly with the valve's limit switch, a triac(electronic AC switch) performs that function. This takes a fairly heavy current load off the limit switch which now just has to pass the very small control current of the triac. After I built this circuit about 20 years ago I did not have to replace any more limit switches for the next 20 years.
When I built again I took the "magic box" with me and hooked it up to my current Erie Zone Valves which have been operating now for 10 years. The box has a bypass switch so that one can revert to normal mode if something should blow in the circuit.
If anyone is interested I could post the simple schematic if I ever figure out how to do that.
Cheers
BTW, I've read the thread about the Beckett Heat manager with great interest and I think I'll get me one
 
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Old 01-27-08, 07:56 AM
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The microswitches in both the Erie and Honeywell zone valves were never meant to carry a heavy load. Most of us in the field realize that the life of these switches can be extended considerably by incorporating a 'relay' to handle the heavier loads.

We usually group one 'red' lead from every zone valve together with the other zone valves, then do the same for the second lead on all the zone valves. so we are only left with 2 red leads from ALL the zone valves.

THEN if we are using anything but a very low powered circulator, we would use these two leads to actuate the circulator through a relay box and we would wire the two leads on the coil side of the relay. The higher side of the relay would take care of powering the B&G #100, or other circulator you have in place once the relay 'closes'.

This system should be used any time there is a substantial current needed for the circulator. I use this system anytime I do not use a Taco 007 circulator or other low powered circulator. I however do find that the microswitches are able to handle the current required for a Taco 007 or a small Grundfos and usually to not use the relay in those applications.

The larger circulators can have an initial draw of 20-40 Amps on start-up, or maybe more, and I'm sure that the microswitches cannot handle these loads repeatedly and for any long period of time.

I believe that the microswitches are rated at about 3-4 amps constant (max), and probably about 15-20A (max) on an initial start for a very short duration.You can go on the web and look yours up or perhaps there is a stamp on the unit.

Anyhow, I'm absolutely sure that their life WILL be extended dramatically by using a relay.

This would be the 'old school' way of doing things.

The 'new school' way is to use a zone controller. A 1 zone would do nicely for this application if you can group the red wires as mentioned.

The multiple zone models have fancy little lights and look impressive, are flexible, and are usually used to control individual circulators using individual thermostats (multiple zones). This is the method I prefer.

Be advised that I have read about using a TOO LOW control current (as you mentioned in your design) where there was long term failure due to the current being TOO low. What the article pointed out was that the relay contacts got dirty much faster because there was not substantial control voltage, which helps keep the contacts clean and residue free. A good point made by the article.

(Old school dog in a new school kennel)
 
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Old 01-27-08, 09:46 AM
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Originally Posted by torpedo203 View Post
. . . Rather than operating the aquastat relay directly with the valve's limit switch, a triac(electronic AC switch) performs that function.
torpedo, that's a good way to go. I've wondered why there are so many relays and switches used in controls. All kinds of inherently unreliable electromechanical devices that can easily be replaced with some electronics. This stuff looks like it hasn't changed in 70 years.

Al.

P.S. lurking is what someone does as they read posts, but tend not to post. trolling is when someone makes posts to elicit an inflammatory reply.
 
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Old 01-27-08, 10:29 AM
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Originally Posted by OldBoiler View Post
This stuff looks like it hasn't changed in 70 years..
Hmmmm... this from a guy who ... uhhh, just how old is your boiler again Al ?

Modern electronics is all well and good... but most techs have a hard enough time telling a SPST from a SPDT ...

What's the MTBF on an old electromechanical relay, compared to a PC board with SMD electronics ? Can a relay be affected by 'dirty' power ? EMI ?

There's pros and cons to both sides of the coin...

Charlie, I'm familiar with the phenom of too _little_ current causing problems. In general though, this can be handled by designing a 'self-wiping' function into the switching devices, and a dab of "Stabilant 22" ... (google it if you're curious)
 

Last edited by NJT; 01-27-08 at 03:51 PM.
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Old 01-27-08, 01:14 PM
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Originally Posted by boilersrus View Post
I hate them too, BUT, someone is gonna start a whole thing now about how GOOD they are!

Charlie
Charlie, I love my Honeywell/Sparco zone valves, never an issue!! Run like little clocks. Can't say that about the Taco heat motor crap I used earlier, though.. What the heck, I love my Reillo too!!!

Pedro
 
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Old 01-27-08, 02:04 PM
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P.S. lurking is what someone does as they read posts, but tend not to post. trolling is when someone makes posts to elicit an inflammatory reply.
As so many politicians say " I misspoke" I meant lurking.
boilerus, all my 5 zones' microswitches are in parallel (as you stated) and then they are simply connected with 2 wires to the relay in my aquastat. The only load the switches have to carry is the relay's coil current. It's an inductive load which can cause arcing, shortening switch life. The triac takes care of that as well, as long as the breakdown voltage of it is high enough. As far as I know my limit switches do not carry the circulator current (1 small grundfos pump) even without my magic box. There's a lot of different designs out there. Can I take from your comments that the newer hydronic systems use individual circulators rather than zone valves?
I've heard of switch problems due to small currents but it hasn't affected the valves I know about. The control current for the triac is only about 1/2 milliamp, which is very small.
Cheers for now
 
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Old 01-27-08, 03:46 PM
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There was a poster a while back who was thinking about installing arc suppressors ( 10K in series with .47 uFd ) across the endswitches ... sounded like a good idea to me ... wonder if he ever tried it ?

We had to re-design a circuit board at my 'day job' that used reed relays to switch some signals. After about 6 months of service, they became unreliable. Manufacturer failure analysis pointed out that they were unsuitable for the purpose because of the very low currents involved (inputs to op-amps, micro-amps). I tend to think that the problem only exists in extreme cases such as this...

Systems can be zoned with either individual circulators for each zone, OR with zone valves. Nothing "new" there. Taco (and others) make zone control panels for both cases. See www.taco-hvac.com if you want to look at them.
 
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Old 01-27-08, 04:40 PM
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Originally Posted by NJ Trooper View Post
There was a poster a while back who was thinking about installing arc suppressors ( 10K in series with .47 uFd ) across the endswitches ... sounded like a good idea to me ... wonder if he ever tried it ?
10,000 ohms in series with .47 mFd won't
do anything, way too much resistance.
I'd suspect for 24 VAC the resistor would be
under a 100 ohms, otherwise there would be
very little effect on the transient signal. There
should be some general values for either 24 or
110 VAC on the Internet someplace?

Pete
 
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Old 01-27-08, 04:47 PM
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Here's is a spec sheet on SBE Orange
Drop transient suppressors, and they show
typical values for the RC components:

http://www.sbelectronics.com/images/PDFs/288p.pdf

Better yet, there are solid state devices (TranZorb) that are also
made for clamping AC transients, these might be more
effective. They are basically two back to back Zener diodes.
They are cheap, and readily available.
Here's a link:

http://en.wikipedia.org/wiki/Transie...pression_diode

When the voltage is removed from the relay coil
collapsing field magnetic field in the coil develops a counter EMF
voltage. Thus the voltage will soar to a very high level to dissipate the
energy released across the load resistance, which is infinite
since the circuit is now open. (Ohms Law.)

Pete
 
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Old 01-27-08, 04:53 PM
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Originally Posted by radioconnection View Post
10,000 ohms in series with .47 mFd won't
do anything, way too much resistance.
Mighta been 100 ohms ... I forget easily !

Some quick calcs tell me that .47 is around 5.6K reactance at 60 Hz, and I would guess that you would probably want the resistor to be about 10% of that, so .47 in series with 470 ohm 1/2W carbon comp should do the job nicely. Polyester film type for the capacitor.

I do think it's worth some investigation ...

"QuenchArc" is another brand I've seen, they're blue... I like blue.

Website

When did Sprague become SBE ?

I'm not crazy about Transzorbs ... hit 'em hard enough and they short right out. They act more as a 'clamp' device anyway... I don't think they would do much to reduce arcing at contacts. I'll stick with the more 'passive' components.
 
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Old 01-27-08, 06:47 PM
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There shouldn't be enough energy in a 24VAC relay circuit to damage a MOV or other device. MOVs are spec'ed for transient suppression.

In my cause all three zone valve switches are paralleled and go the Tekmar, which I assume uses opto-isolators for the inputs. I may add a RC suppressor, since I do want to have a plug in relay that will take over and replace the Tekmar should it fail in the dead of winter That relay will run the burner off the high limit, and the circulators on a heat call.

Peter

Pete
 
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