premature zone valve motor failures?


  #1  
Old 01-01-05, 11:29 AM
jdad
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hydrotherm and zone valve problems

I have a new Hydrotherm EW145 boiler which replaced a 21 yrold Hydrotherm.
I have two serious problems. The Honeywell L8148E Aquastat will not open the circulator when a call is made from the thermostat. I can hear the aquastat click on but I have to manually close the contacts before the regulator will start and allow the rollover switch to fire the burners. The second problem is with the Honeywell zone valves. They will not open when in the auto position. The only way to circulate water through the pipes is to have both valves set to manual open. The system heats both zones fine and shuts down when the temp reaches the thermostat setting. I wonder if the two problems are related. Do I need to buy new zone valves for the Aquastat to function properly? I have replaced the thermostats. All I can say is I'm glad we are having such a mild winter here in alaska!!
 
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Old 02-28-05, 02:48 PM
ripple
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This may be a little late in responding but the two problems you state are definitely related. I just ran into a similar problem with my honeywell zone valves and aquastat L8148E. The one difference being that my zone valves opened on a call for heat but the aquastat did the same thing, it clicked on then off immediately. After the plumber I called searched for two hours he finally discovered the problem.

What happens is after the zone valve completely opens, it activates a mechanical switch that turns on the boiler via the thermostat terminals of the aquastat. In my case the zone valve motor opened the valve but did not have enough torque to actually activate the switch. If you try shorting the two output leads/terminals of the zone valve that get wired to the aquastat together, the boiler should come on and stay on without holding the relay contact lever. In my case, the fix was to replace the zone valve motor. The plumber charged a whopping $400 for this service, when you have no heat on a Sunday you are at their mercy. The motor can be purchased for between $20 and $45, and can be replaced in 5 minutes. I ordered two to have on hand for the next time.
 
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Old 02-28-05, 04:35 PM
ripple
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premature zone valve motor failures?

I have a 2 year old Crown Aruba gas fired furnace with 2 zones of hot water baseboard heat. The system uses a Honeywell aquastat L8148E with Honeywell zone valves. This weekend the system failed to provide heat and the problem was isolated to the zone valve motor, both of them!! It is possible that the upstairs one failed earlier but we never noticed. In both cases, the motor opens the valve but doesn't activate the boiler. It's possible that the upstairs got heat when the downstairs zone came on until the downstairs motor failed. Replacing the downstairs motor corrected the problem but I'm not convinced this is the root cause.

My question is why this premature failure. Could it be related to pressure in the system. The pressure is 20 lbs even though the extrol 30 expansion tank is precharged to 12 lbs. It's been like that since day one and never thought anything of it. Could this extra pressure cause any problems and does it need to be corrected? Can I do this myself?

I've read in other posts about a heat anticipator setting on the thermostat being set to .9 otherwise the zone valve motor could burn out. I use a LUX programmable thermostat and there is no such setting, only a gas/electric jumper. There is also a three jumper block to select 24hr/12hr, C/F, and S/R on/off. The first two are obvious, the third, I have no idea but it's set for S/R off. This thermostat worked fine with my old oil fired furnace and works fine with the new one, except for this issue.

Is two years considered premature for these motors or should I expect to replace them every few years?

Thanks is advance
 
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Old 02-28-05, 05:30 PM
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Zone valves

I recently encountered a similar problem except instead of the motor, the problem was with the micro switch in the zone valve power head. Usually these micro switches are held in place with screws & can be adjusted slightly. Sometimes though, the switches are riveted in place & you have to replace the whole power head. Still it is an easy DIY job.
 
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Old 02-28-05, 05:31 PM
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If the valve was open, the motor was not bad. The end switch could have failed but that is doubtful too. I would check and recheck the wiring on the end switch. The anticipator has little effect for a Honeywell valve. It is only crucially important for a Taco zone valve. The system pressure is fine too so leave that alone. Those valves should last much longer than 2 years. Honeywell had some motor problems but it was almost 10 years ago and they got it fixed and I have not seen motor failures since.

Ken
 
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Old 02-28-05, 05:47 PM
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When you said NEW I am thinking that wiring is wrong. There is probably a 24 volt wiring problem that prevents the zone valve from opening. If this boiler is that new, maybe the installer will correct the problem. I would like to know exactly what contacts you need to close to activate the heat. If the relay in the 8148 closes, there should be circulator and burner operation based on water temperature. Please clarify those details and maybe we can narrow down the problem. Also you might comment on whether the system is brand new and if it ever worked properly since installation.

Ken
 
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Old 02-28-05, 05:48 PM
ripple
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but the new motor seemed to correct the problem

What do you make of the fact that replacing the motor corrected the problem? Is it possible that the new motor has just enough additional torque to trip the switch and the motor fix is temporary? Do I have to remove the head assembly to get to the switch adjustment?
 
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Old 02-28-05, 05:54 PM
ripple
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But why did both valves fail? It seems that it is marginal as grady suggested that the switch might be slightly misaligned. I will investigate further and report back. I am a little leary though since one valve is working properly right now with the new motor and I don't want to break it. The other hasn't had the motor replaced yet so I will try to fiddle with it to see if I can make it work with the old motor.
 
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Old 02-28-05, 06:02 PM
ripple
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We have two threads discussing the same problem. I will continue the discussion here. The system is two years old. We measured the transformer voltage at 26 VAC so it should be OK. We verified the wiring to the thermostats and that looked good. The correct zone valve opens when the each thermostat calls for heat, it just that neither switch closes to activate the boiler. If i manually trip the relay in the aquastat, every the boiler and circulator cycle normally. The system has worked fine for the past two years until this problem showed up.
 
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Old 02-28-05, 06:02 PM
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That is a good question. If you changed only the motor and not the whole head, I don't have an answer for you. The motors actually turn until they reach the point where they can't turn any further and then they stall and sit there until the call for heat is over. Maybe the new one did have more torque. Most of the Honeywell valves I use do not have end switches but there operation is pretty straight forward. I tend to think Grady is onto something with the placement of the switch. I currently don't charge $350 for a weekend call but those H2s look pretty cool. Maybe I'll change my rates and get me one.

Ken
 
  #11  
Old 02-28-05, 06:09 PM
ripple
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When I protested the charge after the work was done, the home office said their standard fee for a zone valve motor replacement was $395 plus $30 extra for the weekend call. I had a feeling I was getting ripped off but how do you know when you can't get an estimate until you know what's wrong and then surprise?

BTW. This thread is discussing the same problem as here, so let's continue over there.

http://forum.doityourself.com/showth...657#post732657

I will look at the microswitch later this evening as see if anything can be done with it.

Thanks for all the input.
 
  #12  
Old 02-28-05, 07:21 PM
ripple
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It appears to be the microswitch

The one that is still bad is actually intermittent. When the valve is open, sometimes it activates, sometimes it doesn't. The switch is held in with two torx screws. It does appear that the paddle that contacts it could come in on a slight angle if not just right. I tried aligning it so paddle contacts is square to the switch surface but I couldn't find a sweet spot that worked reliable. If I apply additional pressure to the back of the paddle while the switch is engaged, it does come on. This might explain why the new motor worked. It seems like both these valves had marginal switches and as the motors aged the defect became apparent. I would expect the switch to activate when the first click is heard. This is not the case with either, they don't activate until the switch is nearly bottomed out.

Can the switches be replaced by themselves? They seem fairly easy to remove or do I have to replace the entire head assembly?

How is the head assembly removed? I loosened the two screws but it remained attached at the valve shaft. How is the head separated from the valve shart?

Thanks again.
 
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Old 02-28-05, 07:37 PM
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All you need to do to remove the head besides what you already did is to put the lever in the manual open position. Then the head will lift right off. The switch is not replacable to my knowledge. It has only been a few years that the motors were available separately.

Ken
 
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Old 02-28-05, 07:40 PM
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Ripple

Just because the transformer was putting out 26 VAC does not always mean full power is getting to & thru the valves. There is current loss thru all of the wiring. It is possible you are experiencing enough loss to not have enough left to close the relay. I have seen this happen more than once when the thermostat wire was too small. It should be 18 AWG with as few splices as possible. This is pure speculation & I doubt it is the case. Another possibility is maybe the motor was just weak & would not complete it's full travel arc. When using zone valves, I prefer to power them thru a separate transformer of at least 40 VA & use the transformer in the aquastat only thru the end switches.
 
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Old 02-28-05, 07:45 PM
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It sounds like it may be time to start comparing date codes on these heads. It is always nice to know the trends before the manufacturers actually admit that they have a problem.

Ken
 
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Old 02-28-05, 08:22 PM
ripple
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both zone valves are F8-9946

Interesting since the system was installed in 2002. I got three year old zone valves. The zone valves do use an independent 40 VA transformer. I applied the 24 volts from the transformer directly to the zone valve with the same result, thus eliminating the wiring from the equation. The "weak" motor was the original theory but it does in fact travel all the way to be nearly flush with the switch case which should be more than enough travel to close it. The switch doesn't actually close until it is exactly flush with it's case. It seems ridiculous for this to be by design, hence the switch must be faulty. Both switches are very similar but the one that works activates slightly higher than the other.

I was able to remove the head by placing the valve in manual and "firmly" pulling on it. I guess I'll need to spend an additional $140 ($70 for each head) to really correct the problem. At least the plumber got me to the right component. I wouldn't have been able to really resolve it without you guys though.

Thank you very much.
 
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Old 02-28-05, 08:43 PM
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Micro switches

I have replaced micro switches in the past but I can't remember where I got them. You might want to try an electronics store.
I just found some for an Erie zone valve which uses the same motor as Honeywell & maybe other parts too? The switch is an Erie # 630-202 & Sid Harvey # B163-52. Maybe your plumber can order them for you if you want to gamble it will interchange with a Honeywell. My guess is that it will.
 
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Old 02-28-05, 08:44 PM
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Honeywell zone valves have been known to stick and motors to fail. Sometimes its better to replace them with a Taco if your having problems. I replaced more Honeywell motors than I did Taco powerheads this winter and Taco out numbers Honeywell here 10 to 1
 
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Old 02-28-05, 09:09 PM
ripple
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temporary fix

I applied a small piece of self adhesive rubber to the paddle that contacts the switch and now it activates every time. This should hold me over as I search for the replacement switch option. Thanks again Grady and Ken.

Al, I agree that the honeywell design seems a little flawed. Do I have to open the system to replace with a Taco or will a Taco powerhead mount on a Honeywell valve? Somehow I doubt it. If the Honeywell gives me further trouble, I may consider your suggestion.
 
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Old 02-28-05, 09:10 PM
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Honeywell vs Taco

Personally, I much prefer the Honeywell but that's a chocolate & vanilla thing. Yes, I do replace more Honeywell motors than Taco but I've never had to replace a whole valve because it was leaking or seized. Problably one of those local things.
 
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Old 02-28-05, 09:21 PM
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Thumbs up Ripple

Originally Posted by ripple
I applied a small piece of self adhesive rubber to the paddle that contacts the switch and now it activates every time. This should hold me over as I search for the replacement switch option. Thanks again Grady and Ken.

Al, I agree that the honeywell design seems a little flawed. Do I have to open the system to replace with a Taco or will a Taco powerhead mount on a Honeywell valve? Somehow I doubt it. If the Honeywell gives me further trouble, I may consider your suggestion.
Now there's a man after my own heart. A little ingenuity can go a long way.

To answer your question to Al: Yes you do have to open the system, and re-wire everything. The Taco is a whole different animal. I have not seen Taco's ESP series valve but it sounds similar to the Honeywell.
 
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Old 02-28-05, 09:31 PM
ripple
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Wow it seems you can get just about every individual part for an Erie valve. I found the part number you suggested here.

http://www.webshop1.com/merchant.mv?...ZoneValveParts

These guys seem to carry everything!! And their prices are good too. The have the powerhead for about $53 when everyone else is $70~$80.

Now a little more research to see if this is the same switch.
 
  #23  
Old 03-01-05, 03:17 PM
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Originally Posted by Grady
Now there's a man after my own heart. A little ingenuity can go a long way.

To answer your question to Al: Yes you do have to open the system, and re-wire everything. The Taco is a whole different animal. I have not seen Taco's ESP series valve but it sounds similar to the Honeywell.
You dont want to see the taco esp valve. I installed 4 in one house during a boiler replacement and it was a nightmare. There is something wrong with the heads. They kept telling me the problem was fixxed just replace the heads again. After the 4th time I cut them out and used the origional type. Of course this was all done under warrenty. I will never buy another one of those.
 
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Old 03-01-05, 03:43 PM
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Erie is the way to go as far as zone valves are concerned.

Grady you have never changed a seized zone valve?
 
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Old 03-01-05, 05:18 PM
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Zone valves.

Originally Posted by LoveBoatCaptain
Erie is the way to go as far as zone valves are concerned.

Grady you have never changed a seized zone valve?
Not a Honeywell. Loads of Taco's. Woops, I did have one seized Honeywell. It was the OLD butterfly type probably close to 50 years old. Rather than change it (a real pain) I rebuilt it in the pipe. That's been at least 10 years ago & it's still working. I've never used the Erie "Pop Top" zone valves but the local distributor quit carrying them because of a lot of trouble & warranty returns. What kind of trouble? I don't know but they only handled them for a couple of years.
 
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Old 03-14-05, 05:21 AM
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I'm probably a little late with ths post, but from my experience with the honeywell zone valves are the micro switches. These are cheap push button switches to replace. I don't think its a motor torq problem that keeps the switch from activating. I think it's the heat from the water that kills these switches. I have replaced two micro switches on my zone valves in 6 years on my boiler.

These zone valves have to be installed on the return side of the heating circuit and even then they are still prone to heat. If they set your aquastat jumper to run the boiler on the high low limiters? The thermostat calls the zone valve, the motor opens the valve and energizes the switch which is wired into the circulator circuit relay, in turn calls the circulator. Once the water temp drops in the boiler the low limit triggers the boiler to fire. Once the high limit is met, the boiler shuts down until the low limit kicks it back in. Once the room thermostat temp is met, it shuts down and kills the zone valve motor voltage. The spring in the valve assembly closes the valve and opens the micro switch killing the circulator.

Anyway these switches can be order from Grainger @ couple bucks apiece. they call them snap action switches. They come in N/O (normally open) and N/C (normally closed)so make sure you order the right switch. The wring diagram on the zone valve cover tells you or it's on the switch itself
 

Last edited by B D; 03-14-05 at 06:38 AM.
 

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