Water Heater Zone Problem

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Old 08-10-10, 09:50 AM
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Water Heater Zone Problem

Set up: Weil-Mclean oil fired boiler
4 zone hydronic system
1 of the zones is to a Bock 50CT Turbostor indirect water heater

Problem: water heater zone won't come on. Replaced zone valve, but I don't think that was the problem. Valve moves to the "open" position, but boiler won't come on.

Aquastat problem?

Help!!!
 
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Old 08-10-10, 10:22 AM
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I should also mention:

The motor on the zone valve seems very hot - to the point you can't really touch it. I know little to nothing about zone valves...is this normal?

Also - this is not my first zone valve problem. This past winter, one of my other zones began acting up. Appeared the zone valve was sticking "open". Replaced the zone valve, and that zone appears to be operating correctly (so far).

Any ideas would be greatly appreciated. Thanx!
 
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Old 08-10-10, 10:54 AM
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Sorry to keep adding posts to this...but as I do more research, I come up with more questions.

To Trooper & Furd: In another thread, you talked a little about end switches - and I think that may be where my problem lies, since I can see the valve opening...but nothing happens after that (boiler doesn't fire and circulator doesn't start).

But I've already replaced the ZV head. Could the motor getting so hot be screwing up the end switch?

I forgot to mention - ZV is a Honeywell V8043E1061 - newer style).

Thanx again!
 
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Old 08-10-10, 12:53 PM
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Troubleshoot with a voltmeter. The end switch should be closing when the valve is opened. That should complete the 24-V circuit to the circulator relay. If the switch is closing, then find out why 24V isn't getting to the pump relay.
 
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Old 08-10-10, 04:13 PM
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All the ZVs the same model?

Are all the red wires from the valves wired in parallel and then back to the aquastat on the boiler? or, is there a 'zone control panel' involved?

Since you obviously aren't heating your home, you might not know if the heating zones are working or not... might wanna check that, cuz it could change the troubleshooting direction.

Lastly, are you sure that the switch for the boiler hasn't accidentally been turned off ?

Do you own and know how to use a multimeter?
 
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Old 08-10-10, 04:56 PM
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Thanx to both of you for the quick response!

I've got a multimeter, but not sure where inside the ZV head to test - or do I just check across the 2 red wires?

Trooper - you make an excellent point - and one I've been dreading to test. All the ZV's are the same, and all red wires tie in to 1 wire to the aquastat (no zone control panel that I can see). So I better get this worked out while it's 90 degrees out, not 20 degrees!

(I hate to assume)...but let's assume the end switch is closing. What's next "down the line" for me to check...and how do I check it? Should I see 24v at the aquastat when the ZV opens/end switch closes?

Funny you mention the boiler switch..thus far, the only way I've been able to get the boiler to kick on is:

1. Turn off the boiler switch.
2. Move the lever on the bottom of the ZV to "manual open" and lock it there.
3. Turn boiler switch back on (ZV unlocks but stays open) - and pray the boiler kicks on.

Usually takes 5 or 6 tries with this before it will kick on. Also I noticed if I wait 20 mins or so before turning the switch back on, it'll work (sometimes). Also, this "fix" only lasts a few days - then quits working.

Arh...
 
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Old 08-10-10, 09:27 PM
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First, make sure the multimeter is set up to read 24 volts AC.

Please be careful, there is 120 VAC exposed inside the aquastat! To be safe, don't touch anything inside!
Make sure power is off to the boiler before doing anything inside the aquastat!

Is your aquastat an 8148A model? (Honeywell)

If you put the meter across the red wires, you should see 24 VAC (might be as high as 28 or so) when the zone is CLOSED. When the zone OPENS the valve, the voltage should drop to ZERO.

You can make this measurement at the aquastat terminals that will probably be labeled T T . This is where the 'endswitches' wire to.

When the zone valve is OPEN, the endswitch is CLOSED, and vice versa. When the endswitch is CLOSED you should read ZERO volts, and when the endswitch is OPEN you should read 24VAC.

Another thing that you can do is this:

Remove the wires from the T T terminals on the aquastat. If you place a jumper wire across those T T terminals, the boiler should fire up, and the circ should run. Don't leave it like this for long as the circulator will be pumping into closed valves... no water will be flowing...

I'm guessing here, but my feeling is that the aquastat is at fault... either dirty contacts on the relay, or a cracked solder joint on the pc board. By putting a jumper across the TT terminals at the aquastat, you will be able to isolate the problem to the valves or the aquastat. If the boiler fires every time with a jumper on TT, the valves are at fault, and vice versa... this will at least get you in the area of the problem.
 
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Old 08-11-10, 05:59 AM
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Trooper - I'm leaning towards the aquastat as well. Since I put in a new ZV head, I can't believe both old & new would have bad end switches.

I got it working yesterday, using my "quick-fix" method. When I get home tonite, I'll check the T T terminals and see what I get (with valve OPEN and CLOSED). Also, I'm gonna crank up one of my other zones and test it then as well. As you mentioned, this may also help me determine whether it's isolated to the WH zone, or the aquastat.

Although it's working today, I'm sure it'll quit in a day or two...that's when I really want to test it.

I'll let ya know.

Thanx for all your help!
 
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Old 08-11-10, 07:31 AM
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Hi Wally, yes, do keep us posted...

I can't believe both old & new would have bad end switches.
Part of being a good troubleshooter is to not make assumptions based on 'beliefs'. Even though you are 'probably' correct, I know that you will do the tests to ascertain the facts.

Also, 99% of troubleshooting is 'visual'. Take a bright flashlight, and carefully inspect the contacts on the relay in the aquastat. If you see pitted and burnt contacts, you will have probably found the problem.

You can also try the 'tap test'. When the unit is malfunctioning, gently tap around the area of the relay on the aquastat. If you have a cracked solder joint where the relay mounts to the board, the tap test should show this.
 
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Old 08-12-10, 08:05 AM
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Unfortunately, I didn't get to work on this much last night. Had a few other emergencies that needed attention, and the system seemed to be working - so it took a back seat.

I did however do some more studying of the 8148A aquastat and V8043E ZV schematics - and I think I have a better understanding of how this works. Let me know if this is right:

1. Line voltage (120V) comes in to aquastat, and is stepped down to 24V which is sent up to ZV.

2. When ZV opens, end switch closes completing 24V circuit, which pulls relay in aquastat sending 120V to boiler & circulator.

Is that basically correct?

Presuming it is, I disconnected the red wires at the ZV, opened the valve (which should close the end switch) and checked resistance across the wires. If the end switch is indeed closed, I should show a short across the wires. Nope, nothin'. I think this is telling me the end switch is still open.

Also, let me throw this out...as I mentioned in an earlier post, the motor on the ZV head gets really, really hot. It seems if I turn off the emergency switch, lock the ZV lever in "MANUAL OPEN" - then wait for approx 30 mins - and turn the emergency switch back on...it will fire up.

Is it possible the motor is getting so hot that it's screwing up the end switch? And letting it "cool down" is making it "all betta"? Hmmmm.....
 
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Old 08-12-10, 08:12 AM
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Not sure why I haven't mentioned this yet - we just built the house in 05 - so the system is only 5 years old.

Trooper - I thoroughly checked the aquatstat - no signs of any cracked solders or any other abnormalities.

It quit working again overnite, and this morning I "tapped" on everything (including my noggin') - nuthin.

Argh....
 
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Old 08-12-10, 04:36 PM
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Is that basically correct?
Yes.

One thing you didn't explicitly state, but think you understand, is that the power for the MOTORS in the ZVs does NOT come from the 8148. The endswitch circuit and the motor circuit are totally isolated from each other. There ARE aquastats that have a big enough transformer to power a few ZV motors, but not yours. (in fact, there is no way with an 8148 to even tap into it's 24 VAC circuit to do so)

The motor circuit is powered by another transformer which you should see somewhere nearby, probably mounted on a 4x4 junction box. If you can find this transformer, as a quick check on it's health, measure the voltage with none of the ZV open, and again with at least one open (and since it's the water heater valve motor that gets hot, that would seem to be the one to use) You should see 24-25 VAC nominal... maybe a little higher, and little difference between loaded and unloaded.

Presuming it is, I disconnected the red wires at the ZV, opened the valve (which should close the end switch) and checked resistance across the wires. If the end switch is indeed closed, I should show a short across the wires. Nope, nothin'. I think this is telling me the end switch is still open.
My old brain is fuzzy, but as I recall, MANUALLY opening an 8043 valve will NOT close the endswitch. ( someone please correct me if that's wrong! ) ... so if you did that test by manually opening, the results may be bogus, and try it again by letting the motor open the valve. It's an excellent test, and you are correct that the red wires should show a short when the valve is opened by the motor.

Let's talk about the ZV motor being hot... they do run warm, but they shouldn't be so hot that you can't touch them... The endswitch shouldn't be affected by the heat of the motor... I say 'shouldn't' but anything is possible I suppose.

Those motors are powered all the time the valve is open, and of course there is a spring return to close them again. What they are NOT designed for is 100% 'duty cycle'. They are intended to open for a time, then close, and cool off before opening again. If the water heater aquastat is calling for heat, and the valve opens but the boiler doesn't fire, the valve will stay open with the motor powered. If this is like eight hours while the family is out of the house during the day, or overnight, then I should think the motor would eventually fry itself. This is probably what you are seeing (feeling!)
 
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Old 08-12-10, 04:36 PM
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Well some good news...I think. Tonite I cranked up the 1st floor thermostat, and the circulator & burner kicked on right on queue. Also, the voltage at the THERMOSTAT terminals inside the aquastat dropped to 0 as I believe it's supposed to.

With this, I'm beginning to lean back towards the end switch, and as I mentioned in my last post, I'm really starting to think it has something to do with the ZV motor getting so hot. If I let it cool down...it seems to work (for a while).

Not sure if it's necessary, but I created a photobucket file with some pics. Hopefully, it's attached here:Water Heater Probs pictures by mattw107 - Photobucket
 
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Old 08-12-10, 05:00 PM
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Hey Trooper! As I was typing my above post, your's came through - LOL!

I understood about the ZV motor being on a separate circuit - but I now also understand what the 2nd transformer bolted to the side of the boiler is for (you're good - you answered my question before I could even ask it! - see my pics)

And I believe you are correct - manually opening the valve does NOT close the end switch. If I get a chance, I'm going to hang my meter on the red wires of another ZV, crank up the thermostat and let the motor open the valve - and see if it shorts...but that's for another day.

Back to the hot motor issue. With all that we've said, let me throw this goofy scenario by you:

1. Water heater thermostat sends a call for heat to the ZV.

2. All operates normal - ZV opens, end switch closes, circulator & burner fire, hot water is delivered, family is happy.

3. After cycling - circulator/burner shut off...BUT...thermostat CONTINUES to call for heat. Circulator/burner cycle again - maybe another cycle or 2.

4. Thermostat continues to send CONSTANT call for heat - until the ZV power head gets too hot and end switch fails.

5. End switch is inoperative until Wally shuts power off for 30-40 minutes, allowing power head to cool, and end switch to work again.

My point is: could the water heater thermostat be sending a constant call for heat?
 
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Old 08-12-10, 05:04 PM
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Yup, the pics attachment worked fine. They're a little dark for my old eyebones to see, but what I can see looks like a decent install.

I believe that transformer on the side of the boiler would be the one that powers the zone valve motor circuit.

This is one of those cases where you wind up chasing 'ghosts' around... you replaced the ZV head with a new one, and it still don't work ... yet, it's a 'new' head! "It CAN'T be that" ... yet it appears that it CAN!

Swap the water heater head with one of the others and see what happens...
 
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Old 08-12-10, 05:13 PM
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My point is: could the water heater thermostat be sending a constant call for heat?
Sure... but let's play with the scenario a bit more:

Water heater calls, boiler fires... water in boiler hits the HIGH LIMIT setting in the aquastat (180 ? ) and the BURNER shuts down, but the CIRCULATOR continues to run.

Let's say that the water heater is not yet 'satisfied', but there is still hot boiler water pumping through the coil inside...

Boiler water cools to the HIGH LIMIT minus it's 'differential' (usually 10-15) and the burner fires again, reheating the boiler water.

I guess what I'm saying is that what you are seeing with the cycling of the boiler _might_ be normal operation. That the boiler is operating off it's high limit setting in it's aquastat, and the domestic water in the heater hasn't yet hit it's setting.

Easy enough to check with the meter though... put the meter on the two wires coming from the water heater thermostat (actually an aquastat) and monitor those to see if it ever gets satisfied.

One weak possibility is that if the ZV motor is getting that hot after an extended ON period, it might be frying itself and not able to 'hold' the valve fully open...
 
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Old 08-12-10, 05:16 PM
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A bit more:

One way to verify the above scenario would be to see if the circulator is still running when the burner cycles off, and if the temp on the boiler gauge is at or near the setting of the high limit in the 8148.
 
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Old 08-12-10, 05:45 PM
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Sorry 'bout the pics - all I had handy was my cell phone.

Anyway - just ran downstairs to check the HIGH LIMIT setting: 190.

I don't actually know for a fact that the circulator/burner keep cycling. I was just assuming that's what would happen if the water heater aquastat was sending a constant call for heat (right?)

In my scenario, I was looking for something that would cause the ZV motor to heat up (to the point you can NOT touch it). Similar to what you mentioned in an earlier post, a constant call for heat at the motor ("100% duty cycle"). This seemed the most probable.

What voltage should I see at the water heater aquastat?
 
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Old 08-12-10, 08:49 PM
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What voltage should I see at the water heater aquastat?
Very close to what the transformer on the side of the boiler is reading... 24VAC nominal.

I was just assuming that's what would happen if the water heater aquastat was sending a constant call for heat (right?)
Yes... if the endswitch were working, the BURNER would cycle as the water bounced off the high limit, but the CIRC would keep on circ'ing. It is worth checking out.

If it were the case though, I would think that at the times when the boiler WAS firing properly, that you would notice your domestic water was VERY hot ?
 
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Old 08-13-10, 07:39 AM
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Originally Posted by NJ Trooper View Post
Yes... if the endswitch were working, the BURNER would cycle as the water bounced off the high limit, but the CIRC would keep on circ'ing. It is worth checking out.

If it were the case though, I would think that at the times when the boiler WAS firing properly, that you would notice your domestic water was VERY hot ?
Yup...I see what you're saying. This is indeed a very elusive ghost.

I honestly don't know if the domestic water is getting VERY hot. When it feels too hot, I just mix in a little cold till it's comfortable. Suppose I could get a pyrex bowl and a candy thermometer and check it. Hmmmm....

For what it's worth:

- the water heater aquastat is a L4080B. Just occured to me...I've never checked to see what it's set at. Will do so tonite.

- everything has been working fine since I "fixed" it yesterday morning at 6:30am. Had a nice hot shower this morning - so 24 hours so far.

- ZV motor is cool to the touch when everything is working. As soon as I notice non-hot water from the tap, the first thing I check is the motor, and it's always hot. It was on the motor before I changed it - and on the replacement. The ghost is living in this hot motor.

I suppose my next step would be to get a beer and portable TV, and camp in basement for a while - to see if the CIRC is running past the boiler, and see if the water heater starts calling continuously...i.e. try to catch the ghost in action.
 
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Old 08-13-10, 03:38 PM
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By the time you notice lukewarm water, chances are good that the water heater has been calling for some extended period of time, and that could explain the hot ZV motor...

Do you know if there is a 'tempering valve' on the domestic hot out of the water heater? If there is, that would normally be set to a safe 120, and the water heater would be set to something like 140. If you have no tempering valve, then the safe setting on the water heater is 120, especially if there are elderly or young living in the home.

I always advocate a tempering valve (which most local building codes require these days) because it allows you to run the water heater hot enough to kill bacteria such as legionella, and yet provide safety against scalding burns by tempering the water to the home. This also has the benefit of 'extending' the hot water... since you will be mixing some cold, you won't draw down the tank as quickly.

try to catch the ghost in action.
Film it... send it in to SyFy channel... make sure you use those creepy infrared lights that make everyone look like demons from he77 !
 
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Old 08-14-10, 07:37 AM
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Water heater aquastat is set at 140. Not sure about a tempering valve - don't think I saw one - where exactly would it be?

System quit working yesterday sometime during the day (while I was at work). I got home, went downstairs, motor was blazing hot (as usual). Just for giggles - I checked the 2 terminals at the WH aquastat: 0VAC - which I believe means it's calling. Right?

It took 2 "fix" cycles (power off - cool down - power up) for it to light.

After it lit - I sat through 3 consecutive burner cycles - all appeared normal. CIRC did not run past boiler. I left my meter on the WH aquastat terminals...never saw anything (which I believe means it was calling continuously - right?). I had to leave after the 3 cycles - don't know how many more it went through.

Crapped out again sometime overnite (and of course motor is hot again).

Originally Posted by NJ Trooper View Post
By the time you notice lukewarm water, chances are good that the water heater has been calling for some extended period of time, and that could explain the hot ZV motor...
Exactly. So why is the water heater calling for an extended period of time? It will often quit overnight - while (obviously) no hot water is being used. I would think at some point, the water heater would STOP calling.

Questions:

1. At the WH aquastat - should I see 0VAC when it's calling, and 24VAC when it's not calling?

2. In general, how many burner cycles should it take to heat up 50 gals. of water (to 140)?
 
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Old 08-14-10, 08:19 AM
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The tempering valve would be located near the hot domestic outlet of the WH, and the cold line would be connected to one side... it might look like this:


photo courtesy Hot Water Heaters Reviews and Water Heating

This one is thermostatically controlled, most of the newer ones are, but there are 'manual' versions as well, and they look pretty much the same, sorta...

I checked the 2 terminals at the WH aquastat: 0VAC - which I believe means it's calling. Right?
Yes, you would see the same 'action' at the WH aquastat as you see on the ZV endswitches.

At that point, you should have checked the endswitch. If the WH was calling the ZV to open, and the motor was hot, but the ZV endswitch was not 'making', then the ZV is definitely the problem child.

So why is the water heater calling for an extended period of time?
Because the endswitch isn't making, and the boiler isn't firing, and the WH doesn't know any better than to stay on the line and wait.

I would think at some point, the water heater would STOP calling.
Yes, it would, but only when the water in the tank got hot enough to meet it's setpoint. If the tank cools overnight (it might, even without HW being drawn), and calls for heat, and the ZV opens but the endswitch doesn't make, the WH will just call and call... there's no 'timeout'... so the ZV will just stay open and the motor will get hotter and hotter... etc.

1. At the WH aquastat - should I see 0VAC when it's calling, and 24VAC when it's not calling?
Yes, see above, same as endswitch.

2. In general, how many burner cycles should it take to heat up 50 gals. of water (to 140)?
Ummmm... it depends... on a lot of things... if everything is working properly, and the boiler is firing when it should, as it should, the water in the tank won't be completely cool when it fires, and it might take only one cycle to 'recover' from a hot water draw. If the tank is real cool because the boiler didn't fire, it might take a couple cycles to recover.
 
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Old 08-14-10, 11:25 AM
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Ref the tempering valve - no gots. I've followed that pipe up out of the water heater - nothing that looks remotely like that. Oh well.

I'm thinking more and more that this is a water heater aquastat problem - sending a continous call for heat.

Thinking more about last night:

System hadn't been working since sometime in the afternoon - let's say noon.

I got home at 5:00. ZV motor is hot. WH aquastat terminals = 0VAC (calling for heat). Water in boiler 80 deg.

I do my "fix" routine and burner fires - obviously endswitch is making. Boiler water goes to 190 and burner stops. Boiler water drops to 180 and burner fires again - does this 3 consecutive cycles - 3 cycles took approx 15 mins (I'm guessing). No hot water was used during this time. 0VAC at aquastat this whole time (continuous call). Endswitch obviously still making during this time ('cause burner keeps coming on). Unfortunately, I had to leave.

I'm thinking the aquastat keeps calling (even though 3 burner cycles should have heated the water enough).

Poor defenseless endswitch works as long as it can and keeps cycling the burner - until the constant call overheats the ZV motor, causing the endswitch to finally fail...burner stops firing.

If the aquastat was working, it would stop calling...I would think...after 3 burner cycles and no use of hot water.

Also - the endswitch appears to work fine WHEN the motor is allowed to cool.

Also also - this new ZV powerhead is acting EXACTLY the same as the original powerhead (hot motor) when I replaced it. I can't believe BOTH would have the same abnormality - and I don't wanna drop $100 on another one. It's got to be something else in the process. WH aquastat is the only logical suspect.

Yes, Regis, that's my final answer...I think.
 

Last edited by Wally107; 08-14-10 at 12:21 PM.
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Old 08-14-10, 12:46 PM
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Hey Trooper - while I have a spare moment, I gotta tell ya...thank you, thank you, THANK YOU. I don't think you Moderators hear it enough.

Funny story: Last week, our dryer stopped working. Push the button - nuthin. Spent a few hours on a similar DIY appliance forum, and learned it was probably a thermal fuse and thermostat. Got the parts at my local appliance shop ($40) - 15 minutes behind the dryer - badda bing - dryer works like new. Saved $100 on a service call and family thinks I'm a hero.

This hot water mess started about 3 weeks ago, and although I consider myself fairly handy around the house - I stood and stared at my boiler and didn't think I'd ever figure it out.

Now, thanks to you, I have a pretty firm grasp on how this segment of my homes mechanical infrastructure works. Although we haven't figured it out yet...it's certainly not due to a lack of understanding.

Can't wait till the next party, and I can talk about my "zone valve powerhead endswitch"...I'll be the coolest dude there!

So, again, hopefully this internet thing will catch on, and you Moderators will continue to disguise us wannabees with your wisdom. Thanx.
 
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Old 08-14-10, 06:30 PM
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Well, it quit working again today - probably sometime late afternoon 'cause there were at least 3 showers taken today and some dishes washed - I'm just now using the last of the hot 50 gals.

I found a L4080B aquastat on ebay for $50 - thinking about grabbing it.

But before that - would there be any investigative value in pulling off the one on there, and looking at the sensing probe and inside of the well? Maybe something funky is going on in there.

To pull it off, do I just loosen the set screw on the side?
 
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Old 08-14-10, 07:33 PM
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In my endless thirst for knowledge - I just minaturized myself, and climbed inside the ZV powerhead (actually, I took apart the old one which I kept). I now understand how the motor/endswitch relationship works.

The motor has a VERY small, round brass gear near the bottom. That gear meshes with a somewhat larger, halfmoon brass gear. The larger gear has a small lever (or flat thingy) on the upper end.

When the motor is energized (along with opening the valve) it turns the small gear, which in turn rotates the larger gear moving the lever (or flat thingy) on the end up against the endswitch (which fires the boiler).

I contorted myself in enough to look into that side (right side) of the powerhead. I turned on the power and watched the gears move. The lever rotated up towards the endswitch...but stopped about a hairs width before touching it.

With a thin flat blade screwdriver, I gently rotated it onto the switch - and the burner fired. Interesting. The endswitch itself is fine...but for some reason the gears aren't rotating quite far enough. I wonder if the motor getting so hot is warping the metal - or maybe the plastic gear bushings - enough to cause this.

The thick plottens...
 
  #28  
Old 08-14-10, 09:36 PM
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Breakthrough

OK...I may have stumbled on to something in my last post. I just came up from 3 hours in the basement. Here's what happened tonight.

(All of the following is just after I "nudged" the flat lever thinginy up on to the endswitch - in my last post)

I must have finally got enough hot water in the tank, because it finally was satisfied (24VAC at the aquastat) - yahooo!

Leaving the meter connected, I turned on 2 faucet taps running hot water. After about 10 minutes, aquastat called for heat (dropped to 0VAC). Burner kicked on - yahooo! I quickly closed those taps.

After 3 burner cycles, aquastat satisfied (24 VAC). Burner was off at this moment.

Watched boiler water drop to 160, just to make sure it didn't fire again on it's own aquastat.

All was quiet. I came upstairs to type this.

So...here's my new theory:

Water heater aquastat is NOT defective - appears to be working properly.

When it calls for heat - ZV motor opens *HOWEVER* thanks to the halfmoon gear inside not rotating far enough to depress the endswitch, nothing happens.

And since nothing happens, aquastat keep calling (causing motor to get hot).

My quick "fixes" were nothing more than sheer luck - after powering on-off enough times, it finally rotates that gear the little extra nanocintilla of a micrometer it needed to depress the endswitch.

Possible fix - depending on your knowledge of the inner workings of the 8043:

Unscrew and slide the motor (with small gear attached) out, just enough to rotate the halfmoon gear up 1 tooth. Then slide the motor back in.

This would ensure that it rotates up far enough to firmly depress the endswitch, possibly giving it that 1 extra burner cycle to satisfy the water heater.

Your thoughts?
 
  #29  
Old 08-14-10, 09:43 PM
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It's not impossible that you got a 'bad' one. Was it an ebay special? or did you pick it up at a supply house? What if... some unscrupulous character replaced the bad head on his system, and returned his bad valve in the new box to the same supply house you bought yours?

Maybe you can give that lever a 'tweak' and bend it enough that it operates the switch reliably?

I wouldn't be surprised if it took 3 or more burner cycles to bring the tank up to temp from 80. Let's see... 1 BTU to bring 1 pound of water up 1 degree... 8 pounds to a gallon... times 50 gallons... 400 pounds of water... from 80 to 140... that's 60 degrees... so 400 times 60 is 24000 BTU... let's say your boiler is 100K BTUH... that's 15 minutes of BURNER time... assuming 100% efficient... maybe it's 80% or so (probably less)... so what, maybe 20 minutes of burner run time? That's BURNER time, not counting when the circ is running but the burner has cut out on high limit.

Can't wait till the next party, and I can talk about my "zone valve powerhead endswitch"...I'll be the coolest dude there!
Too bad yer already married... your new vocabulary is one helluva chick magnet!

I don't think the problem is the WH a'stat, and I think now that you've 'gotten small', you agree. The ZV has to pass the signal through to the boiler, and it's not doing that. I guess the heat could be a contributing factor, but it wouldn't be getting hot if it wasn't powered up for so long waiting for the boiler to fire... circular logic...

The statement below is true.
The statement above is false.

Don't get caught in the trap. If the WH a'stat is calling, but the endswitch isn't making, the problem is in the ZV head.

So, SWAP THE HEAD with one of the heating zone heads and see what happens.

If you don't have a tempering valve, think about adding one at some point in the future. Not a bad thing to have. And, while you are at it, I'm willing to bet that your WH does not have a 'heat trap' set up on the hot outlet pipe either... see:

http://www.comfort-calc.net/Indirect_Piping.html

This will prevent the hot water from 'floating' up out of the WH when no hot water is being drawn.
 
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Old 08-15-10, 07:25 AM
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Was it an ebay special? or did you pick it up at a supply house?
Both original and replacement were from supply house. I'm still a little concerned they both had the exact same problem.

I don't think the problem is the WH a'stat, and I think now that you've 'gotten small', you agree....circular logic...Don't get caught in the trap. If the WH a'stat is calling, but the endswitch isn't making, the problem is in the ZV head.
In my defense - 2 heads having the exact same issue, plus the several posts I've read about problems with the L4080 - it was a reasonable suspect. Honestly, if I didn't see it actually working properly last night, I'd still suspect it. Lesson learned.

So, SWAP THE HEAD with one of the heating zone heads and see what happens.
Finally have a couple of days off - I'll give it a try.

If you don't have a tempering valve, think about adding one at some point in the future. Not a bad thing to have. And, while you are at it, I'm willing to bet that your WH does not have a 'heat trap' set up on the hot outlet pipe either
I've never sweat a pipe in my life, so I'll leave this to a qualified professional - let me know next time you'll be in upstate NY, Poughkeepsie area
 
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Old 08-15-10, 08:29 AM
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One thing to keep in the back of your mind is the possibility of TWO individual problems... maybe even three...

1. Bad zone valve... caused by the heat generated by #2 causing the motor to weaken and possibly warp the mechanism.

2. Intermittently sticking WH a'stat.

3. Defective VALVE portion of the ZV...

We haven't considered the last. What if:

The valve portion is bad, and somehow preventing the motor from FULLY opening the valve, and that is what is intermittently holding the motor back from contacting the endswitch ?
 
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Old 08-15-10, 10:38 AM
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The valve portion is bad, and somehow preventing the motor from FULLY opening the valve, and that is what is intermittently holding the motor back from contacting the endswitch?
I thought about this too, as I watched the gear rotate up and then stop before contacting the endswitch. If we use as a reference a 360 deg circle, it probably needs to rotate another 1 or 2 deg to make contact. I wonder how much flow restriction it would be causing (?).

I suppose this would explain:

1. 2 heads acting the exact same way, and...

2. 3 burner cycles to satisfy WH a'stat that just started calling and should be fairly hot. I thought 1 should have been sufficient - unless the incoming flow is restricted.

I suppose putting one of the other powerheads on may shed some light on this.

I suppose the good news is, when I bought the replacement, I didn't know I could get just the powerhead, and I bought an entire 8043 - so I have a brand new valve sitting in the box. Just need to have someone come over and swap it out. Can't believe it's too difficult a job.
 

Last edited by Wally107; 08-15-10 at 12:39 PM.
  #33  
Old 08-16-10, 12:23 PM
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Zone valve

I used to run across this same problem fairly often. My repair is a pair of needle nose pliers. I bend the tab enough to make good contact with the micro switch and call it done. Sometimes the gears strip and in those cases I'd replace the head.
 
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Old 08-16-10, 03:56 PM
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That would be my approach too HP... I'm thinkin' that Wally is having too much fun learning stuff to take the easy approach though!

Maybe you can give that lever a 'tweak' and bend it enough that it operates the switch reliably?
 
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Old 08-16-10, 07:16 PM
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Trooper - you're right. I absolutely LOVE learning how things work. And if the knowledge I gain saves me a buck or two - all the better!

Well, today I pulled off the WH head, and the 1st floor head, with the plan of swapping them (as we discussed).

When I got the WH head off, I decided to check the valve, to see if it was "sticky" or just to see if it turned OK. I'm not sure how easy it's supposed to be, I wasn't able to turn it with my fingers - but it did turn fairly easy with a pair of pliers, and it seems to rotate fully from OPEN to CLOSED. Just for the heck of it, and since I had the head off anyway, I compared it to the 1st floor valve - seemed pretty much the same. So I suppose that tells me the valve is working properly (although who knows what the rubber ball is doing inside).

But then I noticed (and this will be tough to explain) that, when the valve is closed, the "flats" of the stem are roughly horizontal (let's say 9:30 and 3:30 position). However, looking into the opening in the back of the head - unenergized and in the closed position - the flats are more like 10:30 and 4:30 position. I decided to put it back on, probably more carefully than I did the first time.

As I slid it on, I made sure the stem was going in, lined up with the flats inside the head. This had the head "cocked" a little "counterclockwise". Once I was sure the stem was seating, I carefully rotated the head (clockwise) until it was in line with the valve. This rotating moved the lever a little closer to the endswitch (encouraging).

I flipped the power on, and watched the lever rotate. This time it firmly depressed the switch - no doubt.

I let the system run till the aquastat was satisfied (took 4 burner cycles).

I think I'll leave it alone, and see if it craps out again. If it does, that'll tell me that - for some reason - the motor is over-rotating to the closed position.

If that happens, I'll try to bend the lever. After looking at it closely, I'm not sure how easy that is...but if HP says it can be done, I'll give it a try.
 
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Old 08-17-10, 06:24 AM
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ZV lever

The lever bends fairly easily which led me to the theory I have, that over time and thousands of open/close cycles, the lever bends from those thousands of contact cycles to the point that it no longer makes sufficient contact to close the switch.

In my area of service over the past 40 years the Honeywell valves are among the most commonly installed so I've had ample opportunity to study the cycle of operation. I have 3 on my own system and have one that tends to stick open occasionally. Too cheap to replace it.
 
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Old 08-21-10, 11:36 AM
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Any new developments Wally ?
 
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Old 08-26-10, 09:17 AM
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Hey Trooper - sorry I disappeared for a few days.

I'm afraid to claim victory yet, but all appears to be working fine. I can only guess that re-installing the powerhead did the trick.

It's still odd why the original head stopped working...but at this point, I'm not asking questions.

Again, thanx! to you and the others that helped out...couldn't have done it without ya!

My next project is to replace the anode rod. From everything I've read, 5 years is a good time to at least take a look at it. Our water here is notoriosly crappy, so I think I'll give it a try.
 
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Old 08-26-10, 08:53 PM
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We'll keep our fingers crossed... from what you described, it sounds as though the head wasn't 'indexed' with the valve...

Don't try to get that anode rod out with anything but a good snug fitting socket and a long breaker bar. If you bugger up the points by slipping a wrench on it you will have a problem.

Check your overhead clearance too... you may not have enough headroom to pull the rod out. If you are going to install a new one anyway, you can just bend to old one. You can buy what they call 'segmented' anode rods that will allow you to bend them a little to get them into the heater.

I've got nasty water here too, but getting a new well drilled in a couple weeks down to 220' that should get me good water... how I'm gonna pay for it is another matter...

but I digress...
 
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Old 09-07-10, 05:52 AM
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I'm baaaaack....

Not sure what I did in a previous life, but it must have been really bad. No hot water yesterday...groan.

As usual, powerhead motor was hot - must have been calling all day. And the lever was almost touching the endswitch - but not quite.

I wonder if the valve stem is "rounding out" the double-D hole in the motor...hmmmm. And if so, I wonder if a few wraps of electrical tape around the stem will provide a more "snug" fit...hmmmm.

Will also investigate bending the lever (on the extra powerhead), see if that works.
 
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