Aquastat not working in auto

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Old 10-06-08, 08:15 AM
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Aquastat not working in auto

Hi everyone,

I'm new to the forum. I found this site trying to research a boiler problem I'm having, and I hope to gain some insight. I'm stumped. I looked at PAGREGG's recent topic and it's sort of similar, but I'm not seeing a clear answer from it. Oh, there is no domestic hot water coil, it's heat only.

I have a natural gas fired boiler. I figured out I needed a thermopile generator, which I installed myself..yeah! I also installed a new Honewell programmable thermostat, which seems to work well. Anyhow, I have three zone heat and each thermostat calls for heat perfectly, the zone valves open on demand and the boiler responds, no problem - in manual mode. I tested it yesterday and was happy with the results. I then turned off all the thermostats and took my kids for a hike. I get back about three hours later to find out the the boiler has been cycling the whole time keeping the water in the boiler hot, I don't want this. I did some research and found the aquastat should be on AUTO mode so the boiler only turns on when heat is demaded from a thermostat (I think this is correct). So, I switch it to auto and test a thermostat. The zone valve opens, the circulator kicks on, but the boiler will not fire. It just circulates forever. The main gas valve does not respond at all. I waited and waited until the water running through the pipes eventually turned cold....and nothing.

Sorry for the long message. Any help with this would be wonderful. I really want to learn and be able to fix this myself if at all possible. What additional information can I supply?

Thanks in advance for replies.
 
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Old 10-06-08, 11:18 AM
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BTW, the Aquastat is a Honeywell L8048B.
 
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Old 10-06-08, 04:35 PM
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Hi Squid, welcome to the forums...

What additional information can I supply?
Tell us the make model of the boiler.

Is there a typo on the aquastat number ? Please double check.
 
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Old 10-06-08, 07:00 PM
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Thanks Trooper.

It's an old American Standard boiler - probably when the house was built in the late 60's.
Boiler# is GPM-6
Series# 1BSE-J1
http://************/view.php?pic=2exvar8&s=4

The "can" on top had a small drip leak that was discovered a few weeks ago, thus the rust on the floor. I fixed that and looked through everything. All looks ok, except for this issue. No water got to the stat at all. I pulled all the burners and cleaned everything. Barely anything to clean.


The Aquastat # is correct. Honeywell L8048B 1131 2 120V 60 cycle. There are two sets of contacts. As you can see, the bottom two are a little dicey, but it still moves in an out.

http://************/view.php?pic=5e8g40&s=4
 
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Old 10-06-08, 07:30 PM
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Originally Posted by squidster View Post
Thanks Trooper.

It's an old American Standard boiler - probably when the house was built in the late 60's.
Boiler# is GPM-6
Series# 1BSE-J1
Shoot, that ain't old, you wanna' see an old American Standard? And it's still running to this day.

http://www.dynamicefi.com/~al/OilBoiler.html

On the site I mentioned from the '60s. I'll bet it is really from the late '50s...

Still running a vintage EH-6 burner. With what I can tell the original parts: x-former, pump, motor, etc. They don't make 'em like they used too. Can't go wrong when it fires up day in an day out. Even better when it's -10 outside. Who wants to lose heat then?

However, there is a Carlin 100 CRD lined up for install. Should bump the efficency a few percentage points. And reduce soot. But that "New Arco Flame" will be around to take it's place if the 'C' burner doesn't fire up some cold night...

Al.

{edit: almost forgot about your issue. See if there is an Auto/Manual switch someplace on a control. Seems gas setups have this to be able to run the system without a call for heat.}
 
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Old 10-06-08, 08:10 PM
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I'm assuming that when you replaced the powerpile, you didn't touch any of the wiring in the aquastat ?

If that is a safe assumption, then I believe it's also safe to say that one of the sets of contacts on the relay is not 'making'.

Do you own a multimeter and know how to use the OHMS scale ?

I'll tell you this now, the L8148J is a direct replacement for your aquastat.

You may be able to clean the contacts on that relay... DON'T USE SANDPAPER! If you want to try, I'll tellya how, but first let me know about the multimeter...

By the way, that ground wire that's draped over the screw bracket for the cover... that is no longer up to code as a means to ground appliances... it might have been good for the dead men from the last century, but it should be improved. Also, that plastic "romex" wire isn't acceptable either. It should be type MC , like the other one with the metal armor on it.


Would it be possible to get a clearer, higher resolution picture of the aquastat ? (see if your camera has a 'macro' setting)
 
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Old 10-07-08, 06:17 AM
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Originally Posted by OldBoiler View Post
Shoot, that ain't old, you wanna' see an old American Standard? And it's still running to this day.

http://www.dynamicefi.com/~al/OilBoiler.html

On the site I mentioned from the '60s. I'll bet it is really from the late '50s...

Still running a vintage EH-6 burner. With what I can tell the original parts: x-former, pump, motor, etc. They don't make 'em like they used too. Can't go wrong when it fires up day in an day out. Even better when it's -10 outside. Who wants to lose heat then?

However, there is a Carlin 100 CRD lined up for install. Should bump the efficency a few percentage points. And reduce soot. But that "New Arco Flame" will be around to take it's place if the 'C' burner doesn't fire up some cold night...

Al.

{edit: almost forgot about your issue. See if there is an Auto/Manual switch someplace on a control. Seems gas setups have this to be able to run the system without a call for heat.}


HA HA! I used to have one of those in an old row house I lived in when I was going to college. Nothing more than a 1/4" thick steel drum with fire brick in it. Oil fired, gravity system. It was circa 1940. Never failed.
 
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Old 10-07-08, 06:32 AM
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Originally Posted by NJ Trooper View Post
I'm assuming that when you replaced the powerpile, you didn't touch any of the wiring in the aquastat ?

If that is a safe assumption, then I believe it's also safe to say that one of the sets of contacts on the relay is not 'making'.

Do you own a multimeter and know how to use the OHMS scale ?

I'll tell you this now, the L8148J is a direct replacement for your aquastat.

You may be able to clean the contacts on that relay... DON'T USE SANDPAPER! If you want to try, I'll tellya how, but first let me know about the multimeter...

By the way, that ground wire that's draped over the screw bracket for the cover... that is no longer up to code as a means to ground appliances... it might have been good for the dead men from the last century, but it should be improved. Also, that plastic "romex" wire isn't acceptable either. It should be type MC , like the other one with the metal armor on it.


Would it be possible to get a clearer, higher resolution picture of the aquastat ? (see if your camera has a 'macro' setting)

I didn't touch the aquastat wiring at all. When I installed the thermopile generator I did forget which wire went under which screw, ie, the red an white. I may have them switched/reversed, but I figured it's just a switch and it didn't matter really. Or does it?

Yes, I have a multimeter and I know how to use it, no problem.

I was skeptical about the wiring (old), but figured, hey!, it's worked for 40 plus years, right?.....

I'll get some BX an replace the feed and ground it properly as well. Thanks for reinforcing me to do the right thing.

I'll get a better picture this afternoon for you.

Question. If everything works in manual mode, save the constant cycling, would the contacts be in play? Just trying to learn something. That bottom set ought to be cleaned up, for sure.


Here's another piece of the puzzle...maybe, maybe not. The new thermostat I installed is a Honeywell programmable RTH230B. I looked at it again last night and noticed I didn't remove the jumper from Rh to Rc. This is a two wire loop on this particular thermostat, heat only. However, I put the switch on it to the off position and tested the aquastat auto mode on a different thermostat, which controls a separate zone valve altogether. The jumper on the new TT, also being in the off position, shouldn't affect the auto on the stat for a different TT and zone, right?
 
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Old 10-07-08, 09:50 AM
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One more thing that came to mind. I'm pretty sure the aquastat was set to manual last year (I didn't touch it)and I don't recall the boiler "cycleing" on an off every few minutes. I don't know if this is relevant or not.
 
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Old 10-07-08, 05:54 PM
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Question. If everything works in manual mode, save the constant cycling, would the contacts be in play? Just trying to learn something. That bottom set ought to be cleaned up, for sure.
What the auto/manual switch does is 'bypass' the contacts on the relay switch the aquastat. So, the answer is no, those contacts are not in play. It's probably that nasty looking bottom set of contacts that are causing your problem. You can try cleaning them but if they really are that bad, then in the interest of reliability the best bet is to replace the aquastat.

As I said, don't use a file or sandpaper. Unless it appears that someone already has. There is a plating on the contacts that you don't want to remove. Take some rubbing alcohol and dip a piece of heavy 'card stock' paper ... maybe a shirt cardboard, or something like that. With the POWER OFF! put this strip in between the contacts, and with finger pressure push the relay closed and rub back and forth. If they are REALLY cruddy, then go ahead and try a strip of 600 grit paper, but don't expect the contacts to last long after that. You _might_ get another winter out of them though. That contact is not switching much (if any) current, so I don't expect them to be really bad as far as pitting goes. It's possible that the really bad ones are running the circulator pump but are still 'making' contact. So don't just clean the cruddy ones, clean them all. When contacts don't switch much current, they do have a tendency to oxidize and not 'self clean' themselves.

When I see the close-up, I can tell you what to check with your meter...

If that was in manual last year, the boiler would have had to have been cycling ... the only control over the burner with the switch in manual is the 'High Limit' control...
 
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Old 10-07-08, 06:58 PM
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Thanks for the response. I have a feeling I'm looking at a new Stat.

Finally, the picture. When the pic opens click on it and then click on raw image.

http://************/view.php?pic=eijytw&s=4



Best I could do with the camera I have.
 
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Old 10-07-08, 07:47 PM
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Doesn't get much better than that Squidster! Perfect pic...

I think that 6832 on the brown limit switch is a date code, 32nd week of 1968.

Set your meter to the lowest ohms scale ... 200 ohms probably ... or if it's analog, maybe X1 ...

Turn power off to boiler, and disconnect and TAPE the wires that are on B1 and B2 . Don't allow them to touch together or the burner will start even with the power off. You might want to switch the gas valve to the PILOT position if it has one, just to be safe. Otherwise BE CAREFUL!

Understand that when the power is turned back on, there is 120 VAC very close to where you will be working, so again, please be careful !

Turn power back on and have someone turn thermostat up to activate the relay, or use a jumper across the t'stat terminals.

Measure between B1 and B2 with the ohmmeter. You should have near zero ohms ... continuity ... between those terminals with the switch in AUTO. With the switch in MANUAL, you will have continuity between them at all times EXCEPT when the boiler is hot and the HIGH LIMIT (that's the brown switch with the two terminals on top) is open.

I highly doubt that those fried terminals on the bottom of the relay are the burner switches. They are certainly for the circulator. The burner would not fry them like that.

So, try cleaning those relay contacts repeat the test above. Make sure there's no dead spiders stuck between the contacts.

PLEASE BE CAREFUL!

Start shopping for a new aquastat, you may need it. I've had good luck with www.patriot-supply.com ...
 
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Old 10-07-08, 07:53 PM
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One more thang...

That 'can' that was leaking is a float type automatic air vent. The tire cap on top needs to be loose in order for it to do it's job. You probly know this already, but just in case thought I'd mention it.
 
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Old 10-07-08, 09:20 PM
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Yeah, I can never remember the proper name for it. And yes, I have the cap turned out 1 turn.

With the gas valve in the off position (no pilot) I ohmed it out with B1 and B2 disconnected, power on, w/o thermostat and got 0 ohms. When the TT was turned up, still 0 ohms. I repeated the process with the switch in manual and with the meter set at 200 it hung out at 5.9 for about 20 seconds or so then drops off to 0. I would have to shut off the TT and turn it back on to show ohms in manual again. Is it supposed to open the circuit after a short period if the burner doesn't ignite? Sounds like a logical safety measure.

Basically I get 0 ohms when the switch is in auto in any situation.

I guess it's time for a new stat??

Circulator works in auto or manual when the TT is up, so I guess the contacts are ok, even if they look bad, right?
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Last edited by squidster; 10-07-08 at 09:44 PM.
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Old 10-08-08, 04:50 PM
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'ang on a sec mate ... you said ZERO ohms ... do you really mean INFINITE ? NO READING ? OPEN CIRCUIT ?

Zero ohms is what you would get if you touched the meter probes together, short circuit, continuity.

So what you were seeing was an OPEN circuit, correct ?

There is no timer in that aquastat. If you were seeing it go open after a few seconds, that would indicate that the auto/man switch is probably also 'flaky'.

Did you try cleaning the contacts and repeating the test ?

L8148J 1009 at Patriot-Supply $150

Yes, probably time for a new one... 40 years is a good run.

When you install the new one, pay STRICT attention to the fact that for millivoltage gas valves, you MUST remove the TP-Z jumper before installing the a'stat. The J model is used with BOTH millivolt AND 24VAC gas valves, so there will be an extra terminal called B3 . Your valve will wire to B1 and B2 . Leave B3 open, no connection. Everything else is pretty simple wire for wire ... except there is a GROUND screw, and the circulator has it's own terminals, C1 and C2, it won't 'share ' the neutral screw with the incoming line anymore. When you replace it would be a good time to use MC armored cable for the line going in.

One other thing, the new one will come set up for horizontal mounting. Instructions are in the book for converting to vertical which you need.
 
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Old 10-08-08, 07:07 PM
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Correct me if I'm wrong. Ohms is a measure of electrical resistance. My ohmmeter should show continuity if it's a closed loop. If 0 ohms were showing, that would mean an open circuit...no? Again, I'm in learning mode. What I recorded was electrical activity with TT on and off.


When I say 0 ohms, I mean there was absolutely NO activity on my meter. e.g. it showed... "0.L" ...no numbers at all. If I touch the two probes together I get activity, i.e 0.2..0.3 etc. There was absolutely no activity on my meter when the TT was on or off..period. In manual, when I turned on the TT the meter went to 5.9 at 200 ohms for 20-30 seconds, then nothing.

please advise.
 
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Old 10-08-08, 07:55 PM
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Yes, Ohms is a measure of electrical resistance.

ZERO ohms means NO resistance, or a SHORT CIRCUIT, or CONTINUITY.

If there is NO activity on the meter, the resistance is INFINITE. or EXTREMELY high.

When you short the probes on an ohmmeter, you well get a very low, nearly zero ohms.

When the leads are hanging in the air, you will get no reading, or infinite, or OPEN circuit.

O.L. on the meter means 'OverLoad' which on a digital meter means INFINITE or OPEN CIRCUIT. If it were an analog meter, the needle would not move.

But now I'm confused about something you said...

You said that the meter shows like 5.8 ohms with the switch in manual, WHEN THE TT IS CLOSED. I believe that with the switch in manual, it should not matter at all if the TT is open or closed, because the relay switch is bypassed.

Can you verify that you do NOT read a very low resistance with the switch in manual even if the TT is OPEN ?

Try a higher ohms scale... 2000 ...
 
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Old 10-09-08, 06:28 AM
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Hmmmm. Maybe I better explain a little better. I don't think I was too clear.

The ohm meter shows OL, which means "infinity" on this meter, open circuit, not "overload") when it is turned on with the probes touching nothing. assume the 5.9 I got was probably 590 ohms. I haven't looked at my manual lately.

You said that the meter shows like 5.8 ohms with the switch in manual, WHEN THE TT IS CLOSED. I believe that with the switch in manual, it should not matter at all if the TT is open or closed, because the relay switch is bypassed.
When I said the TT was closed, I meant closed circuit, calling for heat. Sorry I wasn't clear. Yes, I realize the relay switch should be bypassed to run the burner, but when TT called for heat, the relay engaged to run the circulator, that is when I got the reading (when the relay engaged). Also note that I had the pilot OFF with the gas valve knob in the OFF position. I don't know what part, if any the milivolt generator would have played since there was no pilot. The power (120V) was on.

OK, the procedure...

With the power to the boiler ON and the switch in MANUAL I touched the ohmmeter probes to B1 and B2 and nothing registered on the meter, 0 ohms. While holding the probes on
B1 and B2 I had someone turn on the TT. The zone valve began to open and the contacts on the aquastat closed (made a connection) at that point the ohmmeter registered 5.9 on the 200 setting. I assume sending power to the main gas valve to open. This lasted maybe 20 seconds or so and then the ohmmeter dropped to 0. I assume the reading dropped off because the boiler didn't fire. (I had the gas turned off to run the test)

Since the boiler will fire in the manual mode I assume this is what it is supposed to do.

I repeated the exact process with the switch in the AUTO position. I got NO reading (infinity) on the ohmmeter at all times throughout the process. No power was being sent to the main gas valve at any time.

With that said, and barring any change in thought you may have with the aforementioned, I would agree that it's time to change out the a'stat. whew....

I so appreciate all the time and patience you've given. I'll let you know how it works out. I'd like to get it done within the next week.
 

Last edited by squidster; 10-09-08 at 06:53 AM.
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Old 10-15-08, 06:20 PM
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Trooper,

I got the A-stat and have it mounted. You said to remove the TP-Z jumper. There is a jumper, but it is from W to Z. Please tell me if I need to remove this or not.
I don't want to screw this up.
Thanks

Oh, BTW, Patriot supply is tops in my book. I saved soo much $$
 
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Old 10-15-08, 06:35 PM
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A booklet came with the a'stat, correctamundo ? You should in addition to axing here, be sure to read it...

For millivolt gas valves, the W-Z jumper remains in place, the TP-Z is removed. I'm going from MEMORY here, and it's not what it used to be, that's why I recommend double checking with the booklet.

I've been very happy with PS... I ordered some oil nozzles Monday morning, and I received them Tuesday morning ...

They also have an ebay store, and sometimes you can get slightly better pricing there... it's worth checking their own site, AND the ebay store to compare prices. Paul is a good guy ... very helpful ...
 
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Old 10-15-08, 06:53 PM
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Yeah, nevermind. I just looked at it again. They provided a TP-Z jumper, but only for a 24V system. The W-Z jumper already installed should remain. I was a little confused with the wording, but I figured it out.
I live in York, PA suburbs. I got around to ordering it on Tuesday morning and had it today. They are on the ball. I'm still blown away by the savings!


Stay tuned.....
 
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Old 10-15-08, 07:45 PM
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It doesn't work.

I accidentally hooked the thermostar wire to TV and W when it should have been hooked to TV and T. After the test I realized what I did and put the TT wire to TV and T. Still doesn't work.

The zone valve opens, but no circulator and no burner. I triple checked all the wires.

If I manually push in the contacts the burner will fire. No circulator.

Any ideas?
 
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Old 10-15-08, 08:03 PM
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I can put the switch to manual and the boiler will fire, but the circulator will not turn on and the system is cold.
 
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Old 10-15-08, 08:16 PM
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You won't get the circ running with the switch in manual, that's normal.

Lemmee take a look at the PDF for that 'stat and I'll get right back to ya... standby
 
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Old 10-15-08, 08:19 PM
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OK, thanks. Standing by....
 
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Old 10-15-08, 08:24 PM
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Old 10-15-08, 08:29 PM
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When you say 'thermostat wires to TV and W' do you mean the wires coming from the endswitch on the zone valves ?

By putting those wires there, I hate to tell ya this, you may have fried the transformer in the a'stat, or possibly the end switch on the zone valve. If you look at the schematic, you will see that TV and W are across the transformer secondary, and by closing those contacts, you created a short circuit on the transformer.

Here's what to do ... Set your multimeter to AC VOLTS, to measure 24 VAC ... make sure no thermostat is calling for heat, and no zone valves are open... with the power on (BE CAREFUL!) measure from TV to W ... you should see 24 to 28 VAC there. If not, the transformer is toasted... If you DO get 24 VAC there, apply a jumper from TV to T and see if the relay pulls in... it should, because that jumper is doing what the zone valve end switches should be doing.

If the jumper pulls the relay in, disconnect the wires on TV and T... set your multimeter to ohms... and clip onto the disconnected wires. Force a call for heat from each one of your t'stats in turn. Each one should cause continuity on those wires.

I'll hang around for a while if you wanna test now...
 
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Old 10-15-08, 08:35 PM
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Originally Posted by squidster View Post
If I manually push in the contacts the burner will fire. No circulator.
Wait a minnit... pushing in the relay should fire the burner AND run the circulator ... something else going on here... double check the wiring to the circ. After you do the other tests, I want you to set the multimeter to measure 120 VAC and clip on to C1 and C2 and push the relay in by hand ...

Measure the voltage on L1 and L2 ... it sounds as though you may not have power going to the a'stat ... you turned the service switch back on, correct ?

If you didn't have power going to the a'stat, then you may have lucked out with your wiring error ... you may not have caused any damage ...
 
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Old 10-15-08, 08:36 PM
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Damn. I'll check right now....
 
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Old 10-15-08, 08:42 PM
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Ok.

With power on and no TT calling for heat I get no voltage between TV and W.

With a TT calling for heat in AUTO(zone valve open) I get 120V between C1 and C2 when I manually press the contact. The circ does come on, but only when I manually press the contact.

Scratch that. I can get circ with or without TT calling for heat if I push the contact manually.
 
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Old 10-15-08, 08:51 PM
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Do you think this has anything to do with the one new programmable TT I installed? Even if I have it in the off position?

We can work on this more tomorrow if you want. I can stay up now, but maybe it's too late for you. Let me know.
 
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Old 10-15-08, 08:53 PM
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Crap ...

Screws are tight on the Z-W jumper ?

It does sound like the transformer is pooched...

You can use an external transformer on that aquastat.

You must have another transformer running the zone valves, correct ? you can 'rob' 24 VAC from that... or, purchase and install another transformer external to the a'stat...

Connect one side of external transformer secondary (24VAC) to B3, REMOVE Z-W jumper, and connect other side of external transformer secondary to W ...
 
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Old 10-15-08, 08:58 PM
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Originally Posted by squidster View Post
Do you think this has anything to do with the one new programmable TT I installed? Even if I have it in the off position?

We can work on this more tomorrow if you want. I can stay up now, but maybe it's too late for you. Let me know.
No, nothing to do with the new t'stat ...

I'm good for another hour or so ...

Check yer PMs...
 
  #34  
Old 10-15-08, 08:59 PM
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Screws are tight.

A separate 24V transformer is running the Z-valves.

I'll try that.

Sometimes I swear I do the most stupid things.
 
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Old 10-15-08, 09:02 PM
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Ok, hang on. Be right back
 
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Old 10-15-08, 09:04 PM
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Originally Posted by squidster View Post
Sometimes I swear I do the most stupid things.
I bet you can't top my most stupid things !
But, we'll never know cuz I ain't tellin' !
 
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Old 10-15-08, 09:15 PM
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Ha Ha!

Ok, Hold on just a sec..


Whoop, there it is!!


Let me see if I can get the cycle.



Hmmmmm. It's been about 5 minutes or more since I turned off the TT and the circ pump is still on.

Should I jump TP and Z?
 
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Old 10-15-08, 09:33 PM
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NO! You don't wanna fry your gas valve, do ya ?

The circ is still running ? ...

You wired the external 24 VAC to B3 and W ... correct ? and removed the Z-W jumper ?

Disconnect the thermostat wires from TV and T and do the ohmeter check on them. With all the ZVs closed, you should have open circuit there...
 
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Old 10-15-08, 09:37 PM
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Ok, hold on.. Be right back

With 120V off and the external 24V supply still connected, all TT's off. I get a closed circuit between TV and T. It is not an open circuit.
 
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Old 10-15-08, 09:49 PM
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Crap...

That means that there's also something happened to the endswitch in one or more of the zone valves.

What kind of zone valves ? You don't have any locked in manual open, do ya ?

You are checking the WIRES right ? not the terminals on the a'stat...

A little explain...

When a t'stat calls for heat, it operates the zone valve motor. There's an 'end switch' in the zv that then closes the circuit and operates the a'stat.

So, IF you are checking the wires, and all the valves are closed and not calling for heat and you are seeing continuity on those wires, that means that one of the endswitches is 'welded' shut ...

Leave the wires disconnected, turn the power back on, and apply a jumper to TV and T on the a'stat. This will prove that at least that part is working if the relay closes and the circ runs and the the burner fires (if the water in the boiler is cool enough, below high limit).
 
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