aquastat wired incorrectly?

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Old 12-20-08, 06:36 PM
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aquastat wired incorrectly?

First off, thank you for all of the valuable information members have added to this forum. I'm a first-time homebuyer with zero experience with boilers. This site has allowed me diagnose and fix a pressure problem (expander), and I've learned quite a bit about aquastats and their low, high and differential settings, warm and cold start setups, etc, which brings me to my question - I hope someone can help.

I have a Peerless oil boiler model WBV-03, a TriangleTube Phase III a hot water heater, a Honeywell 8124A aquastat, and RA89A relay. I believe my controls are wired incorrectly. Here's why...

Correct me if Iím wrong, but everything I've read on this website suggests that with my type of setup, the high limit on the aquastat is used when there is a call for heat, and the low setting and differential is used to set the hot water heater temperature. So, if I have the high limit set at 180, and there is a call for heat, the boiler should heat to 180 degrees and turn off. And if my low setting is 120, and while there is no call for heat, the boiler will keep warm based on my low limit and differential setting so that I have hot water on demand.

I have two circulators Ė the one to heat the house is wired to the RA89A relay which is also connected to my thermostat upstairs. When there is a call for heat, the relay clicks, and the circulator does its thing, but the boiler does not kick on if the water temperature is below the aquastatís high limit because I do not see the RA89A relay connected to the aquastat in any way.

The second circulator (for the water heater) and the water heater's thermostat is what's connected to the aquastat's thermometer and circulator connectors.

I'm I correct in thinking that this is wired incorrectly?

Iíve posted some pictures if it helps.

Iíve examined the schematics for the 8124A, but it shows it working with a R845A relay. Is there a way to connect my existing RA89A relay so that I could utilize my high limit setting? I have to admit - Iím not very good at schematics, so I can't figure out how to wire this system properly. Am I using the wrong aquastat for the application? If not, could someone please explain what gets connected to what?


Thank you-

Gerry








 
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Old 12-20-08, 07:26 PM
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Gerry, to do this properly you need the R845 relay. The R89A relay won't be used.

The R845 has two of relays. One relay will be wired to run the circulator. The other relay will be wired to signal the L8124 triple aquastat. This is done with the ZR & ZC terminals of the L8124.

Here is a link to the pdf:

http://customer.honeywell.com/honeyw...m?form=60-2061

Figure 11 shows how it is done.

Your Fig 19 that you posted shows the same thing. Since that diagram also shows the internal workings it is more confusing to look at (at least for me).

But you are correct. Your system isn't wired correctly.

Al.
 
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Old 12-20-08, 07:40 PM
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thanks, Al.

Just to be sure, does the water heater get connected via the R845, or should it remain connected to the L8124A?

Thanks again,

Gerry
 
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Old 12-20-08, 07:46 PM
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It could be wired either way. Since it is already on the triple I would just leave it that way.

Al.
 
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Old 12-20-08, 07:49 PM
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thanks again.

BTW, I was cleaning the equipment (we refinished the basement) and I was pleasantly suprised to find a temperature control on the top of the Phase-III water heater! Sweet.
 
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Old 12-20-08, 08:03 PM
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To add a little, is it possible that the heat emitters are designed for a lower temperature? I believe that some radiant systems are setup for low water temperatures, below that of the high limit. Just a thought of why it may be the way it is.

You mentioned in the first post that the L8124 would operate differently with a call for DHW vs a call for heat. I don't believe that this is true. If I understand the internal wiring correctly, it doesn't matter if the call comes in on the TT terminals or the ZC/ZR terminals. The DHW tank temperature is controlled by the thermostat (aquastat) on it.

Al.

{edit: OK, you found the control on the DHW tank. That's what controls when the DHW circulator runs to heat up the tank. Note that if the boiler water temperature is too low the circ's will be turned off. The L8124 triple is a difficult aquastat to understand. }
 
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Old 12-20-08, 08:27 PM
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Hi Al,

I'm not really sure what at what temperature the emitters are designed for. When I moved here a few months ago, the hi/low was set at 200/180. I've lowered it since. They are brand-new Slant/Fin baseboards. Are you suggesting I leave things as-is? I'm confused.

In reviewing my first post, my stating that the L8124 would operate differently with a call for DHW vs a call for heat was only my understaning of how it works - not how it's working now. If there is a call for heat, the R89A turns on the circulator and nothing else. If the water temp drops below the low limit minus differential, the L8124 fires up the boiler, but the high setting is ignored... and runs until the low limit plus differential is reached.

Wouldn't it be more efficient if the system was set up to use the high limit for heat and low limit for hot water?
 
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Old 12-20-08, 08:33 PM
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I agree something is all messed up ...

One thing that jumped at me; there is a GREEN WIRE on terminal C1 ... that's just plain wrong. NEVER should a GREEN wire be used as a HOT wire. GREEN is ALWAYS GROUND. This is how accidents happen and ppl get hurt/killed by grabbing a wire that's supposed to be ground and it turns out to be hot.

The R8845U is a replacement for the R845 and is a bit less $$.

Stranded wires should never be shoved under a terminal screw without using a lug. Not that I see any on your wiring, but neither should stranded wires ever be tinned with solder and used under a screw terminal.

Without being able to trace out the wiring, it's difficult to say just how it should be wired... but there's enough there to know it ain't right.

I don't understand why there's a 'triple' aquastat at all... there's no reason to run that boiler as a warm start with the indirect.
 
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Old 12-20-08, 08:41 PM
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Me, I'd 'rip it out' and start over ...

L7224U aquastat, Taco SR 503 relay panel .
 
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Old 12-20-08, 08:48 PM
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Originally Posted by debtman3535 View Post
Hi Al,
...
Wouldn't it be more efficient if the system was set up to use the high limit for heat and low limit for hot water?
The reason it isn't done that way is that a high water temperature is required to heat the DHW within a decent time frame. If the boiler temperature is low the DHW will take too long to recover. Other then that, yes, holding the boiler at a lower temperature is more efficient.

NJ, I too noticed the stranded wire under the screw terminal. I figured being on LI it was already a plus that BX was used

Al.
 
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Old 12-20-08, 09:14 PM
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Gerry, here are two links that explain how the triple aquastat works. At first it seems to defy logic, but once understood how it works, then you will know that it does defy logic:

http://www.firedragonent.com/triple.pdf
Column - Plumbing and Mechanical

You could lower the LO setting quite a bit. Having it maintain the water at 150 is a little on the high side. However, it really comes down to how quickly the DHW needs to recover. The previous owners may have been using a lot of hot water for some reason or another.

I previously mentioned the water temperature for heat. The Slant fin basebase is most likely fin-tube. Which will typically run up to 180* F. So in retrospect, the previous use of the RA89A relay doesn't make sense.

Al.
 
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Old 12-20-08, 09:49 PM
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Al, with the way that thing is wired, in that the space heating thermostat doesn't fire the boiler... the space heating relies on the temp in the boiler being maintained at a high enough level to heat the home. It's bass-ackwards... so lowering that LOW setting is going to reduce the water temp into the space heating circuit, and possibly present flue gas condensation issues.

The DHW will fire up to high limit as it's currently wired.

No amount of fiddling with the settings can correct this... it must be re-wired with the proper controls.
 
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Old 12-20-08, 10:08 PM
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Thanks guys.

I knew the wiring was messed up!

I'm not sure what to do... I really donít want to make this a cold-start because I'm afraid I'll have water on the floor - it's happened to me already... I woke up one morning to no hot water... the filter needed changing so the boiler wasn't getting enough fuel and wouldnít' fire up.


I read the links Al provided and have a better understanding of how my aquastat works, but high limits still have me confused... it appears that they should only be used with tankless coil setups and not my own. Yes?

What if I drew up a diagram of how everything is wired and posted it... would that help? If so, I'll do it tomorrow.

Thanks again -

Gerry
 
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Old 12-20-08, 10:12 PM
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Originally Posted by NJ Trooper View Post

The DHW will fire up to high limit as it's currently wired.
...that's not happening now. The boiler only fires until the low limit + diff is reached.
 
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Old 12-21-08, 09:00 AM
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Originally Posted by debtman3535 View Post
...that's not happening now. The boiler only fires until the low limit + diff is reached.
If you've got the ID aquastat wired to the TT terminals, it would fire up to the high limit as long as the ID called for heat long enough.

I suspect that what you are seeing is the ID call being satisfied before the boiler hits high limit and shutting down.

With the settings that you have shown in the pic, the LOW limit will fire the boiler up to (160-10)+23 ... or 173 ... which is darn close to the high limit anyway.

That 'formula' is how the LL works... there is a FIXED -10 differential at all times. If you set the Low setting to 160, the boiler will cool to 150 before firing up ... the ADJUSTABLE DIFF setting is added to the FIXED setting... so the boiler will cycle ON at 150, and OFF at 150 + 23 ... or:

(LOW SETPOINT - FIXED DIFF) + ADJUSTABLE DIFF

As long as the 8124 is functional, and your boiler does not like going cold start, I would replace both relays with the SR502 and keep the 8124 ... and all will be well. One of the advantage of using the 502 is that the indirect can be set up for priority. Then, set the LOW on the 8124 to the minimum (which should be warm enough to keep it from leaking), and the diff at 10.

The heat calls will allow the boiler to fire to High limit, as will the indirect calls.

Where DOES that green wire on C1 go ? really, that creeps me out.

=============

pod, I moved your questions to a new thread...
 
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Old 12-21-08, 10:02 AM
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Originally Posted by NJ Trooper View Post
Al, with the way that thing is wired, in that the space heating thermostat doesn't fire the boiler... the space heating relies on the temp in the boiler being maintained at a high enough level to heat the home. It's bass-ackwards... so lowering that LOW setting is going to reduce the water temp into the space heating circuit, and possibly present flue gas condensation issues.

The DHW will fire up to high limit as it's currently wired.

No amount of fiddling with the settings can correct this... it must be re-wired with the proper controls.
NJ, if the wiring/controls are not changed then I agree. However, once the RA89 is replaced with the R845 (or similar) the setup will then work correctly.

At this point the LO limit can be lowered. The reason it is currently set high is that it is wired/controlled incorrectly. Correct the wiring/controls and then turn down the LO setting.

I was thinking that we all agreed that the current wiring/controls is incorrect and will be changed. The next step is to get the controls set properly.

Al.
 
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Old 12-21-08, 10:26 AM
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Thanks, guys.

NJTrooper - you were correct in stating that the call was satisfied prior to hitting the high limit... I cranked up the water temp a bit on the indirect and the boiler kicked on and met the hi limit.

I'll take a look now to see where that green wire is going and report back shortly.

Thanks.
 
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Old 12-21-08, 10:57 AM
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ok... I checked out that green wire. It's spliced into a black wire using a wire nut, which runs up to the circulator for the water heater.

The other circulator is wired the same way at the RA89A.

Instead of connecting both of the wires belonging to each of the circulators to the relays, whoever wired this, wire-nutted all of the live wires together, and only ran the circulator's ground wires to the aquastat/relay.

Is this ok?

Also, do the circulators run in the correct direction regardless of how they are wired..? I ask becuase from the schematic it appears that it doesn't matter which way the circulators are wired to the relays. It just says "C1" and "C2". So either wire can be connected to either C1 or C2, yes?

So it's agreed that I need to replace my RA89A relay and rewire?

NJTrooper- you suggested replacing both relays with the SR502 as long as the 8124 is working... I only have one relay though. Was that a typo?

And just to verify, the water heater should be connected to a SR502 and the boiler to the 8124, and wired as per figure 11 on http://customer.honeywell.com/techli...0s/60-2061.pdf , yes?


Thanks a bunch guys...
 
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Old 12-21-08, 12:51 PM
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I had your setup confused with another which had two relays.

You could certainly replace the 89 with an 8845 ... or a Taco 501.

I would re-wire so that the heating circulator is being run from the 8124, and the indirect circ running on the replaced relay.

I would not use the ZR/ZC terminals.

Wire the indirect circ to the new 8845. Wire the Red and White wires from the indirect to the T T terminals on the new relay. Wire the existing thermostat to the T T terminals on the 8124 in PARALLEL with wires coming from the extra set of contacts on the 8845 ... I'll try to find some time to draw a schematic later...

On that aquastat, the L2, B2, and C2 terminals are all connected internally. They are all NEUTRAL and NOT switched through the relay. The HOT terminals are L1, B1, C1. B1 and C1 are SWITCHED hots...

It is possible to make the neutral connections to the burner and the circulator outside of the aquastat, and only run the B1 and C1 switched HOT to the burner and/or circulator, and I suspect this is what was done.

The circs will not run 'backward' if you reverse the connections, but if the terminals are labeled H and N or wires are BLACK and WHITE, those conventions should be followed.
 
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Old 12-21-08, 01:04 PM
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OK, there WAS a reason I recommended using the TACO panel, or two separate relays.

That reason was because you don't need to 'hold off' either circulator during a Low limit call ... either or both circulators should be able to run freely when there is either an indirect call, or a heat call. The only reason the circs are held off on a triple a'stat is so that the boiler can give full duty to keeping the boiler hot when there is an internal tankless coil. Your system has no tankless, and the only reason you keep it hot is because you say it leaks when it cools. You don't need, or even want the 'circulator control' feature of the 8124.

I'm going back to my recommendation of the Taco SR502/503 (very similar to each other... not sure why Taco markets them under separate numbers).



SR502 at Patriot Supply - $105
 

Last edited by NJT; 12-21-08 at 01:53 PM.
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Old 12-21-08, 08:00 PM
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wow.. thank you very much for the schematic. That'll make things pretty easy.

I'll pick up the relay but I'm going to wait till after Christmas to do this... I'll post when complete.

I never expected this type of help.... I thank you both for all of your time and recommendations - and Happy Holdidays to you and yours.

Gerry
 
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Old 12-21-08, 08:54 PM
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Great... let us know how it works out for ya.

After you get the relay installed, turn the low setting all the way down, and leave the high at 180. Set the diff to 10-15 or so, and watch your fuel consumption go down... you'll probably save enough fuel in 1 season (maybe less) to pay for the relay box.

Happy Holidays!
 
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