Repairing R8182D Aquastat

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Old 11-01-13, 01:08 PM
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Repairing R8182D Aquastat

I have 3 of these units and would love to get a working unit. Can anyone help diagnose where the issue is. Should I de solder every component and test individualy. I need help and heat
Thanks, Bruce
 
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Old 11-01-13, 01:19 PM
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Can I bench test the units. The unit I have installed right now is older then the 8182. It only has the high limit control and the board is much more simple. I have a 8182 that had a wire soldered in for connection. Maybe that would be a good one to start with. I just want a simple aquastat that works. I do not need the low limit which in my opinion starts to make this unit very complicated. I realize that the photo cell can not be umped out because of a past issue. Some kind of electronic do hicky that needs to be toggled on and off to work. I do not have a true understanding of electronics but want to learn.
Have been reading on this forum and see that the thermostat should have 24 volts at it. Is this correct I thought that the thermostat was just a switch and you where closing a circuit
Would appreciate help and knowledge
Bruce
 
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Old 11-01-13, 01:28 PM
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Welcome to the forums.

You have to power unit up and check the transformer(s).
Check the relays for good coils and contacts that aren't pitted or corroded.
Check all solder connections.
The parts that will be hard to check are the aquastat section and the fire eye sections

You may be fighting a losing battle.
 
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Old 11-01-13, 01:39 PM
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That why I was thinking of desoldering because everything is so tight and my brain also starts to freak out but I want to master this. The thing I find weird with the unit in place now is i pulled in the contacts last night to call for heat and sometimes the circulator would run others the burner and circulator would run. I thoiught there was one relay for circulator and other for heater.

Which tabs do I check on the transformer
 
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Old 11-01-13, 01:47 PM
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De-soldering is risky. You end up applying too much heat and you can EASILY damage components and the pc board itself. No, not advised.

Can you read and understand schematic diagram? That's the place to start.

Do you know the functions and properties of the various components? Another good jumping in point.
 
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Old 11-01-13, 02:05 PM
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If you could walk me through it i would be thrilled.

I understand that the coils reduce the voltage to energize the relays that move 120 volts through them. I wish my brain could comprehend how the voltage is going through the board and coil/relay.

I forget the name I believe diode allows the voltage to flow one direction needs to be shutdown and then can allow to flow.

I can not figure out how to isolate individual circuits to trace that everything is working in that circuit.

I understand the basics of the heating system in that the thermostat calls for heat [and then] based on the temperature of the water the circulator will run or the BURNER comes on to run the furnace.

Not sure what is going on in the high and low limit segment. can we bypass that just to make sure the other components are working
Thanks
 

Last edited by NJT; 11-01-13 at 04:02 PM.
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Old 11-01-13, 02:27 PM
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Looking for the paperwork now that comes with the unit. I believe the schematics are in there. One of my problems is my add takes over and my brain starts thinking about the thermostat curcuit when I m looking at the furnace relay as an example. If you could tell me do you see this this should be the reading there ect I could do this. For example I just looked at the coil why are there 6 pins soldered?
 
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Old 11-01-13, 03:06 PM
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I don't have one here to look at so I can't give you "hands-on" answers. I just found an online schematic that be of help. Figure 11 on page 9.

R8182D Aquastat manual - PDF
 
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Old 11-01-13, 03:44 PM
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Let me answer your questions first...

Have been reading on this forum and see that the thermostat should have 24 volts at it. Is this correct?

I thought that the thermostat was just a switch and you were closing a circuit
Yes, that's correct. It is a switch.

In this diagram, pretend that the battery is the 24V transformer, the bulb is the relay COIL in the aquastat, and the switch is the thermostat.


image courtesy tufts.edu

You know that when you close the switch, the bulb lights.

If you measured the voltage across the switch with the switch OPEN, you would read the battery voltage! Why? Because the bulb (or the coil of the relay) is NOT an 'open' circuit. It has a resistance that will pass the current through it.

So, in an aquastat we can take advantage of the fact and by reading the voltage at the thermostat terminals we can determine 'health' of the transformer and the relay coil.

If we read 24VAC we know two things... that the transformer is working, and that the relay coil is not burned out.

If we do NOT read 24VAC we know that one or both the transformer or the relay coil are burned out.

This test will not tell us which one, but the absence of the voltage at the thermostat terminals tells us that at least ONE of them is bad.
 
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Old 11-01-13, 03:59 PM
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The thing I find weird with the unit in place now is i pulled in the contacts last night to call for heat and sometimes the circulator would run others the burner and circulator would run. I thought there was one relay for circulator and other for heater.
I have to guess here... because I wasn't there... BUT:

When you manually pull in the contacts, you are bypassing the thermostat. I think you know that already...

On that relay are TWO INDIVIDUAL sets of contacts. ONE relay controls TWO switches at the same time.

When the coil of the relay is energized it 'pulls in' the contacts.

One set of contacts runs the circulator.

One set of contacts runs the burner.

Here's the difference... in SERIES WITH the set of contacts for the burner is a HIGH LIMIT SWITCH that monitors the water temperature.

When the water in the boiler is above the setting of the high limit, that high limit switch OPENS and the burner will not fire.

Because you are pulling in the relay contacts, the circulator will still run, but the burner will not add heat until the water has cooled off again.
 
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Old 11-01-13, 04:03 PM
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I understand that the coils reduce the voltage to energize the relays that move 120 volts through them.
I believe you are thinking of a TRANSFOMER. The transformers in aquastats reduce the voltage from 120VAC down to 24VAC and this voltage is what powers the relay coil.
 
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Old 11-01-13, 04:07 PM
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For example I just looked at the coil why are there 6 pins soldered?
I'm not sure what part you are calling the 'coil'.

If you are looking at the RELAY then there are 6 pins because there are :

TWO connected to the COIL of the relay.

TWO connected to one of the sets of relay contacts.

TWO connected to the other set of relay contacts.
 
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Old 11-01-13, 05:12 PM
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ok
My one transformer is putting out 20 volts is that enough or is that going to create a chatter.
I am bench testing
Can I by pass the limit switch for now to make sure everything is working
Bruce
 
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Old 11-01-13, 05:17 PM
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ok
Now I am going to look now butcorrect me if im wrong you are saying the 2k relay controls both burner and circulator is that on 8182d & H
The book is calling the 1k relay the circulator relay when does that activate
Thanks
 
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Old 11-01-13, 05:29 PM
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putting out 20 volts is that enough or is that going to create a chatter.
It's on the low side, but it should be enough to pull the relays in.

Can I by pass the limit switch for now to make sure everything is working
The HIGH limit? as long as you are bench testing, yes, sure, why not?

Don't forget, there are two limit switches in there...
 
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Old 11-01-13, 05:33 PM
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you are saying the 2k relay controls both burner and circulator is that on 8182d & H
No... the 2K relay is the SAFETY relay. Those contacts are ALSO in series with the HIGH limit.

You are going to have trouble bench testing because the 8182 had the cad cell circuit in it. If you hook up a cad cell, and cover it so no light, make sure reset button is in, then give call for heat, and shine light on cad cell, the 2K relay should stay pulled in.

The 1K relay is the one that I was talking about in previous post.
 
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Old 11-01-13, 05:39 PM
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ok
ive got to take a ten minute break for dinner, then I need to solder in a jumper for the thermostat transformer on one of the other units it burned out
After I fix that what should I look for there is probably i good reason for that leg to burn out( aka red wire doing nothing from main feed)
 
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Old 11-01-13, 05:41 PM
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That 2K relay is operated by the 'safety circuit' in the lower right of the diagram. When the reset button pops up, 2K relay OPENS the circuit to the burner to prevent it from firing. The OTHER 2K contacts 'latch' the circuit so it stays in the 'safety lockout' mode.
 
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Old 11-01-13, 06:36 PM
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Im not yet completely understanding this. I think the unit I just soldered the jumper is working.
when electricity is aplied the 2K (burner motor and ignition relay) pulls in. No photo eye so safety shuts unit down. Wait 30 seconds reset relay pulls in I jump photo eye relay stays on I jump thermostat pins have 120 at b1 & b2 but not at c1 c2 is that because water temp is below low limit
Thanks Bruce
 
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Old 11-01-13, 06:40 PM
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So if the 8182h that is actually on the furnace has no voltage at the thermostat terminals there is probably a bad transformer in that unit.
That would make sense when I take it off I will probably find a pin that needs to be soldered. I think I tried using that one last year as well and if I tweeked the aquastat in a certain way it would run.

I have not heard back in a little while so I am trying to figure this out. I just found something else out. Not good to have jumper atattched to cad cell terminals when furnance safety cuts out. Probably one of the main reasons for all my problems.
I washeating the bulb up to try and figure out why there is still no voltage at c1 and c2 reached a limit which shut the burner off but jumper was attached to cad cell resistance started to build at b1 & b2.
Still not sure if this unit is good to go. Whats the deal with these limit settings
Thanks, Bruce
 

Last edited by relivenwvo; 11-01-13 at 07:31 PM.
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Old 11-01-13, 08:08 PM
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have 120 at b1 & b2 but not at c1 c2 is that because water temp is below low limit
Yes, I would think so. Circulator will not run if below low limit.

So if the 8182h that is actually on the furnace has no voltage at the thermostat terminals there is probably a bad transformer in that unit.
Either a bad transformer, OR a bad 1K relay coil.

I think I tried using that one last year as well and if I tweeked the aquastat in a certain way it would run.
More evidence of bad solder... very typical.

Whats the deal with these limit settings
Not sure what you're asking here Bruce?

How do they work? Is that what yer looking for?
 
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Old 11-01-13, 08:19 PM
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ok
I think I actually just learned something. The tt terminals supply the thermostat with electricity. You can not just short the tt terminals together
 
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Old 11-01-13, 08:22 PM
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So I need to pull the 8182h and am ready to do that my final concern on my bench is that the circulator solonid is not pulling in how to I set the unit up on the bench for that test
I have power on...calling for heat...cad sensor jumped...used heat gun on prope do i need to hook a thermostat up to the aquastat
 
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Old 11-01-13, 11:31 PM
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Yes.....you can just short the TT terminals. That's what the thermostat would do. You should measure +/-24vac on the TT terminals. When you short them the voltage would become 0 across them and the 1K relay would activate.
 
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Old 11-01-13, 11:50 PM
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So If I have 20 volts at tt the boil runs to get up to temp but the circulator doesnt run my problem is where? Im thinking it has something to do with the low limit curcit
 
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Old 11-02-13, 08:21 AM
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The tt terminals supply the thermostat with electricity. You can not just short the tt terminals together
Ummmm... no... Shorting the T T terminals together is what causes the aquastat relay to close.

SOME thermostats do take power from the T T terminals, but MOST do not.
 
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Old 11-02-13, 08:32 AM
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boil runs to get up to temp but the circulator doesnt run my problem is where? Im thinking it has something to do with the low limit curcit
Yes, it might have something to do with LOW limit.

BUT it COULD BE a problem with the contacts or the solder connections at the 1K relay.

Look at the LOW LIMIT BLOCK on the schematic again.

Notice that the " R " terminal is always connected to 120VAC ... trace back to the " 1 " terminal. You should always have 120VAC there.

The LOW LIMIT block switches this 120VAC between the " B " and the " W " terminals.

Those terminals never both get power at the same time, it's one or the other.

When the boiler cools to the LOW LIMIT setting MINUS 10 degrees, the LL block switches the power ON to the " B" terminal. This is connected to the HIGH LIMIT block and the burner will fire until the LL setting is reached. The circulator can NOT run during this time because when the switch is made, the power is REMOVED from the " W " terminal.

Once the LL setting is reached, the LL block will switch the power back to the circulator and it will be allowed to run during a heat call.
 
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Old 11-02-13, 09:20 AM
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Please Id really like to finish this thing. How do I bypass the limit switch to make sure the rest of the unit is working. Correct me if Im wrong, Yellow wire feeds the solenoid to turn on B1 and CAD coil 120 volts main voltage Black wire main voltage to limit switch. White wire main voltage to circulator soleinod to C1. Blue wires main voltage to zr and ??
Can i manually attatch wires to see that everything else is working and how?
How does a main power line becoming a common? Is this because of the coils? Do they switch when you try to follow lines?
 

Last edited by relivenwvo; 11-02-13 at 09:38 AM.
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Old 11-02-13, 09:34 AM
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To bypass the LOW LIMIT switch and convert the aquastat to a COLD START unit, you can do this:



Please understand that the boiler will NOT stay warm with this bypass and if you are using it for domestic hot water it will NOT work. You will only have hot water when there is a heat call and the boiler is HOT.
 
 

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