Honeywell R8182D High Limit
I have a Burnham furnace with a Beckett burner, 3 heating zones and a tankless coil. According to the Honeywell manual, when a thermostat calls for heat, both the circulator relay and burner relay should energize until the water temp reaches the HI set point. Mine does not do this. When calling for heat, only the circulator relay energizes and when the water temp drops below the LO setting, the circulator stops and the burner comes on. It seems like the aquastat is working with the LO setting only. I never see the water temp reach the HI setting. Any ideas? TIA. Oooohhhh Wilbur.... It does sound from your description that there is something amiss with the high limit part of the aquastat. What are the settings on the three dials ? HI set to 200 LO set to 170 DIFF set to 15 Are those your 'normal' setting? or did you bump them up to get heat in the home? Normally the high would only need to be 180, the LOW (for safety purpose of not having SCALDING hot water from the taps) would be like 150 (which is still capable of scalding, but you have about 1-2 seconds to react). The diff is OK... could go to 20... but 15 is fine. I'm assuming that you use your boiler for domestic hot water, thus the 'triple' aquastat. If so, is there a TEMPERING VALVE installed on the hot domestic line to the home? Yes, there is a mixing valve to lower the temp of the domestic hot water. I have recently bumped up the temps a little, but I think the system has been operating this way for a long time. I only just noticed it. I have no problem heating the house but I would like to lower the LO setting and have the aquastat working the way it should. Looking at the schematic for the 8182D, it would appear that one of the relay contacts, 1K2 is not making connection. This could be due to dirty or burnt contacts, a spider between the contacts, or possible a cracked solder connection on the pc board. There are two relays in that aquastat, 1K and 2K ... 1K is the one closest to the edge of the board... TURN THE POWER TO THE BOILER OFF! and get in and inspect the relay contacts. Get a good flashlight and yer strongest spectacles and see if you can see the contacts and inspect them for damage/wear/spiderwebs... I downloaded the schematic as well. I guess I shoulda done this in the first place, duh! With 1K energized, I should have voltage at ZR, which I don't. I believe this is the problem since that powers the high limit circuit. Thanks Troop! I looked at the relay contacts as best I could. They seem ok, but they were real hard to see with the thermostat tranformer right there. It looks like I'll be pulling the board off. That board comes out of the case pretty easy... you probably already see that all you have to do is bend the metal tabs... hopefully yer good with a soldering iron, cuz I'm betting that you are going to find a cracked solder joint. I'm sure you also know to use only ELECTRONIC solder, ROSIN CORE, right? Be careful removing the board that you don't 'kink' the capillary tube on the sensing bulb! Most plumbers are mis informed or dont know what they are doing.. Read this please. Diff to 20??????? The high only for heat. (hot water) Guide to Setting Wiring Heating System Boiler Aquastat Controls, set the HI limit LO limit and DIFFerential dials on controls like the Honeywell R8182D Combination Control Aquastat Low heat hot water. Summer? Best High, Low, DIFF Settings on a Heating Boiler Aquastat? Originally Posted by NJ Trooper That board comes out of the case pretty easy... you probably already see that all you have to do is bend the metal tabs... hopefully yer good with a soldering iron, cuz I'm betting that you are going to find a cracked solder joint. I'm sure you also know to use only ELECTRONIC solder, ROSIN CORE, right? Be careful removing the board that you don't 'kink' the capillary tube on the sensing bulb! Thanks for the tips . I'm so disorganized... right now I have to find my soldering iron, lol! I'm gonna wait 'til tomorrow to do this. If something goes awry (and it usually does,) at least I'll be able to run out for parts and hopefully minimize the down time. I'm actually looking forward to finding something wrong, I think it's been like this for a long time and I never noticed. Originally Posted by lawrosa Most plumbers are mis informed or dont know what they are doing.. Read this please. Diff to 20??????? The high only for heat. (hot water) Guide to Setting Wiring Heating System Boiler Aquastat Controls, set the HI limit LO limit and DIFFerential dials on controls like the Honeywell R8182D Combination Control Aquastat Low heat hot water. Summer? Best High, Low, DIFF Settings on a Heating Boiler Aquastat? Thanks, I read that yesterday. It's what prompted me to look more closely at how my heating system operates. hi guys - Originally Posted by lawrosa ...Diff to 20??????? I lurk around the forum here in the shadows trying to learn everything I can. Don't think there is a better place to learn. Read the referenced stuff on the hi/lo/diff settings a few times. Read hi/lo/diff explanations before (really good ones right here on the forum). But I don't know what you mean lawrosa and it's bugging me! I'll probably be red faced but please help! Did you read the links? 10 degree diff . [text removed - there is no point in repeating the wrong info here... yes, we read those links - NJT ] Mike NJ Yeah, I'm confused by Mike NJ's post too... and there is misleading info at that website. I've browsed that place on numerous occasions and found plenty of BS there. They said: we prefer to set the differential to its smallest number (usually 10 degrees) so that the boiler will come on as soon as possible to make domestic hot water And that's just plain misleading... even wrong. It makes absolutely NO DIFFERENCE what the DIFF is set at as to 'when the boiler comes on'. If the LOW setpoint is say 150, the boiler will ALWAYS fire up at 140, whether the DIFF is set to 10 or to 25. The 'bottom' of the window is ALWAYS ' LOW SETPOINT - 10 ' The 'top' of the window is where the DIFF comes into play, and the 'equation' for that is: (LOW SETPOINT - 10) + DIFF If your LOW setpoint was 150, and your DIFF 20, then: (150 - 10) + 20 = 160 The boiler will fire at 140, and cut off at 160. With a DIFF of only 10, the boiler will STILL fire at 140, but cut off at 150. The reason for the wider diff is to allow for a longer ON cycle, and also for a longer OFF cycle. The boiler will cycle less, and this is a good thing. There are other logical reasons for running a wider diff, which I won't go into here because this is NOT 'our' thread and is drifting from Mister Ed's focus. Please start a new thread if you wish to discuss further the logistics of setting the DIFF control on a triple aquastat. I would set 190 hi 120 low 10 diff. You said your house heats fine. Here is what honeywell suggests for low. Set low-limit indicator at the minimum temperature recommended for domestic hot water supply. This setting must be at least 20°F (11°C) below high-limit setting to prevent one switch from locking out the other. Also for why no circ on low. You have the low set too high the circ wont come on. When R to B (low limit) is made by a drop in water temperature, it acts as a call for heat, pulling in relay 2K to turn on the burner. Circulator cannot operate. I dont know whats misleading. Read page 6 I guess its like the bible and how you analyze the info. Its what you want to believe. http://customer.honeywell.com/techli...it/69-0599.pdf Originally Posted by lawrosa Also for why no circ on low. You have the low set too high the circ wont come on. No matter where the LO setting is, the circulator pump will stop when the temp reaches the low setpoint -10 in order to give priority to domestic hot water. My HI setpoint is not working so I had to bump up the LO setting to get decent heat, however the circulator and burner are always cycling. That's what I'm trying to fix. Found the problem!!! Just like Troop predicted... a bad solder joint. Looks like they were pretty stingy with the solder all around. Anyway, it's fixed and running! Now I have the burner and the circulator on at the same time with a call for heat and the constant cycling should be done with. This should heat the house faster, help reduce the amount of fuel usage and I can back down the LO setpoint. Yay! Thanks again Troop, and everone else, too. Great site! That's pretty typical. I hope you reflowed all the suspect connections while you had it out. Mike NJ - like I said, if you wish to discuss how the triple aquastat works, and the various possible settings, I'll be more than happy to add my 5 cents ... in another thread . and by the way, 120 is WAY too low to make domestic hot water with a thankless coil setup. Yeah I had this control on the boiler in my previous home. The HW was still too hot at 120f. I may had other issues come to think about it. I never thought PCB issues on a new control. Are these USA made controls now? Or did Honeywell outsource. 5 cents thats it?? At least 10 cents LOL. Merry Christmas. Mike NJ Since the issue is fixed, I think we can carry on here for a bit... I never thought PCB issues on a new control. I didn't see any mention of a new control? The HW was still too hot at 120f. Even in the summer? Don't forget that the LOW and the DIFF only control the 'minimum' the boiler will go down to. In the winter time if you happen to draw domestic hot when the boiler is sitting at say 180, you will of course get some VERY hot water... and that's exactly the reason that there should be a temperature regulated mixing valve on EVERY thankless coil installation. What you get is not predictable. It depends on the temp of the boiler at the time you draw that water. Thankless coils are like a box of chocolates... Originally Posted by NJ Trooper …Don't forget that the LOW and the DIFF only control the 'minimum' the boiler will go down to. In the winter time if you happen to draw domestic hot when the boiler is sitting at say 180, you will of course get some VERY hot water... and that's exactly the reason that there should be a temperature regulated mixing valve on EVERY thankless coil installation. What you get is not predictable. It depends on the temp of the boiler at the time you draw that water. Thankless coils are like a box of chocolates... Trooper you are describing exactly what I have. I have the thankless coil and in the winter seems like I get much hotter water on average when I draw DHW. I have a stationary tub in the basement and when it’s winter and I draw HW water there, if don’t remember and I am not cautious, that water sometimes would like to burn my hand off. Same with the showers. But in the summer I don’t have a problem. I don’t have a mixing valve and I if I understand what you are saying the boiler water temp when randomly drawn would be much hotter in the winter. I guess sometimes even near 180, my Aquastat high limit. A box of chocolates is a great metaphor. Originally Posted by NJ Trooper … the LOW (for safety purpose of not having SCALDING hot water from the taps) would be like 150 (which is still capable of scalding, but you have about 1-2 seconds to react). … That describes my situation exactly . Seems like I have a very short time to get out of the way. Guess even less than 2 secs when my water is near 180? Resulting from this thread I looked all over today to see if maybe I had a mixing valve somewhere that I missed. But I don’t think so. I see the shutoff for the HW on the HW pipe coming out of the boiler thankless coil, and then on the house side (or maybe I mean service side?) of that shutoff valve there is nothing but pipe going to the fixtures. Would I just turn off that HW shutoff coming from the thankless coil, then cut into the HW pipe on the house side of that shutoff to add the mixing valve? Seems like I shouldn’t have to mess with the boiler? But maybe that’s incorrect? Can you recommend a mixing valve? Or should I start a new thread if the topic is mixing valves? Would I just turn off that HW shutoff coming from the thankless coil, then cut into the HW pipe on the house side of that shutoff to add the mixing valve? Seems like I shouldn’t have to mess with the boiler? But maybe that’s incorrect? All the plumbing is on the domestic... no boiler piping at all. There are numerous makers of these, the Taco seems to be the easiest to find in my part of the woods. There's a diagram in this PDF of how it would hook up. It's a THREE pipe setup, you have to cut into both the hot and the cold. The 'mix' comes off the tee. The other advantage to these is that they 'extend' the capacity of the coil a bit because there will be less flow through the coil. Thanks Trooper! (little slow responding, log in problem, probably ok now) I understand what you are saying. I'm looking into Taco now. They even have a nice diagram. Thanks! I have been having similar issues with R8182D aquastat. Burner will work fine for a few days and then will not kick on at all. I hit reset button and it will work again for a few days. I tried to look into R8182 but did not see any obvious problems. How do I clean the contacts? I cannot seam to see into them nor do I see get into them to clean them. Could it also be the cad cell flame detector that needs cleaning or replacement? Please HELP!!! I have been having issues with my burner not kicking on...it will work for a few days and then not kick on. I hit the reset button and then it will work again for a few days. I have a Honeywell R8182D aquastat. I looked into the unit and there are no obvious issues. How do I clean the contacts? I cannot seem to see into them nor do I know get into them to clean them. Do I have to remove the entire board by removing all of the wires? Can this problem also be caused by the cad cell flame detector - maybe this needs to be cleaned or replaced? Please HELP! Start a new thread. It gets cofusing when someone hijacks anothers. Mike NJ [ Mike, in this case it's OK because the previous discussion has ended... give the guy a break, he's new here! - NJT edit] [Bruce, in general it is best to start a new thread even if your problem is the same thing, and ALWAYS start a new thread if there is ongoing discussion with the original poster... as Mike says, it can get confusing trying to answer two peoples questions in a single thread... ] Bruce, if the reset button pops, it doesn't automatically mean that there's something wrong with the aquastat! It COULD and probably DOES mean that something is wrong with the burner. That reset button will only pop when the aquastat calls for the burner to fire, and the CAD cell does not 'see' flame within 30-45 seconds. When was the last time your burner was serviced? Oil filter changed? etc etc ...
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