Honeywell Aquastat L8148E

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Old 02-17-10, 10:47 AM
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Honeywell Aquastat L8148E

I have a Honeywell Aquastat model L8148E on a 2 zone gas fired hot water boiler.

Some how the wire connection to the tabed B1 terminal developed a problem, and I've needed to trim the head off the wire and attach to the terminal with an alligator clip to restore heat.

I'm thinking about just soldering the wire to the terminal, but I would prefer replacing the wire harness that connects to terminals B1 (blue wire) B2 (2 red wires) and Z (yellow wire) to power coming from the cutoff switch.

I couldn't find any mention of a part number of this component, and am not sure if it came with the aquastat or was provided by the installer.

Does anyone know if this is a standard orderable part.

Thanks.
 
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Old 02-17-10, 11:10 AM
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I'm a little unclear...

Is the problem with the terminal in the aquastat?

Or is it only with the connector on the end of that one wire?

If it's just the terminal on the end of the wire, replace that and be done with it... you can buy them terminals at HD or Lowes in the electrical dept... and rather than crimp the terminal on, buy the type that you can solder onto the wire if you so wish...
 
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Old 02-17-10, 11:16 AM
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Just the connector at the end of the wire.

Buying a head I can solder the wire to and then connect to the terminal is a good idea.

It would eliminate concerns I had that a botched crimp job would cause similar problems in future or eat through the small amount of wire on that lead.

Thank you for your suggestion.
 
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Old 12-28-10, 03:35 PM
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L8148E adjustment issues

Hello I'll try to make this quick... Recently I was trying to raise the temperature of my boiler as the weather got colder from 150 to 180 to help heat the upstairs unit better (I didn't realize that most the radiators were off until after I did this so maybe there was no point) but anyway it seemed to work as the temperature immediately began increasing to 180 and appeared to hold there. The upstairs unit got very hot as i had the thermo around 70 and all was good... and hot.

Today I noticed the water temperature all the way down to 80,(i assume because both thermos were not telling the boiler to come on?) I immediately turned the upstairs thermo up to around 68 and the boiler kicked on and began heating the water up, this time though i checked a bit later and the water was all the way up to 210, so I immediately turned the thermo back down.

I don't know what I could have done by simply turning the wheel up to 180 but something isn't working correctly. Previously when the temp was set at 150 it seemed to kick the boiler on as soon as it was down to 140 and heat back up to 150. I would love to hear that there's an easy fix like resetting something but if I need someone to come check this out I'd like to know asap also. Thanks a lot!
 
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Old 12-28-10, 03:51 PM
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Evidently, you jacked up the aquastat too far if the water temp is getting ot 210 deg. Turn it down. You can't really depend upon the aquastat setting - it could be off.
 
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Old 12-28-10, 05:31 PM
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In addition to what Mike said, let me ask you this:

When you saw the temp up to 210, had the thermostat actually been satisfied for some time? and the burner was shut down ALONG WITH the circulator being OFF ?

IF SO, then you don't really have a problem at all... what you probably saw was HEAT SOAK. When the boiler is shut down after the thermostat is satisfied, and the boiler was at, or near, HIGH LIMIT, the heat that is in the cast iron of the boiler transfers to the water in the boiler and will continue to heat up... NORMAL.

However, if the burner were still firing, follow Mike's lead and turn it down some... try 170 and see what ya get. WATCH a burn cycle and see what temp the BURNER cuts off at... and remember that the boiler thermometer could also be a bit off... like some of my relatives.
 
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Old 12-29-10, 09:47 AM
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Thanks guys, From what I could see the boiler was approaching 210 with the aquastat set at 180 and the burner was still on, i got nervous so I immediately went up and turned upstairs thermostat down and the boiler shut off along with the pump.

I have since turned the aquastat back down from 180 to 170ish and am going to try and analyze a full cycle this afternoon. I think by turning on all those radiators upstairs and playing with thermostats and aquastats i have it all off-balance right now.

If I get this high temp thing figured out I do have a question about the aquastat.
I understand your setting the high temp and it has a 10 deg differential. But am I correct in saying that if both thermostats aren't requesting heat that the boiler allows the water to cool below the 10 deg diff and as soon as one thermostat requests the heat, the boiler turns on, begins heating the water to the set high temp and that zones circulator pump also begins pumping?

If you could also reccomend what to look for to be operating most efficiently or point me to a previous thread that would be appreciated, right now the boiler seems to be operating less which I would think is good.
 
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Old 12-29-10, 11:37 AM
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update

I came home today and saw the boiler was reading 230 and set at 180 and still on... I immediately turned it down to 150 and it shut off which at least is a good sign but it seems very odd it's getting that hot. I'm a little worried about it but for now I'm going to wait for the upstairs to cool off and run it through a cycle and see what happens.
 
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Old 12-29-10, 12:33 PM
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am I correct in saying that if both thermostats aren't requesting heat that the boiler allows the water to cool below the 10 deg diff and as soon as one thermostat requests the heat, the boiler turns on, begins heating the water to the set high temp and that zones circulator pump also begins pumping?
Sounds correct... if there is no call for heat, the boiler can go completely cold. (COLD START). Some systems DO maintain a minimum temperature, called WARM START, but yours ain't one.

came home today and saw the boiler was reading 230 and set at 180 and still on...
yeah, that ain't right... maybe that's why it was set to 150 to start with?

There's several possibilities here...

1. Your boiler temp gauge is not accurate.

2. Your aquastat is not accurate.

The aquastat could just be out of calibration, and as mentioned earlier, as long as it is REPEATABLE, i.e. you set it to 150, and it ALWAYS shuts off at 180, that's not a problem.

Your temperature sensing bulb may not be inserted all the way into the immersion well.

The immersion well location might actually have cooler water around it than the location of the thermometer on the boiler...

Set it back to 150 ... where it was... and watch a cycle or two... if it cuts off at 180 every time, fuhgeddaboudit... grab a beer and relax.

Unless you really must know... then, the first step would have to be verifying the temp gauge on the boiler and going from there.
 
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Old 12-31-10, 09:40 AM
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Alright I set it back down to 150 and it seems to have settled down. I watched a couple cycles a day later and it was heating to 165 then shutting off and getting up to 175 then cooling back down to about 155 before the cycle started again.

I still don't like that it was getting all the way up to 230 even when set at 170 so I'm going to keep an eye on it and hopefully it's good for now.

I have a crown Aruba 140 series boiler. Does it have some kind of internal protection from getting too hot? Not that I even know what too hot is but the boiler thermo only goes up to 240 and it was getting pretty close to that.
 
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Old 12-31-10, 09:51 AM
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Does it have some kind of internal protection from getting too hot?
Other than the primary aquastat, no. Some boilers have a 'secondary high limit' that is a backup for the primary in case it fails. Some local jurisdictions require they be added by code if they are not supplied with them.

I would consider a high limit setting of 200 about the highest you would want to go, and then only in cases where the home did not have enough baseboards or radiators installed to meet the heat loss of the home with 180 water.

After the burner and circ cut off, I don't think it would be at all unusual or alarming to see the temp go up to perhaps 210... maybe even 220...

Try bumping the setting up 5 at a time until it cuts off reliably at 175-180 and leave it at that for a while and monitor it.

The aquastat has a temperature sensing bulb on the end of a capillary tube that is inserted into an immersion well into the boiler water. If that sensing bulb isn't fully inserted into the well, the boiler will get hotter than the setting ... maybe what you have going on... or, aquastat is simply out of calibration... and that's not really to worry about unless it is not REPEATABLE, EVERY TIME. If it's ERRATIC, it would need replaced. Sorry for repeating myself...
 
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Old 12-31-10, 05:07 PM
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Thanks. A couple hours after I watched those cycles i wandered downstairs and saw it back up around 215 while still set at 150. I guess I'm going to have to have someone come check it out because it's not repeatable every time.

I'm still so perplexed that it seemed to be running so well at the 150 setting (I never saw it above this) before I tried to turn it up to 180 and now it's so erratic.
 
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