Aquastat vs Primary Control


  #1  
Old 01-28-05, 12:13 PM
theTrooper
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Aquastat vs Primary Control

Can someone tell me the difference between an "Aquastat" and a primary control (ignition controls)? Is an aquastat a fancier controller or is it just a component of any control (that maybe can be added to or removed from a controller)?

Are aquastats only useful if the boiler is also used as the domestic hot water heater?

I have on oil boiler (hot water radiator) that uses a Honeywell R8182D Combiniation Protectorlay and Hydronic Heating Control (I'll call it an aquastat). When I bought the house the boiler was originally not only providing the heating but also the domestic hot water. A few years ago we had a gas fueled hot water heater installed and had the domestic hot water pipes on the boiler caped.

It was all fine for a few years but these days the aquastat seems to be acting strange and I was wondering if I do need to replace it, will I need to replace it with the same model or can I get a cheaper and simpler model? Is that where a primary control come into play?

Thanks in advance for any help or advice you can give!
 
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Old 01-28-05, 06:57 PM
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Aquastats

The R8182D maintains boiler temperature. You could replace it with an R8124 aquastat & R7184 primary control. This combination would serve the same purpose as the R8182 but you would only have to replace the failed aquastat or primary control instead of the entire combination contol. You could also use an L8148 & R7184. The L8148 does not maintain boiler temperature but fires the burner on demand from the thermostat. I do not suggest an L8148 on a "pin" boiler. With cast iron radiators, unless you have a by-pass loop, I don't suggest the L8148 at all.
 
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Old 01-28-05, 09:42 PM
theTrooper
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Aquastat

Thanks Grady,

Sounds like you know the R8182D. If it's not too much trouble could you tell me what you think about this problem I'm having with it?
Occasionally (mostly in the dead of night) the burner motor and ignition relay "toggles" on and off very rapidly. Sometimes 6 to 10 times within just a few seconds. Just as though someone was flipping the power switch on and off. I sometimes worry that it is not going to stay on, however most times it finally does. There were a few times where I gently tapped the relay and then it stopped toggling.
Does this sound like a problem with the aquastat settings or is the primary control going bad. I think I can get a new R8182D at a reasonable price, so I wouldn't mind replacing it.

Thanks again.
 
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Old 01-29-05, 10:38 AM
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It does sound like the problem is in the aquastat. If you can get it to do it on a repeated basis, you would have a better chance of being assured that it is the culpret. Imtermittent problems are the hardest to diagnose. If you are up for an adventure, you could pull it out and take the board out of it and look for a broken solder joint. That is actually the most prevalent thing I find wrong with those controls. Next would be when the safety control part goes bad. If you decide to replace, (I don't know what a good price is on that control. They are expensive) use the 7124 aquastat and the 7184 safety control. The new aquastat has replaceable relays and some nice features and is less expensive than the old 8124.

Ken
 
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Old 01-29-05, 04:02 PM
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Ken's right on both counts. Wow, that's a switch, we agree on the whole thing. Broken/loose solder joints are the usual culprit. Once in a while the coil on the relay gets weak. The 7124/7184 combo is a nice set up & the replaceable relays are a major cost savings. Instead of having to replace the entire aquastat if a relay goes bad you can simply plug in a new relay.
 
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Old 01-29-05, 04:25 PM
theTrooper
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Aquastat

Thanks Guys,

Ken, when you say it sounds like a problem with the aquastat, are you refering specifically to the aquastat component OR the entire combination control in general?
If I remove the controller board from the box and examine the back there is a chance I may see a broken solder joint. If that is the case, I can easliy resolder it.
However, if the problem is not evident, I suppose I would try to replace the entire combination control with another R8182D (there are new ones on ebay for around half the retail price).
If I went with a replacement R8182D, my only concern would be dealing with the immersion well insertion into the boiler. It's an old rusty boiler so I don't want to disturb it (that and the fact that I don't have the proper tools!)
I was hoping that I could just disconnect the wire leads to the well instertion and leave it (and the old housing) connected to the boiler and then just swap out the old circuit board with the new board.
Does this sound realistic?

I'm less confortable with the 7124/7184 solution because I not sure if the wiring for these two separate controls would be less obvious to me.
Isn't the 7184 a Beckett control and isn't it a microprocessor control?
Seems like it would be a more difficult thing for me to do.

One last thought about this alternate solution-- since I don't use the boiler for domestic hot water, wouldn't I only need the 7184?
 
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Old 01-29-05, 05:50 PM
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The 7184 alone would not control the temperature of the boiler. As long as there was a call for heat, the burner would run. NO TEMPERATURE SAFETY. Yes, the 7124 is an electronic control. Removal of the 8182 does not require the removal of the well but there is a capillary with a bulb which goes into the well & is part of the 8182. With any luck the bulb will slip out of the well easily. If there is a hard grey compound holding the bulb in place, use WD 40 to soften or flush out the compound.
 
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Old 01-29-05, 05:59 PM
theTrooper
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Aquastat

I just took a look at how the contoller was connected to the well and it looks like that by following your advice about the bulb, that it will be no problem to remove it. I think I'll be ok now.
Thanks for all your advice. Thanks to Ken also.
 
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Old 01-29-05, 08:50 PM
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One of the nicest features of the 7124 is that you can have it NOT maintain boiler water temp if you so choose. Just turn the dial. Previously, it was a problem to do that with other controls. Good luck.

Ken
 
 

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