Replacing defective Honeywell Aquastat L8148A-1017

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Old 05-03-13, 05:35 PM
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Replacing defective Honeywell Aquastat L8148A-1017

I am replacing a Honeywell Aquastat relay on my Crown Freeport oil fired boiler, hot water heat system in my house. I removed the old relay, labeled all the wiring, and carefully compared the old with the new...so far good. The new aquastat came with Heat conductive Compound with directions for its use. However, the well on my boiler appears to be deeper that pictoral description that came with the new unit. Additionally, there is a fine oil in the well that I assume does the same as the compound provided with the new. The install instructions say to bottom out the bulb in the well and ensure that it touches the side of the well. Then fold the packet of compound and carefully work into the well. Squeeze out the compound as you pull out the packet. I'm not sure I can accomplish that. Does anyone know anything of the oil..is it a special heat conductive type? I don't think the compound AND the oil is intended. I would really appreciate any expertise out there...thanks.
 
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Old 05-03-13, 05:44 PM
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I think they want you to put the compound in the well FIRST, and then insert the bulb.

BUT, I personally would not use the compound at all. Just make sure the bulb goes to the bottom and stays there. There have been cases where the bulb was impossible to remove from the well when it came time to replace an aquastat because the stuff had 'hardened' a bit. I believe that one of the posters with that problem ended up having to replace the well.

I have no idea what's in there now... but that compound will ultimately have the 'oil' separate out of it so I suspect that may be what you see.

Was there anything on the old bulb when you pulled it out?
 
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Old 05-03-13, 06:22 PM
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What was on the bulb was what appeared to be fine machine oil...I put a screwdriver down the well to determine depth, and there is about 4 to 5 inches of golden tinted oil...too much to be old compound I would imagine..but not impossible. With regard to the bulb and it's placement...I don't think I have enough leader on the bulb to bottom out...I do have enough to immerse in the oil. The system has worked for many years until now. I am getting the impression that the oil bath is not a commonly used technique...thank you for your reply...I feel like I'm workin it now...Paul
 
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Old 05-03-13, 06:47 PM
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Your well must be vertical. The oil is fine, just something to facilitate the heat transfer to the thermal bulb of the control. The paste is easier to use on a horizontal well.
 
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Old 05-03-13, 08:17 PM
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That makes great sense....what type oil is it, and how full should the well be with it....?? It appears that the well is structurally sound, ie no water leaking in or evidence of leaking. But is this some kind of heat conductive special oil? It seems pretty thin..maybe 10 wt. I appreciate the help, Furd.
 
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Old 05-03-13, 11:55 PM
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It could be any of several oils. It is NOT "motor" oil as you would use in your car's engine. It might be refrigeration oil, steam turbine oil, electric motor bearing oil or just 3-in-1 oil. Yes, it is thin to allow it to flow between the thermal bulb and the inner wall of the well. No matter what its composition it will have significantly better thermal transfer than would an air space between the well and the bulb. You need enough oil to immerse the bulb but not any more than to reach the upper end of the bulb. The tighter the fit of the bulb (the closer the bulb OD is to the well's ID) the less oil needed.
 
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Old 05-04-13, 07:26 AM
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Thank you for that....I'm on it...next for me will we draining and re-flooding the system, as the failure of the original relay caused an escape through the pressure relief valve...30 lbs...and I have gurgling water sounds in the pipes... I'll review the forum for that issue...thanks again, Paul
 
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Old 05-04-13, 08:36 AM
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Paul, there's probably no need to drain and refill the system. All you should really have to do is purge any air that's in the system. You may be able to do this without 'draining' it completely, which would end up with more work for you in the long run.

The oil could also be plain old 'mineral oil' too.

the failure of the original relay caused an escape through the pressure relief valve...30 lbs
How do you know that it was the aquastat relay that caused this?

More often than not, excess pressure and the relief valve blowing is caused by the EXPANSION TANK losing it's air... read this:

http://www.doityourself.com/forum/bo...sion-tank.html

And this:

http://www.doityourself.com/forum/bo...ure-gauge.html

Make sure you cover all the bases or you may go around in circles.
 
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Old 05-05-13, 03:14 PM
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Well, I followed the instructions, ie got the expansion tank at 12 lbs, but may have drained too much water out of the boiler...all gauges (which haven't been verified for accuracy), are reading zero...when I open the make up water valve it doesn't sound like any water going into the system, nor do the pressures change...I fired the boiler and the outgoing pipe gets hot, but the return does not, nor do the baseboard heaters feel warm...No circulation?? It may be more labor intensive, but I may be better off at this point draining the whole thing and starting from scratch....Note: After I installed the aquastat and tested the cycling, it seems to cycle more that it used to..On till high limit temp reached (150) and about 5 mins later on again for another 3-4 mins, then off again ad infinitum......Normal??? Thank you for all your help...its working...I'm gonna get there.
 
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Old 05-05-13, 03:22 PM
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I made the assumption that the relay had failed due the failure of the system to shut down....however...the thread on the expansion tank was right on...no water in the bladder, but no air pressure either. And I ended up using "turbine oil" in the well...that part of the project went well. As you can tell your "running around in circles" statement is right on target, too. Ha
 
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Old 05-06-13, 07:52 AM
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when I open the make up water valve it doesn't sound like any water going into the system... ...I may be better off at this point draining the whole thing and starting from scratch...
Paul, if you can't get water into the system for whatever reason, how will draining and starting from scratch be helpful?

It sounds to me as if you have a defective 'pressure reducing valve' that isn't allowing water through.

If you go ahead and drain, you will end up in a WORSE position than you were. An EMPTY system with no way to get water back into it.

You need first to diagnose why you can't get water into the system.

Can you take some pictures of your system showing the piping and valves all around the boiler?
 
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Old 05-06-13, 10:12 AM
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Thanks for hangin in there with me NJ Trooper.....The first pick is the fresh water supply with a backflow preventer...I can't tell if it is a pressure regulator or not...
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The second shows the item above and the three manual zone valves...the pipe to the zone valves come from the boiler..the pipe the backflow preventer is the return water to the boiler...

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The vertical pipe center of pic goes to the expansion tank..

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This is what is in the "furnace closet" in the house. In 1989 or so, when the new boiler was installed, it was installed on a pad outside the home.

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this is the boiler..three valves...2 1/4 turn..water in, and water out, and a drain valve...2 control boxes..ect....
 
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Old 05-06-13, 11:43 AM
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first pick is the fresh water supply with a backflow preventer...I can't tell if it is a pressure regulator or not...
I don't see a backflow preventer. The red valve is your 'regulator', aka 'pressure reducing valve'. Being red, almost definitely a Bell & Gossett... see if there's a model number label on it...

On the other side of that big nut on the bottom is an inlet screen that may be clogged up. I don't know that I would recommend taking it off without having a replacement O-ring on hand though. The existing one may be just fine, but what if it's not?

Too bad there's not another shutoff valve on the other side of that unit... would make it so much easier to replace the valve without having to drain the boiler...
 
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Old 05-06-13, 01:03 PM
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You are correct...pressure reducing valve...B&g...moded B8...so no backflow prevention???
 
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Old 05-06-13, 02:24 PM
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So, are there general draining and flooding procedures to follow or is every installation a little different? Since I have no shut off valve on the other side of the pressure regulator, if I do take the strainer off to clean it I will lose water from the pipes above. ( Which very likely is the issue as I'm on a well)
 
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Old 05-06-13, 03:05 PM
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so no backflow prevention???
Not in the 'modern' sense. Most jurisdictions these days mandate that a SEPARATE backflow preventer be installed. I think the most common of these would be the Watts 9D.

Here is a PDF file that covers your reducing valve:

http://s3.pexsupply.com/product_file...92-Install.pdf

are there general draining and flooding procedures to follow or is every installation a little different?
Every system is different. Some installers try to save a few bucks and don't install the 'extra' valves that would make the process so much easier (called 'purge stations').

I will look again at your pics to see what you've got.

if I do take the strainer off to clean it I will lose water from the pipes above. ( Which very likely is the issue as I'm on a well)
There is 'supposed to be' a check valve in the B8... and there are steps in the PDF file that explain that you need to drop the boiler pressure to zero (yours already is) before removing the strainer.

You shouldn't lose much water... (famous last words) ...

Even after cleaning the strainer, you might find that the valve STILL doesn't work... the regulator part could be stuck too.

Next post a little more about a 'work around' ...
 
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Old 05-06-13, 03:16 PM
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I looked again at the pics and can't identify what I call a 'purge station'. This would consist of a shutoff valve right next to a drain valve. The purpose of this is to be able to direct the water through the loops rather than 'short circuit' through the boiler. Water, like electricity, will seek the shortest route. By placing shutoffs in the proper locations, one can 'force' the water to take the path YOU want it to take, rather than the path IT wants to take.

I also don't see anything that will allow the 'work around' that I thought I would mention.

What that work around would consist of is a garden hose and a washing machine hose. This would let you make a 'double female' garden hose that you can screw onto the boiler drain and onto a hose spigot. Then by SLOWLY! (remember, you don't have the pressure reducing valve in line!) opening the hose and boiler drain you can 'backfeed' water into the system while watching the pressure gauge. Shut the water off when it hits 12-15 PSI.

It would also be wise to check the air charge in the expansion tank while the system pressure is at zero. There are step by step instructions in this thread, follow the steps to the letter:

http://www.doityourself.com/forum/bo...sion-tank.html

Read this one too while you are at it:

http://www.doityourself.com/forum/bo...ure-gauge.html
 
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Old 05-06-13, 03:27 PM
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I'm on private well also... when I installed my new system last fall I decided to take some steps to keep my reducing valve operational for as long as possible.

In this pic, from right to left, on the bottom you can just see the feed shutoff valve. Next, there is a hose spigot before the pipe turns to the left. There is a WYE STRAINER next, this stops the 'big chunks' from passing. Then the Watts 9D backflow preventer, a Watts 1156 reducing valve, and then up to the system connection. There is also a shutoff valve on that gadget that the tank is hanging from.



I don't like 'dead ends' on my water system and the run from the main line to the boiler is about 10' or so... a perfect place for creepies to breed. Periodically I hook a hose to that spigot and flush the feed line out. This also gets rid of 'crud' that might collect. Your run is VERY short, you probably don't need to do this...

I've now got a valve on the bottom of the wye strainer to flush that out on occasion also.

Hopefully this puts an end to my clogged up reducing valves.

Something to think about if you re-do any of your plumbing... if you end up having to replace the reducing valve... at LEAST put a shutoff between the boiler and the reducing valve.
 
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