Aquastat on Weil-McLain Gold 80 Water Heater not working

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Old 01-22-15, 10:57 AM
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Aquastat on Weil-McLain Gold 80 Water Heater not working

I'd like to raise this thread from the dead.

http://www.doityourself.com/forum/bo...plus-40-a.html



I have a Weil McLain boiler and Ultra Gold 80 water tank, with an aquastat; very similar (maybe a bit more complex - 6 zones) to the pictures posted here. I'm having what sounds like a very similar problem.

I built this house 13 years ago, and the HVAC company which installed the boiler/hydronics set the boiler for 140. I have since found that to be too low; there were many occasions where the calls for heat from the in-floor heat were not enough. During those times, taking morning showers was an unpleasant experience (cold water).

I've since adjusted the boiler temp to 180, but now a new problem has arisen; one that I believe has been masked by too low a boiler setting in the past: my shower mixing valve cannot adjust to the extreme temperature; we get water that is only tolerable when the Kohler K-304 valve is barely open - which means we're taking showers in the main bath that have very weak pressure.

This is not a problem upstairs; either because the valve up there is better able to mix hot/cold, and/or because the length of run to upstairs is long enough that the hot has cooled into a range that it can handle.

So I've screwed with the aquastat - and I found something interesting. The water temperature does not react until I'm in the lowest (coldest) end of the aquastat range, at which point it simply shuts off. So: I go from scalding boiler temperature water - 180 degrees - to cold. There is no middle ground; the aquastat seems unable to maintain it - and because my main bath shower is literally right above this tank, I get the hottest possible water through a run that is no more than 15 feet total.

Bad aquastat? Is there a way to be certain?

Thanks!
 

Last edited by lawrosa; 01-22-15 at 01:59 PM.
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Old 01-22-15, 02:36 PM
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I'm a little confused by a few things you've written...

there were many occasions where the calls for heat from the in-floor heat were not enough.
You mean the water wasn't hot enough to heat your home? Is that why you raised the boiler temp to 180F?

In-floor heating should not be using water that hot... it should not need to if it's designed properly.

I agree that the boiler aquastat should never have been set down at 140F , but there should have been other provisions for limiting the water temperature into the underfloor heating, such as thermostatic mixing valves, etc...

I've since adjusted the boiler temp to 180, but now a new problem has arisen; one that I believe has been masked by too low a boiler setting in the past: my shower mixing valve cannot adjust to the extreme temperature;
If raising the boiler temperature has raised the temperature of the water in your indirect water heater, then there is something else wrong.

You are probably missing check valves somewhere that would serve to prevent the 180F water from flowing through the indirect when you are doing space heating.

The ONLY time you should be getting flow through the indirect coil is when the control on the indirect is calling for it, and that should not be set above 125F if you have no 'tempering valve' (which you SHOULD have) on the water heater outlet, and maybe 140F if you DO have a tempering valve.

So now what I'm going to ask for is pictures that I can study because I believe you've got a piping issue... perhaps several...
 
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Old 01-22-15, 06:17 PM
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In answer to your first question, my 6 zones each have TACO mixer valves, and @ calls for heat, the temperature of the main loop was not enough to prevent AUX heat from kicking on in several zones - and during this time, the water tank didn't contain water hot enough to take comfortable showers. As a result, I turned up the temperature of the boiler to 180.

My aquastat appears wired directly to a TACO pump which pulls 180 degree water directly off the main loop - so the aquastat should only activate that pump when the temperature inside the tank drops too low.

That doesn't appear to be the case. I'm getting water that is either too hot to mix @ the main bath shower, or the water is just cold. The faucets in the house are getting water which is too hot as well, but that at least is controllable, though dangerous. Here are pics:





 

Last edited by Subdermal; 01-22-15 at 06:35 PM.
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Old 01-22-15, 06:21 PM
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One of the variables that led to the need to change the low setting on the boiler is the fact that I have a loop - and a sub-loop from that loop - that heats the 4 car garage floor, and the front stoop. The garage is on a thermostat; the front stoop is on a switch that allows manual activation to melt snow/ice. Those calls for heat have a huge impact on boiler activity.
 
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Old 01-22-15, 06:39 PM
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Who closed this red bypass valve?
How long has it been closed?


With these pics it may take some time for us in internet land to sort out your issues...

You would really need to take many pics from all angles and label what you have. What is what, and what goes where.

What were the boiler temps during cycles before you turned up the aquastat? The boiler never really got hot did it?

 
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Old 01-22-15, 06:47 PM
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Am I imagining, or did the post I put up with pictures from all angles disappear?

In answer to your question, lawrosa: that valve is there to bypass the loop and drain water from the boiler. There are two valves directly above that tee pipe that can isolate the boiler from the main loop and drain the boiler. I think that is the only purpose of that valve, as the bottom of the left vertical pipe goes directly to the floor, and has a petcock (closed) on it.

As for your other question: I've never had to turn up the aquastat. When the boiler temp controller (bolted onto the main up pipe; seen in that pic) was set at 140, the water in the tank stayed cool enough to avoid scalding. When I turned the boiler temp up, the hydronic zones ran more efficiently, but the tank became nothing more than another zone - but without a mixer valve, so the temp was too high (the aquastat appeared to need turning down).

I turned it down - to no effect - and kept doing so in increments, with no change in scalding hot water. Until one final minute notch, when it seemed to stop calling for heat altogether. At that point in the dial (well into the cold zone of the dial), I could move the dial slightly hotter, and an immediate output to the TACO pump (pictured) was noted. Moving it back a touch colder turned it off immediately, and would NEVER activate the pump.

So I'm thinking bad aquastat.
 
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Old 01-22-15, 06:50 PM
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On an aside: in this forum, is the privilege of "replying with quotes" reserved until a minimum post number is hit? I have only a "reply" option, which doesn't allow me to quote the poster to whom I'm replying.
 
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Old 01-22-15, 07:10 PM
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In answer to your question, lawrosa: that valve is there to bypass the loop and drain water from the boiler.
That is called a system bypass. That is there so the boiler will heat to temp and the boiler dont condensate..

Think about it.. If all your zones where calling for heat do you think that boiler would be able to heat to temperature????

The system bypass alows hot boiler water to go right back to the boiler to help raise the temp..

Can you take a pic of the piping above that bypass?

I restore your post with the pics, but we need more..

Page 27 and 28 here. figure 22...

http://www.weil-mclain.com/en/multim...Manual2011.pdf


Is any of this related to your issue? Maybe/probably... You may have a t stat issue with the indirect but I wonder if that boiler is all plugged up. Thats why I asked how long that valve has been closed...
 
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Old 01-22-15, 07:12 PM
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On an aside: in this forum, is the privilege of "replying with quotes" reserved until a minimum post number is hit? I have only a "reply" option, which doesn't allow me to quote the poster to whom I'm replying.
Do you have an advanced tab?? Says go to advanced menu. Its next to post quick reply...

After 6 posts you should see it/...
 
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Old 01-22-15, 07:15 PM
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The boiler heats very effectively; I don't see any indication that the boiler is plugged up. The bypass valve should be open, you're saying? It's always been closed, from day one - at least that I'm aware.

I'll take and post a couple more pics right now...
 
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Old 01-22-15, 07:20 PM
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Trooper will be along hopefully to offer advice...

I have not had time to study your issue.. I assume its piped like in diagram 22 from the link I showed you?

Test the stat on the indirect with a simple continuity meter..
 
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Old 01-22-15, 07:26 PM
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Couple more pics of the system:






This is a shot of the main loop - which runs behind the two air handlers (which are equipped with supplemental hydronic radiators. There are two stubs there for an add-on, if it is desired:



There are two expansion tanks in this system because the loop for the garage and stoop is antifreeze, with a heat exchanger. The larger tank is for the main loop (above the boiler); the smaller one mounted high is for the isolated antifreezed loop for the garage/stoop.
 
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Old 01-22-15, 07:34 PM
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It is piped at least very close to diagram 22 in the manual, yes - though it's more complicated - and the relief valve appears to be directly off a drop, and not off the boiler.
 
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Old 01-22-15, 07:42 PM
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in this forum, is the privilege of "replying with quotes" reserved until a minimum post number is hit? I have only a "reply" option, which doesn't allow me to quote the poster to whom I'm replying.
At the top of the reply window there is an icon all the way to the right that will put the {QUOTE} and {/QUOTE} symbols into your reply. Any text between them will appear in quotes. I used squiggly brackets so they would appear here, when you click it you get square brackets.

Good lawd man... I don't know we'll be able to make sense of that system without a college course!

I see that you do have a check valve in the line to the water heater...

I turned it down - to no effect - and kept doing so in increments, with no change in scalding hot water. Until one final minute notch, when it seemed to stop calling for heat altogether. At that point in the dial (well into the cold zone of the dial), I could move the dial slightly hotter, and an immediate output to the TACO pump (pictured) was noted. Moving it back a touch colder turned it off immediately, and would NEVER activate the pump.

So I'm thinking bad aquastat.
You're referring to the control on the water heater, correct?
 
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Old 01-22-15, 07:48 PM
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A few more pics; this one taken facing up to see how the garage zone pipes off the main loop:



Close-up of the temp control module & boiler gauge:




This is the lowest setting on the aquastat that still runs the TACO pump to heat the water in the tank. Lower than this, it shuts down completely; higher than this doesn't make a difference:



I'm not sure how to learn more from a continuity test than I do just by observing the pump turn on/off when I fiddle with the knob. The issue is how frequently the aquastat cycles the pump to maintain a desired temperature in the tank - and I'm not getting any cycling. That pump is either on, or it's off.
 
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Old 01-22-15, 07:52 PM
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Hi Trooper!

Yes, I'm very familiar with manipulating codes; the problem is that when I hit 'reply', I'm not getting your text popping up in my reply window, and I'd have to cut portions of your text from the page itself and wrap it in quotes in order to reply question by question. *EDIT* Nope. I cannot highlight your text off the page and cut/paste. I'm working off an iPad, and this forum doesn't appear happy with Apple.

I am referencing the water heater control, yes: the aquastat.
 
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Old 01-22-15, 07:55 PM
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It is piped at least very close to diagram 22 in the manual, yes
Nope.. Like figure 20 right? You have those close space tees and shown a min of 12" apart???
 
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Old 01-22-15, 07:55 PM
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I just noticed that that water pressure in the main loop appears a little low - the reading looks only like 11-12psi. Isn't that about 6-7 psi too low?

It's supposed to have an automatic fill feature. Hm.
 
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Old 01-22-15, 08:01 PM
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lawrosa: now that you draw my attention to other schematics, it is sorta a combination of dia20 and 21, I think...

I think I have zone valves in there too. I dunno. Here's what I see:

I see a boiler running hot water in a big loop, and with 5 indoor main floor zones; one isolated zone (antifreezed, with a heat exchanger fed heat from the main zone), and 3 secondary radiators installed on air handlers (two of which are pictured; the third is in an upstairs closet for the floor).

And another loop feeding heat to the Indirect water heater (Gold 80).
 
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Old 01-22-15, 08:02 PM
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I just noticed that that water pressure in the main loop appears a little low - the reading looks only like 11-12psi. Isn't that about 6-7 psi too low?
Depends on the temperature. Cold system 11-12 is probably fine... hot should be a few to say ten higher.

Sounds like the water heater aquastat is funky to me.

Yes, you would have to cut and paste to between the quote brackets but you might be right, not apple friendly...
 
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Old 01-22-15, 08:09 PM
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Thanks for the input!

Yeah: underneath your post, I see only a 'reply' button; normally I'd see a 'reply with quote' option - and I don't.

I'd done a bit of searching, and it seems like Weil-McLain has had an issue with bad aquastats. I think I'll call them and see if I can get shipped a replacement, as some have been accommodated. Apparently, Weil-McLain acknowledges bad aquastats - saying something like 'voltage spikes cause failure', or somesuch - and they send new modified ones.

Some of those have failed as well, however. Anyone know of another brand aquastat that would fit in the same spot? I know this IDWH has a 'well' into which the aquastat leads drop....
 
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Old 01-22-15, 08:18 PM
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The expansion tanks are set to activate @ 12psi; so I assume that this pressure is acceptable for this system. I can't see where to add water to it regardless (isn't that the water supply right w/regulator above the expansion tank to the right above the boiler?); though there has to be a way if I needed to.

MODERATORS: I suppose you could change the thread topic title to "Aquastat on Weil-McLain Gold 80 Water Heater not working"...
 
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Old 01-22-15, 08:32 PM
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MODERATORS: I suppose you could change the thread topic title to "Aquastat on Weil-McLain Gold 80 Water Heater not working"...
Done .
 
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Old 01-24-15, 07:08 AM
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Ok - so it seems that posters agree that it is the aquastat which is not functioning as any more than an on/off switch, correct?

Judging by the trouble that other consumers have had with Weil-McLain aquastats, does anyone know of another more reliable aquastat that would fit in the Weil-McLain Gold Plus 80 well?

I also have another question for experts: does it seem stupid that my AUX heat source are radiators installed in the air handlers? It seems to be pointless to me. If my boiler goes out, I have no backup, other than my fireplace. If there is a call for heat, it's because my main loop temp has dropped (likely due to excessive load from a large garage slab in very cold weather), and that means the radiators will be unable to get hot enough either, and the forced air will simply be cold - though I suppose you could argue that the radiators are directly connected to the main loops (no mixer valves), so at least they should be somewhat hotter.

So shouldn't the valve that lawrosa pointed out was a bypass valve to allow the boiler to reach proper temp not be a hard valve, but one which is actuated by a temperature sensor on the main loop? Or - alternatively - shouldn't my system have the ability to deprioritize the garage slab's call for heat if the rest of the house needs AUX heat to maintain temperature?

 
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