Thermostat on Water Heater not working Weil Mclain Gold Plus 40

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Old 11-30-11, 08:38 AM
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Thermostat on Water Heater not working Weil Mclain Gold Plus 40

Hi,

I just moved into a house that has a Weil Mclain Gold Plus indirect water heater. I have the temperature set to the factory recommended setting (I'm guessing this should be ~120-130 degrees). Our water is much much hotter though out of the faucet. It is close to 160 degrees. Is it possible that that the thermostat is not working correctly. Any advice on where to start?
 
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Old 11-30-11, 12:31 PM
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Some of the possible problem areas are: the aquastat may not be calibrated correctly, there may be thermosiphoning between boiler and indirect,or the heat circulatory may be pumping through indirect on a thermostat call for heat.Try turning the aquastat down or even off to see if it makes a difference.
 
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Old 11-30-11, 04:15 PM
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just moved into a house
So you don't know if this is a new problem, or has existed for a long time then?

the heat circulatory may be pumping through indirect on a thermostat call for heat.Try turning the aquastat down or even off to see if it makes a difference.
That would actually be a pretty good, simple test to do for starters.

ALL THE WAY down on the aquastat. If the water stays that hot, then the problem is elsewhere... the installers might have goofed on something.

After this, turn the aquastat (you called it a thermostat) on the indirect back up to 100 and let the system recover the temp in the tank. Measure the water temp again, is it proportionally lower than before when it was set at 120-130 ?

Tell us a little more about how the system is piped:

How many circulator pumps are on your system?

Do you know if the system has electric zone valves?

How many heating zones (thermostats) do you have?

Does the water get to the indirect via a pump, or an electric valve?

We can probably answer these for ourselves if you wish to take a bunch of in focus, well lighted, large enough for old dudes to see, NOT cell phone pics, and upload them to a FREE account at Image hosting, free photo sharing & video sharing at Photobucket and come back here and drop a link to your PUBLIC album.

Take enough pics that we can see the entire system from several angles, in addition to any closer shots of the piping to and from the indirect, and to and from the zones.
 
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Old 11-30-11, 05:36 PM
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Thank you guys for the quick replies! It's awesome to know that there's a place out there where peoples are willing to help out.

Originally Posted by NJ Trooper View Post
So you don't know if this is a new problem, or has existed for a long time then?

Correct, I would assume this was an existing problem. The water has been very hot since we moved in and the aquastat has always been set at a reasonable level.

That would actually be a pretty good, simple test to do for starters.

ALL THE WAY down on the aquastat. If the water stays that hot, then the problem is elsewhere... the installers might have goofed on something.

I just did this, how long would I have to wait to test it?
After this, turn the aquastat (you called it a thermostat) on the indirect back up to 100 and let the system recover the temp in the tank. Measure the water temp again, is it proportionally lower than before when it was set at 120-130 ?

Tell us a little more about how the system is piped:

How many circulator pumps are on your system?
There are 3 circulators
Do you know if the system has electric zone valves?
The circulators are tied to a Taco box
How many heating zones (thermostats) do you have?
We have two heating zones.
Does the water get to the indirect via a pump, or an electric valve?
Not sure on this one, how can I tell?
We can probably answer these for ourselves if you wish to take a bunch of in focus, well lighted, large enough for old dudes to see, NOT cell phone pics, and upload them to a FREE account at Image hosting, free photo sharing & video sharing at Photobucket and come back here and drop a link to your PUBLIC album.

Take enough pics that we can see the entire system from several angles, in addition to any closer shots of the piping to and from the indirect, and to and from the zones.
Here is the link to my photos. Let me know if you need details about any area. Heating System pictures by rebelins6 - Photobucket
 
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Old 11-30-11, 07:12 PM
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DISREGARD the grayed out text below! Sorry... I posted before I saw the last picture! DON'T OPEN THAT VALVE!

What I THOUGHT I saw was a 'STOP VALVE' between the water heater and the relief valve.

In the last pic it becomes clear that this is a DRAIN VALVE... or more likely what is called a PURGE VALVE, used for letting the air out of the tank as it is filled.

It is NOT a hazardous condition!

Again, sorry about that!


I believe that I see a MAJOR problem right off the bat!

On the top of the water heater is a valve with a red handle... and on top of that, I believe that what I see there is a PRESSURE RELIEF VALVE.

This is DANGEROUS!

If that red valve is accidentally CLOSED, and there is a problem with that system where the pressure in the heater goes too high for any reason... KABOOM! It ain't pretty when this happens!

Take a look at that relief valve above the red handle valve, tell us what the tag says. It may in fact not even be the correct valve for the application.

Please check immediately that the red handle valve is OPEN! and when you are sure it's open, get a screwdriver and take the handle off. Have the valve removed at your earliest convenience.
 

Last edited by NJT; 11-30-11 at 07:31 PM.
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Old 11-30-11, 07:30 PM
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Can we get closer, clearer pics of the yellow circled items ?

 
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Old 11-30-11, 07:38 PM
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I just did this, how long would I have to wait to test it?
After seeing the pics, I don't think there's a mess-up with the piping.

There might be a problem with one of the circled yellow items in previous post, but let's have a close look at those before deciding. It's possible that one of those valves is either stuck open, or has been manually opened by accident.

Turn the aquastat (thermostat) on the water heater back up again... to say 100 and leave it there for a day or two and note if the water temperature has gotten cooler.

Not sure on this one, how can I tell?
We can tell by seeing the pics, thanks!

The black circulator on the left appears to be the one that is pumping to the water heater. When the water heater is calling for heat, the black pump should run. The green TACO box has lights on the side of it, right? Those lights will tell you which zone is calling for heat.

All in all, your system looks pretty darn good!
 
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Old 11-30-11, 07:48 PM
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In this pic:



Tell us the readings on the boiler gauge, pressure and temperature.

Turn off the power to the boiler and slide the gray cover straight off the control box (you may have to loosen one screw on one side). Tell us what model that control is (label inside cover) and what the setting(s) on the control dial(s) is(are).
 
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Old 11-30-11, 08:40 PM
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Here are the zoomed in photos


 
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Old 11-30-11, 09:02 PM
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Boiler gauge reads 40 psi for pressure (theres also a red arrow pointed to 70 psi), and 170 degrees.

Aquastat relay is a Honeywell L8148A. I'm not really seeing any dials on the inside though.
 
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Old 11-30-11, 09:20 PM
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Never mind, I found it. Looks like it is set just under 190.

 
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Old 12-01-11, 02:41 PM
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One of the first things to check is the flo-chek valves... that's those three in the first picture, one on each 'zone' return.

I can never remember which knob turning direction is 'normal' for these, but I believe it's FULLY CLOCKWISE.

If those valve are not in the proper position, you will get unintended flow through a zone when it's not wanted or needed. This will happen when ANOTHER zone calls for heat... (by the way, the indirect counts as a 'zone', so you have a three zone system, one zone is the water heater)

So first check that they are all fully clockwise.

I believe that the other valve I asked a pic of is a 'vacuum breaker', and you can forget about that... not the problem. I thought it might have been a 'mixing valve',.., but it's not.

Everything looks fine with the 8148... you could set the temp at 180F ...might save a quart or two of fuel. 180 is the more or less 'standard' temperature.

more...
 
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Old 12-01-11, 02:49 PM
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Boiler gauge reads 40 psi for pressure (theres also a red arrow pointed to 70 psi), and 170 degrees.
There may be two scales on the temperature gauge... one in FEET , one in PSI.
I suspect you may be reading the FEET scale, please check again... 40 PSI is way too high... but if you are reading the FEET scale, that is equal to around 18 PSI which is fine.

Next we'll look at the aquastat (thermometer) on the indirect tank...

Do you own and know how to use a multimeter?

Oh... one more thing... inside the green TACO box that the circs are wired to are some slide switches... can you take a close up of the inside of that box as well?
 
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Old 12-01-11, 02:52 PM
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Originally Posted by NJ Trooper View Post
I can never remember which knob turning direction is 'normal' for these, but I believe it's FULLY CLOCKWISE..
Yes, the normal position is fully CW - this allows the check valve to drop closed when the pump is off. CCW manually jacks the valve open.
 
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Old 12-01-11, 07:16 PM
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Sorry for the delay tonight. I checked the flo check valves. Two were a little loose so I tightened them up (though not the one for the indirect zone).

You're right, I was reading the inside of the pressure dial. Its about 20 psi


Here are pics of the inside of the Taco box and the aquastat.


 
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Old 12-02-11, 03:59 PM
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Everything I've see so far looks just fine...

In the Taco box, which of the three sets of thermostat wires is coming from the water heater?

Do the thermostat wires correspond correctly to the position of the zones? In other words, the 2 wires from the water heater thermostat are going to the same 'channel' in the Taco box as the black circulator pump?

And the 2 heating zones correspond to the correct pump?

=====================================

So, have you tried turning the thermostat on the indirect down yet? Looks like it's still at the 'factory' position. I'd like to know if it has any effect at all... this will help to diagnose the problem.

Turn it so it's pointing straight 'down' just to where it goes from light green to yellow. Take a long shower and see what happens.
 
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Old 12-02-11, 04:07 PM
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You've probably already seen this? If not, keep a copy of it near the panel somewhere.

http://www.taco-hvac.com/uploads/Fil...ry/102-168.pdf
 
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Old 01-22-15, 02:00 PM
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Old thread closed...

New thread here:

http://www.doityourself.com/forum/bo...ml#post2377277

Thanks....
 

Last edited by NJT; 01-22-15 at 02:28 PM. Reason: added link
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