Aqua Stat relay tripping

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Old 02-02-13, 04:57 PM
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Exclamation Aqua Stat relay tripping

I just moved into my first home. Everything was running fine until we got some 10degree weather and the thermostat was set to 68 and the house was at 57. I have two zones and replaced the battery's in each thermostat. When I went into the boiler room I noticed the relay on the aqua stat was tripping and not allowing the circulator pump to come on. I shut the boiler down and checked the power and wiring. Everything is correct and working. If I push the relay closed the boiler kicks on and everything is okay but as soon as I let go it trips shuts down. My question is can I just change the relay? Or do I need to replace the whole thing?

I posted some pictures .
 
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Old 02-02-13, 05:51 PM
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First, turn the pump setting all the way down to the lowest temp - the red knob under the black knob. If that doesn't solve the problem, check the voltage to the primary of the relay, when there is a call for heat. It should be 24V.
 
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Old 02-02-13, 06:01 PM
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Sounds a little cryptic Doug... let's try this:

Liza,

Some of what you are seeing may be NORMAL operation.

There are THREE dials inside the aquastat box.

DIFF

HIGH

LOW

Tell us the settings on each dial
 
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Old 02-02-13, 06:08 PM
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Liza, in this picture, can you please get a clear shot of this valve from an angle that we can clearly see it?

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And if not too much trouble, please rotate pics upright...
 
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Old 02-02-13, 06:11 PM
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In fact, while you have the camera out, please pull back and let us see the installation from all angles.
 
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Old 02-03-13, 01:02 PM
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Thank you for the quick response

I changed the setting for the lo and it still didn't click on. Right now I have a pice of wood holding the relay closed and it's working correctly. The relay voltage is correct 24v. I'm using my iPhone so I'm not sure I can rotate the pictures. But I will post some more and a video.
 
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Old 02-03-13, 01:46 PM
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Old 02-03-13, 01:50 PM
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the You tube video

IMG 1679 - YouTube
 
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Old 02-03-13, 02:18 PM
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If you're sure the low-voltage coil of the relay is getting 24V, but isn't closing, then it would seem that the relay is shot. Be careful about poking around inside that enclosure, since 120V is exposed inside. Maybe show us exactly where you are measuring the 24V. When you defeat the relay, I assume that both the burner and pump run?

What is the model number of the aquastat? Should be printed on the inside of the metal cover.

By the way, defeating the relay with a stick isn't safe unless you are watching the pressure and temp.
 
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Old 02-03-13, 02:58 PM
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Right now I have a pice of wood holding the relay closed and it's working correctly.

Let's back up a bit here.

When your thermostats call for heat, do the zone valves open?

When you wedge the piece of wood in there, are you also having to manually open those zone valves?
 

Last edited by NJT; 02-03-13 at 03:28 PM.
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Old 02-03-13, 03:14 PM
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Here's what I want you to do, and I caution you that there is 120VAC exposed inside that aquastat and you can be KILLED if you get across it!

PLEASE understand what you should, and should NOT touch!

You obviously have a voltmeter and know how to use it.

Set the meter for AC VOLTS.

Turn ALL thermostats all the way down.

MEASURE the voltage between the " T T " (Thermostat) terminals inside the aquastat.

It should be 24 VAC.

Turn one of the thermostats all the way UP to force a call for heat.

Listen for the corresponding zone valve to open, you should hear a 'whirring' noise. When the whirring stops, the valve is open.

MEASURE the voltage between " T T " again.

It SHOULD BE ZERO, and the boiler should FIRE (at least the circulator should run, the burner may not fire if the boiler water is at or above 185° (high limit setting of the aquastat).

Turn that thermostat all the way down.

Repeat for each thermostat.

If the " T T " terminals do NOT go to ZERO volts when there is a call for heat, the problem is NOT in the aquastat itself, but rather in the ZONE VALVES... or the wiring, or the transformer that powers them.

If NONE of the thermostats / zone valves cause the voltage at " T T " to go to ZERO, the next thing to look for is a 24VAC control transformer mounted on a 4" utility box...

Looks like this:


image courtesy pexsupply.com

Measure across those two screw terminals. You should read 24 VAC or a little higher. If you do NOT read 24VAC, you probably have a bad transformer.

Let us know the results...
 
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Old 02-03-13, 03:18 PM
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I do not see a pipe leading to the floor coming off this valve.

It appears that this valve has in the past spewed some water... evidence by the streaking on the boiler.

When this valve spews hot boiler water it will soak the electrical controls... NOT GOOD!

All building codes (even if your basement appears to be a cave... dirt walls?) REQUIRE that the safety relief valve be piped to within 6" of the floor, and AWAY from anyone who might be standing near the boiler.

This is DANGEROUS! 180° water and even hotter steam can KILL!

Relief valves like this should be installed with the stem pointing UP, per manufacturer's guidelines.

I would like you to have that valve replaced and installed properly, for your safety.

There needs to be an elbow pointing UP with the valve on TOP, valve UPRIGHT.

Then, a pipe coming out the valve, with an elbow pointing DOWN, with a pipe to the floor.
 
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Old 02-03-13, 03:30 PM
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By the way, with the exception of the DIFF setting, your OK with the others...

I would turn the diff to at least 15, even 20.

Are you making domestic hot water with this boiler via a 'tankless coil' inside the boiler, or do you have another stand alone water heater?
 
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Old 02-03-13, 07:53 PM
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Okay this seems to be more then i can Handel now. I think I might call someone so they can fix the hot water valve and whatever's wrong with the relay. I'm a pretty good DIY person but sometimes you just have to call a professional. Thank you everyone for your help but I'm growing I the towel on this one I've been fighting with it for 3 weeks now and just want it fix.
 
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Old 02-03-13, 09:23 PM
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In the first picture of the first post I see the control (thermostat) cable coming into the aquastat housing through an unbushed hole. Look closely at the loop of cable and it appears there is a hole in the outer jacket. The inner conductors may be damaged/broken at this point which would cause the lack of operation.

WHY, oh why is it that installers routinely make a huge rat's nest of the zone valve wiring with wire nuts and big bundles of wires? It is a simple thing to remove the cover and make the connections INSIDE the zone valve enclosure and it makes the installation far neater.

That particular model of Honeywell relay is known to be problematic (the relay itself, not the control) and shoving the wedge in it like you have done has probably done far more harm than you can imagine.

If it were mine I would save the dual thermostats within the control and use them in conjunction with an external transformer and sealed plug-in relay but I know that most DIYers would rather not have a custom control.


Okay this seems to be more then i can Handel now.
What does a German-born but often considered to be English, composer of the baroque era have to do with this problem?

http://en.wikipedia.org/wiki/George_Frideric_Handel
 
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