Circulator Pump not working all the time when called for

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Old 11-25-12, 05:37 PM
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Circulator Pump not working all the time when called for

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I have been having a problem with the boiler not coming on when the thermostats call for heat. When It first happened I turned the power switch to the boiler off and back on and the circulator pump came on and then the boiler fired up. It just started doing this. At different times I will have to do the same thing to get the boiler to kick back on. When it does come on, the house heats up fine.


Is it most likely the aquastat relay or could it be something else? The aquastat on the boiler now is a Honeywell L8148G .


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Old 11-25-12, 06:02 PM
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Do you have any zone valves?

A voltage meter would be very helpful in tracking down the problem.
 
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Old 11-25-12, 06:03 PM
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I have three zone valves, and one thing I tried was to open the valves to let a constant flow of water though them, but when done so, the circulator would not kick in.
 
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Old 11-25-12, 07:07 PM
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Your experienc seems a little strange. Best to troubleshoot with a voltmeter and determine where the volatage is being interrupted for the contols.
 
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Old 11-25-12, 08:00 PM
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You will need a volt meter to check what is going on here. When your thermostat makes a call for heat, it sends voltage to the zone valve. The zone valve opens and activates the end switch and that sends voltage to the boiler so it can turn on. It is possible that the end switch is bad. However, if this happens for all zones valves, it probably is something else.
 
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Old 11-26-12, 03:20 PM
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I dont have a volt meter, but what I did do was to open each zone by opening the manual switch. I did each zone individually and nothing happened. Then opened all three of them at once, and again, nothing happened.

I then went to the aquastat and took the cover off. When I turned the power switch off and back on, I noticed where the clicking was taking place. I then pushed the relay forward and as soon as it made contact, the circulator pump came on and then the boiler started up.

This is what seems to be the problem, but why and what would cause this? And can it be fixed, or does the whole aquastat need to be replaced?
 
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Old 11-26-12, 03:32 PM
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Don't jump to conclusions without backup data, you will be spending money and effort on things that don't need to be changed.

If they are Honeywell valves, manually opening them may not activate the endswitch or fire the boiler so the point of that test is moot... irrelevant.

I'm not saying that the trouble is not in the aquastat, but it is actually the LEAST likely suspect in this case.

If these are HONEYWELL zone valves (or others, but NOT TACO) then;

Do this:

Turn all the thermostats all the way down.

Position yourself next to the zone valves and have a helper turn up the thermostats one at a time.

You should be able to hear the 'whirring' of the motor in the zone valves as the valves open.

Do you hear it?


You need to troubleshoot systematically, and understand what results you should expect to see.

You need a multimeter and know how to use it.
 
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Old 11-26-12, 04:20 PM
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Hello,

The three zone valves that I have are the TACO zone valves
 
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Old 11-26-12, 04:50 PM
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Oh darn...

Yeah, they don't make a whirring noise...

BUT, the DO get WARM after a few minutes.

Do you notice that the valve head is warm when the thermostat has been calling for heat for a bit of time?

What I'm thinking is that you may have lost your 24VAC source that opens the valves...

It would be easy to check if ya had a meter.

Do you know anyone who has a meter and knows how to use it?
 
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Old 11-26-12, 06:58 PM
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I will ask someone I know tomorrow. I should be able to hook up with someone who has one
 
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Old 11-26-12, 07:06 PM
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Oh ya,

I did feel the valves and two of them where very very warm, 1st floor and 2nd floor. The basement valve was just barely warm, but I dont keep the basement thermostat very high either, 58-60. The basement is finished, but gets very little use, if any.
 
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Old 11-26-12, 07:16 PM
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OK, if the valves are warm to hot, that means that you have 24VAC power going to them.

Maybe you can do another test without a meter:

Take a short piece of scrap wire. Strip a bit of insulation from both ends.

VERY CAREFULLY touch this wire between terminals 2 and 3 on any one of the zone valves.

DO NOT TOUCH terminal 1 with the wire!

When you touch this wire to 2 and 3, you should hear the relay in the aquastat CLICK! and the pump and boiler should fire up.

Does it?
 
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Old 11-26-12, 07:54 PM
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I did try what you said with the wire, and you could hear the relay click, the boiler fired up, but the circulator pump did not kick in. I held the wire in place again on a different valve and the circulator pump again did not come on, but the relay did click and the boiler did fire up
 
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Old 11-26-12, 08:56 PM
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OK...

Now, when the thermostats themselves call for heat, does the EXACT SAME THING happen as when you touch the wire on 2 and 3 ?

If the zone valves are all working properly, it should.

Before I proclaim a problem with the aquastat, which you may well have, you need to have your friend with the meter come over.

WARNING! 120 VAC LIVE VOLTAGE INSIDE AQUASTAT! YOU CAN BE KILLED! DO NOT TOUCH ANY EXPOSED TERMINALS!

Set the meter for AC VOLTS and place one probe on the C2 terminal and the other probe on the C1 terminal. WARNING! 120 VOLTS AC!

When you touch the wire on terminals 2 and 3 of the zone valve, and the relay clicks, and the burner starts, the circulator is SUPPOSED to start.

You should see 120 VAC on the meter in this condition.

If you see NO VOLTAGE, or ERRATIC VOLTAGE, there is a problem with the aquastat.
 
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Old 11-27-12, 12:27 PM
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Hello again,

I got out of work a little early to try this.

I tried your test with a thermostat, turning them up to call for heat, and the same things did happen, about two minutes after turning it up, the click happened and the boiler fired up, but the circular pump DID NOT come on. The boiler then turned itself off.

I turned the thermostat down low, and I then waited about ten minutes and tried what you said with a volt meter, 120V, (I borrowed one) to terminal 1 and 2, and touched the wire to 2 and 3. The click took place and the boiler fired up, but no circulator pump came on again. I did this to all three, same results.

I then got the circulator pump and boiler to run, and then tested the volts from terminals 1 and 2 on the zone valve that was calling for heat, and again there was no volts between the two terminals.
 
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Old 11-27-12, 04:53 PM
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I'm sorry Kem, I should have been more explicit.

The C1 and C2 terminals are inside the 8148 aquastat, I didn't mean terminals 1 and 2 on the zone valves... my bad.

WARNING! 120 VAC LIVE VOLTAGE INSIDE AQUASTAT! YOU CAN BE KILLED! DO NOT TOUCH ANY EXPOSED TERMINALS!
 
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Old 11-27-12, 06:10 PM
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Good evening,

My fault for not noticing the difference from terminal 1 and C1. I should have looked at it closer. My fault.

But I did do what you had said, and when the volt meter is on C1 and C2, the meter does show a solid reading of 120V when Terminal 2 and 3 are connected with the wire. And this time also the pump did kick on, but this has happened on occasion in the past
 
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Old 11-27-12, 06:14 PM
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Yeah... more I think about this, you've got a cracked solder connection at the relay where it's soldered to the circuit board.

If you can't solder, you need to replace the aquastat.
 
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Old 11-27-12, 06:26 PM
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I'll take a look at that now and see if I can notice anything. It would be great if that was all it was. It has been a while since i have done any soldering to terminals, but if that is all it is, that would be easy enough.
 
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Old 11-27-12, 07:01 PM
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Hi again,

I'm not sure if this would mean anything, but while looking at the aquastat, there looks to be some dried out material behind the relay. Do you think that would have anything to do with the problem?

Let me know if the pic came through,
 
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Old 11-27-12, 07:05 PM
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One more pic. It may give a better view
 
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Old 11-27-12, 07:29 PM
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No, I can't see the 'dried out material', but what I do see is the fact that you've got an older aquastat that probably doesn't have the soldered in relay. I believe that yours has WIRES connecting all those terminals together underneath the board.

Can you get a good close look in the SIDE of that relay and view the actual contacts? If you are lucky all you may have to do is clean the contacts with a good quality cleaner like " De-Oxit Gold " which you may find at Radio Shack.

Do NOT use anything abrasive on the contacts!

OR, maybe you will find that they are all worn out... pitted and melted...

Bottom line is this though, if the zone valves are calling for heat and the relay is clicking, and you aren't getting 120VAC to the yellow wire to the circ, the problem is definitely in the aquastat.

What exactly the problem is we don't know yet, but I will say at this point it can probably be found with a close visual inspection. The defect won't be 'hidden'. Well... it could be on the bottom of the board if it is a bad solder... so maybe a little bit hidden!
 
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Old 11-29-12, 07:47 AM
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Thumbs up

Hi,

I decided to get a new aquastat to repair the problem. I found out the boiler was installed in 1974, so the odds where better if I replaced it. I was kind of nervous too if I had it all apart and could not find any spots that needed soldering and then had to put it all back together to do the same thing again.
But the new aquastat solved the problem and the heat is working fine now.

I just wanted to say thank you very much NJ Trooper for all your help. You are the best. I understand the system a lot more now after listening to the way you wanted to check other things first. You are the best.

Thanks Again. Kevin
 
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Old 11-29-12, 03:43 PM
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Good deal Kevin. I sorta knew that's where this would end up but you needed to make the decision, not me! I don't mind spending other ppl's money, but only if it's on beer!
 
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Old 11-29-12, 03:58 PM
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If you ever make it to the Boston area, let me know and I'll take you out for one.....or two. I'll even throw in a steak
 
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Old 11-29-12, 04:04 PM
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Boston? Home of my favorite brewery! Say hello to Jim K next time you see him... Andrew too!
 
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