Everything works except no water circulation

[stevemason5]

I have a Sears/Kenmore gas furnace hot water heating system thats acting erratically.

What works:

1.) The house thermostat appears to work.
2.) I hear the electronic igniter "clicking".
3.) I hear the gas supply flowing.
4.) I see and hear the gas ignite and stay lite.

What does not work:

1.) The Grundig circulator pump (which makes a humming sound when it operates) does not appear to be operating (no hum, as before).

2.) The heating system works as described above but seems to cycle on and off without water circulation - the circulator hum is no longer there. In the past, I am 90% sure the circulator pump kicked in whenever the furnace was activated by the room thermostat.

3.) MOST IMPORTANT: When the furnace is activated (by initially raising the temperature setting of the room thermostat) the igniter lites the gas and the furnace runs for a few minutes, then it shuts down. The new room thermostat setting is completely ignored and little heat reaches the room radiators. STATS: The furnace reads a temperature of about 180 degrees F with a water pressure of about 18 psi.

I suspect (but I am likely WRONG) the furnace is reaching a top temperature and then cycling off as a protective measure because the pump is not circulating the heated water to the room radiators and returning cooler water for reheating. What I cannot understand is why the pump does not operate. Also, the furnace temperature reading does not appear to be very "high" (high enough to cause a furnace shutdown) or beyond a normal Winter operating temperature.

Sorry for the long post - just trying to describe the problem.

Thanks for all your help.

Steve

[oil lp man]

The problem could be the thermostat itself or thermostat connections on the thermostat, or the thermostat connections on the circulator control, or the circulator control itself could be bad, or the 120 volt connections at the circulator control are loose, or the connections at the circulator are loose, or the circulator could be bad or the capacitor at the circulator could be bad.
If you have a volt-ohm meter and know how to use it, you will figure it out.

Its even possible that there is air in the zones and the circulator won't pull.
Chances are the control will only fire off the burners if its calling for heat so that would ELIMINATE the thermostat and connections as being the problem.


[Edited by oil lp man on 10-05-2004 at 12:45 PM]

[stevemason5]

Thanks oil lp man.

I started checking voltages with an ohmmeter and was about to remove the circulator capacitor when...

I found one loose thermostat connection (left by the furnace man). I tightened it and it looks like its working.

Seems like its almost always 1 or 2 simple things.

I'll post again if anything changes.

Steve

[h2045]

It`s a boiler NOT a furnace

[stevemason5]

My hot water circulator problem returned (likely never left).

The room thermostat initially turns on the boiler (igniter clicks, gas flow and flame all present and working) and the circulator operates. It all runs fine for about 15-30 minutes then everything shuts down. The initial shut down ignores the room thermostat. Later, it turns on again. Sometimes, everything including the circulator, works. Other times, the igniter kicks in, the gas flows and the boiler lights and runs, but the circulator does not operate.

Specs around shut off time - Water temp about 185 deg F, water pressure about 13 psi.

I've checked the electrical connections and they look okay but will check again. I do not think its an air pocket. Its circulator operation related.

Help appreciated !

Steve

[oil lp man]

When it happens again, if you put a jumper across the thermostat connections of the aquastat control and you don't have power(120 volts) at the circulator terminals at the aquastat control(C1 and C2) then your aquastat control is bad.

[stevemason5]

oil lp man,

I identified the C1 and C2 (circulator) connectors with black and white wires. Also, I found the thermostat connectors as follows:

TV: with a red wire
W jumped to the TV connector
T with a green wire
Z with a white wire

Which two room thermostat wires do I jump (then check C1/C2 for 120 VAC) when the circulator is not working ?

More info:

Inside the Honeywell elctrical housing I found a transformer, a (I believe) gas valve relay and a device with a gear in it with (I think) temperature markings stamped into the metal. I carefully checked and found 120VAC current at the line (L1/L2) connectors. Inside the circulator electrical housing I found connectors and a cylindrical device that looks like a electrolitic capacitor. On the outside of the Grundfos circulator there is a 1" slotted screw in the center of the housing that dripped water a bit when I turned the screw counter-clockwise a half turn (retightened).

Where is the aquastat ?

Steve

[oil lp man]

Originally posted by stevemason5
oil lp man,

I identified the C1 and C2 (circulator) connectors with black and white wires. Also, I found the thermostat connectors as follows:

TV: with a red wire
W jumped to the TV connector
T with a green wire
Z with a white wire

Which two room thermostat wires do I jump (then check C1/C2 for 120 VAC) when the circulator is not working ?

More info:

Inside the Honeywell elctrical housing I found a transformer, a (I believe) gas valve relay and a device with a gear in it with (I think) temperature markings stamped into the metal. I carefully checked and found 120VAC current at the line (L1/L2) connectors. Inside the circulator electrical housing I found connectors and a cylindrical device that looks like a electrolitic capacitor. On the outside of the Grundfos circulator there is a 1" slotted screw in the center of the housing that dripped water a bit when I turned the screw counter-clockwise a half turn (retightened).

Where is the aquastat ?

Steve

You're scaring me. I thought you had a better idea of what you were doing. The electical housing you are talking about is the aquastat.
You need to jumper the TV and T terminals.
I'm done.

[Edited by oil lp man on 10-11-2004 at 01:00 PM]

[hetrola]

Your hight limit is shutting the boiler off at 185 deg. Your circ. pump should be running and this is normal. your boiler maintains temperature. if your circ. pump is not running on calls for heat then you should call in a pro.

[GradyWhite244]

Grundfos circulator? Is the circulator body hot? If it is, the circulator rotor is probably stuck. A common problem with Grundfos.

[heatpumpman24]

Just a guess, but maybe the control for the pump is bad, or maybe just the pump is bad...

[keith1]

Gradywhite is right,on the back of the circulator pump is a silver slotted screw.Unscrew it-will get water seepage.The shaft is slotted,take a screw driver and give it a few turns with power off course.Try that.Grundfos is notorious for that.

[stevemason5]

Thanks guys.

Looks like I scared oil lp man, sorry about that. I am not an expert but I have some tech backround, I listen pretty well and proceed slowly with great caution.

I did short out the TV and V terminals to test for C1 and C2 current. Before the jumping TV and V there was 120 VAC current at the C1 and C2 terminals but no circulator motion. After shorting out the TV/V terminals there was 0 VAC at the C1/C2 terminals and, of course, no circulator motion. Hope I did not fry something. If I did, I'll live with the consequences.

The 185 deg F shut down makes sense. If the circulator does not operate, the boiler heats the stagnate water near the aquastat themostat and shuts it down at the aquastat setting. Since the circulator does not supply colder water to the system, the heat in the water just builds up near the thermostat. I checked the aquastat setting - sure enough, it is set at about 180 deg F.

I am leaning toward the Grundfos UP 26-64F circulator as the core problem. If C1 and C2 are energized with 120 VAC during operation, why is the circulator not operating ?

I removed the silver shaft screw and turned the the shaft a few times. It seemed to turn pretty easily (I used a very small screwdriver). Then I energized the circulator with 120 VAC separate from the aquastat. I got nothing. No hum, no warmth or vibration on the circulator housing. Looks like a dead circulator or a dead starter. I called a Grundfos distributor. They no longer make this unit so replacing the starter circuit is out. Replacing the starter capacitor may be an option.

Questions:

Is there a test to check the circulator starter capacitor ?

This Grundfos has a pronounced hum that is transferred to the house via the radiators. Can anyone recommend a reliable and quieter replacement circulator that will fit in the above Grundfos installation ? A few rough dimensions: from flange to flange, the Grundfos is 6 1/2" tall and the flange bolts are 3 1/4" apart, center to center.

Thanks.

Steve

[hetrola]

you more than likely have air in the system.
Do you have an air seperator such as a spiro-vent. You might have an air seperator above your expansion tank, and depending on your radiators you might have them there.
If some radiators are warm, follow the piping to the next radiator until you find a colder one, and remove the air. If you have trouble identifying the piping system call a pro.


The pump will make a little humming noise. If it resonates through out the house follow the pipe the pump is connected to and see if it is touching a floor joist. If it is put something between to absorb the sound.

[epacertified]

I would imagine all ciculators fit.
I have been fooled by a bad circulator more than once
If you have a 120v at pump then there are only two things that can be wrong.
Air in the system(I,ve seen the best Plumbers have problems getting air out of some systems)
Bad circ motor(sometimes they start and two min later their not spinning any more and still have 120v present.

[stevemason5]

Thanks again.

I did a few more tests.

On a cold start, everything worked except the circulator. There was 120 VAC at the circulator terminals on the body of the circulator. I heard and felt no humming on the circulator.

I took a risk and slowly opened the Grundfos at the dime-sized screw in the center of the circulator body. A little water came out. The shaft was not turning. I turned the shaft with a screwdriver to see if it would catch and run - it did not.

I tested the circulator for 120 VAC after the first premature shut-down (prior to reaching the room thermostat set temperature). It continued to show 120 VAC current even after shut-down (likely to continue circulating heat to the house). The boiler temp was 140 deg F. The aquastat set temp was about 180 deg F.

Its odd that the system shut down at 140 deg F before reaching the aquastat set temp of 180 deg F.

On the second cycle (again the room thermostat temp had not been reached) the boiler temperature reached almost 180 deg F with the aquastat still set at 180 deg F. I assume the aquastat senses a pre-set temp and when it is reached it shuts everything down. The circulator continues to run to distribute heat to the house (and cool down the aquastat till the next cycle).

None of my radiators was hot. Even the hot side pipes about 5 feet from the boiler were cold.

My opinion (which may be wrong) is that air in the pipes is not the main issue since currently the circulator is not operating. There is no flow so I cannot tell if there are any air pockets. Thanks for the "hum" advice. I'll check for joist contact and install some barriers.

I'm looking at a circulator by B and G, model NRG-22 I think. It has the same dimensions as the Grundfos. It seems pretty popular around here (Chicago) and the price looks right ($65). Is that a good choice ? This is a 3 BR, 2 bath, 2 story home.

I appreciate all the expert advice. Its very kind of all of you to spend some time to help out. Thank you.

Steve

[slimwoodie]

probably $ 2300 worth of peoples time on this $ 115 dollar service call ..... just go and buy a $ 50 circulator, and be done with it ..if you had called a contractor, you woulda had heat long ago ....

[hydronicsman]

The B+G would be dead last for my choice. They like to seize.

See if anyone has the Grunfos SuperBrute 3 speed. This pump is NOT your old one-no worries.. You can tailor the speed and pump curve to your system.

Taco's 00 series is the next best. The 007 probaly matches your old pump's performance.

Don't bother with the old pump's start cap..like Slim said, change the pump and be done.

[stevemason5]

Thanks again.

Warning: LONG POST AHEAD

Looks like problem solved. It seems to be working well. Plus, I better understand my boiler set up. Thats important because I am responsible for this house plus two attached small apartments 24 hours a day, 7 days a week. I have often (but not always) had poor and often expensive advice/work in the past. I like to learn the facts before I decide what to do. If I called a contractor/plumber/electrician./repairmen everytime something went wrong, I'd be in the poor house.

TACO 007 vs. B&G NRF-22

A well known fact: The performance curves and prices on these two pumps are virtually identical.

I replaced my burned out Grundfos with a B & G NRF-22. I initially bought a TACO 007 (the Grundfos's were hard to find and expensive) but I had a lot of difficulty finding the right sized flange assy's for my set up. Really preferred to go with TACO. I heard they are a bit quieter, too. Still, the B & G has much, much better support around here. If it doesn't work out, I'll give B & G a hard time and replace it with a TACO.

B&G Reliability

I did a little research on the B & G circulator pump problem. From talks with distributors and a customer feedback rep at B & G there was a problem with the T or TR-100 series (something like that). I understand it been fixed. If it was not fixed, their whole product line reputation would be on the line. It would be pretty foolish not to fix it.

From what I hear, the water cooled pumps I looked at fall under the "throw-away" category. Not sure I agree. There are some replaceable parts. Not sure what I'll do next time.

A Short HVAC Story

My dad's new boiler system has a TACO 0010 circulator. But...
His old boiler set-up ran a long time before he had to replace it. He regularly oiled the old system's circulator pump (sorry, he does not remember the brand, he's 79 with a poor memory). He also tinkered with boiler settings making it much more safe and efficient. Prior to replacing the old boiler, the circulator pump was still there and still working, after 40+ years of operation.

Again, thanks for the help and patience.

Steve

[hydronicsman]

Glad to hear you did ok

For the trades, changing out a 007 complete is more cost effective than fooling around with the parts that make it up-one call back would cost us more than it's worth.

Tip: if the system had a 3 piece circ like the Taco 110, and has zone valves, and you swap the 110 for a 007, sometimes you'll get banging of the zone valves after the swap. That's cause the 110's pump curve is more linear than the sharp ramp-up of the 007. Doesn't happen often, but sometimes..

I think you have a 3 year waranty on your new 007. Happy Hydronicking!