circulating pump runs 24/7 sometimes

Royals

I have a hydro-therm

model hc-125 GAS system that heats using baseboards in my home. 3 zones with one circulating pump. It has

been running trouble free for many years, only had to replace the

circulating pump about 5 years ago. Lately I have noticed the circulating pump would sometimes be running with no call for heat. The boiler not running and all zones closed. What is happening is that when i call for heat, everything thing is fine, and when heat is satisfied, sometimes the circ pump does not shut down and will continue to run for days, or until i reset the system(kill power). This happens about once every week or so. Your thoughts

Mark Eatherton

Sticky relay...

I have seen numerous of these over the years. The relay for the pump gets stuck in the closed position. TIme for a new aquastat relay assembly...



ME

Royals

circulating pump runs 24/7 sometimes

thank-you for the quick reply. I assumed it was the relay assembly, but you just confirmed my suspicion...i'll get one ordered today.

Royals

bill_105

Another option

I just did this. Let the existing miserable relay be itself and put in a Grundfos Alpha. That pump gets power 24/7, and, you save money!

You see that annoying "Click Here" thing to the right? That's the ticket!

Royals

circulating pump runs 24/7 sometimes

Can i use the Taco SR503-2 for my setup? Documentation shows it allow for 3 zones. But I only have one circulating pump on my setup, and the installation of this SR503-2 shows 3 thermostats and 3 circ pumps.

icesailor

Running Pumps:

A "SR means that it is a "Switching Relay". You need a "ZC 503" That controls three zone valves and a circulator. "ZC" stands for "Zone Controller. They look the same on the outside. Different on the inside.

bill nye_3

polarity?

I would check for proper voltage. Make sure the black is black and the white is white. Most relays, electromechanical, that I have seen "hang-up" is when the polarity is reversed. Make sure the black is hot and the white is neutral.



 Also, if you have zone valves make sure the end switch is not "sticking" and holding the pump in.

chapchap70

Why would the Alpha be powered 24/7?

"I just did this. Let

the existing miserable relay be itself and put in a Grundfos Alpha.

That pump gets power 24/7, and, you save money!"





Could you explain this please?  I'm not familiar with the particular boiler referenced.  If there are zone valves, wouldn't there be deadheading. (unless there is a bypass but why circulate water around the boiler when no zones are calling?) 



I can see putting in the Alpha with the zone valves to control the flow and watts and powering it up when there is a call for heat but I don't understand what you mean by having it powered all the time.

bill_105

The Alpha

I wish I had a better answer,but here goes. The Alpha can be wired hot continuously. There is a wattage sensor that seeks to solve all of the worlds problems. It's not pressure.  As zone valves open and close it sees a need to do all this. Mr. Wizard is out there somewhere.

I've heard the better answer. I would like to here it again. I've put in a bunch of them, and I don't even do this stuff anymore.

I've been told that certain homeowners, at the beginning, willl sit and stare at the LED numbers, change like magic. Getting tired of the computer and TV?, go watch the Alpha!

Jean-David Beyer

Any idea why?

"Most relays, electromechanical, that I have seen "hang-up" is when the polarity is reversed."



That is not my understanding. The only AC relays I know of that did this were used in railway signaling. It is easier to make DC relays work like this, but here, too, the only ones I have ever seen that did this were used in railway signaling. Those had a permanent magnet in the magnetic path. I cannot imagine why these would be used in a heating application. Railway signaling relays tend to cost over $1000 a piece, and some over $10,000. They are used in what are called "vital circuits", meaning if they misfunction, you could kill a train load of people and enrich a lot of lawyers. Hence the high price.



But I am not a professional heating expert. The only one in my heating system is just a Honeywell RA832A, The relay in that one would work either way, but you better wire the whole thing up correctly or you would have other problems.

Paul48

Alpha?

From what I read, the alpha does not have a zero output in its functional parameters. Which means it would still have to be controlled by the boiler controls.Am I reading it wrong?

Mark Eatherton

You could, but...

You couldn't use the automatic,learn optimization mode cause every time you restart it, it has to learn everything all over again, and it takes a while for it to learn the system, again...



I leave mine running all the time and it works great .



ME

Mark Eatherton

I stand corrected...

I was told by another good friend that the Gfos alpha CAN be cycled on/off without any issues. Entirely possible, but have not had any time to observe it in action. When cycling it on and off, It only pushed 1 GPM, when I left it constant on, it hit 2. GPM. I may not have given it enough time to stabilize before making changes. Impatients is a virtue of mine :-)



ME

bill nye_3

hang up

I don't know the scientifically correct answer, but maybe the way the circuit is completed through the windings of the relay or the motor.



But I have done this many times, pull the relay in manually by lifting the "clapper"(not the correct term I am sure) and the circuit will remain engaged. I have found reversed polarity several times this way. Have done it with 8184G and aquastat type controls.

Paul48

Big Savings?

I'm not sold on it........Running at max., it's slightly over 60 watts (1/12th HP). One claim I read was that it was estimated that half of the electrical use of some homes in Europe was attributed to the circulator.....imagine that. Honestly, I think the Taco Delta-T, designed to optimize efficiency of the system as a whole is much better as an upgrade to a system. Just my thoughts.......MERRY CHRISTMAS!

Ron Jr._3

Homeowners and installers

have been known to watch the numbers change on the Alpha



Our first job with this circ was last week . Caught myself watching the display for a good long time !



 I hope they come out with an Alpha that can ramp up to full speed for an indirect . One circ for a whole system ( non-pri/sec ) would be great .

kcopp

It will not....

run on full speed often. It will find the proper setting and go w/ that. Mine runs at around 20 watts but will drop down to 8 sometimes. as each zone valve or TRV in my case closes the circuit needs less flow so the pump can slow down. Plus unlike most single speed pumps this will perfectly match the flow rate you need for the circuit. ...no more over-pumping zones. There are your savings.

Steamhead

Another nice, job, Ron

keep 'em coming!

Ron Jr._3

Thanks Frank !

Keep posting your beautiful installs too !

Gordy

Big Depends

In my mind on where, and how a delta T pump is used in a System. Taco's delta T pumps come in a wide range of sizes 003 up to 0014 so power consumption could be way more than an alpha depending on the size of pump used.



I don't know if delta t operation is the catch all answer. Again it all depends how the heating system is designed. Zoning with valves, or pumps. One circ one zone total system. Emitter type rads, baseboard,gravity conversion, radiant floor, radiant ceiling, radiant walls. What Delta T you use for the type of emitter 20* for baseboard, 10* for floors, 10* to 20* for ceilings etc. 



 The circ could be chasing the delta t tail through the whole heating cycle which is what it is designed to do, but how efficient is a circ that is constantly changing its speed, and does it really get there before the end of the heat call which usually is not very long in a residential scenario especially with micro loads/zones.



 This also has a lot to do with how system, and emitter piping is installed. If those piping arrangements are kept with in industry practice where there is low head, similar length loops etc. then small pumps can be used regardless.



 So then do delta P, T, and auto adapt circs become a band aid for poor install practice? Or maybe allow some design lattitude where what was bad practice now can be fine?



Only try to learn here Thoughts please. Sorry to hi Jack thread, but sometimes you have to sieze the moment.



Gordy

Paul48

apples to apples

Let's just say, that if either will work in a given situation, which do you choose......The Alpha designed for electrical efficiency(at least $3/mo.), or the Delta-T designed for system efficiency with the added bonus of electrical savings?

Gordy

Not apples to apples

Both can give you some of the same things except for Delta P which the alpha can do. Taco gives a wider range of sizing which is great for larger systems where a 15-55 is to small.



 The alpha bosts 45 watt max power consumption, but it is .65 amps which is 74.75 watts at 115 volts. So I don't know where the other  30 watts gets used, or does not get used

gilligan

zone valves

I've seen powerheads on taco zone valves short out and power the end switch with no call for heat.when you are witnessing the problem pull off each end switch wire individually to check

SWEI

power usage

So-called smart circs save energy in two ways:  The first is by varying their speed, which reduces power consumption by pumping less as the load decreases.  The second is by using an electronically commutated motor.  That increases electrical efficiency of the motor itself (typically from about 50% on a small single phase motor to 90+% on an EC motor.)  There's a further interaction between these two because EC motors don't lose much efficiency as they get turned down, while the power consumption of single phase motors on TRIAC phase choppers does not scale down linearly.



The delta-P and delta-PV algorithms on current smart circs works like magic (really) on multi-zone circuits.  Delta-T is a better option for boiler loops and dedicated zone circs.



The missing wattage you see is probably power factor.