View Full Version : Novice question - is my cartridge circulator bad?

11-03-2009, 09:23 AM
Hi all,

Novice question here. My mom's house has 4 zones running off a Taco SR 504 switching relay. This morning she noticed that the one zone (sun room) isn't warm. Baseboards (hot water oil) are cold. I just went up to look at things. Turn thermo way up above room temp, hear click on control panel, went to basement, red light is on on SR as expected. That for me rules out thermo and switching relay. Next thought was air lock in the zone since I've had that happen in my house once. I can't seem to find a place to bleed only the one zone, but that might not be relevant right now. I turned down the themo and cranked up another zone and went down to listen to the cartridge circulator on that zone and hearing the slight whiring of what I assume is an impeller in the unit which makes the water move. Ok, turned that good zone back to normal temp so it's not running, cranked up bad zone again, no noise on the circulator.

Do these things just go? The house is 7 years old. I did notice that while the model/make is the same as well as all specs on the sticker, this one is black vs green and looks kind of corroded.

The circulator is a Taco model 007-F5 with the following specs:
hp: 1/25
amp: .71
hz: 60
volts: 115
rpm: 3250
psi max: 125
max h2o temp: 240f

If it is this, it's beyond my plumbing expertise so I will have to call someone (we're in northeast PA). Figured I might call my local plumbing supply house to at least get an idea on part price, knowing there's other parts like fittings and such that will be needed.


11-03-2009, 09:35 AM
Many of the Taco circulators can take a new cartridge. this means no particularly special skills or tools required. Often, a total replacement is done since for a pro, it may take about the same time, and if there's an issue, a full new one is less likely to result in a call-back later, but (in my limited experience) a cartridge replacement is supposed to replace all of the wear parts, so is pretty good fix. I haven't looked, but the instructions are probably on the www.taco-hvac.com (http://www.taco-hvac.com) website. If you can find them, read it, then determine if you feel competant to do it; otherwise, call a pro.

Depending on use, a circulator could die in that timeframe, but they often last longer.

The light turning on is not an absolute indication that power is actually geting to the circulator...you'd need to check the voltage. the relay could be bad. The indicator is (I think) showing the control logic's request for the relay to operate, not that it did. So, it could be the control circuits. Easy to check with a meter.

11-03-2009, 09:54 AM
Thanks for the insight. I looked on taco's site and found that this has the replacement cartridge but I'll be darned I can't find out any instructions on how to do it..... This thing for some reason looks different than the others (black one in picture) with what I'd call "corrosion" on it.

As for the power thing, sorry to ask such a simple question but can you let me know where I'd attach a volt meter to read it? The wires go from the control unit to the circulator in flexible metal conduit.


11-03-2009, 10:26 AM
Ok wait a second.... I just engaged my brain. The conduit doesn't have a thing to do with it. You mean in the SR box, put a voltimeter between the black wire (H) on the screw or something at the bottom which goes to the circulator and then on the white wire (N) on the screw as well. Just like if I took the two sides of the voltimeter and put them one in each side of a wall outlet? And if I don't read 120v across that, then I know the relay (that's the clear square cube right?) is bad and should be replaced?

11-03-2009, 03:32 PM
Yes, there are screws to attach the wires from the circulator at the relay control box. When the relay is energized, you should be able to measure 120vac from the black wire to a white one.

Peter Griffin
11-03-2009, 05:07 PM
Better yet, take the wiring cover off the circulator and check voltage at the circulator. If it has power but will not run, it is bad. Changing it out requires draining the pressure off of that zone (perhaps the whole system if it is not isolated)

11-03-2009, 05:49 PM
Ok I just came back from there. I first swapped an ice cube relay from a known good zone into the problem zone, no dice. Then we put things back the way they were and turned on the bad zone with the thermo. Voltmeter reads 120 in the box at the screws just like it should. So this being said, I was assuming, ok, spend the $60 and get the innards to replace the cartridge since I can easily isolate top and bottom and shut off the power, pop open the 4 5/16" screws and do that before having to pay a plumber..... but....

Now Peter's post has be concerned..... Since I have 120 at the screws and from there I go right to the circulator, isn't that enough? Now sure how I'd get the wiring cover off. If I open the clamp there where the metal shield meets the circulator will I get to bare wires to test? And if I get 120 there, doesn't that still mean I can replace the innards with the cartridge replacement without taking the whole circulator out of commissions (which is something I would call a plumber for).


Peter Griffin
11-04-2009, 02:36 AM
There are two yellow wires under the cover that attach to the wires going to it with a couple of wire nuts. shut off the power before changing things.

11-04-2009, 04:57 AM
Ok I get it. So throw the thermo up, and then check voltage down at the circulator to confirm 120 there. If no 120, then it's the whole thing that has to be replaced, not just the cartridge.

Let me ask you this, in looking at my picture up above and looking at what you'd buy as a replacement pump looks like, it looks like when you buy new, you reuse the pipe side flanges. So that being said, I could replace the whole thing with no soldering right? Just new gaskets, 2 bolts in each flange and the wire nuts? If so, that's pretty easy and for the price difference, I might just do the whole pump. And I should add, each zone pump has a ball valve about 8" up on it's line and then coming out of the boiler, on the cast iron pipe branch that goes to the bottom of the 4 zone pumps, there's another ball valve. So I can shut it off so that nothing is coming from the boiler to any of the pumps and nothing is coming back down from the zone to that pump.

11-04-2009, 08:36 AM
If the pump and the model are the same, then it should bolt on and swap the wiring to it. It is my understanding that that cartridge contains the motor, but not the shell. I've never done it...so, take that with a grain of salt! Depending on where you can buy things, a whole pump might be cheaper than the cartridge. Sometimes, if it is a common, high-volume part, a place like HD has it for less than a small plumbing place can buy it because they buy them by the thousands for the whole company.

11-04-2009, 10:24 AM
My mom is on her way down, pump in hand, to get the whole thing. There were 4 connections in the wiring box. I tested the first 2 coming in and was getting 120. So then I tested the 2 further down the line involving the capacitor and it was dead. I'm wondering if the capacitor died and I suppose you can put a new one in there but then it could be something further in so I'll be replacing the whole thing. I carefully drew all the wire connections before I disconnected anything so I know how things go back together and I'm going to pull the old innards out of that pump before i pitch it since that was turning freely and looked fine, JUST in case i need to deal with this again.

So we'll see how the install goes tonite. I'm making sure to get new flange gaskets since these were brittle and we'll turn on the water to test for leaks before we turn power back on. Thanks everyone for your help and I'll keep you posted.

11-04-2009, 03:14 PM
Wahoo! Took me about 45 minutes and all is back up and running. Put the pump on with the bolts, hooked up the wires, opened the valves to make sure there were no leaks, then turned the power on. Almost had a heart attack because I turned "bad" zone thermo up and good zone thermo up and neither threw light on relay box yet sub box that is the hot water tank was coming on. Then I remembered the panel in my mom's has that zone set as priority so once that came up to what it needed, other zones came on, had the happy hum on the new circulator, baseboard got warm and all is right with the world.

Thanks to everyone for all your help and guidance!