One zone not getting heat, circulator cartridge replacement time?

Hi all,

I'm a novice at the HVAC stuff but pretty handy in general. My mom has a 4 zone hot water baseboard system in her house. One zone (sunroom) isn't giving heat. Turn thermo up, Taco SR 504 panel lights as it should, baseboards are cold. Ok, I thought it was an airlock but since I couldn't find a place to bleed just that zone, I moved on to other things. Turned on "good" zone, listened at circulator (Taco 007-F5) and can hear the hum of the impeller. Turned good zone off, turned bad zone on, no hum.... ok, I'm thinking I'm making progress and ruled out thermo since it's sending signal to the SR correctly. Pulled "ice cube" relay out of good zone, put it in bad zone, same behavior, no heat, no hum in the circulator so I think that ruled out dead relay. Put relays back in original place, took voltmeter to circulator size in SR box, and I measure 120v so that tells me relay is definitely ok because it's switching the thermos 24v to the 120v.

Does all this mean that I should get the replacement cartridge part for the 007-F5 circulator and do that? As I understand it, you isolate with the valves, kill the power, open 4 5/16" bolts, slide one cartridge out and the other in.

I figure that I can do, but replacing of the whole circulator would be a job for a plumber since I'm not a good solderer and definitely never worked with cast iron pipes.

Is there something else I should check? I can't think of what else it could be since I don't hear the hum of the impeller but I don't know if they just go either, but I figure they must since they've made it so easy to replace in the field.

I'd hate to have to send my mother to the plumbing supply store for a $60 part to find out that wasn't it.

thanks!

 

If you are sure that you can't hear anything at the pump, and are sure that the pump is getting power, it would be worth trying the cartridge replacement I guess... but you can get a brand new pump online for about the price of the cartridge, and there should be no soldering involved.

There should be two 'flanges' on either side of the pump with two bolts each. Pretty easy to swap out... but...

You talked about isolating the pump with the valves... does that mean that there is a valve on both sides of the circulator? that would make it real easy to swap out either just the cartridge, OR the pump.

I would open the connection box on the pump first, just to check that there is actually 120 making it all the way to the pump and that there's not a wiring problem inside the box.

You can use a screwdriver as a 'stethescope'... put the HANDLE to your ear, and the blade on the pump and listen.

 

Definitely can't hear anything at the pump. I know There's 120 in the relay box on the screws leading to this zone pump.

As for the flanges, I didn't realize that the pipe sides of those stayed, I thought both sides had to come out. So that being said, I should be able to get it out. I have a ball valve right above each pump so that gets one side. And then in the cast iron piece going across from the boiler to feed each circulator, I have another ball valve so I can shut that off to stop the water from going to any of the circulators.

If there's a wiring problem in the pump (I'm assuming by box, you mean the box that's about 1.5" x 3" on the side?).

Thanks for the help so far.

 

If there's a wiring problem in the pump (I'm assuming by box, you mean the box that's about 1.5" x 3" on the side?).

Yes that box should have 120 volts (give or take ) in that box....And make sure that zone is calling for heat Beer 4U2

 

Definitely calling for heat so no issues there. I think I had an incomplete sentence there. I meant to say if there's a wiring problem in the pump, the whole thing has to be replaced, right?

thanks!

 

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.

 

If you had 120+- volts AT motor and not running motor bad but cap if got one could have been prob

GOOD LUCK N LET US KNOW

 

One thing I noticed is that all the water that came out when I started to loosen the flange bolts was rusty colored with some grit/slime in it and STUNK like nothing I've ever smelled (and I've replaced an old metal septic tank that fell apart when I lifted it with the backhoe and hadn't been pumped ahead of time so I know smelly). Of the 4 circulators, the rest were light green, and this was black yet was the same model/specs/brand as the other. It also had a lot of buildup around the bolts and stuff so I don't know if when the house was built a spare or old one was used or what. The impeller part looked perfectly clean. I also put a bucket under the top side and opened that shut off when it was out to see what color water came out of the line and that was clear so I'm not concerned that there's something in that loop but man did that stink.

 

serviceperson would put a (Stink Bomb) in water to sniff out a leak if any was in concrete. But if you get this running a boiler needs to be drained and serviced at least every 2 to 3 years.

 

Huh interesting. There's nothing in concrete with this line and it's a ranch and everything is exposed in the basement. I know we get the boiler cleaned each year by the oil company but never thought about a full drain and clean. Maybe the water in the loops all stinks like A$$ and I just don't know it because I didn't open those up.

 

Oil burners need service EVERY year, you can often 'get by' with a gas burner for quite a while, although the flue passes should be checked that they are clear of debris (rust n' stuff)...

However, you should NEVER drain a boiler unless there is some reason to do so... like changing a pump/valve/etc... fill it up, get the air out, and fuhgeddaboudit... there is nothing to be gained by draining and refilling. In fact, it's a BAD thing, because every time you add fresh water, you are also adding dissolved oxygen and it's the oxygen in the water that causes RUST. Once the system is up and running all the dissolved oxygen is driven out of the water and the system will NOT rust on the inside. Bottom line: Don't drain unless you have to.

 

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 remember 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.

As for the no draining on the boiler, I'm glad to hear that since I know other than the yearly cleaning around September, neither my mom's nor our place has had them drained in the 7 years since we both built and my dad passed away 2 years ago but I know he wouldn't have let something like that go.

Thanks to everyone for all your help and guidance!