One zone of baseboard heat system not working

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Old 09-28-08, 02:09 PM
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One zone of baseboard heat system not working

Hi folks - thanks again for the help last season getting my baseboard/boiler setup running again. I learned a lot.

Here's the current problem: The system is 4 zones - 3 for baseboard heat, one for a boiler mate. One baseboard zone will not get to temperature. In fact, it feels like it is circulating cold water.

I first suspected there was air in the system that the pump couldn't circulate through. So, I bled the system zone by zone. I tested all zones after that, no change (nor the sound of air in the pipes).

The pump is humming and warm, but I don't know for sure if it is circulating properly. There is plenty of pressure in the lines of that zone - opening a bleed screw revealed a plenty of flow. If the pump is not functioning, I'm assuming this is just fresh supply water being forced through.

All valves are in the open position, and the thermostat is functioning properly (activating the system).

The zone is on the second floor, and has about the same distance as zone 2 (also second floor), which is functioning well.

Pressure/temperature on the gauge is right on target (12-15 pounds cold/hot).

At this point, my only guess is that it is the pump. The pump is currently a Taco, and was replaced at some point prior to my purchase of the house. An educated guess tells me that it is no newer than 10 years old.

Here is a photo of the pump array - zone in question is the Taco on the far left (closest to the boiler mate):



Before I replace the pump, is there anything obvious that I'm missing?

Thanks in advance!

Ken
 
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Old 09-28-08, 02:13 PM
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Also - the photo is from last season, prior to replacing the pressure reducing valve, purge valves, one pump (not zone in question), expansion tank, and some other miscellaneous goodies. Don't be concerned with the corrosion around the relieve valve - that's all new now.
 
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Old 09-28-08, 02:50 PM
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when you purged the zones, how exactly did you do that ?

With the boiler turned off and cool, did you close all the valves on the return lines, hook a hose to the drain on the return of the troubled zone, open that drain and then open the fast fill on the pressure regulator ?

If you did this any other way, it's possible that you didn't force the water through the zone, but rather through the short length of pipe between where the feedwater taps in, and the the drain.

Those valves must be closed, you want to force the water to take the proper path through the zone.
 
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Old 09-28-08, 03:02 PM
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Thanks to you're instructions last year, I believe I did it properly.

One zone at a time, I attached a hose, closed the valves on the other zones, opened the one where the hose was, opened the supply/fast fill. Closed that valve, removed hose, then moved onto the next zone.

I did not shut the valves on the supply side (after the boiler) on the other zones. Should I be doing this as well, or just the valve at the drain (pictured above)?

Thanks
 
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Old 09-28-08, 03:45 PM
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I remember! I have two synapses still firing, and they take turns...

OK, good.

Just the valve below the drain should be sufficient.

But, before we condemn the circulator, is there a flow check valve in each zone piping ? I'm guessing yes.

If so, give that flow check a sturdy rap with the bald headed end of a broom.
Don't KILL it, just a good stiff rap. DON'T use a hammer...

Do the same to the circulator... while it is supposedly 'running' ... in a few places ...

I don't usually advocate violence, but it may just be that the circ is froze up from being off all summer.
This is a good argument for controls that excercise the pumps during periods of non-use.
Some circs have a plug on the motor end which can be removed to spin the motor with a screwdriver, but unfortunately, the Taco does not.
 
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Old 09-28-08, 07:10 PM
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I've got a 10 pound sledge that'll do the trick!

Sounds like good advice. I'm a big fan of physically persuading inanimate objects to conform to my will.

I'll give that a shot tomorrow night. Luckily, we're not in need of the heat yet - just getting ready. Of course, the zone that's malfunctioning heats my 4 month old son's nursery. I keep telling my wife that having a heated room will make him weak. She's not buying it - so I think I've got to get this running before his room becomes my room.

I'll report back with the results of that endeavor. I think I'll try one more bleed, just to make sure I did it correctly.

Thanks again for the help!

Ken
 
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Old 09-28-08, 07:18 PM
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Oh - one other clue that has me thinking it's the pump... The supply side pipe before and after the check valve are hot to the touch. The return side is cold.

When I opened one of the bleed screws on the second floor, I accidentally backed it out all the way, and had a domestic version of Old Faithful. There was lots of pressure (shot up and out at least four feet through the bleed hole), but no air spurts.

I'm still going to beat the pump sensless, I mean gently. The good news is that I already have a new pump. I bought it when we first moved in a few years ago, as I was convinced I'd be swapping a pump at 3am that winter.
 
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Old 10-01-08, 06:40 PM
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Update:

Did the gentle/medium tapping on check valve and circulator while "running". No change. Re-Bled the system to double check I did it correctly - no change, and no big air chunks coming out.

Drained the system down, removed the old circulator, installed the new one (after nearly destroying it because I needed to flip the housing 180 degrees to get the elec. box away from pipes). Refilled, bled, activated the system.

Still no circulation.

HOWEVER -

The check valve in question now sounds like there is shrapnel inside it. It used to make this noise on occassion, but not like this. I'm sure my light tapping did not destroy this thing, but while the system was bled, I turned the valve a few times to loosen it up.

I think that maneuver was the last straw on that camel's back, and is most likely the culprit of the non-circulation issue.

Here's the problem. The check valve is in a crappy spot. I can replace it one of two ways:

1. Buy a new valve, remove the innards, and replace the old comonents with them, leaving the body in place. I don't know if that's possible/feasible. Please advise.

2. Cut out a section of pipe, splice it back together with a section of hydronic appropriate PEX, which I already have in prep for the addition of some baseboard in an addition. This would make the re-installation much easier for me, as I can bridge the nasty location with a pre-assembled check valve "cartridge" made from PEX. I could do this with copper as well, but I already have the appropriate PEX and supplies here - I'd just need the new valve.

Could I be missing anything else? Is there a problem with mixing in the PEX right at the boiler essentially? Any thoughts would be great.

Thanks so much,

Ken
 
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Old 10-02-08, 10:42 AM
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Good stuff Ken, and thanks for the chuckles.

I'd take the check valve out and replace the pump with a Grundfos 15-58 with the internal check valve. Then that other pump could be the 3am option.
 
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Old 10-02-08, 10:52 AM
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Not a bad idea, but cutting out and patching the section of pipe with the valve is just as much work as replacing it, so I think that's going to be the direction I go.

After thinking about the actual construction of this bridge, it will be less work to do it out of copper - so disregard the PEX aspect of the question.

I also realized that last season we didn't run that zone - the room was unoccupied. However, when the adjacent zone would be running, the now dead zone would make some tapping noise. I'm presuming that was this check valve in the early stages of death.

Considering the circulator I removed last night is probably still good, I'm going to open it up, clean it, and save it for my spare.

Ken
 
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Old 10-17-08, 06:36 PM
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Ok - here's the final update on this situation.

First - I like the Popeye addition to the "P" word. What's the story there, is it not well received? I just finished doing a lot of work with it, and I liked it.

Anyway, back to the update.

Instead of just going ahead with the valve replacement, I decided to wait and finish the entirety of the hydronic system expansion that I was planning for my addition (it is a formerly unheated, enclosed porch that I've converted into living spaces). I installed new sections of baseboard in the addition, cutting and splicing into an existing loop that was on the former 'exterior' wall behind the porch. I added about 8 total feet more finned baseboard than what was previously on the zone, which heats the entire first floor.

In addition to the new runs of baseboard - which were all plumbed with HeP E X - I also decided to cut in two additional 4' sections of fins into our two upstairs bedrooms. Previously, the baseboard that was installed (as a retrofit from steam prior to my owning the house) ran around most of the perimeter of the room, with a small section of fins under the windows only. The rooms are dreadfully cold when it is below freezing outside, and some nights the heat does not keep up. I have insulated the attic (previously none), and replaced the windows. Hopefully the addition of a small section of fins in the vast span of piping will make a noticeable differnece.

So, the sum total of my hydronic retrofit was to:

1. Add new baseboard to addition, cut into a removed run on main level.
2. Replace the failed check valve.
3. Cut in new finned sections to existing bedrooms upstairs.

This was all done with a combination of the P word and copper.

The result? After an extensive bleeding (I may or may not have been doing it slightly wrong after all...) We're golden! New baseboard heats up nice, no leaking from any of my sweat or P E X connections, and the new fins upstairs have me excited for the first sub-freezing night.

My baby's nursery will be warm without the use of the scary electric baseboard space heater we've been using temporarily.

Thanks again to everyone here for all the professional input.

Finally, if any of you are interested, I have quite a lot of 3/4" HeP E X left over that I will likely never use. Let me know if you may be interested in picking it up at a good value.

Ken
 
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