Hydronic heat issue, any experts? (1 Viewer)

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KLF

Frame waxer
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Hoping someone here does this for a living or has been through this and can confirm my suspicions.

Situation: Hydronic (baseboard water) heating system, 2 zones plus an indirect tank for domestic hot water, so 3 Taco 555-102 valves. House built in 1995, everything is original, oil-fired Smith boiler serviced every year. Single Taco 006-B4 circulator. Honeywell L8124A boiler controller, pretty simple.

Issue: discovered the other day that zone 2 (upstairs) won't get any heat when the thermostat calls for it. If I manually open the Taco valve with the lever (very stiff), heat flows. Checked voltages, it is getting 24V AC when the system calls for heat, it just seems the valve isn't opening.

I also realized that the circulator is running all the time, 24/7/365. It's so quiet that I never heard it, but now that I think about it, I don't ever recall the system not making that hummmm when it's switched on. Doesn't seem right.

I chased all the wires, and it appears to be hooked up correctly. If I disconnect the (green) wire from the #3 terminal on the #2 zone valve, the circulator stops running. Doesn't matter if the zone is calling for heat or not. If I hook it back up, and disconnect any of the other #3 terminals, the circulator keeps running. Meter tells me there is a short between terminals #2 and 3 on the #2 valve, but not the case with the other 2 valves (when they are closed).

So... my YouTube training and Googling tells me that the Taco power head has failed, that it is not opening the valve AND there is a short across the #2 and 3 terminals that is causing the pump to run all the time.

Make sense? I just want to be sure before I go plunk down ~$100 for a new power head. Or could the entire valve need replacing?

:beer::beer:
 
Taco zone valves are notorious for failing. Most only last for a year. Only sure way to solve the problem is to change out to Honeywell valves and Grundfos pump.:santa:
 
Thought I'd close this out in case anybody else finds it with the same problem.

Bought a new Taco Power Head at Home Depot yesterday, ~$82. Very easy to change, took only a few minutes. Shut off boiler (turn the breaker off so the transformer is also dead), disconnect the 3 wires. 1/8 turn and the head pops right off. Installed the new head, connected the wires, everything is working fine now.
 
Glad you got it working! I don't want to get into a Taco/Grundfos/Honeywell debate on here, (those get almost as bad as the "which oil is best for my 80" threads) :bang:
But it looks like your zone valves have lasted 20 years, so I guess that answers it. And like you discovered, very easy to work on and readily available.
I guess it's been working fine, but it seems to me a 006 pump is pretty small for that system? how big is the house?
nothing to worry about, just curious. I've been in the field for 20 years and am always looking to learn more.
Cheers:beer:
 
Not to start a argument but here in Alaska, I think the Taco zone valves get worked harder than in the lower 48 so they fail sooner. Maybe there made better nowadays but in the 70s & 80s they would only last about 1 year before the coil got fried. The only saving grace. they are easy to change the head.:beer:
 
No worries. I learned long ago not to argue about which whatever is better. Every guy has his own preference and experiences with different brands /piping designs/systems, etc. There have been many times i was convinced the way i did something was best, just because that was the way i learned how to do it. Then i researched or tried something else, and guess what? That worked just as good or better. Like i said, I'm always looking to learn more about the trade, and different ways to make it better. I do like the Honeywell valves, i agree they are stouter. The taco's have gotten significantly better than they used to be though.
 
House is about 1500 sq. ft. I'm not happy with the heating system, but I'm convinced it's the lousy insulation in the house. House is framed well and they did a good job on the trim and finish work, but the insulation is terrible. Had an energy auditor come over on Friday, getting some prices to do some upgrading. My oil bills are just too darned high. I was shocked at the amount of frost on the underside of the sheathing in the attic, we found icicles on some of the shingle nail tips. Windows are good, but there is no insulation or spray foam around the perimeter of them, so that's gotta get fixed. Need to seal up the floor headers in the basement too.

There's no way I'm cutting out the 3 Taco valves and sweating in new Honeywell valves. That just doesn't make sense.
 

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