System 2000 / radiators won't cool off / boiler ignores thermostat
All of a sudden, the last 2 days, it's been hot as hell in the house, even though it's late October in NY. The radiators upstairs won't cool off, even after the temperature reaches its target on the thermostat (Nest).
I've "jiggled" the zone valve to see if it was stuck open or had some sediment in it, and that did nothing.
The boiler energy manager lights are all normal, but the zone is still hot. I've tried a reset as well. I've also tried turning off the system from the Nest.
1. Could it be a bad circulator pump?
2. Could the energy manager be shot?
3. If shot wouldn't that affect the downstairs zone or the 3rd zone?
4. What should I do first here?
Thanks in advance!
Comments
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Nest... Maybe remove the nest and try it with a simple thermostat. They're have been multiple problems with a Nest where it works fine, even months or a year, then things go wonky.
But if you replace with a simple thermostat to see if your problems go away, then you can start troubleshooting the components.
When you say it stays hot, is the boiler still running? Are the circulators running. Is the boiler only running for domestic hot water, and how water is migrating into the zone (sounds like it)?
I doubt it's the Manager. But you or someone who knows how to do some electrical troubleshooting, is going to have to test components to see if something is getting power that shouldn't or something like a zone valve is stuck open.
Even though it's Sunday, the EK bat signal somehow goes off and someone from EK will probably pop on soon.
There was an error rendering this rich post.
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See if there's actual side to side free movement on the zone valve lever. There's always a little play in the lever but it should have some resistance to manually open it and lock it.KyleO said:
I've "jiggled" the zone valve to see if it was stuck open or had some sediment in it, and that did nothing.
Compare that zone valve to the others.
Maybe there is some sediment keeping it from fully closing. Try running that zone and maybe it'll free it up.
And yes, it could very well be the Nest. Is it 24v powered? Is it using a resistor?0 -
Thanks again @HVACNUT, and yes by jiggle I mean I opened it several times and let it close on its own /with the spring/ just to open and close it in case it unlodges any sediment.
All 3 zone valves perform the same way, they lock open and they slide back and close if you don't leave them locked open.
I did it with the zone running to "flush" it.
The Nest is 3+ years old with no problems, and yes low voltage. I'll try going back to the stone ages with a thermostat.
But where do I go from there?0 -
Thanks @STEVEusaPA, appreciate the guidance on a Sunday.STEVEusaPA said:When you say it stays hot, is the boiler still running? Are the circulators running. Is the boiler only running for domestic hot water, and how water is migrating into the zone (sounds like it)?
The boiler stops running and still sends so much heat upstairs that it heats the floor to 78 degrees when the thermostat is set to 67 degrees. Sweating in October. But no extra lights on the manager, just power. Meaning the circulator and boiler shut off but the pipes are still scorching hot for far too long. Normally it keeps circulating the extra energy, but this is extreme. We weren't calling for hot water either, everyone was sleeping (or sweating trying to sleep). Had the AC blasting.0 -
Have you disconnected the nest?0
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Here’s an old standby for runaway heat, mice chewing on wires.
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Old generation nest with 2 wire. Pretty basic. Switching to a Honeywell Vision Pro 8000 now.
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Lovely. I luckily don't have that issue! Tested connectivity from the thermostat to the boiler. It turns it on and off. The issue is, when off, it keeps heating the zone far too long. I have an old school thermostat on it now and will monitor.GW said:Here’s an old standby for runaway heat, mice chewing on wires.
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Only a 2 wire. I've had this happen. I don't know why yours took so long, but if you sit in front of the boiler long enough, you might see that 2nd floor zone light go on at the Manager and the circulator start, and the burner fire. The Nest is using W as a Common (through the relay coil) to charge itself during the off cycle.
You need the resistor. See the bottom right diagram.
It doesn't seem like a shorted sub base, otherwise the Manager would show a heat demand always.
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Yes if I set the upstairs (zone 2) temperature to a higher temp, it triggers, the boiler fires, temp rises, circulator kicks on, heat flows.HVACNUT said:Only a 2 wire. I've had this happen. I don't know why yours took so long, but if you sit in front of the boiler long enough, you might see that 2nd floor zone light go on at the Manager and the circulator start, and the burner fire. The Nest is using W as a Common (through the relay coil) to charge itself during the off cycle.
You need the resistor. See the bottom right diagram.
It doesn't seem like a shorted sub base, otherwise the Manager would show a heat demand always.
I do not have a resister on the boiler, so I guess that's my problem. Pic attached. Weird that it worked for years without one, what changed? Nest SW update or something?
Also strange that the exact same nest is working fine on Zone 1 (downstairs) and wired the same way.
Thanks @HVACNUT0 -
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If you disconnect the t-stat wires and the heat goes off, you absolutely have a t-stat issue.
The Nest gathers quite a bit of information about it's user. Is there a chance it detected that you have been enjoying your Sundays too much and decided to give you something to occupy your time
"If you can't explain it simply, you don't understand it well enough"
Albert Einstein1 -
Great comments, all!You’ve left a lot of clues with @KyleO ’s response.
My number one suspicion would be @KyleO changing over from air-conditioning to heating. The nest prioritizes power stealing from the air-conditioning system. If that system is off, then it will power steal from the heating system. That condition would lead to the overheating described.The second most likely issue would be that the zone valve flapper is not properly sealing even though it’s opening and closing properly when tested using the lever.Check it out and let me know what you think…
Thank you,
RogerPresident
Energy Kinetics, Inc.0 -
I'm with Roger. I think your zone valve is bleeding by, and if it is indeed a Honeywell, it most likely needs to be taken apart and have a new conversion kit put in it.
Something I have done is to take a towel dipped in cold water and rub down the pipe above the zone valve, and then feel if it appears to be getting hot real quick. The farther you can get from the zone valve, the better.
Rick
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Hey Roger, thanks for the response.Roger said:Great comments, all!You’ve left a lot of clues with @KyleO ’s response.
My number one suspicion would be @KyleO changing over from air-conditioning to heating. The nest prioritizes power stealing from the air-conditioning system. If that system is off, then it will power steal from the heating system. That condition would lead to the overheating described.The second most likely issue would be that the zone valve flapper is not properly sealing even though it’s opening and closing properly when tested using the lever.Check it out and let me know what you think…
Thank you,
Roger
I should have mentioned that there are 6 nests, covering 3 zones, oil baseboard heat and forced air conditioning, so separate nests for heat and AC. That's why I was able to run both last night as we laid there and sweat.
On your second point, I'm suspect of this too, but don't have an idea on how to confirm this, unless I just replace it, or swap out the valve for a zone I know is working (like zone 3, the basement). I did open and close it several times with the system running in an attempt to flush out any sediment so it can properly seal, but tempted to just buy a new one and install it.
Should I also install a resistor on the energy manager where I hook up to zone 2? Or I guess all 3 zones as they all use nest in a 2 wire config.
Of course as luck would have it, the weather changed here in NY again, and it was in the mid 60s, so my house never really called for heat all day. It's 73 downstairs and 71 upstairs, both well above what I set the thermostats too. So haven't really seen if I still have the issue with the non-smart Honeywell thermostat.
Thanks again for the help here!0 -
Thank you, @KyleO .
I should have picked up on the Nest point; switching from AC to heating would only be an issue on an air handling zone that serves both where power stealing from the AC is no longer available when the system switches to heating this time of year - sorry for my error.
Regarding how to test the problem zone, props to @rick in Alaska for a simple and effective test with the wet towel (test with no thermostat call on the problem zone, and a thermostat call on any other zone).
One other point comes to mind that may be possible. The Nest could be aging and the battery life may be shorter, requiring much more frequent charging. This would be solved with any of the work arounds with power stealing thermostats which can be found here on our website.
RogerPresident
Energy Kinetics, Inc.1 -
If you pull the powered off the valve and manually close it you should be able to tell if you are getting blow by by feeling the pipe. Sometimes the problem is a locked up mechanism in the power head, sometimes the guts of the valve itself is damaged."If you can't explain it simply, you don't understand it well enough"
Albert Einstein0 -
OK thanks @Roger I just bought 3 resisters and will try that option. The Nests are only 3 years old, but maybe that's aged. I really don't want to run a common wire so will try to make these older generations work.
FYI, the Honeywell thermostat seems to be doing good, not sweating upstairs anymore. But the downstairs is well above the set temperature (72 versus 66) so I'll do the cold towel test tomorrow and report back. Smart @rick in Alaska.
Thanks again for the help here community!1 -
Will do. The weird thing is I purposely did NOT add the resistor to the other 2 zones, which still work fine. Odd that only one Nest decided to cause an issue. Still not really sure what the root cause was.Roger said:You’re welcome @KyleO . Keep an eye on it to make sure we’re not missing anything with potential zone bypassing.Roger0 -
Their time will come. Don't lose the resistors.KyleO said:Will do. The weird thing is I purposely did NOT add the resistor to the other 2 zones, which still work fine. Odd that only one Nest decided to cause an issue. Still not really sure what the root cause was.
The Nest battery charges while the thermostat contacts are open (not calling for heat).1 -
Almost a year later, the other zone started heating way above the thermostat level. Installed another resistor in hopes of the same problem. Maybe their time did come HVACNUT!HVACNUT said:
Their time will come. Don't lose the resistors.KyleO said:Will do. The weird thing is I purposely did NOT add the resistor to the other 2 zones, which still work fine. Odd that only one Nest decided to cause an issue. Still not really sure what the root cause was.
The Nest battery charges while the thermostat contacts are open (not calling for heat).
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2 years later....
I have resisters installed on the system manager for zones 1 and 2 (with the same 2 wire older generation nest thermostats that have worked for 7 years). Now zone 2 (upstairs) is heating up anytime the thermostat/boiler kicks on for another zone, making it unbearably hot upstairs. What gives?
What should I try next? This system 2k has been nothing but problems.
Thanks community
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Time to investigate the zone 2 zone valve. If it doesn't close, you'll get exactly these symptoms.
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Thanks for the tip! Yes it closes when I shut off all zones via the thermostats and the boiler stops recirculating after cooling. But for some reason the zone valve is opening when other zones call for heat. This happened before and installing the resistors helped, but now it's back.
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I've said it before, and others have said it, and I'll say it again.
The resistor trick is a very delicate kludge. Sometimes it does work. Sometimes it doesn't. As equipment ages and values change, what worked once doesn't work any more.
Take all the resistors off. Run a C and R wire to each of the power hungry thermostats, from a big enough transformer to power them. Then if something doesn't work, you have a system which is at least correct, and which can be maintained.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
Do you have 2 wire zone valves? If the second floor zone valve is opening during a heat call from another zone, then it could be a short in the Manager, or a short in the wiring between the two, or a short in the Nest. It would need 24 volts to physically open. If you have an electrical meter, you can test for 24 volts across Z*(whatever terminal the second floor zone valve connects to), and the 24 vac terminal. If it DOES have 24 volts, check the T* side for 24 volts. If not, remove the wire from Z*, and test it. Cycle another zone to see if the second floor heats.
It could be the zone valve is not being powered open, but not fully closed.
If the second floor zone valve is opening AFTER the other heat demand ends, then it could be a zone purge setting gone awry.
I wish I had your type of "nothing but problems". Whatever it is, it's a simple fix.
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If you still don't want to go with Jamie's suggestion regarding the C wire, I'm afraid you're going to be plagued by the Nest (or other power stealing 'stat) forever. Those resistors are simply a band-aid for a recurring problem.
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Thank you for everyone’s helpful posts.
@KyleO , if you disconnect the Z2 zone valve wire, and you find that the second zone continues to heat when there’s no call, then the problem is mechanical (like a worn out valve or debris obstructed valve that won’t close). If disconnecting the Z2 wire prevents that zone from unintentionally heating over a long period time, then it could be an intermittent “ghost call” from the power stealing thermostat (trying to charge with too much current so it looks like an actual call); you can also check for 24 V from Z2 to 24VAC, although the zone valve light would usually be on if you had power there.
Roger
President
Energy Kinetics, Inc.
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I'd look at a zone valve control panel such as the Taco ZVC. This unit provides a common-wire hookup for Nest or other fancy thermostats, and can operate pretty much any zone valve hookup. With this unit you can do away with those problematic resistors.
https://www.tacocomfort.com/product/zone-valve-controls/
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
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The Manager on the EK provides a Common. The issue is a 2 conductor thermostat wire.
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Yes it's a 2 wire nest. I wish it was as easy as running a common wire. That would lead to several holes in the walls/ceiling unfortunately.
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unfortunately that’s what has to be done!
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can you get a smart thermostat and put it next to the boiler, and just put a remote wireless temperature sensor where the current thermostat is?
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Well, actually unless some brilliant soul has stapled the old wire to something inside a wall where you can't get at it, one can almost always pull the new wire through using the old one. I've done it more than once! You do have to be a bit careful about it, as the connection between the new wire and the old one must not be larger in diameter than either of the wires, and must be rock solid. This isn't as hard as it sounds, as normally new wire — with modern insulation — is no fatter than the old wire, even if it has more conductors. And I simply use staggered old fashioned telephone linesman splices from all the old wires to all the new wires (you'll cut them out later), hammer them down, and solder them.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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Add a Fast Stat FSCM00 kit to each thermostat. That will allow you to use those awful Nest thermostats with that nice boiler you have. I've done this on quite a few EK boilers for customers that insist on having a WiFi thermostat.
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It's an original 2 wire (12 guage) from the 80s, definitely stapled. We tried pulling new wire to a transformer for the Ring doorbell a while back and had to run a new line, but luckily that was an easy snake to power, unlike the heat thermostats that are on the opposite side of the house from the boiler.
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I'm actually in love with this idea! I could even get rid of the 4 nests (2 for heat, 2 for AC, on the 2 main floors). Thanks for the great tip!
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