Zone valve triggers circulator but does not trigger boiler

clydesdale

Does anybody know what it wrong here? It will trigger the circulator but not the boiler. So, I trigger another zone and then the boiler goes on and I get heat from the zone that I was not getting heat before. I hear that means it could be the end switch. Can I replace just this end switch or do I have to replace the whole zone powerhead? Thanks.

hot_rod

It depends on how it was wired.

Typically the end switch triggers the boiler heat call, and the boiler pump, if the boiler pump wires to the boiler?

In some cases a relay box has the zone valves and boiler connected, so the relay box could control the boiler, instead of the boiler control.

Some, not all zone valves have a manual lever that makes the end switch. That would confirm if the switch is good or bad.

But some zone valves only close the end switch when the motor opens the valve.

A pic of the zone valve may answer some questions. How old are they, usually you can find a date code on the zone valve.

Jamie Hall

If opening the zone valve turns the circulator on… it's not the zone valve end switch, since that is turning the circulator on…

Some other wiring or component problem.

kcopp

prob the boiler operating control has lost the burner circuit.

HydronicMike

End switch only (usually) triggers the circulator. The burner runs if the boiler temperature is less than the high limit setting. It may be possible you're at/over high limit and it takes another zone calling to drop the temperature enough to fire the burner.
If the zone valve is pulling in the circulator relay, it's not the zone valve. If you do, for some wrong reason, change the head, make sure you kill power to the transformer. It may still be energized if the main switch is turned off, depending on where it gets it's power. If you short wires from the transformer you'll smoke it.
Are you sure the circulator is moving water?
Are you sure the zone in question has water, is not air locked? If it's not moving water, it won't drop temperature, and it won't fire the burner.

If all that properly checks out, you would have to start troubleshooting the aquastat.

EdTheHeaterMan

It is not the end switch unless your zone valves are connected to a zone valve relay of some kind like the ZVC made by Taco. There is an easy fix for that if you do have a ZVC relay box, but I need to see a picture of the wires inside the ZVC relay box.

HVACNUT

Where do the end switch wires go? Pics?

clydesdale

Sorry, I got busy with snow removal and couldn't get back till now. So, let me add to this. I shut the heat off in that zone and the lever stayed over to the left. As a result, every time another zone was on, this zone came on as well. I had to manually move the lever over to the right in order to get the heat to shut off, so I thought. Here is a pic of the zone valve. I am not sure this zone is actually shutting off. If it isn't can I shut the blue levered ball valve attached to the pex to shut the water off going out to the garage? I think I need an education in how this zone valve and lever are supposed to work. I turned another zone on and thought I would see the lever move. I did not. Yet the zone worked beautifully. Thanks.

clydesdale

OK, another update. I took the cover off again. I had the lever pushed over to the right, BUT, I don't believe the valve closed. I was able to assist the spring and it moved MUCH more. I check a zone that is fine. When I push the lever to the left, against resistance, it then springs back all the way. On the zone in question, when I push the lever to the left, it only springs back a touch. I can move the lever all the way to the right, but the spring does not move. I can then assist the spring and move the mechanism down. So, does this mean it is stuck open? I believe so. Thanks.

hot_rod

if the valve has power to it the lever will be loose and floppy, about 30 seconds after power is applied

If the power is off and you open it by pushing against the spring tension, then it will spring close quickly, 5 seconds or so, and all the way close

You cannot push the lever to close if it is being powered

clydesdale

I looked closer. When I call heat for the zone the arm starts to approach the micro switch, but it does not reach. I then help it along to touch the micro switch and then and only then, the boiler kicks on. At this point, the main lever is loose. When I then shut the zone off, the arm will back off the micro switch enough to shut off the boiler. But, I have to help the lever close all the way and I assist a spring as well and I imagine that then shuts the zone. This way, the next time the boiler is turned on by another zone, the zone is question does not get heat. Does this sound like the zone valve is gummed up and sticky? Thanks.

hot_rod

How old is the valve? There should be be a date code printed on the end.

there is a pinion gear on the motor and a sector gear on the valve stem. Occasionally a tooth gets stripped on the thin brass sector gear and prevents the valve from fully opening.

Or the valve mechanism is sticky.

You can get a replacement upgrade kit for the valve. But if the motor is bad also?? At that point just replace the entire valve.

In either case you might just get a replacement. Unless you want to disassemble and determine which part, motor or valve mechanism, is bad

clydesdale

Hot Rod, thanks a bunch, as usual. I have figured out that the motor works, but gets stuck. It does not move the arm enough to hit the micro switch and when it is shut off, it does not spring back enough to shut the zone off. So, I think it is sticky. I watched a youtube vid on how to clean it. But, a new one will be here on Friday and I will replace it and then clean the original one at another time. I believe the date code is 1836. So, 36th week of 2018, according to google. But, Amazon account says I bought a controller in 2022. So, I think this must be that valve controller. This is zone that is only triggered about 10 times a year. So, maybe it got sticky from lack of use.

My bigger issue is that I still did not get glycol into this system and we have frigid weather coming. A family health crisis sidetracked that whole job. But, I have the system cleaner, glycol, and pump ready to go. I just don't have a full grasp of the process. I was watching youtube vids last night and had to stop because the plumbers camera work was getting me nauseous. I will have some questions in that thread soon. I believe this zone valve issue will be solved with the new valve on Friday. Thank you!!!!!!

hot_rod

yes the grease in the gear train under the motor can get sticky and cause enough drag to limit the range. If the motor has been stressed, I agree, replace the entire head.

Glycol is less critical is the home is occupied all winter. If you leave for days or weeks, the glycol is a bit of insurance against freeze damage.

However glycol in the heating system does not protect the plumbing.

At the very least turn off your water supply if you leave the home in the winter for extended periods.

Grallert

If I've read this right I think the valve stem on the valve it's self is stuck. With the powerhead removed you should be able to move that stem with you fingers. It's not uncommon for them to get jammed up enough to stop the spring from returning the ball to it's seat or prevent the actuator from reaching the end switch.

hot_rod

The life expectancy of the ball inside and the stem o-rings has a lot to do with water quality, I believe.

As I recall theses were only a few years old and the ball completely deteriorated, Perhaps a combination of aggressive fluid and excessive velocity eroding the ball.

Other HW are running fine after 15 years or more.

We estimate perhaps 5000 cycles per year, most manufacturers design the components for 100,000 cycles or a 20 year life span. We have cycle testing machines in the lab, a few years back we put some Sunnywell, a HW knockoff, valves on the test bench and got about a years worth of cycles before they failed.

I did see the You Tube where a tech completely cleaned the old grease out, but he put oil on the plastic gears, I doubt that rebuild will last too long, the grease is an important part of the design.

Normally open valves have a shorter life span as well as valve inside the fin tube enclosure due to ambient temperatures.

A HW - Caleffi comparison, gears and springs are substantially different engineering

Grallert

I've not seen any as bad as those. Boy oh boy. Luckily the repair is pretty simple. In my experience I think it's been unmaintained antifreeze that's cause the trouble but I'm not sure.

hot_rod

https://forum.heatinghelp.com/discussion/comment/1883168#Comment_1883168

\

yeah, any time you work on ANY glycol systems, take a ph meter and get a reading. The acceptable ph varies a bit from brand to brand.

DowFrost PG vs Fernox, for example. I think Dow suggest dumping the Dowfrost if it gets in the 7s?

clydesdale

I replaced the zone valve powerhead. The issue may be two fold. The gears were very screwed up and when I pull the lever, they pop and grind and generally sound terrible. But, I could not twist the ball valve by hand. I had to grab some pliers and without much effort, was able to turn it back and forth until it loosened up to where I could easily turn it by hand. It is now working. I think I need to periodically run this zone. It is for the garage and I rarely use it. Thanks.