Boiler control problem

My home heating boiler has been having a problem this fall. I installed it five years ago and it has been working just fine until recently. The boiler has a Honeywell control with a Becket burner and three Taco zone control valves and two programmable T'stats and one twist knob control t'stat for the Boilermate. There are three zones, two work as they always have. When heat is called for the circulator pump comes on and runs for around 90 seconds, then the boiler fan comes on for around 30 seconds, then the burner fires up. There are three zones, two of them work as I described. The third zone, controlled by a programmable T'stat keeps ending and then restarting the process. It will stop wherever it is in the start-up process, and then restart it. it will shutoff when in circulator only mode, and it will shutoff while in burner fan mode and it will shutoff after it has fired up. This will go on for approx. 10 minutes before it finally keeps running. The fact that two zones work as they should eliminates a problem with the boiler control or burner. I replaced the T-stat but it made no difference. I have gone over the control wiring very carefully. There is no moisture at the zone valve. There are three zones two work as they should. Any ideas?

Do all three thermostats connect to the same controller? If so, try putting the bad zone on one of the other zones. If the bad zone starts working, then it's the controller....or whatever the part is that the thermostats connect to.

I'm not very HVAC literate and can't picture the setup you described, so maybe this will help, maybe it won't.

Good luck!

Are your zone valves the type with "end switches" that close to start the next part of the heating sequence when they are nearly fully open?

showcrop,

If I read this right, you have a large hot water heater (boiler) that is fully wetted and full of water.I have to make some assumptions....the "twist" knob control is for the temperature which the boiler turns on and off? The zone valves are strictly open/shut. The t-stats contacts are what are probably wired in parallel, so any one of them can call for heat. Does the circulating pump runb all the time? I would have thought so, but I am not there to look for myself.

So, if possible, describe a "normal" functioning of your heating system, by t-stat. That's a good start,. You use "it" as a descriptor, but I cannot determine what "it" might be.

Sorry for your troubles, bbut I have some experience with hydronic systems that may be of help.

D.

(quoted from post at 14:43:19 11/11/19) showcrop,

If I read this right, you have a large hot water heater (boiler) that is fully wetted and full of water.I have to make some assumptions....the "twist" knob control is for the temperature which the boiler turns on and off? The zone valves are strictly open/shut. The t-stats contacts are what are probably wired in parallel, so any one of them can call for heat. Does the circulating pump runb all the time? I would have thought so, but I am not there to look for myself.

So, if possible, describe a "normal" functioning of your heating system, by t-stat. That's a good start,. You use "it" as a descriptor, but I cannot determine what "it" might be.

Sorry for your troubles, bbut I have some experience with hydronic systems that may be of help.

D.

Click to expand...

There are 10 "it"s. I think that you are referring to most of them which refer back to the "problematic" zone.

(quoted from post at 14:33:15 11/11/19)
Are your zone valves the type with "end switches" that close to start the next part of the heating sequence when they are nearly fully open?

Click to expand...

Bob, I believe that the zone valves, which have three terminals, are the type with the end switch, and it is looking to me now that my problem is a bad contact inside the valve control head that is keeping the switch from closing fully so that it reopens. I will see if I have a spare valve.

(quoted from post at 14:43:19 11/11/19) showcrop,

If I read this right, you have a large hot water heater (boiler) that is fully wetted and full of water.I have to make some assumptions....the "twist" knob control is for the temperature which the boiler turns on and off? The zone valves are strictly open/shut. The t-stats contacts are what are probably wired in parallel, so any one of them can call for heat. Does the circulating pump runb all the time? I would have thought so, but I am not there to look for myself.

So, if possible, describe a "normal" functioning of your heating system, by t-stat. That's a good start,. You use "it" as a descriptor, but I cannot determine what "it" might be.

Sorry for your troubles, bbut I have some experience with hydronic systems that may be of help.

D.

Click to expand...

The twist knob thermostat is on the Boilermate. There is one circulator that is contrlled by the individual T'stats.

showcrop,

I honestly did not wwant to contribute to frustration. My apologies. I tried to draw on paper your sytem and probably came across as too questiony.

D.

(quoted from post at 15:20:52 11/11/19) showcrop,

I honestly did not wwant to contribute to frustration. My apologies. I tried to draw on paper your sytem and probably came across as too questiony.

D.

Click to expand...

No, no frustration, no worries I just did my best to figure out what it or its you were asking about.

(quoted from post at 18:06:15 11/11/19)

(quoted from post at 14:43:19 11/11/19) showcrop,

If I read this right, you have a large hot water heater (boiler) that is fully wetted and full of water.I have to make some assumptions....the "twist" knob control is for the temperature which the boiler turns on and off? The zone valves are strictly open/shut. The t-stats contacts are what are probably wired in parallel, so any one of them can call for heat. Does the circulating pump runb all the time? I would have thought so, but I am not there to look for myself.

So, if possible, describe a "normal" functioning of your heating system, by t-stat. That's a good start,. You use "it" as a descriptor, but I cannot determine what "it" might be.

Sorry for your troubles, bbut I have some experience with hydronic systems that may be of help.

D.

Click to expand...

The twist knob thermostat is on the Boilermate. There is one circulator that is contrlled by the individual T'stats.

Click to expand...

You should be able to wring out the zone valve with a multi meter in a few minutes.

Maybe just swap 2 heads and see if the problem moves???

If you have only one pump for several stats you may also have loss of voltage between the zone valve and pump control.

Also, can you post a pic or 2 of these zone controls?

(quoted from post at 16:47:32 11/11/19)
Also, can you post a pic or 2 of these zone controls?

Click to expand...

By zone controls are you referring to the zone valves?

My only reply is; Hire a professional. Cheap at almost any cost to get your system working. Winter is on the way.

Since you say it has a Beckett burner, I assume this is an oil-fired boiler. There should be a flame detection indicator light on the Beckett controller that lights up, indicating everything is good. I mention this because it sounds like there could be an issue with the burner, except it apparently isn't going into lock-out. (After three failures to ignite, a Beckett unit will lock out and has to be reset.)

I concur that the problem is likely the Taco zone valve. My experience is with Honeywell valves, but I assume the Taco valves are similar. A bad switch in the valve can give buggy behavior.

(quoted from post at 22:29:22 11/11/19) My only reply is; Hire a professional. Cheap at almost any cost to get your system working. Winter is on the way.

Click to expand...

I built the system; I'll maintain it, LOL.

Another thought: The Beckett controllers have their own internal 24V thermostat power. It will operate a thermostat but not much else. Assuming your Taco valves are 24V, there must be an additional transformer somewhere else in the boiler to operate the valves. Is it possible your dodgy valve is picking up power from the Beckett controller rather than the external transformer? That could explain the burner shutting down midway in its cycle: The load of the valve could be enough to draw down the voltage of the Beckett thermostat source to the point where the control thinks there's no call for heat.

Thanks for all the replies. I picked up a new control head for the valve this morning and it is working as it should again.