Older zone valve controller not sending 24v to the zone valve.

tctran_jm3

Hello. I have an erie vl500 boiler boss zone valve controller. The system is about 20 years old. This is a five zone controller. As cold weather will be soon upon us in the Northeast, I turned on my thermostats to make sure things are working. Bad news, only 1 of the zones is working properly. The vl500 zone valve controller has two lights per zone. A red light that shows a call for heat has been made, and a green light to show that the valve is open and the end switch has closed. Zone 1 works perfectly. Both lights are lit up and the zone valve wires are showing around 25v tested on a multimeter. Zones 2 through 5 will have the red light lit, showing a call for heat. However the green light showing the end switch has closed does not light up for zones 2 through 5. I've verified that the zone valves have not opened. In fact, if the thermostats are calling for heat, the zone valve cannot be manually opened, there is a ton of resistance. I tested the voltage on the zone valve wires for zones 2 - 5 when the thermostats are calling for heat and they measure roughly 20v. I tested the thermostats and r / w is showing around 28v. If the thermostats are off, I can manually open the zone valves.
Its very odd to me that zone 1 is providing enough voltage to open the zone valve, but not for zones 2 - 5. Any thoughts on how to troubleshoot further is greatly appreciated.


Tom.

EdTheHeaterMan

Is there a priority switch somewhere on the Boiler Boss? If Zone 1 is the priority zone, then all other zones will be off as long as zone 1 is calling for heat when the priority switch is in the ON position

tctran_jm3

EdTheHeaterMan said:

Is there a priority switch somewhere on the Boiler Boss? If Zone 1 is the priority zone, then all other zones will be off as long as zone 1 is calling for heat when the priority switch is in the ON position

Thanks for the response. Yes there is priority and it is set to off. I'm testing with just one zone on right now, zone 4. Nothing else is on. I hear a slight buzzing sound and the voltage for the zone valves is at around 20v. It seems as if it's trying to open the valve, but doesn't have enough power to do so.

EdTheHeaterMan

Have you tried each zone individually?

tctran_jm3

EdTheHeaterMan said:

Have you tried each zone individually?

Yes, I have tried each zone individually, but I've only measured zones 3 and 4. I'll try to measure zones 2 and 5 tomorrow morning. thank you.

hot_rod

If you cannot open the valve manually with the  metal lever, the motor may not open them either

Jamie Hall

I hope your measurement of voltage between R and W at the thermostat is with the thermostat either off or disconnected. If the thermostat is calling for heat, the voltage should be 0.

EdTheHeaterMan

Do you have the model number or part number of the boiler boss control for zone valves? I can only find the zone circulator control information. I remember selling that stuff in the 1990s. I even put Erie Pop Top valves on my own system. Needed to replace all of them with Honeywell after just 10 years.

You may need to go with a new control. I'm a Taco fan but there are others available. Taco ZVC

tctran_jm3

hot_rod said:

If you cannot open the valve manually with the  metal lever, the motor may not open them either

The valve can manually be opened if the thermostat is NOT calling for heat. When the thermostat calls for heat, the valve cannot be manually opened -- lots of resistance.

tctran_jm3

EdTheHeaterMan said:

Do you have the model number or part number of the boiler boss control for zone valves? I can only find the zone circulator control information. I remember selling that stuff in the 1990s. I even put Erie Pop Top valves on my own system. Needed to replace all of them with Honeywell after just 10 years.

You may need to go with a new control. I'm a Taco fan but there are others available. Taco ZVC

Thanks. The model number of the zone valve controller is VL500. There must be a short somewhere that is causing the drop in voltage. I just don't know where to start to figure out where the short may be.

Jamie Hall

Shorts don't cause a drop in voltage. Rather what does is a combination of excessive resistance and current draw, or an inadequate supply power (which is really the same thing).

109A_5

Hello @tctran_jm3,
Many zone valves and other accessories
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/VL500-Brochure.pdf

Controller
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/VL500-Submittal.pdf

Does the 20 VAC measured change much regardless of just a single zone like zone 2 call for example or many zone 2, 3, 4, 5 Call ?

You did not really state what zone valve 1 is getting. Is zone 1 also just 20 VAC ?

hot_rod

tctran_jm3 said:

hot_rod said:

If you cannot open the valve manually with the  metal lever, the motor may not open them either

The valve can manually be opened if the thermostat is NOT calling for heat. When the thermostat calls for heat, the valve cannot be manually opened -- lots of resistance.

It could be the valve is full open when the thermostat calls?
If so , you will not be able to force the lever any further. Without damaging the insides.

If only one light lights, call for heat, for a particular zone, you most likely have a failed end switch. That is the most common failure with those valves.

tctran_jm3

109A_5 said:

Hello @tctran_jm3,
Many zone valves and other accessories
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/VL500-Brochure.pdf

Controller
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/VL500-Submittal.pdf

Does the 20 VAC measured change much regardless of just a single zone like zone 2 call for example or many zone 2, 3, 4, 5 Call ?

You did not really state what zone valve 1 is getting. Is zone 1 also just 20 VAC ?

Thanks. Zone 1 is getting 25vac and is opening fine, no issues. I have not tested if multiple zones are open and if the vac drops on 2-5.

tctran_jm3

hot_rod said:

tctran_jm3 said:

hot_rod said:

If you cannot open the valve manually with the  metal lever, the motor may not open them either

The valve can manually be opened if the thermostat is NOT calling for heat. When the thermostat calls for heat, the valve cannot be manually opened -- lots of resistance.

It could be the valve is full open when the thermostat calls?
If so , you will not be able to force the lever any further. Without damaging the insides.

If only one light lights, call for heat, for a particular zone, you most likely have a failed end switch. That is the most common failure with those valves.

The valve is not fully open. You can definitely tell if a valve is open by how the lever feels. I don't think it's an end switch issue. I don't think enough power is being sent to open the valve.

tctran_jm3

Jamie Hall said:

Shorts don't cause a drop in voltage. Rather what does is a combination of excessive resistance and current draw, or an inadequate supply power (which is really the same thing).

Thanks. Any ideas on how to test excessive resistance and current draw, or inadequate supply power?

tctran_jm3

Jamie Hall said:

I hope your measurement of voltage between R and W at the thermostat is with the thermostat either off or disconnected. If the thermostat is calling for heat, the voltage should be 0.

Yes, with the thermostat disconnect on the wall and measuring r / w with a multimeter.

109A_5

Hello @tctran_jm3,
I would guess there is a defect with the controller. Unless you or a willing friend can do a bit of reverse engineering and electronic repair it probably is less expensive to replace the controller.

Did you exercise the priority switch ? Oxidized switch contacts.

Why would 4 zone valve motors fail at once ?

To me it is more likely there is a defect on the board that influences the non-priority zones. And I only see one relay and I don't think it is for the priority.

You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens.

tctran_jm3

109A_5 said:

Hello @tctran_jm3,
I would guess there is a defect with the controller. Unless you or a willing friend can do a bit of reverse engineering and electronic repair it probably is less expensive to replace the controller.

Did you exercise the priority switch ? Oxidized switch contacts.

Why would 4 zone valve motors fail at once ?

To me it is more likely there is a defect on the board that influences the non-priority zones. And I only see one relay and I don't think it is for the priority.

You could monitor the 24 VAC to the Circuit Board and see it it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens.

Thank you so much for this. I think I've reached the point you've mentioned and will just have both boards swapped out with taco 6 zone valve controllers. I think your comment about a defect in the board that influences non-priority zones is likely the answer.

hot_rod

The ice cube relay you see it most likely a double throw multiple contact version that makes the decision

Sometimes they are common off the shelf replaceable, sometimes they are soldered to the board.
Or it could be a bad solder trace on the back side.
It depends on how deep you want to get into that relay, compared to a fresh new one.
Caleffi has some nice features on the relay boards for adjustability, service, and indication.

EdTheHeaterMan

After you replace the Erie Boiler Boss with a Taco or Caleffi zone valve controller and you get the same result, what will you check next?

I see another box just above the box in the photo. What is that control?

What zone valves do you have?

I would verify that everything else is working fine before I condemn the Boiler Boss Control. Are all the thermostats working?

Are all the zone valves working?

@109A_5 has a good point when he said

"You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens."

To do this, since zone 1 is working, I would take the thermostat wires off zone 2, at the control, one at a time, and test the other 3 to see if the problem goes away. Then place the the zone 2 thermostat wires on zone 1 and check to see if that thermostat is able to operate the zone 1 valve. If that works properly, then put zone 2 thermostat wires back and do the same with zone 3, then 4, then 5 until you get to see if all the thermostats work properly

Once that is done and you have determined that all the thermostats are working, then I would take Number 2 zone valve wires off at the control and test all the other zones. If you have the same problem, then put the #2 valve wires on the zone 1 valve terminals at the control. If that valve works properly then follow the same steps with zones 3, 4, 5.

Once you have determines that all the thermostats and all the valves will work on zone #1, then you can be sure that the control is the problem. If you find a defective thermostat or valve actuator or wiring circuit, along the way... then you need to correct THAT problem.

Purchasing the controller and spending the time to remove and reconnect all those wires, only to find that a valve actuators, or thermostat that is defective or you have a wire that is damaged by a fastener or staple, will make you unhappy that you now own two perfectly good zone valve controls and could have saved a couple hundred bucks if you looked at the second or third place ...first.

Most companies will not take electronic controls back once the box has been opened.

Teemok

Trouble shoot and prove a failure point. Both boards failing at the same time is long odds. Please tell me that 24v fuse is good.

tctran_jm3

EdTheHeaterMan said:

After you replace the Erie Boiler Boss with a Taco or Caleffi zone valve controller and you get the same result, what will you check next?

I see another box just above the box in the photo. What is that control?

What zone valves do you have?

I would verify that everything else is working fine before I condemn the Boiler Boss Control. Are all the thermostats working?

Are all the zone valves working?

@109A_5 has a good point when he said

"You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens."

To do this, since zone 1 is working, I would take the thermostat wires off zone 2, at the control, one at a time, and test the other 3 to see if the problem goes away. Then place the the zone 2 thermostat wires on zone 1 and check to see if that thermostat is able to operate the zone 1 valve. If that works properly, then put zone 2 thermostat wires back and do the same with zone 3, then 4, then 5 until you get to see if all the thermostats work properly

Once that is done and you have determined that all the thermostats are working, then I would take Number 2 zone valve wires off at the control and test all the other zones. If you have the same problem, then put the #2 valve wires on the zone 1 valve terminals at the control. If that valve works properly then follow the same steps with zones 3, 4, 5.

Once you have determines that all the thermostats and all the valves will work on zone #1, then you can be sure that the control is the problem. If you find a defective thermostat or valve actuator or wiring circuit, along the way... then you need to correct THAT problem.

Purchasing the controller and spending the time to remove and reconnect all those wires, only to find that a valve actuators, or thermostat that is defective or you have a wire that is damaged by a fastener or staple, will make you unhappy that you now own two perfectly good zone valve controls and could have saved a couple hundred bucks if you looked at the second or third place ...first.

Most companies will not take electronic controls back once the box has been opened.

Thank you so much for taking your time to write this out. I will try to answer the questions you listed.
1) The box above in the picture is another erie vl500 boiler boss. I have 8 zones in total. The original configuration was 4 and 4 with zone 1 empty on both control boards. Last year, 2 valves wouldn't open and I had a plumber come in and replace. The original valves are erie 4 wire valves. He replaced with schneider electronic 4 wire valves. The valves wouldn't open and the plumber didn't want to spend too much time diagnosing so he moved the valves to zone 1 of each board. So my current configuration is valves on top board 1, 2, and 5. Valves on bottom board 1,2,3,4,5.

2)The zone valves I have are: 6 erie valves and 2 schneider valves. All 4 wire. believe the model is: 1" Sweat 2-Way PopTop Zone Valve w/ End Switch (24V) SKU:VT2417G13A02A

3) Can you please explain what is meant by: "You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should."
I can try to swap out the wires as you've detailed in your post. I believe all of the thermostats are working properly as i tested vac with them removed from the wall.

4) I agree that putting in new boards and having the problem still exist would be very frustrating. I'd like to try to figure out what might be the cause as well. I'm not a professional and don't want to create a larger problem. My plumber thinks swapping out the boards would be more cost effective than spending hours trying to figure out the problem.

thank you again.

tctran_jm3

hot_rod said:

The ice cube relay you see it most likely a double throw multiple contact version that makes the decision

Sometimes they are common off the shelf replaceable, sometimes they are soldered to the board.
Or it could be a bad solder trace on the back side.
It depends on how deep you want to get into that relay, compared to a fresh new one.
Caleffi has some nice features on the relay boards for adjustability, service, and indication.

I actually have 2 control boards, 8 zone valves in total. Both boards are erie vl 500. The top board has a similar problem to the bottom board in that 2 zones don't work (zones 3 and 4). The bottom board has issues with zones 2 - 5. I swapped out the fuses and relay cube from the top board to the bottom board to see I could get zone 2, 3, 4, or 5 to work on the bottom board and no changes were observed.

tctran_jm3

Teemok said:

Trouble shoot and prove a failure point. Both boards failing at the same time is long odds. Please tell me that 24v fuse is good.

I actually have 2 control boards, 8 zone valves in total. Both boards are erie vl 500. The top board has a similar problem to the bottom board in that 2 zones don't work (zones 3 and 4). The bottom board has issues with zones 2 - 5. I swapped out the fuses and relay cube from the top board to the bottom board to see I could get zone 2, 3, 4, or 5 to work on the bottom board and no changes were observed.

hot_rod

Here is how I would try a simple troubleshoot.

Remove the thermostat wires in the relay box from the bad zone. Jumper those connections. Does the valve light come on? Is 24V present on the bottom "motor connection? Is 24V at the zone valve. If yes it should open. If jammed after a minute the motor will be very hot.

If you have 24V at the zone valve does the lever move or get loose when power is on the zone valve? It takes a minute or so.
If yes does the second light come on back at the relay box? If no, disconnect the end switch wires in the relay box and jumper. This takes the zone valve and end switch out of the loop. When you jumper the end switch connections, you eliminate the end switch from the circuit. If nothing happens, like the signal to the boiler, then I would suspect the relay box itself.


Eliminate the thermostat.
Eliminate the zone valve motor
Eliminate the zone valve end switch

EdTheHeaterMan

3)Can you please explain what is meant by: "You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should."

I copied that from someone else. All I wanted to say is "Eliminate all the other parts as the problem one at a time." If every valve works and every thermostat works then all you need to eliminate are the wires. After ruling out the thermostats and the zone valve actuators, start connecting everything back up one at a time until you find the problem. Once (If) you find that problem, then skip that one zone and go on to the next. You may find that you can save $$$ by doing this yourself. Paying a pro to do this can get expensive

When ever I came across a zone valve issue my first step is to have the customer purchase a zone valve controller.... You already have them. So use the control to help diagnose the problem by eliminating one wire at a time until the problem goes away.

OR

Take all the wires off and start by putting each wire back on one at a time until you have a problem. It is the only way to do the process of elimination. One step at a time

Since your plumber has an issue last year, and he fixed it by using the unused zones, you can do the same thing. Place the problem zones on the unused zones on the other control, one at a time.

And I would recommend getting rid of the Erie/Schneider valves completely when you need to replace them. I had nothing but problems with them. When I installed Honeywell valves my problems went away. You can try Honeywell, Caleffi or Taco. Stay away from B&G or White Rogers zone valves.

This would be a summertime job because that requires removing the water from the system to replace the actual valve component.

109A_5

Hello @tctran_jm3,

hot_rod said:

The ice cube relay you see it most likely a double throw multiple contact version that makes the decision

Looks like the relay is for XX Boiler Control and the Circulator.




"You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens."

To expand on this; If the loads, the zone valve motors are overloading the 120 VAC to 24 VAC transformer it is easy to tell. Transformers usually output their rated Voltage when loaded to their rated VA capacity. No or lightly loaded in this case 27- 28 VAC, full load 24 VAC. You mentioned 20 VAC on the bad zones, (assuming your meter is accurate) so where is the missing 4 to 8 Volts at ? Or are the loads (zone valve motors) overloading the transformer ? So the whole system Voltage is now low.

With a defective zone activated is there 24 VAC or greater at the transformer (Yellow annotation in picture).

With a good zone activated and a defective one activated is the good one getting 24 VAC or greater and the defective one 20 VAC or less ?

With your latest added historic information I suspect poor solder connections on the circuit board probably where the wire terminals connect to the Circuit Board, or maybe the TRIAC type switching device is failing, although higher than normal 'On' resistance is an odd failure for a TRIAC, but not impossible.

Swapping all 6 wires of a working zone with a non-working zone, does the defect follow the wires (thermostat and zone valve) or remain with the controller's zone Circuit Board terminal connections.

Solder joints and/or TRIACs are inexpensive repairs if you can do it. At 20 years old it easily could be solder joints, in general a very common failure.

And Yes, prove the defect before randomly wasting money.

tctran_jm3

109A_5 said:

Hello @tctran_jm3,

hot_rod said:

The ice cube relay you see it most likely a double throw multiple contact version that makes the decision

Looks like the relay is for XX Boiler Control and the Circulator.




"You could monitor the 24 VAC to the Circuit Board and see if it drops lower than it should. You could carefully swap zone 1 thermostat and zone valve with a defective zone and monitor what happens."

To expand on this; If the loads, the zone valve motors are overloading the 120 VAC to 24 VAC transformer it is easy to tell. Transformers usually output their rated Voltage when loaded to their rated VA capacity. No or lightly loaded in this case 27- 28 VAC, full load 24 VAC. You mentioned 20 VAC on the bad zones, (assuming your meter is accurate) so where is the missing 4 to 8 Volts at ? Or are the loads (zone valve motors) overloading the transformer ? So the whole system Voltage is now low.

With a defective zone activated is there 24 VAC or greater at the transformer (Yellow annotation in picture).

With a good zone activated and a defective one activated is the good one getting 24 VAC or greater and the defective one 20 VAC or less ?

With your latest added historic information I suspect poor solder connections on the circuit board probably where the wire terminals connect to the Circuit Board, or maybe the TRIAC type switching device is failing, although higher than normal 'On' resistance is an odd failure for a TRIAC, but not impossible.

Swapping all 6 wires of a working zone with a non-working zone, does the defect follow the wires (thermostat and zone valve) or remain with the controller's zone Circuit Board terminal connections.

Solder joints and/or TRIACs are inexpensive repairs if you can do it. At 20 years old it easily could be solder joints, in general a very common failure.

And Yes, prove the defect before randomly wasting money.

Thanks EdTheHeaterMan and 109A_5.
So I ran an abbreviated test tonight. I removed ALL of the thermostat wires and zone valve wires for every zone (1-5). The board was practically empty. I moved wires that use to reside in zone 2 (6 wires in total) into zone 1 and tested by calling for heat on the thermostat. The zone valve opened and the end switch connected. From my perspective the zone opened correctly. I then removed all of the wires in zone 1 and moved them to zone 2 -- no other zones were connected to the board. I tested by calling for heat on the thermostat. The zone valve did not open and the end switch did not connect. I then moved all of the wires from zone 2 to zone 3, again, no other zones were connected to the board. I tested by calling for heat on the thermostat. The zone valve did not open and the end switch did not connect. I was only getting 20vac on the zone valve wires when I had them in zones 2 and 3. I was getting 25vac when connected to zone 1 on the zone valve wires.

At this point, I know the thermostat and zone valve are working as it opened correctly when I connected to zone 1. The zone valve would not open when connected to zones 2 and 3. It's a pain to move those wires into the tiny ports. But after this test, can i conclude that there is something that wrong with the board?

Two new Taco (6) zone valves will set me back $400 + installation. Trying to troubleshoot the board would probably cost more?

thanks again.
Tom.

109A_5

Hello @tctran_jm3,

tctran_jm3 said:

Trying to troubleshoot the board would probably cost more?

From your findings and your historical account it does seem like the board(s) are bad. With the way you cleared all the wires off the top edge of the board I probably would have used that opportunity to release the barbs on the 4 plastic standoffs holding the board away from the metal cabinet and inspect the solder joints.

If you sent the boards out for repair it probably would not be worth the cost. If you or a friend has a soldering iron re-flowing a bad solder joint and adding some fresh solder (or removing most the old solder from the joint and re-soldering it, is better) is fairly easy and not real expensive. TRIACS are not expensive either, if needed. The part number is usually on the device. I'm betting on bad solder joints. If you are curious about cost there is soldering irons on Amazon.com (search for "soldering kit") and probably plenty of soldering videos on Youtube.com. The way I see it, for my home projects my labor time is free to me.

The HVAC industry for the most part would just change the box or two, not repair it or even try to. Their labor time is not free to you or me. I suppose you could replace the controllers and sell the old ones on eBay and recover a few $$ for your effort.

If you are going down the road of replacement Supplyhouse.com often has the .PDF of the install manual with the part listing. You can look them over before you purchase anything.

tctran_jm3

109A_5 said:

Hello @tctran_jm3,

tctran_jm3 said:

Trying to troubleshoot the board would probably cost more?

From your findings and your historical account it does seem like the board(s) are bad. With the way you cleared all the wires off the top edge of the board I probably would have used that opportunity to release the barbs on the 4 plastic standoffs holding the board away from the metal cabinet and inspect the solder joints.

If you sent the boards out for repair it probably would not be worth the cost. If you or a friend has a soldering iron re-flowing a bad solder joint and adding some fresh solder (or removing most the old solder from the joint and re-soldering it, is better) is fairly easy and not real expensive. TRIACS are not expensive either, if needed. The part number is usually on the device. I'm betting on bad solder joints. If you are curious about cost there is soldering irons on Amazon.com (search for "soldering kit") and probably plenty of soldering videos on Youtube.com. The way I see it, for my home projects my labor time is free to me.

The HVAC industry for the most part would just change the box or two, not repair it or even try to. Their labor time is not free to you or me. I suppose you could replace the controllers and sell the old ones on eBay and recover a few $$ for your effort.

If you are going down the road of replacement Supplyhouse.com often has the .PDF of the install manual with the part listing. You can look them over before you purchase anything.

Thanks.

I have a soldering iron and solder, just not good at removing old solder. Its odd to me that all non-priority zones stopped working. When the zone valve control gets replaced, I'll shoot off some pics of the back of it. Feel it's the least I can do for all of the advice I received in this post. Thanks everyone for your thoughtful responses.

Tom.

Teemok

I don't know if you have the means to do a load check ( amperage draw ) on the ZV motors. Putting a meter in series on each ZV motor is easy enough. It does sound like a fault is in the boards priority circuit. Capacitor, resister, switch, solder it could be anything. If both boards failed at similar times the same way due to a design or aging component limitation, that's not that odd. Near simultaneous bad solder joints would be. I'd want to be sure I'm not sending the new ZVC's into a failure mission by putting excessive amp draws on small switches.

109A_5

Hello @tctran_jm3,

tctran_jm3 said:

I have a soldering iron and solder, just not good at removing old solder. Its odd to me that all non-priority zones stopped working. When the zone valve control gets replaced, I'll shoot off some pics of the back of it. Feel it's the least I can do for all of the advice I received in this post. Thanks everyone for your thoughtful responses.

Spring loaded solder sucker or bulb works Ok or wick or braid works too for removal.
Edit: Add fresh solder to the joint then remove the old and the new then re-solder the joint.

Your history of the other board bothers me. If I read your history correctly only 'some' of the non-priority failed in the same way as all of the non-priotity zones on this board.

Inspect the joints for any flaws, cracks, rings of dilapidated solder around the components leads. look sharp or use magnification.

I think if it was maybe a priority logic thing the 20 ish Volts would not be on the failed zones, it just would be zero volts.