No heat - transformer failure x 2

EricPeterson

Our house is heated by a Burnham ES2 boiler with three zones / thermostats.
I know the boiler was working at 2AM this morning when I heard it go on and off.
But woke up this morning to a cold boiler.
All thermostats calling for heat and all zone valves powered and open.
Removed the front boiler panel to see a dark control board.
Checked voltages and saw that there was primary power to the transformer but nothing coming out of the secondary from the transformer.
Disconnected power to control board and replaced transformer with spare (not same model but identical rating - 24 VAC, 40VA/40W) using the primary and secondary wiring harness connectors.
Connected power to control board, and checked that the replacement transformer was providing 24VAC.
Connected secondary to control board, which powered up and went through a number of states, with the last state being:
59 - Line voltage error

Then the control board went dark.
The spare transformer had now also failed.

Anyone seen anything like this before?
The line voltage checks out at 120 VAC.
I'm off to the hardware store to get another transformer and try again.

Frustrated,
Eric Peterson

nicholas bonham-carter

Some fault seems to have fried the second transformer, so it would be wise to find that before installing another.—NBC

Jamie Hall

nicholas bonham-carter said:

Some fault seems to have fried the second transformer, so it would be wise to find that before installing another.—NBC

You are so right. There is a fuse in most of those small transformers on the secondary side. Chances are you've blown another one. The line voltage error suggests a large current draw on the transformer before the fuse blew, since those little transformers have a lot of voltage drop on high current. So... find the short.

CBRob

You can get transformers with a breaker, I just found one from honeywell.

Will help with troubleshooting and not going through transformers

EricPeterson

Agreed.
The only two things I can think of that would fry the transformer would be:

1. direct short of the secondary.
   
2. too much power being drawn from the secondary.
   

Zone valves / thermostats are all powered separately and the sole interface to the system is a contact closure when calling for heat.
So the only users of secondary power are the logic boards and downstream components. Logic boards are:

• IQ Boiler Control
  
• IQ Option Panel
  

I did observe the control board going through these states:

• 1 - Standby
  
• 17 - Self Test
  
• 15 - Waiting for limit to close
  
• 59 - line voltage error
  

I might have missed intermediate states.
Meanwhile the option board was flashing "Err" and "1". I did find a reference for this board that indicates:

• Status=Low Input Voltage
  
• Boiler / Control Action(s)=AC voltage is too low
  

https://manualslib.com/manual/23092/Burnham-Es2-Es2.html?page=20

Anyone out there with experience troubleshooting Burnham logic boards have any suggestions as to how to proceed in isolating this fault?

At this point all I can think to do is power up the logic board after first disconnecting everything connected to it, then connect things one by one until a fault occurs.

Eric Peterson

Jamie Hall

The problem may not be in a board. Test the wiring from the transformer to the board first, unless it is hard mounted to the board.

HVACNUT

Have you tried disconnecting the molex plug to the transformer and powering up the board without 24v to it?
Are you using any of the optional IQ cards? It seems like an internal short in the board on the 24v side.

EricPeterson

The 24v secondary powers the board.
Just bought another transformer, but model with breaker not available.
So I would like to add a fuse inline for troubleshooting...,anyone know what size would be needed to protect a 24VAC transformation rated at 40 VA?
Guys @ Lowe’s thought it should be 1.6 A fuse.

Eric

HVACNUT

3 amp slow blow.
Not exactly the best way to troubleshoot though.

HomerJSmith

Try this transformer with a reset button.
https://www.supplyhouse.com/Functional-Devices-TR75VA001-Transformer-w-Circuit-Breaker-Foot-Single-Threaded-Hub-Mount-75VA-120-to-24-Vac

You can try the "Lil Popper Fuse Tester 3 AMP 24V ".

Where the 24V secondary connects to the wiring or board--measure the ohm resistance. It should be higher than 5 ohms.
The higher the better. You can get an inexpensive meter with digital readout at Harbor Freight.

If the board is bad, replace the board.

EricPeterson

@HomerJSmith - thank you for those suggestions.

And now some good news.

After going through four 3A fuses and troubleshooting, the boiler is operational but I have some more work to do in isolating the wiring that connects to the boiler and calls for heat.
I will report more on what happened later when I have more time. What threw me off most of all is that nothing changed from the setup that has been working for a number of years.....thanks for all the tips and feedback, and also to two sales guys @ Lowes in Naperville (Joe - an ex-building engineer, and Roger) who listened to my story and gave some suggestions.

Eric

HomerJSmith

"I will report more on what happened..."

I should hope so. You don't think we work for free. We want to know the problem and the solution to add to our knowledge and take pleasure in knowing that we helped someone.

EricPeterson

I bought a second replacement transformer at Lowes, and then protected it from overload with a 3A fuse.
Then I tested plugging in different connectors on the control board and found that the fuse blew when I plugged in the connector labelled "Control". This connector has wires going to the option board and some other places. The only thing on the option board is the connection to the thermostats (labelled TT). So even though it made no sense to me, I next tried plugging in the Control connector with the connection to the thermostats removed.
The fuse did not blow.
Then I connected the two TT terminals together with a jumper, simulating a call for heat.
The fuse again did not blow, but it kind of blew my mind.
The boiler was now running and I let it run for a couple of hours to warm up the house.
My boiler system is zoned with three White-Rogers zone valves.
For the call for heat, I was using the connection diagram found here, in particular according to Figure 9 on page 4, with the T1 and T2 being the TT terminals on the Burnham option board.
Now as I said this has been working for a few years, 8 years if my memory serves me correctly. So I was quite surprised to find that all of a sudden this setup is blowing transformers (and fuses).
I have now isolated this electrical connection with a relay and the system again seems to be running fine.

I hope this explanation makes sense.
Thanks to all for helping out on the Wall.

Eric Peterson

HomerJSmith

I think one of your thermostat wires is grounded. Touching the thermo wire together just completes a connection that the thermo would do. The thermo is just a switch that closes when the temp goes below set point. Grounding one wire on the thermo, like to a copper pipe etc would blow the fuse.

A short to the pipe inside the zone valve or wiring to a pipe could do it too.

EricPeterson

Time will tell. System will be under observation. At least now any fault is isolated from the boiler. If there an issue it appears to be intermittent which is harder to find.

Jamie Hall

I like @HomerJSmith 's conclusion. And what is more interesting -- just to add to the fun -- it's going to depend on which transformer wire connects through to the T-T wires... one will blow a fuse from time to time. The other won't. As you note, intermittents are such fun...

neilc

couldn't EricPeterson just flip the wires at the trans and change the common side?
(trans is out of phase ??)
I'm not sure on this one , , ,

Jamie Hall said:

I like @HomerJSmith 's conclusion. And what is more interesting -- just to add to the fun -- it's going to depend on which transformer wire connects through to the T-T wires... one will blow a fuse from time to time. The other won't. As you note, intermittents are such fun...

EricPeterson

What's interesting is that with this setup, depending on how many thermostats are calling for heat, the loop through the low voltage wiring to the TT terminals passes through three zone values and one to three thermostats.
I can check each of the thermostat wires now in isolation from the others. What exactly should I be testing for each of these?
Continuity certainly - either open or closed.
Would a high resistance when closed be an issue?
@HomerJSmith - are you suggesting I should also check continuity between each loop and ground?

Eric

Jamie Hall

Say again? Are you saying that the thermostats and zone valves are wired in series in some way?

It ight be very helpful -- to you and to us -- if you could draw up a circuit diagram of this setup.

And yes you should check resistance to ground. You should also determine what is intended to be grounded, if anything.

EBEBRATT-Ed

@EricPeterson

I have always had issues with multiple zone valves and there auxillary switches being comingled with the thermostat wiring.

Never seen the White Rogers but Taco valves are similar.

To me everything works better when the thermostats opens and closes the valves using there own separate 24 volt transformer and the auxilliary or end swithch that starts the boiler is just a set of contacts. the boiler 24v power and thermostat 24 volt power are seperated. Using a rely helps prevent issues and makes it far easier to troubleshoot

EricPeterson

The basic circuit diagram from White Rodgers can be found here :

• Figure 2 on page 2: shows the internal working of the valve.
  
• Figure 9 on page 4: shows how multiple valve are wired together. Thermos are connected to "4" and "5" on their respective valves.
  
• Note that "5" is internally connected to "2" on each valve, and "5" is connected to one the TT terminals on the boiler.
  
• The other TT terminal is connected to "3" on each valve.
  
• When any of the valves open, "3" is connected to "2"/"5" thus closing the loop calling for heat.
  

If more detail is needed I can work on a circuit diagram. But it will not be as nice as the WR one.

Eric

EricPeterson

@EBEBRATT-Ed I agree. The zone valves and boiler each have their own transformer.
I have taken it once step further as you indicate and now the zone valves trigger a relay that closes the connection to the boiler when calling for heat.
As you say this makes for easier troubleshooting and better protects the boiler's low voltage circuit.

Eric

Solid_Fuel_Man

Keep in mind that you can ground either leg of the secondary of the transformer. One or the other most likely is already grounded for you in the board. Now you cannot ground the other side or else you get a short.

Are your thermostats mechanical, battery powered digital, or power stealing electronic? Or are there 3 wires R,W, and C?

EricPeterson

@Solid_Fuel_Man - all thermostats are digital models. For each thermo two wires connect to terminals "4" and "5" on their respective zone valves.

I am now running the thermostat loop through a separate low-voltage circuit powered by 20VA transformer. This circuit is connected to a relay, when there is a call for heat the relay closes the TT contacts on the boiler.

So the thermostat loop is working fine powered by a 20VA transformer - but all it does is close the relay. The same loop was causing a 40VA transformer to fail - which was powering a number of things on the control board.

So what I am thinking now is that perhaps there was a poor connection from the thermostat loop to the TT terminals, causing it to draw too much amperage and then fail the transformer. Recall that when I powered up the first replacement transformer, both boards came up and reported:

• option board: "Err" / "1" - Status=Low Input Voltage, Boiler / Control Action(s)=AC voltage is too low
  
• control board: 59 - line voltage error
  

But for now the system is working and I will continue to monitor the situation.

Eric

Jamie Hall

A poor connection won't cause an excess current draw. Never does. A short, on the other hand... surely will. What a poor connection might do is cause that low input voltage error,, but that won't blow a fuse, never mind a transformer, by itself.

Solid_Fuel_Man

Absolutely correct.

EricPeterson

I don't understand the short comment related to the thermostat loop - which is after all shorting (connecting) the TT terminals when there is a call for heat. Anyway...

Addendum - something I forgot...

• Sometime last year or the year before, the boiler was not responding to a call for heat, which comes in on the TT terminals on the option board.
  
• The TT terminals connect to the logic board through a wiring harness, and I determined that there was no continuity between one of the terminals and the logic board.
  
• So I chalked it up to a connector issue, and spliced in the wires from the thermostat loop directly to the wires on the harness, thus bypassing the TT terminals.
  
• So just last week I took out the option board and saw the fried trace on the back of the board. Apparently whatever recently caused the transformer to blow had sometime in the past fried the wiring on the board - which I did not notice at the time. See image below.
  
• The option board was replaced with a new one.
  

So this fault in the thermostat loop apparently started well in the past, and is highly intermittent. Still a mystery - but at least now I have isolated it from the boiler through the use of a relay powered by a separate transformer - so if the intermittent occurs again I expect this transformer to be sacrificed.

On the boiler I have a replacement 40VA transformer in place, which matches the rating of the original. I would instead like to use a transformer with a built-in circuit breaker. SupplyHouse has such a model but it is rated at 75VA. Am I correct in thinking that it would be unwise to go with a larger transformer here, to avoid any potential damage to the logic and option boards, which may have been designed for a 40VA transformer?

--Eric

PGB1

Just a quick couple of suggestions: (I'm not a hydronic technician, rather I'm an electrician with industrial control system design background. I do have industrial hydronic control system experience, but not much residential, so I'll focus on basic electrical, leaving the Burnham specifics to the experts who are helping you. )

A) If you are losing 3 amp fuses in series with a 40 amp 24 volt transformer, focus on short circuit instead of over-current. The transformer windings will open before a 3 amp time delay fuse will fail due to over-current.

If yours are motorized zone valves, use a 1.7 or 1.8 amp time delay fuse instead of the 3 amp. It will better protect the transformer and the PCB traces. The 1.7/1.8 amp fuse will tolerate the current if all zone valve motors are opening or holding open at the same time (hence time delay) plus the current from the the anticipators, as well as if the pump & burner relays are called (which, on most systems, won't happen until the zone valves are 100% open.) By coincidence, this is what I have in my home with 3 motorized zone valves. It's been fine for 30+ years. (Now I jinxed it!)

C) I've helped friends & family on their system failures and, every once in a while, I find a zone valve that will create a short circuit at the instant, or seconds after, the end switch closes. It's always been with Honeywell 804VE valves. I dissected one once & found that when the motor was stopped due to travel limit, a weak winding would short. (Why? These motors have a higher current in hold-open than when moving. The winding insulation varnish starts to break down over time, especially because these are always warm. The very small increase in wire diameter when warm allows the short.) This is a remote chance, but still a possibility.

Hope This Helps!
Paul

PGB1

PS: I don't know how the sunglasses guy picture got in there. Please pardon the typo (that I'll never be able to replicate if I tried). Paul

Solid_Fuel_Man

It's your B and ) directly after

EricPeterson

@pgb1 - thanks for the comments. The sunglass emoji was created by the website code which translates the text "B)" into this emoji

Here are my responses:
a) When troubleshooting I was using 3A fast acting fuses to protect the $38 replacement transformer. I went through a few of these fuses until I determined what was causing the fuses to blow - and that is still the weird part. What was causing the problem is what I am referring to as the "thermostat loop" - which is the circuit that passes through the zone valves to close the TT terminals on the option board which provides the call for heat. Once I removed that loop, the fuse did not blow. When I jumpered the TT terminals the boiler started up normally.
b) these are White Rodgers motorized zone valves. They are powered by a different transformer than the one on the Burnham control board. I have never had any issues with the transformer that powers the zone valves. Here are the installation instructions for these: link.
Refer to Fig. 2 to see the internal workings, and Fig. 9 to see how the thermostat loop works.
c) I have not had any issues with the zone valves. The conjecture here seems to be that the thermostat loop somehow caused, through the TT terminals, a condition that caused the boiler transformer to short out (happened twice last week) and also for the trace on the option board to fry a year or so ago. In summary when I was having the problem:

• thermostat loop passes through the zone valves and connects to the TT contacts on the option board
  
• on a call for heat by any one of the zone valves, thermostat loop closes the TT contacts on the option board
  
• TT contacts pass through the option board to the control board where they activate the firing and running of the boiler.
  

The change I made last week was to connect the thermostat loop to a relay in order to isolate it from the boiler. When the call for heat comes in now it activates the relay, and the secondary circuit on the relay closes the TT contacts.

Hope this makes sense.
Eric

Solid_Fuel_Man

Oh....

So you are using the end switches from zone valves to the TT on the boiler?

Sounds like you have a cross connection from the transformer to the board.

There should be no power available from the end switches to the TT on the boiler.

There is either a short to hot or a short to ground in your wireing or inside a zone valve actuator.

Fuse each zone valve individually with a smaller fuse that the 1.5A and you will find which one it is.

RJO

I have a Burnham ES2 boiler that had 2 fried circuit boards due to a power outage Dec 24 2021. Two boards replaced in 2nd week of January - cost over 3000. Had electrician put in whole home surge protector. Just had another blackout and basement smell like burning electronics. Took off the panel. Both status windows out - no errors no ppwer. Reset the Boiler switch in the circuit box. Still no power. Not technical - is there a reset button or anything I can do to reset it, or like Dec, is it dead. Does this model have a lot of problems with these boards. My last boiler lasted 53 years. This, less than 3.

Jamie Hall

Any of the modern electronic boards can have trouble with surges. And I'm sorry to say that a whole home surge protector won't help. They simply aren't fast enough. If you have more or less regular problems with surges, and it sounds like you do, the individual equipment needs to be protected. I might add that this applies to high fidelity sound systems as well...

EdTheHeaterMan

@RJO You should probably start your own discussion. Referencing this discussion in your discussion might help but I believe it will only confuse the issue.

Regarding your issue: A surge protector may help. But a surge protector can expire. How much of a surge any surge protector can handle is measured in Joules. If you have a surge protector that will protect up to 1000 Joules, that means it can handle 1000 surges of 1 Joule each or 1 surge of 1000 Joules, or any other combination like two 500 Joule surges. Once you have all the surges add up the the total Joules that device can protect against... that device is then all used up. So a surge protector should be replaced every so often, because they can become used up, and will no longer offer any protection to your electronics.

It sounds like the electronics on your boiler are gone and will need replacing. Check to see if your homeowners insurance covers this problem.

mattmia2

A surge protector will only protect from the ac line. something that is frying boards more likely came from the low voltage wiring or the plumbing.

HomerJSmith

Question: Has any other electric device, light bulbs, etc failed at the same time? Is your boiler on a multi-wire circuit? Is the breaker in the panel a single 1" or 1/2" breaker or two 1" breakers with a tie between the handles (switches)?

I don't use or recommend the surge protector that looks like a breaker that snaps on to the buss bar in the panel. But it is better than nothing. I recommend a whole house surge protector and a surge capacitor set up. But...I still use a computer grade 4000 Joule surge protector on Mod/Cons. I would plug your boiler into a computer grade surge protector, also. Most good computer grade surge protector have fast acting MOVs in them. At above 130 V, they will clamp in nano secs.

No surge protector will save you from a ground fault (short). If the board or wiring is grounding out somewhere in the cabinet, you can blow the board or transformer. It can be an intermittent short. Check the cabinet wiring etc.

You can buy a line monitor and plug the boiler into it. It will provide high and low voltage peaks and dips and frequency, etc. Perhaps something like the following:
https://www.amazon.com/Electricity-Towallmark-Backlight-Consumption-Kilowatt/dp/B08TH719NS/ref=sr_1_303?crid=1Y2GQERYLTB6Z&keywords=ac+line+monitor&qid=1666870184&qu=eyJxc2MiOiIzLjY1IiwicXNhIjoiMy4yMCIsInFzcCI6IjEuOTIifQ==&sprefix=ac+line+monitor,aps,206&sr=8-303

EricPeterson

@RJO - As the OP for this thread, I have a few comments.

First, as @EdTheHeaterMan indicated you should start your own thread. The only commonality here is that you are having a problem with the ES2 boiler.

Second, the problem I came to the Wall with was the failure of a transformer that powered the electronics - Control board and Option board - for the ES2. The result was that there was no response to a call for heat because the electronics were not working. I did not experience "fried boards".

There was a tangential problem in that a trace on Option board had failed previous to the transformer issue. In my case it appears all the issues were related to the low-voltage wiring for my three zone valves and using the wiring diagram provided by the manufacturer (White-Rodgers). I solved the problem by using a relay to isolate this low-voltage wiring.

Anyway, my problem was not related to any kind of power spike or power outage.

Third, it would be most helpful in your new post if you were to provide a wiring diagram for your installation. Since you are "not technical" this may be a stretch. If you paid so much to fix the problem then perhaps you could ask whoever did that to provide such a diagram.

If I paid that much then I would expect pretty good service including a follow-up call. Was the work guaranteed for some time period? I don't know about surge protectors but I have none and living in the same house for almost 40 years have never experienced a power surge. I do know that you can buy replacement boards for the ES2 @ SupplyHouse for a very small fraction of whatever you paid someone to fix your problem.

I hope you find a solution to your issue. Winter is coming.

Eric