WM series 2 Ultra 155 6-25 error code

stephen11962

This is re-posting (5/10) of a problem I am having. The first posting said b-25 which is a misreading of a digital 6.
Ultra 155, TekMar controls, 8 years in service, 6-25 error code, outlet temp rise too fast.
The cause of the problem in the end was a bad temperature sensor. I replaced that and the error codes went away. The initial reason for becoming aware of the error code was a cracking sound coming from the boiler which was loud enough to hear upstairs, the boiler being located in the basement. That noise is still there after replacing the temp sensor. I am fairly sure that the cracking sound is a differential expansion (or contraction) between components of the boiler caused by a rising (or falling) temperature. This occurs at 175 degrees +/-. I have monitored the noises by waiting for the noises while holding a screw driver to various parts to feel the origin of the cracking sound. My best guess about the origin is the connection of the boiler water outlet to the house hot water supply. There is a compression fitting between the two. I have tried (very) slightly loosening or tightening the nut compressing the joint with very little lasting effect. The noise still exists and it is annoying but more importantly worrisome -too loud to be unimportant.
WM tech support was useful in suggesting the causes of the error codes, but not in locating the source or solution of the cracking noises.
Help!

Ironman

Can you post some pics of the boiler and its piping?

stephen11962

I am not sure how these will help but here are some photos.
The part where I can 'feel' the the noise is at the top of boiler, at the crest of the large round portion of the combustion chamber which is connected to the hot water supply outlet.

kcopp

Further back

lchmb

has the PH level of the boiler water been tested? Sounds like a perculator?

njtommy

Check your pump on the boiler it may not be working. You should have a another pump for the system side. If the primary loop pump(boiler pump) isn't working this would explain the temp rise to quickly. Could also explain the noises your getting could be steam pockets.

stephen11962

The system is controlled by Tekmar Reset Module (422), Zone Manager (336) and various Tekmar thermostats in the house. When the boiler is firing the Reset Module has icons that list what is happening in the system. That includes why the boiler is firing and which pumps are on. If there is a problem the Reset Module will have an "!" indicating an error. The Zone Manager has further information about the secondary loop pump and which zone pumps are on. No error signals are on and otherwise the system is working.
(Sometimes I wish that there were LED indicator lights on each of the pumps to see at a glance which were on/off. Everything else in life seems to come with LEDs.)

lchmb: pH of boiler water has not been tested. 8 years ago the water was very acidic which pushed me to install a neutralizer to prevent corrosion of brass fittings in the plumbing system. That was done about 4 years ago. I do not know if that change in water pH would finally reach the boiler by now. Last pH test for domestic water was 7.2.

Ironman

Need some pics from farther back that show the piping and pumps.

lchmb

If in neutralizer you mean a water softener that could cause issues with the boiler. Weil mclain has an additive they send with most of their boilers (don't remember the name) it may help to have it added

stephen11962

Here is the best possible. Cannot back up farther and the piping is complicated and hard to comprehend even in place. If you are looking for something in particular, ask. That might be more effective.

njtommy

Can you do us a favor and measure the distance between Ts on supply and return?
They look to be very far apart. Should be a lot closer spacers then that.

Also just cause your controller says the pump is on doesn't mean the pump is actually running. This is a daily round about with the damn control guys when they say up units running says so on the computer.

Ironman

The circulator on the primary loop is incorrectly installed with the motor shaft vertical: it has to be horizontal or the bearing will seize. This may be your problem.

Tom_133

The tees are too far apart, but sadly I have seen many of these and though it's far from acceptable it will "work". What you have (I am sorry if someone else already said this) is a B-25 and that comes when you hit high limit. So either you have a bad supply or return sensor, or the black pump on the left side of your venting, almost connected to the boiler is spanked. You can test that with an amp probe. The B code is a soft lockout and means that it shot up to quickly and that the burner is off for 10 mins, I would say that the pump is bad. That is typical but the sensors are cheap so test pump before you swap it out.

stephen11962

lchmb
Not a water softener. The neutralizer has calcium carbonate in some form that raises the pH. If nothing else it makes the water 'harder.'

njtommy
distance between Ts on supply and return? Distance is 18.5" I do not think there is anything to be done about that. But what is the consequence of that?

Ironman
" the motor shaft vertical:" Yes, indeed it is. This was by the installer 8 years ago. That circulator is working, I think. So, I am not a plumber, what kind of claim to I have about correcting the problem and maybe replacing the pump?

Tom
"...either you have a bad supply or return sensor..." Yes, the supply sensor was bad and I replaced it and the error code b-25 went away. Testing the pump may test my competence. I do not have an amp probe but I do have a reasonably sophisticated multi-meter. Any suggestions whether I can use that and maybe how?

I should take a moment and thank everyone for there attention and gestures of help. Thanks!

Ironman

" That circulator is working, I think."

Please tell me how you know this when it would give the very symptom that you're experiencing if it wasn't working.

lchmb

correct me if I'm wrong but presently your chasing a crackling sound only in the boiler...no more code issue's...

njtommy

The Ts should be no farther apart then 12" as per Weil Mclains specs. Having the Ts that far apart does not allow hydronic separation between boiler primarily and secondary piping. This is important especially with you error codes. A set up like this will not allow enough water flow through the boiler hence getting temp rise too quickly. It can also cause the pumps to fail. It should be repiped.

Tom_133

njtommy - The manual does say no more than 12" apart but Weil Mclain didn't mean for every install, that was a maximum based off pipe diameter. They have later changed that to 4 x the pipe diameter which we know is correct. I assume this boiler has been in place and working for many years. No reason to overwhelm people if it "works". I hate the "it works" thinking and I do my best to do it right, but he might as well fix the small problem (cheap sensor) and tackle the big one when that worthless aluminum heat exchanger gives up the ghost in a few years.

njtommy

@Tom it maybe works, but it's not right. Even at 4-6 times pipe size it's still too far apart to be correct and work correctly. WM knows they have heat exchanger problems and well being this one is older I'm shock it hasn't been replaced yet.

stephen11962

@lchmb

lchmb said:

correct me if I'm wrong but presently your chasing a crackling sound only in the boiler...no more code issue's...

The error code, b-25, disappeared after replacing the senor. I am now concerned about the 'cracking' noise. It sounds unhealthy

stephen11962

@Ironman
I assume that the pump was working because the boiler was supplying DHW and heating the house for the past 8 years. Wrong assumption?
I will verify this out later. I am away tomorrow. I have learned how to use the multi-meter to check amperage.

Ironman

stephen11962 said:

@Ironman
I assume that the pump was working because the boiler was supplying DHW and heating the house for the past 8 years. Wrong assumption?
I will verify this out later. I am away tomorrow. I have learned how to use the multi-meter to check amperage.

A wet rotor pump will give you the same amp reading if the pumps is running or locked up.

Grundfos has a key chain with a magnetic indicator that makes it easy. Without that, the simplest way would be feel the inlet and outlet of the boiler and the primary loop at the same time. If the primary is not getting hot with the boiler pipes, that circulator is bad.

stephen11962

@njtommy
@Tom
The discussion about the excessive distance between the Ts is worrisome. Can I assume that this could lead to premature equipment failure? Are the problems I am now having somehow related to this?
Boy, the cost of re-piping would be huge! I can imagine having a nasty discussion with the original installer to correct this. I just looked at the WM install manual and 12" is repeated on almost all types of installation.

Ironman

The 12" is what's spec'd to achieve hydraulic separation between the loops. As already stated, the actual, technical number is 4 x the pipe diameter. Without this, the flow between loops may interfere with each other SOMEWHAT. Technically, the common piping between the Tees should have been increased at least one size also, but most of us never do this. At worst, you have a slight bit of interference, but nothing to be concerned about. This is NOT what's causing your problem!

Most, if not all of the pros on here are hydronic oficionados: we're perfectionists. If we see something wrong, we'll point it out. The problem is that sometimes we forget that folks come here wanting the answer to a specific problem and they take every answer we give as being related to that. Again, the distance between the Tees is not causing your issue.

If I were gonna pic your install apart, I'd ask why there's an intermediate primary loop between two secondaries? It appears from your pic that's unnecessary: the house loop could Tee directly off of the boiler loop. Is it a big deal? No. Just an extra loop and pump. Unless that pump fails; which I suspect it has since it's mounted wrong.

Tom_133

Well said Bob. This is a wild shot but make sure the heat exchanger cover nuts are tight. I just went to one the other day that were loose and it burned a hole through the plastic cover of the boiler.

njtommy

It's hard to identify a cracking noise some times, but it is possible to have not enough waterflow through the boiler to cause the noise.

This is my thoughts. If the primary pump isn't working correctly the boiler would generally be going off on high limit fault. Or if the pump has slowed down for some reason it would show not enough flow but still some causing temp rise too quickly code.

It's not odd to have sensors fail, but it is odd to keep having the same one fail. I do wonder if it has been a problem or an issue for some time, but you just haven't caught it. It's not uncommon either how often do people really look at their boilers? Even us in the trade neglect things do to lack of time.

Now this is the beginning of the heating season some some problems may not shown there heads yet till we get some long run times in and really cold days.

My next questions is , is the pressure good generally around 12-15pisg. Also is the water make up valve working? You could have just a bit of air in the system to start causeing noises. It's no surprise the noise is at higher water temps.

Piping is completely up to you it's your money. We can only make recommendations.

njtommy

Also is the sensor in a well or is it exposed to the boiler water? It's been years since I worked on an ultra boiler.

Tom_133

The sensor is not in a well and they are a pretty poor sensor in terms of durability. I have bumped a few in my time and split them apart. They can get put back together but for the money I swap them every 5 years or so on the clean and tune.

njtommy

Then I will say this. The system was opened most likely theirs air in the system. I would purge the zones and try it again till all the air is out

Ironman

The sensor screws into a pocket in the block. That functions like a well: no water comes out when changing it.