Embassy Model 160 problem (L17 error code)

yhc

A couple months ago, a routine annual service was done on my Embassy boiler. At the time, the technician discovered that the main heat exchanger was leaking and replaced it under warranty. Since then, however, I had multiple issues with the boiler requiring a several service calls. After replacing the blower and control panel, it was discovered that the main culprit was bad wiring harness. The harness was replaced and it seemed like it was working for a few weeks.

Unfortunately, I have been getting L17 error code a several times in the past couple weeks, requiring resetting the system. A couple of weeks ago was the last time one of the techs came out. During the visit, a couple of components were replaced (see attached pic).

Since then, the boiler would run for a few days to a week but then it would trip again with L17 error code. Thankfully it has been restarting when reset. I am waiting on one of the techs to make another visit. Meanwhile, are there any troubleshooting I can do? Any thoughts?

kcopp

There are 2 sensors that are monitoring temp. Sounds like either you dont have flow or you may have an air bubble running around air locking the system...
Bad circ pump? Bad connection?
I am surprised they found the heat exchanger. Im even more surprised they went to all the wrik of swapping it out. That is not simple w that boiler.

yhc

Thank you so much for the info @kcopp.

- The wiring harness has been swapped out twice in recent weeks, so I would think/hope the connection is good. Is there a way to troubleshoot this?
- The pressure gauge shows 15 PSI. Wouldn't that indicate it has adequate water flow and pressure?
- is there a way for me to bleed the system to see whether there is an air bubble in the system?
- is there a way for me to check circulation pump?

Thanks again for your time and expertise.

kcopp

Loose connections happen sometimes.
Specifically I would want to know if the circulator inside is working. Pressure is an indication but you could have 15 psi of air in the boiler and yet no flow.
Place you hands on the supply and return piping.... there should be a difference in temps.
If its the combi there is a bleed port on the left side of the tank on the bottom. That gets air bound from time to time.
can you use a non contact electrical tester to see if there is power to the circ pump?
These boiler were ok.
I have a number still out there . When they worked they were great.
Unfortunately I had way to many HX leaking and I stopped installing.

109A_5

Hello @yhc,
Seems relatively straight forward. I think I would get a feel for how these temperatures run.



https://www.globalindustrial.com/site/images/Embassy/ONEX_Manual.pdf

yhc

Thank you both @kcopp and @109A_5 for your replies.

I am assuming those 2 parts pictured above are U1 and U6 sensors that were replaced a couple weeks ago.

To answer your questions kcopp:

Place you hands on the supply and return piping.... there should be a difference in temps.
- there definitely is a temp difference between the supply and return piping when the boiler kicks in and slight difference at maximum input
- Just from what I feel by hand, there does not seem to be more than 55'F temp difference when they at maximum input to trip the error code.

If it's the combi there is a bleed port on the left side of the tank on the bottom. That gets air bound from time to time.
- bleed port opened and no air came out. Water pressure decreased then is slowly coming up, now at around 12 psi

can you use a non contact electrical tester to see if there is power to the circ pump?
- yes, there is power to the circ pump, using non-contact tester

Please let me know if there is anything I can check.

Meanwhile, a couple additional questions.
1. will the boiler pressure eventually come back up to 15 psi or is 12 psi good to go?

2. from the drainpipe that connected to the bleed port, I see a slow drip still coming down after 1 hour. Is there a way to close this up or does the bleed port need to be replaced?

kcopp

Bleed port usually is an open and close set up. 1/4 turn. Should not be leaking. Did you get any Air?
Its this unit set up w/ an outdoor temp sensor?
What temp does it usually run at?

yhc

Darn...I misunderstood and opened up the pressure relief valve on the left bottom of the boiler. Did not get any air by the way. The pressure relief valve has not been exercised in years. It's dripping every few seconds.... Any trouble shooting tips for the pressure relief valve other than replacing it?

It does not have an outdoor temp sensor. And it usually runs in 160~165'F.

Will the boiler pressure eventually come back up to 15 psi or is 12 psi good to go?

Thank you again for your expertise.

kcopp

Only way to fix the PRV is to replace. You should be able to add water to the system. There is a fill valve.
The Bleeder valve is Inside the boiler. The tank is covered in styrofoam.

yhc

@kcopp here are some additional information.

Bleed port was opened, and no air came out from it.

U1 and U6 sensor temperature differences increased up to 21'F during the initial phase then it stabilized at around 11'F temp differences between U1 and U6 sensors. Both of these sensors are new.

Circ pump is getting power, and it seems like the pump is working. Not clear why the temp difference varies between the initial phase vs. later. Could it be that impellers in the pump are not working properly until it gets warmed up and "lubricated" once it kicks in? Since the system needs to be drained when the PRV is replaced, would it be worth awhile to go ahead and replace the circ pump? The pump is 10 years old btw.

Any input/guidance would be appreciated.

kcopp

has it been running fine since you reset it? It may have been a one time thing.

yhc

Good morning @kcopp. It has been running fine since the last time it was reset on Feb 24, 2024.

However, after the wiring harness was replaced early February, it has been reset a several times with L17 error code.

Feb 6
L17

Feb 8
L17
L02
- flue sensor replaced by tech when a leak was detected.
- wiring harness replaced for the second time.

Feb 14
L17

Feb 21
L17

Feb 22
L17

Feb 24
L17

kcopp

What are the chances the sensors were reversed?

yhc

Are you referring to U1 and U6 sensors?

Also, would you kindly explain how reversing U1 and U6 sensors effect the boiler function? Isn't the control panel monitoring only the temperature difference?

109A_5

Hello @yhc,
To me the issue is, is the intermittent L17 error temperature differential real or erroneous. Real could be a water flow issue, pump issue, or a zone issue or the boiler is too big for the load. Erroneous, well, sound like you have already changed most of the stuff that may cause erroneous issues.

Looks like sensors U1 and U6 are not interchangeable, however sensors U1 and U8 appear to be the same part number.
Not sure which of your sensors was actually changed U1 or U8.
Also not sure if this is a typo in the L17 error things to check text.

yhc

Thanks so much for pointing that out @109A_5 As you have pointed out, it most likely is a typo but not sure whether the <55'F temperature delta should be between U1 and U6 or U1 and U8....

The temps reported yesterday were between U1 and U6 btw.

yhc

I learned that the troubleshooting tips on L17 in the manual is NOT a typo. The acceptable delta between U1 and U6 is 5~8'F per my technician. On the other hand, the delta between U1 and U8 should be less than 55'F as the manual states.

Since my last entry, the circ pump is replaced, U1 and U6 sensors replaced again and purged as much air out of the system as possible when the PRV was replaced. The old circ pump actually looks to be in good shape but I wanted to rule it out completely as the culprit.

Now the delta between U1 and U6 runs 6~8'F (vs. 11~21'F before). I am hoping the boiler will run trouble free for many more years to come, now that most of the components have been replaced!!

Thank you @kcopp and @109A_5 for your help.

kcopp

Glad it worked out... I have not run across that one before.