Noritz Combi Nightmare

boilertech

Hi.

I am struggling with a new Noritz CB 180 installation.

We have a brand new install - less than a month old. Its a CB 180 in a condo serving both domestic hot water and a First Co Airhandler Hot Water Coil.

The system worked great for the first week. After that, the client called complaining that it shut down on Error 54 (low water pressure/ system pressure 4PSI below heating loop set point) every morning. They would reset the unit and it would run fine until the following morning. This unfortunately started happening more frequently - several times a day.

What we figured out was that the system pressure was plummeting when the domestic side was in use. We installed a set up that allowed us to manually fill and monitor system pressure both at the unit and in the loop at the same time. System pressure during heating loop use is all over the map. It goes as low as 16, spikes as high as 37, T&P does not trigger. We manually fill, heating loop gauge goes up to 15 PSI, unit works, we tap domestic water, heating loop pressure gauge that we installed simply drops to zero, units digital read-out is all over the place, system codes out of 54.

My suspicion is a bad pressure sensor or three-way mix inside the unit but any insight is greatly appreciated.

kcopp

Did you make a call to Noritz? I am not familiar w/ this unit. You are Prob correct. What type of radiation is in the system? I have had pressure sensors fail before on newer systems.

boilertech

Ive spent 4+ hours on the phone with Noritz tech support sending them pictures of the install and jumping through all kinds of hoops. Quite frankly, because these systems are so new, I'm not sure that Noritz knows what to do either.

I think if the pressure sensor doesnt solve the problem, it simply may be a "lemon" and I'll have to lean on Noritz' warranty department

kcopp

Can you jump out/ around the pressure sensor?

boilertech

The pressure sensor is supposed to detect and adjust based on a 4 PSI differential between the set point and detected system pressure. It has a 4-wire plug that goes into the circuit board. Not sure how I could replicate that with a jumper.

Im going to put a high-flow auto fill on the system to supplement the system's internal auto fill and see if maintaining 15PSI exclusive of what the Noritz is doing will keep the system from coding out.

If it all passes the pressure sensor anyway, and its bad, then at least I know I'm not losing pressure and its a signal issue. If I have my auto fill feeding the system exclusive of the noritz and my external pressure gauge is still dropping to 0, then I know Ive got a different problem.

kcopp

Where the pressure is all over the place makes me wonder about the expansion tank?.... is it bad? is it sized properly?

boilertech

The expansion tank is a new 2gal, 12 PSI unit. I suppose it could be defective.

Jamie Hall

Or it could simply be that whoever installed the new tank didn't set it up properly. I hope it wasn't you! If it was, my apologies -- I'm sure you would have gotten it correct, but not everyone does.

kcopp

I don't think it is big enough. I don't use less than a #30... Boiler is 180K btu. That's a lot of expansion. How much baseboard?

jimboski

I just installed the same unit and am having the same problems. What was the issue of the unit?
Jim

EBEBRATT-Ed

Sounds like an expansion tank problem Are you positive you don't have a cross connection between the DHW and the heating system

Gordy

Don’t skimp on the x tank sizing. To big hurts nothing, but the wallet. To small causes problems, and hurts the wallet as you’ll have to get a bigger one anyway.

southpa4

Did anyone find a solution?

serosmaness

Our Noritz boiler is coming up with the same code. For the first two months the boiler worked fine, now error 54 is showing up quite often.

BillyO

doesn't that boiler come with an internal factory installed auto water feeder? an additional one isn't necessary. Did you pipe water make up to designated port on boiler for water make up?

serosmaness

The boiler has a factory installed auto water feeder for the space heating system. My boiler comes up with the error during domestic water heat. Our infloor heat seems to work flawlessly.

serosmaness

The boiler I have won't work without the water makeup hooked up.

BillyO

just looked at 3 way valve, same company as HTP combi. I can guarantee you will need to replace 3 way valve. I replaced all 4 that I installed in HTP combos within last 2 years. Noritz should replace part but I never used Noritz before. About an hour start to finish.

BillyO

if you spent 4 plus hours with tech support and they can't figure out problem, would be a great reason never to use their product no matter how new it is

BillyO

Any update?

serosmaness

I am just going to use mine as is. At this point if I let the domestic hot water run long enough the boiler will heat.

BillyO

that's one way to deal with problem im guessing

BillyFris

Installed cb199 bad pressure sensor right of the box. Talking to tech he said to set pressure higher than 12 psi. Brought pressure up to 15 and adjusted x tank. New sensor was reading 56 on the control panel with no relief going off. Confused the hell out of me. Going higher on initial set up gives you more lead way I guess. Did you use there pressure valve if not you need to cap there connection

kcopp

The pressure sensors in some of these high efficiency boilers can and do get fouled.
This can be especially true if its a older system and had not so clean water in it.

serosmaness

I was able to stop the error code 54 on my boiler by stopping a few leaks on the space heating portion of my system. It seems all it takes to set off the code is a dripping leak.

Piaopiao

I have error code 55 - it’s combi 199k machine. Any advice?

maxsoda

I am having the same problem on my 199. My pressure gauges are showing 12 - 15 psi which should not cause a pressure error. Seems to happen everytime the stat has not called for heat for a couple hours. Any ideas?

donnyp

Cb199 worked ok for 3 months, now seeing code 54 and a leak inside the box on return block. Noritz sent orings and a new plastic block. It looks like I have to remove the side of the box, plate exchanger to get the return block out. Nightmare. Any advice appreciated?

delwalk

@donnyp if the unit is new under warranty return it and get the NRCB199DV. Find a local sales rep to work with to make the exchange.

If not see if Noritz will give you a five pack since you'll be exchanging that block and o-rings every year. It's a known problem with that unit.

Unfortunately swapping the CB199 with the NRCB199 means completely redoing your piping layout.

motoguy128

We are in the process of replacing a one year old (4 year  old stock) CB199 on a Duplex house that’s been a nightmare.  Poor installation on top of it but nothing that is causing the contt board failures they have.  They even put it on Large UPS.  Junk. 

For kicks I might install it at my house on my indirect (on my stem boiler now) snd pipe in my kitchen to the domestic and see what it does.  If it fails I just turn Couple valves then someday put new boiler on.