Rinnai i120c combi boiler losing pressure (error code 430)

[staffax]

I have a Rinnai i120c that is losing pressure from about 22 psi to 6-8 PSI after about an hour of running.
While it runs, the internal gauge shows about 29 PSI (external around 22 PSI) but the condenser emits around 1/4 cup of water during the run.
I'm only running CH at the moment.
Any ideas of what could be the issue?

 

[Fitter30]

What gas r u burning? Lp has .81 gallon water in a gallon of lp.Run the pressure up to 25 lbs with everything off let it sit for hour and check condensate trap. Has to be a leak some place. What are your heat emitters? Quarter cup of water is 2 oz that isn't your problem unless it's leaking in the heat exchanger and flashing to steam. Put your ear up to it when firing listen for a hiss or water sizzling.

 

[Sponsor]

 

[staffax]

What gas r u burning? Lp has .81 gallon water in a gallon of lp.Run the pressure up to 25 lbs with everything off let it sit for hour and check condensate trap. Has to be a leak some place. What are your heat emitters?

LP. Baseboard heat. I have tested that, it loses pressure from 25 to around 8. Maybe the condensation is normal, I just don't see it leaking anywhere else. I only see condensation drain while it is running, nothing when it's done (and that's when it is losing pressure). I even tested closing inlet/outlet valves below unit and letting it sit, it does the same thing, so the pressure loss must come from inside the unit somewhere.

 

[staffax]

What gas r u burning? Lp has .81 gallon water in a gallon of lp.Run the pressure up to 25 lbs with everything off let it sit for hour and check condensate trap. Has to be a leak some place. What are your heat emitters?

Also, for my understanding, the condensate trap (marked in red) is supposed to be full, correct?

And the "overflow" goes out the condensate drain outlet (the closer one), correct?

 

[staffax]

I ran another test, isolated the boiler, turned it off, shut the in/out valves for both CH and DHW.

With hot water in the boiler:
24 lbs start, after 4 min 23 lbs, after 12 min 21 lbs, after 23 min 18.5 lbs.

Flushed hot water out, replaced with cold water:
25 lbs start, after 6 min 25 lbs, after 16 min 24 lbs.

Open valves to system:
23 lbs start, after 10 min 22.5

Not seeing any trace of water from pressure relief valve, or inside the unit. And I only get a few drops from the condensation drain, is that enough to cause the pressure drop?

 

[staffax]

The HVAC installer came out yesterday. He can't explain why this is happening. He also had Rinnai support online, but they were not helpful.
So his suggestion is to make an automatic fill valve into the CH system. Should that really be the solution?

 

[Fitter30]

Also, for my understanding, the condensate trap (marked in red) is supposed to be full, correct?

And the "overflow" goes out the condensate drain outlet (the closer one), correct?View attachment 102567

Condensate trap would be full till more enters it then it runs out. Is there a drain valve any place in the system? All the piping exposed? Take a pic of the boiler, expansion tank, pump and related piping.

 

[staffax]

Condensate trap would be full till more enters it then it runs out. Is there a drain valve any place in the system? All the piping exposed? Take a pic of the boiler, expansion tank, pump and related piping.

It doesn't appear that it matters if I refill or not. The pressure goes down to around 14lbs, sometimes below the 13 to produce the error code 430, but as soon as the heat kicks in, the boiler ramps up the pressure to 28-29 lbs and it runs regardless.
So I don't think anything is leaking, it seems like somewhere within the boiler, it "absorbs" the pressure between runs. I don't know if that is possible, or even an explanation, but that's what it appears to be doing.

 

[Fitter30]

System looks like its piped wrong. Page 56 of manual. Secondary loop pump is on the wrong side of expansion tank. Tank has to be on the suction side of pump. Also Air scoop and ex tank. Have a piping diagram for it and fill. The coin vent on top of air scoop is the wrong devise should be a auto air vent and would want to put a shut off valve between scoop and vent.
Expansion tank is either bad or the air pressure isn't correct. To check tank need a 0-50 lb tire gauge and either a hand tire pump or air compressor. With using air compressor use short bursts. Boiler water under 100° everything off. Valve on tank opposite of piping. Depress valve small screwdriver water comes out tank is bad needs to be replaced. Air pressure should match boiler water pressure.

https://www.google.com/url?q=https://media.rinnai.us/salsify_asset/s-63ae550b-9d94-41b2-b003-efa62729ded5/800000111-I-Series%2520Condensing%2520Combi%2520Boiler%2520Installation%2520and%2520Operation%2520Manual.pdf&sa=U&ved=2ahUKEwivk4GRtMaKAxXHrIkEHQW6Fd8QFnoECAwQAg&usg=AOvVaw2zvj7k4oRmtGc-ceLG48Dr

Page 2 boiler in diagram just your feed from your boiler. Note auto air vent. Center diagram.

https://www.webstaurantstore.com/documents/pdf/brochure/mc2680-10_22-extrol-brochure.pdf

https://www.supplyhouse.com/Caleffi-502015A-MINICAL-High-Capacity-Automatic-Male-Air-Vent-1-8-NPT

 

[staffax]

System looks like its piped wrong. Page 56 of manual. Secondary loop pump is on the wrong side of expansion tank. Tank has to be on the suction side of pump. Also Air scoop and ex tank. Have a piping diagram for it and fill. The coin vent on top of air scoop is the wrong devise should be a auto air vent and would want to put a shut off valve between scoop and vent.
Expansion tank is either bad or the air pressure isn't correct. To check tank need a 0-50 lb tire gauge and either a hand tire pump or air compressor. With using air compressor use short bursts. Boiler water under 100° everything off. Valve on tank opposite of piping. Depress valve small screwdriver water comes out tank is bad needs to be replaced. Air pressure should match boiler water pressure.

https://www.google.com/url?q=https://media.rinnai.us/salsify_asset/s-63ae550b-9d94-41b2-b003-efa62729ded5/800000111-I-Series%2520Condensing%2520Combi%2520Boiler%2520Installation%2520and%2520Operation%2520Manual.pdf&sa=U&ved=2ahUKEwivk4GRtMaKAxXHrIkEHQW6Fd8QFnoECAwQAg&usg=AOvVaw2zvj7k4oRmtGc-ceLG48Dr

Page 2 boiler in diagram just your feed from your boiler. Note auto air vent. Center diagram.

https://www.webstaurantstore.com/documents/pdf/brochure/mc2680-10_22-extrol-brochure.pdf

https://www.supplyhouse.com/Caleffi-502015A-MINICAL-High-Capacity-Automatic-Male-Air-Vent-1-8-NPT

Thanks. I see what you are saying about the expansion tank being on the wrong side of the pump. I will have to get that corrected at some point. The expansion tank seems ok and is set to about 27 lbs. Would the pump prevent the tank from keeping the boiler pressure?

 

[John Gayewski]

Coming to this late but the condensate has nothing to do with the pressure inside of your unit.


Did you install this system yourself? It doesn't look professionally done.

 

[Fitter30]

Thanks. I see what you are saying about the expansion tank being on the wrong side of the pump. I will have to get that corrected at some point. The expansion tank seems ok and is set to about 27 lbs. Would the pump prevent the tank from keeping the boiler pressure?

Ex tank is doing nothing piped like that. Thays why the boiler pressure is all over the place.Setup for ex tank piped correctly water under 100,° boiler and pumps off, adjust boiler water pressure to 22lbs, adjust ex tank air pressure to 22 lbs. Turn everything back on.

 

[staffax]

Coming to this late but thy condensate had nothing to do with the pressure inside of your unit.


Did you install this system yourself? It doesn't look professionally done.

No, this was done by a licensed installer. Unfortunately not a lot of choice where I live and apparently I did not choose a good one because I had a lot of issues with the install (not counting this one).

 

[dudemanbro]

I have the same issue with my rinnai i150sn. I've narrowed it down to a faulty internal pressure sensor which gives the digital read out as well as sends the signal for that pesky e430 when the boiler cycles off and the pressure drops out. Ive confirmed this with the help of my trusty analog pressure gauge Seems to be a common issue when the boiler cycles off.

 

[SalMazz]

I'm getting an E430 error code after two years, or my second season, here in NY, and I'm not sure why. The error occurs suddenly while the system is running. I spoke to Rinnai, but they weren't very helpful. The boiler provides heat to the house and hot water to only one bathroom. The rest of the house uses a separate water heater. Any suggestions? I've attached some photos. I've checked the expansion tank, and it's at the correct pressure. The unit seems to run fine with the front panel removed. All the components are all new or about two years old.

 

[Reach4]

I'm getting an E430 error code after two years, or my second season, here in NY, and I'm not sure why. The error occurs suddenly while the system is running. I spoke to Rinnai, but they weren't very helpful. The boiler provides heat to the house and hot water to only one bathroom. The rest of the house uses a separate water heater. Any suggestions?

Google.
Turns up several things including https://terrylove.com/forums/index....eries-tankless-combi-intermittent-e430.94371/

 

[John Gayewski]

Your circulator is upside down. I don't think it's causing your problem but it's a pretty fundamental mistake.

I'm not that familiar with rinnia, but have you cleaned the unit since installed? How's your water quality.

 

[SalMazz]

Your circulator is upside down. I don't think it's causing your problem but it's a pretty fundamental mistake.

I'm not that familiar with rinnia, but have you cleaned the unit since installed? How's your water quality.

Yes unit had a full checkup few months ago or September 2024.

 

[SalMazz]

Your circulator is upside down. I don't think it's causing your problem but it's a pretty fundamental mistake.

I'm not that familiar with rinnia, but have you cleaned the unit since installed? How's your water quality.

Can you help me understand what you mean by circulator upside down. I can rotate it so the control dial faces up to the ceiling. Is this what you mean?

 

[SalMazz]

I think it was the circulator, as I adjusted it and now since I done this no error code.