Rinnai EX38CTP -- chilly regulator. Bother

Jamie Hall

Anyone have any bright ideas as to why a brand new Rinnai EX38CTP would run for about 36 hours and then fail to ignite (flashing code 11)? I'm going to get the gas company out here tomorrow (well -- maybe Tuesday?) to look at it, but I know very little about these contraptions... and if anyone has any bright thoughts I'd appreciate it.

When you try to get it to run, you hear a fan start and the set temperature shows (and "L" for ambient -- no kidding) then the fan slows slightly and you hear whoosh and the "on" light goes to red for about 10 seconds, then it shuts down and blinks 11.

General reference -- as I say, unit is brand new (installed Thursday). It's cold in the building it's in (right around freezing at the moment) and a lot colder outside. New propane tank and gas line and regulator. Ran fine for about 36 hours then quit.

I have no clue as to these things...

Thanks guys and gals!

rick in Alaska

Not sure either, but is there a potential the regulator froze up?
Also, it is currently 43degrees here! Having a weird winter so far.
Rick

Solid_Fuel_Man

Any way to check gas pressure Jamie? On a new install I'd also guess regulator froze up. A manometer will tell the story.

Anything else connected to this tank? I assume not as you said new tank.

Jamie Hall

I'm thinking the regulator too -- and no, I'm an oil man. Gas pressure? whazzat. But trying to get someone to come look at it on Veteran's Day weekend? Oh right... Fortunately, it's not a normally occupied building...

Jamie Hall

Ha! Regulator frozen up. Bother. I'm sticking with oil... now. Suggestions on how to keep it from happening again?

Solid_Fuel_Man

A regualtor should never freeze up. There is water in the fuel, or more likely, the tank wasnt properly or completly purged of air/moisture prior to commissioning.

Also your fuel supplier can and should inject methanol into the tank, they can do this while it's full and under pressure. The methanol will keep the water from freezing and the trivial amount simply gets burned with the propane.

Solid_Fuel_Man

Is it a horizontal tank like a 500 or 1000 gallon? Or a series of smaller vertical tanks connected together near the structure?

Jamie Hall

It's one of the smaller vertical tanks. Just one tank -- about 3 feet diameter and 4+ high. (What do I know about gas?). I deeply suspect it wasn't properly commissioned...

Intplm.

Is that a LP model ?? Liquid propane likes to frost up. It's even used as a refrigerant.
I'm curious to know what the gas supplier has to say about how to prevent the freeze up again too.

JUGHNE

That was a common problem here on old installs where they used only one regulator on the tank. Pouring hot water on the regulator would be just part of the farm morning chores, Like thawing out the hand pump and breaking ice out of the stock tanks.

Once dual reg come into use, I haven't heard of that problem.
Red 10 PSI reg on the tank and green WC reg at house. (for my area of NE, anyway).

Solid_Fuel_Man

There are two ways to purge a new tank (or a previously used one which has been open to the atmosphere)

1. Fill with LP vapor to 15 psi and vent it to 0psi to the atmosphere 4-6 times. This shouldn't be done at a customer's house as it vents a lot of stink!

2. (The best way IMHO) vacuum the container to at least 28" of mercury. Then it can be brought back to positive pressure with LP vapor and filled in the normal way with liquid on site.

Solid_Fuel_Man

For what it's worth.

I have a 12 year old intregal twin stage regulator at the tank (500 gallons) and buried 5/8" (16' total pipe length) and onto 3/4 black iron in the house. I installed this and it's been in service for 12 years now. Never had any freez-ups or pressure problems. Total connected load is 120,000 btu/hr. Boiler ECO 70 throttled to (50,000) clothes dryer (22,000) and range (58,000).

I have installed many small requirement LP services with integral twin stage regulators and have never (to my knowledge) has freezing issues due to two stage regs.

I have seen both 1 and 2 stage setups freeze due to water in the fuel, not the regulator setup.

nibs

@Jamie Hall
Jamie, was your tank filled this summer? Many LP vendors blend butane in with the propane in summer, this creates a problem because butane will not vaporize below 32F, that would explain why the rinnai worked until the propane was consumed, leaving butane in the tank.
Have used single stage regulators outside on rv's for years and that is the only problem we have found.
Try a bucket of hot water on the tank.

Jamie Hall

Thanks all... I knew I could count on you! I will talk to the LP supplier (also supplied the tank and regulator) Monday -- no one seems to be around on the weekend.

I like the hot water on the regulator idea, @JUGHNE !

JUGHNE

Of course no water into the reg vent, that would freeze up reg operation. They are usually protected from rain by the tank hood or just installed with the vent down.

Jamie Hall

JUGHNE said:

Of course no water into the reg vent, that would freeze up reg operation. They are usually protected from rain by the tank hood or just installed with the vent down.

At least the installers did that...

ratio

Jamie Hall said:

JUGHNE said:

Of course no water into the reg vent, that would freeze up reg operation. They are usually protected from rain by the tank hood or just installed with the vent down.

At least the installers did that...

You'd be surprised how often that's not the case. If I had a nickle for every time I had to have The Talk with a plummer…

Solid_Fuel_Man

The difference between plummmmers and heating professionals. Each can get away with different things. Our pipes can go up or downhill, and they can bullhead a T.

Jamie Hall

Update... the gas people came out today and said yes the regulator froze up. Maybe we need to put some more methanol in there. And left. Maybe they'll be back tomorrow? One can hope...

Good thing I don't need that space heated just now...

I do like oil heat.

mattmia2

i think that is the equivalent of saying "i think you have water in your oil tank" then leaving

ChrisJ

Jamie Hall said:

Ha! Regulator frozen up. Bother. I'm sticking with oil... now. Suggestions on how to keep it from happening again?

Yeah,
It's not like oil ever has problems when it's cold.

Solid_Fuel_Man

You guys who like phase change for heat.....

Well phase change is used for fuel too @Jamie Hall lol!