# RUUD Direct Vent Water Heater



## HSI (Jun 3, 2011)

A couple of months ago I received a call for no hot water. They also informed me that three other plumbers have been there before me and had no luck. 
The unit is a Ruud Advantage Plus 80 gallon natural gas direct vent heater Model number HE80-199N.
The unit was showing a code of F09. Checked the condensate and it was not clogged. Checked the vent pipe through the roof and went on the roof and it was in good working order.
Checked gas pressure and it was at 11.47 in/wc. When unit tried to fire it would drop to around 10.60.
Was getting spark and as soon as the unit fire it would go back out.
Called the factory and they told me it needed the control panel, display board and new flame rod. They have had problems with the flame rod and they suggested using an LP rod instead of natural gas. Of course the parts were not available so a few weeks go by and the parts came in. Changed everything out and the unit fired. The flame was blowing orange so I adjusted it to blue. After cycling the unit a few times I packed up and headed north.
Get a call late yesterday that the system is down again. The unit has worked for a month. Went there this morning and it is back in the F09 code. Checked everything again and everything appears to be in proper working order except the heater won’t fire. The only difference is the gas pressure is not showing much of a drop when unit tries to light. My assumption is the valve is bad. Don’t want to spend any more of the customers money unless necessary.
Have any of you ran into similar situations? Any suggestions on what else to check?
BTW the date on the heater is 7/28/2010


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## Gettinit (May 9, 2012)

This is a NG heater and the pressure was what and where? Remind us what F09 is. Where is the combustion air coming from?


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## Gettinit (May 9, 2012)

One other thing, I thought the Advantage was like/is the new Apollo heaters. Sealed intake and sealed exhaust powered by fans.


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## HSI (Jun 3, 2011)

Gettinit said:


> This is a NG heater and the pressure was what and where? Remind us what F09 is. Where is the combustion air coming from?


The air is piped through the roof of the building. The pipe run totals about 25 feet. 
F09 is check condensate, check gas pressure, check venting and check flame rod
The pressure was measures in water column


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## HSI (Jun 3, 2011)

Gettinit said:


> One other thing, I thought the Advantage was like/is the new Apollo heaters. Sealed intake and sealed exhaust powered by fans.


Correct power vent.


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## HSI (Jun 3, 2011)

HSI said:


> Correct power vent.


They label it as direct vent


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## Gettinit (May 9, 2012)

What did the hot surface igniter read? The pressure on your gas is high. What size/type of regulator do you have? Where were you testing gas pressure and drop?


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## HSI (Jun 3, 2011)

Gettinit said:


> What did the hot surface igniter read? The pressure on your gas is high. What size/type of regulator do you have? Where were you testing gas pressure and drop?


The regulator is whatever the factory installed. The pressure is measured on inlet side of valve. 
You got on the hot surface igniter. What and how do you measure it?


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## rjbphd (Feb 5, 2010)

HSI said:


> The regulator is whatever the factory installed. The pressure is measured on inlet side of valve.
> You got on the hot surface igniter. What and how do you measure it?


 Read with dc micro meter..


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## Gettinit (May 9, 2012)

I use a 200 ohms scale. I believe it will read 50 to 75 at 70 degrees. Anything higher than 75 I recommend changing. If the tank is cold it should be about room temp. The manufacturer could tell you what you should see at any given temperature. I might have something in writing at the shop but no where near it this weekend. If someone accidentally touched the element it could have caused it to fail already.

To do it my way you would put each meter lead to each of the two connectors coming from the igniter. If you have a micro amp setting on your meter you would run it in series with your meter while it is operating.


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## HSI (Jun 3, 2011)

Gettinit said:


> I use a 200 ohms scale. I believe it will read 50 to 75 at 70 degrees. Anything higher than 75 I recommend changing. If the tank is cold it should be about room temp. The manufacturer could tell you what you should see at any given temperature. I might have something in writing at the shop but no where near it this weekend. If someone accidentally touched the element it could have caused it to fail already.
> 
> To do it my way you would put each meter lead to each of the two connectors coming from the igniter. If you have a micro amp setting on your meter you would run it in series with your meter while it is operating.


I checked the distance between the two but did not check the ohms. It will be at room temp around 75 degrees. Could you pm me what you have when you get back or let me know where to get my hands that info


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## Gettinit (May 9, 2012)

HSI said:


> I checked the distance between the two but did not check the ohms. It will be at room temp around 75 degrees. Could you pm me what you have when you get back or let me know where to get my hands that info


Is it a spark ignitor....I thought it was hot surface? 

I will get you what I have.


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## Gettinit (May 9, 2012)

It is a spark igniter, just got the paperwork pulled up. I would check my grounding wires. Sometimes if the wire from the spark igniter is nicked and touching the jacket it will not send a sufficient signal. I have seen many pinched. If the gap is ok take emery cloth to it and clean it up a bit. If you have a combustion analyzer it would be helpful. It says the regulator if needed should be 10 feet from the heater. You will need to check it just like rjbphd mentioned to see if you are getting enough current back to the valve for main flame. If it were just change clean it and move on, I doubt it is your problem. Sorry for earlier, I just had it in my mind it was a hot surface igniter.

I have seen regulators cause this problem. You will see 1" or greater pressure drop if it isn't big enough. If the vent limiter is clogged or the vent to outside is clogged it will raise the pressure and will not regulate it down. Not far enough away from the heater or burners that are modulating it cannot respond fast enough to keep up.

Too much gas pressure on the pilot may be an issue since you adjusted the gas pressure. It will make the flame too sporadic and out of place if not blowing itself out. 

I have seen bad meters cause this problem because of bad bladders. With monometer on a drip leg it will react like a bad prv, the more you use the worse it gets.

Obviously we need to check for 120V coming in and 24V on the secondary side of the transformer then move on. 

If the blower isn't running fast enough it cannot close the pressure switch. Disconnect the pressure switch (easier and more likely than a bad blower if it isn't making a bunch of racket), start up the heater, when the fan turns on jump the wires together. *This heater may be able to tell if the wires are already jumped together prior to the fan starting.* If it stays on, it still could mean the fan is bad. So, get a monometer and check what your vacuum is. The vacuum minimum setting should be somewhere on the heater or switch. If it is not enough negative pressure it (squirrel wheel) may just need to be cleaned.

I do not check for voltage on the low voltage wires due to stray and ghost voltages. This is why I jump the pressure switch out. 

If they check out start going through the rest of your safeties. Flue temp sensor, blocked vent switch...Most of these are checked because if it is a problem it will not let the heater light leading to the same code.


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## eddiecalder (Jul 15, 2008)

Is there a "vacuum breaking tee" installed in the condensate line after the condensate neutralzer?

Is the gap set properly for the spark electrode?

Did you try jumping the pressure switches?

What was the static to dynamic gas pressure readings of multiple firing attempts?

Is the reg installed too close the the gas valve?

What size is the gas piping to the unit?

Is the unit grounded?

Is the polarity reversed?


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