HELP: HTP Phoenix Light Duty doesn’t fire up

4Johnpipe

San Fran any update???

Alan (California Radiant) Forbes

"If the regulator was the culprit, how were you able to adjust the offset and get it to light off smoothly?"
"Is this regulator an intermittent issue?"
"Wouldn't it function perfectly fine at 8.8 or 10.8? Supposedly it's range is 3.5" to 14"."

I really don't know what the offset does or how it works, but I think it somehow compensated for (what I think is) the bad regulator.

Yes, it should work at 10.8", but what messes it up is the 2" pressure drop. It's not supposed to be more than ¾".

tim smith: The manifold pressure was whacky: -2.35", but the tech. guy didn't want to know. CO2 was fine, but after awhile, adjusting the mix did nothing to that number. Made me think my meter was acting up even though it has new sensors.

I've removed the intake air pipe just to see if it works better. There are no obstructions. Haven't checked the exhaust.

Those of you that know this machine have seen the rubber flapper inside the 90° of the air intake. I suppose it's a check valve. When the unit was lighting off badly, it would blow the rubber flapper the opposite direction and it would become stuck in the closed position. Seems as though this is still happening and the owner had to pull the corrugated tube off the air intake to get the unit to fire.

I haven't heard back from the owner regarding contacting the utility company for a new regulator.

SanFranTH

Hi all,

The Phoenix LD water heater is still malfunctioning. Not always, but quite frequently, when there’s a call for hot water and the unit needs to fire the burner, it shuts down with one of these error codes:

F01 – the control senses no flame after three ignition attempts
F82 – the control detects an unstable flame

I then go down to the basement and try to restart it by pressing the reset button. It now usually starts up on the first or second ignition attempt and brings the temperature up to the set point. Basically, you have to babysit it… At least, when it fires up we have 60 gallons of hot water…

Btw, as Alan said, there is a rubber flapper in the air intake elbow that seems to get jammed when the unit has a rough start. I pulled the corrugated air inlet tube off the elbow to eliminate this potential cause of malfunctioning… the WH is still shutting down; although I have to say, it seems to start up a lot better without the rubber flapper. Personally, I think this rubber flapper in the air intake elbow is a terrible design flaw – it’s prone to jamming and will obstruct the flow of combustion air if it gets lodged. We only found it by chance, nobody probably know s it’s there.

I have not been able to connect with the right person at the gas company to get a new regulator. They keep telling me that there’s nothing they can do based on their previous findings: stable 7” WC at the WH, load test also fine with 6,5” WC (90.000 BTU furnace), everything else works etc.

They want proof for the alleged 2” WC drop; when they were out here for the second time, I put Alan on the phone. He explained everything, but they still refused. They literally said, Alan needs to come out again and proof the pressure drop with a manometer hooked up to the gas valve.

I’m also confused how Alan could measure 10.2” at the gas valve, followed by a drop to 8.2”. The gas company explicitly stated they will not send more than 7” WC into the house. How can it be 10.2” or 8.2” then? Also, it’s a negative pressure combustion chamber… that should not lead to an increase in pressure over the static level of 7” WC. Btw, the first gas technician did check the regulator, I think he actually took it apart; he also put a new seal on.

Not sure if Alan took the manometer pressure after he got the unit to fire.

Any ideas how I can trick the gas company into installing a new regulator? Should I buy a manometer and hook it up to the gas line or gas valve at the water heater?

Rich_49

What gas company is this ? Who regulates them ?

hot_rod

SanFranTH said:

Hi all,

The Phoenix LD water heater is still malfunctioning. Not always, but quite frequently, when there’s a call for hot water and the unit needs to fire the burner, it shuts down with one of these error codes:

F01 – the control senses no flame after three ignition attempts
F82 – the control detects an unstable flame

I then go down to the basement and try to restart it by pressing the reset button. It now usually starts up on the first or second ignition attempt and brings the temperature up to the set point. Basically, you have to babysit it… At least, when it fires up we have 60 gallons of hot water…

Btw, as Alan said, there is a rubber flapper in the air intake elbow that seems to get jammed when the unit has a rough start. I pulled the corrugated air inlet tube off the elbow to eliminate this potential cause of malfunctioning… the WH is still shutting down; although I have to say, it seems to start up a lot better without the rubber flapper. Personally, I think this rubber flapper in the air intake elbow is a terrible design flaw – it’s prone to jamming and will obstruct the flow of combustion air if it gets lodged. We only found it by chance, nobody probably know s it’s there.

I have not been able to connect with the right person at the gas company to get a new regulator. They keep telling me that there’s nothing they can do based on their previous findings: stable 7” WC at the WH, load test also fine with 6,5” WC (90.000 BTU furnace), everything else works etc.

They want proof for the alleged 2” WC drop; when they were out here for the second time, I put Alan on the phone. He explained everything, but they still refused. They literally said, Alan needs to come out again and proof the pressure drop with a manometer hooked up to the gas valve.

I’m also confused how Alan could measure 10.2” at the gas valve, followed by a drop to 8.2”. The gas company explicitly stated they will not send more than 7” WC into the house. How can it be 10.2” or 8.2” then? Also, it’s a negative pressure combustion chamber… that should not lead to an increase in pressure over the static level of 7” WC. Btw, the first gas technician did check the regulator, I think he actually took it apart; he also put a new seal on.

Not sure if Alan took the manometer pressure after he got the unit to fire.

Any ideas how I can trick the gas company into installing a new regulator? Should I buy a manometer and hook it up to the gas line or gas valve at the water heater?

I wonder if the gas company has a data logger that could be put on to monitor pressure for a period of time? This is how we find intermittent voltage problems.

jonny88

On a side note last week I was getting rough ignitions on my boiler like a mini explosion inside chamber.Changed Fenwal igniter assembly because it had to be boiler,right?Problem persisted on we narrowed it down to the regulator was not seating right and letting more gas through than gas valve on boiler could handle.In a nutshell Nat Grid came and changed regulator.No arguments they tested it and changed it.My little tidbit.Call a field supervisor or someone you are paying for their service.

SanFranTH

"mini explosion inside chamber" that's exactly what happened when Alan got it to fire the first time... it was actually pretty scary, I was about ready to run.. there were a couple of more rough starts, but now it's firing up quite smoothly upon reset

Leon82

Whenever there are multiple ignition attempts you may get a poof from the extra gas in the chamber.

What condition was the packaging in when it was delivered ?

4Johnpipe

@SanFranTH the fact that the gas company stated they supply no more than 7" and Alan's reading was greater than that confirms it is a regulator issue. By definition the regulator "regulates" gas pressure. The fact that it is allowing anything more than 7" WC should have been proof enough. The "seal" just prevents gas from escaping around the pressure set point adjusting screw. The diaphragm connection to the metallic gas regulator cannot be changed. These regulators have a life expectancy as I posted earlier.
@Hatterasguy Would you agree that the only thing that regulates gas pressure in the system is the gas regulator? I have also seen faulty regulators that actually allow air into the gas train via the vent at the regulator. Manometers only test pressure they don't care what creates the pressure it could be air or natural gas.
The regulator absolutely needs to be changed as a starting point. I am dumbfounded that a gas supplier would not try this and have a customer go without hot water!
Alan may have go back out an re adjust everything that was done after the new regulator is installed.

4Johnpipe

Pheonix LD and several other products have a gas leak detector on the control board or near it depending on the model. The check valve prevent unburnt fuel from setting this off. The fact that it was blown backwards (hard start) is part of this problem.

4Johnpipe

Doesn't need a different type just a properly functioning regulator.

Gordy

Is a negative pressure gas valve that mysterious? Essentially it senses whether the combustion chamber has negative pressure for proving. Which is by far superior to proving the inducer fan is on. Since even if the fan is on, and there is a leak in the combustion chamber the gas valve would still open with a non negative pressure scenario.

With that being said I'm a little confused. The regulators job is to guarantee a nominal gas pressure on the service side. So if there is a nominal service pressure 7,10,5. Then why would that interfere with a successful ignition. Usually problems arise with low nominal pressure. If other gas appliances are in use with no issues, and the previous one the Phoenix is replacing had no issues. Then why would the Phoenix have issues making same regulator suspect?

4Johnpipe

The problem is the pressure drop through the gas valve. Alan was reading 2" or more. Most if not all modern combustion like the Pheoenix will not tolerate anything greater than 3/4" WC drop. The other issue with a bad regulator is the ability of drawing air in through the atmospheric vent at the regulator outside. When negative pressure combustion pulls on the line and the regulator is faulty it will pull air into the vent. Which in effect is completely bypassing any pressure regulation. While not harmful it certainly will prevent ignition.
We saw this with Super Storm Sandy. The gas company had to replace thousands of regulators and gas meters because water entered gas systems through the vent on the regulator.
It can happen and it does happen. Regulators do wear out. Open combustion doesn't draw on the gas line it simply allows gas pressure to flow via physics of air pressure and combustion action.

Gordy

So in a sense a gas valve was created that does not play well with Exisiting utility equipment.

SWEI

They work fine as long as the utility regulator is functioning properly.

4Johnpipe

What @SWEI said...I'm kind of surprised nobody else has ran into this before...We must be fortunate to have a gas utility company that is aware of this and responds accordingly...

Rich_49

Kinda forces the utilities to do maintenance and upkeep they have ignored for years . No more free ride for them , what a shame

4Johnpipe

I should have said can or may instead of will pull air...The vent can burp when the set point supply pressure down stream of the regulator (in this case 7" WC) goes up or down if the diaphragm / regulator is compromised. It doesn't need a - zero condition. In fact a plugged vent will cause a similar issue. One of the first things we look for is a plugged vent when troubleshooting gas supply issues. We have vents with no screen allowing an insect to build a nest or just plain mud, dirt etc...blocking the vent.

Gordy

Rich said:

Kinda forces the utilities to do maintenance and upkeep they have ignored for years . No more free ride for them , what a shame

Or start charging for regulators that have to be replaced because of a negative pressure gas valve appliance installation. If it becomes excessive they will find a way to come out on top...........

FranklinD

Just mention to the gas company that you think your gas usage is being underreported...they'll replace the meter and regulator before you even hang up the phone. Ha. That's how it is here.

I'm surprised that they're so resistant to simply replacing the regulator. It's not that big of a deal.

jonny88

When Grid changed my regulator on gas meter the tech said he has had quite a few regulators fail.All it takes is for something to get on the washer preventing a seal.He even has had to change regulators on new service installs,after they shoot the new supply line it is possible a little debris can get in the line.I am not saying he does it every day but he has had to change quite a few regulators in his 29 yr career.

SWEI

The utility there was fined $1.4 billion last fall, in large part due to chronically deferred and substandard pipeline maintenance.

Some of the locals there have been known to use the term Pernicious Graft & Extortion.

Alan (California Radiant) Forbes

So, at this point, I don't know if it's the gas regulator or something wrong with the HTP Phoenix gas train. I will continue to ask TH to put pressure on the utility company to replace the regulator. I'll leave my manometer there for them to see the drop in pressure.
However, I will also call Alex at HTP. If it is a problem with their unit, it can't be the first one, no?

SanFranTH

Thanks Alan! We will be out of town for three days, back on Thursday. I will try to get the gas company to the house on Thu or Fri... hopefully I can convince them to install a new regulator.

BigRob

I would install a pressure gauge and observe the reading during operation. If the reading varies more than the regulator spec you are good. If not, it's another problem.

PG&E has an Energy Office on Howard between 4th & 5th. They have tools you can borrow. I borrowed their IR camera. Maybe they have a tool that'll help. I like the idea of saying your bill is too low. LOL.



http://www.pge.com/en/community/energycenters/index.page?WT.mc_id=Vanity_pec

kcopp

How old is the regulator? What is the street pressure before the regulator? I know that here in NH they have had some issues w/ the newer regulators since they redid all the gas lines and upped the street pressure.
Got a pix?

Gordy

..

tim smith

Alan, have you pulled the electrode assembly to see if the gap or something else is off on it. The hard fireup could be caused by something like that then it blows the flapper in wrong position and won't fire then. Just a thought. Weird problems are the nemesis of our trade!

tim smith

If you are staying above 6" wc I would think that the neg press regulator should be able to deal with it. Did they tell you what the neg reading on manifold should be or is it in manual. Should be.

Rich_49

Pages 27-29 Tim .
http://www.htproducts.com/literature/lp-441.pdf

Alan (California Radiant) Forbes

Tim: I have not checked the igniter, but will do so on my next trip - thanks. Also, I have the figures for the negative pressures to the manifold, but can't find them right now. I think they want it ever so slightly negative, like -0.01.

AMservices

I've installed a lot of HTP boilers and serviced many more.
In my experience 9 out of 10 need the gas throttle adjusted, right out of the factory.
Out of all the different boilers I install with negative pressure gas valves and perform combustion test too, none of them need to be calibrated like I have to on HTP products.
I've spent so many hours if not days talking with their Tech support, those guys should be calling me

Rich_49

In my experience , 9 out of 10 boilers period require some amount of adjustment . That is probably why we are supposed to perform combustion analysis on every one of them installed . This is not a manufacturer specific issue as we have all witnessed here on the wall and in our daily work . More often than not our shop is able to find the REAL cause no matter whose equipment we are installing and 8 out of 10 times it is a gas delivery issue or something other and has nothing what so ever to do with the equipment . Yes Virginia , there are alot of regulators and even meters that need replacing . I for one am glad that we can expose equipment that is not operating properly , the utility companies may disagree but it is what it is . There are so many variables that come into play when talking combustion .

Gordy

Rich, I guess for me it's more about understanding the regulator in itself. It's really a simple device. The diaphram integrity being a key element of course. The vent on the back side allows pressure equalization of the diaphram from atmospheric air through the vent orfice.

If the diaphram has a failure then An odor of NG should be evident from the vent. Depending on the severity of the failure when there is not a call for NG on the down stream side of the regulator then gas pressure should slowly fall off allowing the valve to open to maintain the down stream pressure setting.

The whole time I'm not seeing how atmospheric gas could enter the down stream side of the regulator, and foul the system.

While I'm questioning the experiences of the participants, I'm only trying to understand the events that make a regulator function with a non negative pressure gas valve, but yet render havoc to a negative pressure gas valve. Above all being able to suck in atmospheric gas into the system.

The experience of the 2" drop In Alan's readings would point to a fouled spring in the regulator assembly not allowing a more constant pressure.

4Johnpipe

From white paper on regulator relief valves...
PRESSURE RELIEF
FIGURE II-4 is a diagram of a typical relief valve installation. The purpose of the relief valve is
to prevent outlet pressure from rising to an unsafe level when there is a regulator failure.
In general, regulator failure would result in either too much or too little pressure downstream.
The failure would leave the regulator in what could be called a "failed-open" condition (regulator
too far open, even fully open – too much gas flow) or a "failed-closed" condition (regulator too
far closed, even fully closed – not enough gas flow). A relief valve is only useful in a "failedopen"
regulator condition – too much gas flow, resulting in downstream pressure above normal.
Relief valves do nothing for a "failed-closed" regulator condition – too little gas.
A relief valve protects by discharging the excess gas into the atmosphere. As long as a regulator
operates correctly and downstream pressure is normal, a relief valve remains closed. If the
regulator fails and allows too much gas to flow (a "failed-open" condition for the regulator),
downstream pressure will increase. The relief valve will remain closed until pressure reaches its
set point. At that point it will begin opening and will continue to do so as the pressure continues
to rise. It will open far enough to discharge all of the excess gas into the atmosphere. When it
reaches that point, there will be no further rise in the downstream pressure and, if the relief valve
and its installation are correctly sized, the pressure downstream will not be high enough to be
unsafe.
Please notice "to much or too little downstream pressure as well as failed open and failed closed scenarios. This is how atmospheric pressure which can be higher than the 6" of WC in the line can enter the gas train...

4Johnpipe

This is even more descriptive...

The next item is the vent. While often appearing insignificant, the vent is important to a
regulator. Regulators breathe. As the internals move in the work of controlling pressure, a
regulator will inhale or exhale through the vent. Therefore, the vent must be adequately
protected from obstructions such as dirt, insects, ice, etc. If an obstructed vent prevents a
regulator from breathing, the diaphragm will not work properly.
In the event that the regulator fails to open, the higher pressure gas dissipates thru the vent.

Regulators "breathe"

AMservices

On page 27 of the installation manual Rich posted. It says "In the event
the gas valve is exposed to a pressure greater than ½ PSI, 14” water column, the gas valve must be replaced."
Maybe the installer broke the valve when he pressure tested the gas line.
Just a thought.
One other thing, every time I've been calibrating a negative pressure gas valve and it brings me to the point that I have to adjust the off set, even when I get the number's + or - 1 of what the book is telling me I should see, I'm changing that valve before the end of the season.

4Johnpipe

We usually only have adjustments when vent lengths are approaching the longer runs. I've yet to have a problem after dialing in a gas valve though...ever.

Paul48

Ultimately.....How was this problem resolved? Was the regulator replaced?

Gordy

Paul I'm looking deeper than if the regulator was replaced, and if it resolves the problem. What was wrong with the regulator that caused the problem.

I think a deep understanding of the gas supply components will help the masses in trouble shooting, and maybe decrease calls to the manufactors rectifying issues. Plus help installers be more persuasive to the utilities that the issue is on their equipment not yours.