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Got to the bottom of a nuisence F-09 Munchkin problem

hr Member Posts: 6,106
Typical intermitten problem. I would show up, test, adjust, watch, ask questions, etc and everything would work just fine.

I was about ready to get the homeowner a F-09 personlized license plate for their car! They have been patient about the whole issue and have back up furnaces, thankfully.

Somewhere along the line the homeowner and plumber added a natural gas backup generator to the home. Well the thing exercises once a week.

You guessed it. The gas line the plumber installed was never sized for the additional load! I suspect if the Munchkin was running when the generator exercised, the gas pressure plumeted causing the lockout.

Also be aware that most generators require 11- 14" wc. Around here the typical meter set and regulator is a 7" set.

Now the plumber will need to request a 2 psi meter set and add the correct sized regulators at the gen set and appliances. The fuel supplier will also upsize the meter for the additional load.

hot rod

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  • Ted_9
    Ted_9 Member Posts: 1,718

    Nice catch. Thanks for the info.


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  • Hot Rod this has

    become more and more of a problem with many people installing generators. It is a requirement for all generators to be seperately piped and running off a different pressure/piping system. I also want to see about a ten foot run up to the generator of a minimum 1 1/4" line. That will help with the surge problem when the generator first kicks on. The problem is that Home Depot and Lowes and others (some of the contrator supply house do not know) who sell these units often times do not advise customers or contractors of this fact.

    Up here in New England even the gas inspectors are not aware of the need for different lines. Here is a plus however at least up my way the gas company is well aware of this fact.

    We have also had a problem with pool heaters being added at the end of a piping sytem that is not adequate to handle the new 400,000 BTU load that is 100 feet away from the house piping. Again a good reason to run a dedicated line to the pool heater at higher pressure and then reduce pressure at the heater. This is a problem with both Natural and LP gases.
  • gerry gill
    gerry gill Member Posts: 3,078
    oh man,, talk about looking for a ghost..

    you must have serious patience..how did you find that? did it do it while you were there? dought i would have ever put that together..ive been told i wear blinders alot..good job troubleshooting that one.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • jerry scharf_3
    jerry scharf_3 Member Posts: 419
    let's all bug HTP about timestamping faults

    Hot Rod,

    First, that is a great catch!

    I talked to HTP last fall about adding a small amount of code, etc. to be able to put some kind of time stamp on the faults when they come in. I got the standard "would be hard, not a priority..."

    I don't care if it's a date and time, or it's based on the running time that they use for powerup and active time. If I know what time it is now in any form, I can work out what time it was when the fault happened. That would be trivial to do with the PC software.

    That would have allowed you to see the time when the F09 happened and start to see the pattern. You have the diagnostic skills and patience to find this, many people would just say the boiler is junk...

    I'll also open this to more than just Munchkins. Does any boiler control have this timestamped fault capability?

  • hr
    hr Member Posts: 6,106
    Exactly, Tim

    this was a Home Depot purchase, installed after the home was occupied!

    What amazes me is that the same plumber connected this with an 1-1/4" gas line and never questioned the pipe or meter size. And obviouslty didn't read the installation manual requiring 11-14".

    At least I learned a valuable lesson. Took way too many call backs to nail it down, however!

    I finally called the gas company figuring they had a bad reg or something. It was the gas guy that knew about the gen set pressure requirements, and added all the current loads not the designed for gas loads to come up with solution.

    hot rod

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  • hr
    hr Member Posts: 6,106

    my next thought was to have the utility install both a power and gas pressure data logger for a few weeks.

    I had a problem Voyager a while back that turned out to be an incoming voltage issue. At times it would drop below the required minimum for the control.

    The power company said it was still within their "acceptable range" and would not do anything to improve the voltage quality.

    I removed the Voyager and installed a standing pilot cast iron boiler. KISS when the need calls for it.

    Keep the high efficiency stuff in the jobs close to home is my advise :)

    hot rod

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  • Jim Eastman_2
    Jim Eastman_2 Member Posts: 27
    Time stamping?

    HTP has as laptop program that lists the faults and, I believe, the time/date of the fault for all of the faults that the boiler has had. I don't have this program, but my supplier does. We used it to track some intermittent faults that were driving us crazy.

    Maybe Jeff Cook of HTP could shed some light on this diagnostic tool?
  • chuck shaw
    chuck shaw Member Posts: 584
    time stamp of faults

    it is something we in the HTP tech support department have been trying to get for a while. We think it would be a great tool, for trouble shooting, as well as for boiler history. It can also help with that "problem customer". The company that builds the circuit boards for us, has told us that this would be difficult to do. However we still ask them every chance we can, hoping something new in technology, would make it easier.

    Nice work on that one Hot Rod, nailing an intermitant fault is always tricky. When ever I do a class, I try to stress, that sometimes you have to look outside the boiler room into other areas of the home. We have found garage door openers, dimmer switches and blinking Christmas lights that have caused electrical feed back problems, try to figure those out.

    Chuck Shaw
    Tech Support Dept
    Heat Transfer Products
  • curiousity kills
    curiousity kills Member Posts: 118
    Hot Rod

    HOt Rod please read my post on a similar problem I am having with a munchkin.I increased the co2 from 8.5 to 9.5 per munchkin factory tech support.This one lockedout two nights in a row at f09.The HO would reset it.Since I was there Friday I have not had acall on it.The funny thing is the gas co. was changing all the gas meters that day in this complex. I wonder if the regulater was not keeping up with demand at night?
  • Steve_35
    Steve_35 Member Posts: 546
    An option here

    might be to use a UPS to feed the boiler. Set the boiler up with a cord and plug. Plug the boiler into the UPS and the UPS into the wall. You could probably get several hours run time wiht a decent UPS if there wasn't too much ancillary load.

    Worst case scenario it cleans up the voltage. An increasingly important consideration with today's sophisticated equipment.
  • Matt J.
    Matt J. Member Posts: 13
    Hot Rod

    I had a similar problem with a forced-air system in a commerical job. As it turned out our company was just incharge of running the gas lines to the applances. The Hvac company was having a off and on problem with unit locking out. They were sure that the pipe sizing was wrong due to the fact that the pipe sizing on the print was much larger that what we had run. The print was sized for low pressure we ran 2lb. When ask how they knew they just said that the pipe was to small, they hadn't even checked there gas pressures to the unit. In fact they didn't even have a gas pressure tester. So I checked it myself and found that there was a problem. After alot of checking and hair pulling we found a dirt clod in the service line leading into the gas meter, depending on the load it seem to tumble around in side the pipe. Our gas supplier just could figure out how that got in there? ya live and learn! Matt J.
  • My belief on F09's

    I think that a lot of 09 and 10 codes are due to gas pressure fluctuations. Esp with LP as the regulators used for LP seem to be a "bit" cheaper in construction conpared with the typical gas utility's equipment.

    It is very instructive to hook up a water tube manometer to the gas valve and after firing the munchkin on high, fire up all the rest of the gas loads on the system. Even on what looked to be an ample LP gas piping installation, the gas pressure dropped over .5"WC and pressure was set on the low side to start with by the LP company. Also noticed an obvious flutter in the pressure, due to the regulator perhaps. Lotsa stuff out there conspiring against us.
  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    c k

    I see your CO2 numbers, what were your CO numbers like?

    You adjusted the offset, but what were the initial readings?

    You are correct, if the gas company was playing with the lines, you could get an F09.

    Mark H

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  • Boiler Guy
    Boiler Guy Member Posts: 585
    Those intermittent problems are a real head scratcher

    Had a similar situation in a large warehouse complex. Could not keep pilots lit. All suspended equipment was retofitted with spark ignition but problem still appeared intermittently. Took 4 months but finally traced problem to CO system one of 5 sensors was wired incorrectly which caused the main exhaust system to ramp up without the fresh air dampers opening fully. 30,000 cfm exhaust with only 5,000 cfm of relief air. System worked great if truck doors were open though. Switch 2 wires -- problem solved.
  • hr
    hr Member Posts: 6,106
    It could be

    a pipe size issue also. I did as John mentioned above and fired every load in the home with the manometer attached, it did drop a couple inches. It's the generator, that I missed, that would pull the gas pressure way down.

    I would, if possible, measure and recalc the gas pipe size. They need a 3/4" right to the unit also. Could it be the load in other units bringing the pressure down.

    I have heard in some areas the gas main pressure could drop due to additional loads added beyond it's capacity. The whole street or area could be effected. I still think a gas pressure data logger, if they exisit, is the right tool. It's hard to be at the job long enough to find some of these conditions.

    In my case the generator exercised once a week. The odds of me being there at that exact 1/2 hour period of time were very slim.

    The next big challange will be the calorific content of the fuel and how the units work as this changes. Seem as we import more natural gas from around the world it is of different value. How important will this be to the appliance? Lean burns? Rich burns? Maybe some of each throughout the year. Weird stuff going on out there in the energy world. I suspect the LP supplies get blended also causing a challange in adjustments.

    hot rod

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  • Steve_35
    Steve_35 Member Posts: 546

    > The next big challange will be the

    > calorific content of the fuel and how the units

    > work as this changes. Seem as we import more

    > natural gas from around the world it is of

    > different value. How important will this be to

    > the appliance? Lean burns? Rich burns? Maybe

    > some of each throughout the year. Weird stuff

    > going on out there in the energy world. I

    > suspect the LP supplies get blended also causing

    > a challange in adjustments.

    This is already a problem with LP in our area.
  • curiousity kills
    curiousity kills Member Posts: 118

    On low fire co was around 15-25 and hifire 35-45 ppm these were computed #s,not air free but well within standards.
  • Hot Rod, I address this very issue

    of BTU content in my Febuary article in HVAC INSIDER, titled "Winter is Upon Us!.

    I have had some issues with this already.

    By the way the gas company can connect a chart to a system and monitor pressure for as long as a month without changing the chart. It will give you a read out as to spikes or drops in pressure.

    It is rare that high pressure gas systems will have pressure problems, it usually occurs in the inner city with "low pressure" systems. No high efficiency systems shoud be being installed in the low pressure areas as many can not maintain proper pressure through out the winter. I have brought this to the attention of the "Gas Netrwork" here in New England. Munchkins should not be installed in those areas nor any other similar heating system. If you do get ready to have a lot of calls. This has been going on for 25 years now and the utilities just keep putting equipment in and telling you that you can install this equipment anywhere. NOT TRUE!!!
  • hr
    hr Member Posts: 6,106
    I noticed, Tim

    the Munchkin asks for 7-14" on natural. Whereas the Weil Ultra states 5-13". They look to be similar, if not exactly the same gas valve??

    This job would drop to 5-6" when I fired everything in the home. 8" static with nothing firing, even with the reg screwed in near all the way.

    I know the big Raypak hi efficiencies are sensitive to low pressure, but the Lochinvar equivelent not so much?

    hot rod

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  • Gas Companies may have

    to look at setting a different regulator for high efficiency systems that use a negative pressure gas valve system. Most gas company regulators are set to give 6" W.C. pressure out of the regulator. I personally do not want to see less than 1" pipe to any heating system today. If it is the European Honeywell valve V8115V or the Dungs valves they need a stable and steady inlet pressure in order to operate at maximum efficiency and provide non lockout action. There needs to be training provided on the new gas valve technology. I have recently written a new troubleshooting guide on negative pressure concepts and the special set up required. I am getting ready to add the Dungs valve to that guide.The negative pressure gas valve concept has been around for some time now. The problem is most training does not talk about the systems and control side of heating systems.

    The gas company I worked for would not allow Hydropulse or Lennox Pulse combustion systems on our low pressure system due to problems with high cold weather demand causing low pressure. Those units would not run with less than 5" W.C. inlet pressure.

    The manufacturers and the fuel providers need to have a meeting of the minds. Gas company personnel are market driven to sell gas and do not necessarily understand all the special operating charcteristics of modern equipment. The LP guys are really not aware of the kinds of special needs this equipment has.The push for 90+ condensing equipment needs to have some sense of the special problems such equipment creates. The installer has to be aware that time must be spent on looking at all the possible things that can affect the operation of such equipment. All equipment today needs tune up and follow up, we need to build that into the cost of installation so we do not lose our shirts.
  • Dale
    Dale Member Posts: 1,317
    good job!

    Indeed the generators are a big load. As Timmie said the neg pressure valves take all the gas they want and the rest suffer. We just had a big problem with a Rinnai ( sp?) that calls for 7" at the valve inlet on high fire, guess what the pipe wouldn't do it and the water temp was low. As to inlet pressure the meter cost assumes 7-9 inches. If supplied at a higher pressure the customer gets free gas. That's why the 2 pound gas read is multiplied by 1.12 to get the real cost. Timmie is correct in that the safe way is to run 1 inch pipe to the main load center, for the tiny extra cost it's there for the life of the building.
  • jerry scharf_3
    jerry scharf_3 Member Posts: 419
    They need help


    I know the "that's a very hard feature" speech, I've given it myself. :)

    First, don't bother with a real time clock. Asking for more hardware on the board will be a really hard sell. They are already tracking power on hours. One has to assume they keep minutes and seconds to total those hours. Tell them to use that time forthe timestamp. Second, once they use that, you can bet it's a nice integer so storing it along with the fault code wouldn't be too hard. They would have to change the comm protocol to add this extra data when connecting to the boiler with a PC. From there, it's some software that looks at the current boiler time, the current PC time then calculates the fault times assuming the boiler has been on continuously.

    Is it guaranteed to be right? No. Would it be 50x better than not having any idea of when the fault happened. You bet.

    Seriously, if they are interested I would be happy to talk with them and see if they agree that it could be hacked in with little overall impact.

  • chuck shaw
    chuck shaw Member Posts: 584
    That is what we proposed

    we figured that they could just take the run time hours, or the power on hours and add it to the end of the fault code. We didnt even ask for a conversion to be done, I was thinking that someone could just work backwards and do the math in their head or, at least take an educated guess. If they saw something that seemed to happen, every 300 hrs (for example) that could definatly point them in a trouble shooting direction. Or, if it was completly with out a pattern, that may go somewhere else.

    I understand what you are saying Jerry, and your idea makes perfect sense. We have our monthly meeting this week, and I will again present it to everyone.

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