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GV-90+ Ignition problems

CSzCSz Member Posts: 5
I have a GV-90+4 boiler that acts funny: When there is no demand for heat for a long time (e.g. a few hrs) and thus the temperature of the water inside it drops below 120F, on the next heat demand, it would start a normal cycle: blow the air out from the burning chamber, start the igniter, start the gas, but there will be no flame. The flame led flashes for a few seconds, then the gas goes off, the blower continues to blow for half a minute, then it stops for a second and the cycle restarts, this time always successfully. This is not random. It is like clockwork. During a long heat demand, the gas is stopped, the chamber is ventilated, then when the water temperature drops to 160F, the cycle restarts with no problem. There is always flame on the first try.
I had this symptom last year for almost an entire year. It did not get better or worse. At some point I got tired of it, I replaced the burner cone and the igniter (the cone was rusted allover and blackened towards the igniter and the igniter was blackened as well). After replacement, things worked well for a few months, but now the problem is back. My theory is that the igniter does not have enough time to reach the required temperature to ignite the gas, so when it is perfectly clean it works, but as soon as it gets a bit dirty it can only reach the proper temperature if it starts off moderately hot. Any ideas? There are only 2 controls on my board: economy adjust (which I turned to max) and boiler temp (which is at 2 thirds or so). I have no idea what they really do. Can these help with the time the igniter is heated?


  • HVACNUTHVACNUT Member Posts: 3,412
    There will be 3 attempts at trial for ignition before going into a one hour lockout.

    Rust on the burner is from low return water temperature. The flue gasses are condensing in the cast iron block. Condensing should only happen at the Recouperator.
    There will probably be rust and debris in the fire side sections as well and should be cleaned and vacuumed.

    The internal bypass circulator is supposed to keep return water temp at or above 140°. You would need to verify that.
    Are you able to verify the bypass circulator works?

    Can you post pics? The boiler and zone piping.
    How is the system piped?
    Are there added zone circulators, or is it using only the (internal) system pumps?

    With added external zone pumps, the boiler must be piped primary/ secondary to control return water temperature.

    You should really have a qualified tech do an annual maintenance and follow the steps outlined in the GV I&O manual. Penny saved kinda thing.

    The one thing I despise with these boilers is they make no reference whatsoever concerning a combustion analysis. If manifold gas pressure is -0.1 wc and the boiler runs, then that's it. It's all Peachy Keen. Really?
  • CSzCSz Member Posts: 5
    I tried to get professional service on this, but the guys who installed it, despite being recommended by a friend and the owner of the company having a radio show on the subject were total bums. They forgot to install any kind of circulator to send the water to the top floor of my house. The pipes were leaking when they first left the house, they made so many mistakes, even I could tell. Of course, I called them back, I asked for their boss to come in and I pointed out many mistakes compared to the recommendations in the manual. The guy insisted that the variances were OK. But when I had him to sign off on that in writing so I can get that to the manufacturer he relented and redid the work close to the recommended specs. So I cannot trust those guys to do the maintenance. I called some other company, the guy came in looked at the work and said: Without even testing anything that this installation is not how they do things and he does not want to get involved, so I am left on my own. People who actually know their job don't want to touch my installation with 100 foot pole, and the guys who would be forced to I don't trust even as much as I would trust myself.
    For some reason the internal circulation does not work. While the system is working the water is kept between 160-180 degrees, it dips a bit below 160, but rarely hits 150, due to the fact that I have a fast external circulator and not so big of a radiant surface so the boiler keeps up, but when the system starts then the water inside it has already cooled to 140 or less and the water in the pipes is even cooler and it is allowed to get into the boiler. I see on the internal display the temperature drop to around 100 degrees. I haven't seen lower than that, but that is too low I think, anyway. This has been so from the moment it was installed and I raised this issue with the installer and he said that this is normal. I find it hard to believe that the system would use gas just to keep itself warm when there is no demand for heat, but on the other hand, the outside water should not enter the boiler before it is ready to accept it, yet that happens.
    I have 2 external circulators: one for heat and one for hot water. I have an external bypass, but the idiot installers made it slightly longer than it should be (14" rather than 12") and installed a ball valve on it as well and a 90 degree elbow. To my current regret I agreed with them to just block the valve open rather than insisting that they take it off and completely redo the bypass according to the manual. I don't know what relevant pics to post. The installation is straight forward even though it is more complicated than what I saw in other people's houses: I have 3 heating circuits, each with a thermostat and an electrovalve, all starting from a manifold that a circulator feeds. When any of the valves is open a signal is given to an external 2 circuit priority board external to the boiler. The other circuit has its own circulator, no valves and is its command originates from the temperature sensor in the hot water container that the circuit heats. This is the higher priority circuit of the two. The priority board does not start the heat circulator when there is hot water demand, but it sends the signal to the boiler when either circuit demands heat. The external boiler bypass short circuits, of course, all these circuits. The internal circulators of the boiler exist, but do not seem to be doing anything. I can test whether they get powered but it is hard for me to see if they actually work. By the looks of it they don't seem to be doing much.
  • HVACNUTHVACNUT Member Posts: 3,412
    Where are you located?
    It might take some time and some money, but there are competent contractors out there. Looking at it isn't going to fix it.
  • lchmblchmb Member Posts: 2,991
    I think you need to look outside the boiler in the area of your gas supply. Is this LPG and was it properly converted? Is the gas pressure properly set? As far as the economy setting, I usually put that at the number of zones you have less one (4 zones I set it to 3)...
  • CSzCSz Member Posts: 5
    It is not LPG it was natural gas since it was installed. I was able to prove that running the igniter 20 seconds prior to starting a cold cycle makes the fire start properly, so clearly the problem is that the igniter is too cold. It does not have enough time to heat up. I can easily fix it by building a circuit that starts the igniter a few seconds earlier than it is started now or by adjusting the timer on the circuit board that drives the boiler. But that won't fix the circulation problem. I will have to take out and test the internal circulators for that and also I would like to know a few more things:
    1. Is the fire supposed to start even if there is no heat demand from the house, just to keep the water in the boiler warm?
    2. How long should a burner take until it looks rusty?
    3. For how long should an igniter look like new?
    4. How much gas should a Weil-McLain GV90-4 burn while on? The manual says that the pipe capacity should be 140 CFH, but that may have a wide margin compared to the actual consumption. Mine uses between 90 and 102 to the best I could measure.
    5. For how long should the fire burn at one time? In my case the fire generally burns only for a 1 minute or so (except for the first time when it has to raise the temperature from a low value) and then stops due to reaching the high temperature, then it starts again after 1 minute when the temperature reaches the low of 160F and it repeats this relatively short cycle until the heat request disappears. Does this sound normal?
    Thank you anyway for all the insights I gained so far. I am located in central Massachusetts inShrewsbury and I had bad luck with almost every technician I hired so far, despite recommendations from Angie's List and neighbors. You seem to be a guy who understands his trade. If you are near by, I'd pay you to come and take a look at this. I paid on a guy who claimed to have "20 years of experience in HVAC", and his confident answer was that my gas pipe must be obstructed by incorrectly placed thread sealant, even though that does not explain any of the simptoms I am seeing.
  • Tom_133Tom_133 Member Posts: 689
    Im sorry Im jumping in a little late and haven't read everything.
    Have you changed the igniter? Have you ohm'd it? I have seen igniters do what you are saying, when hot the boiler runs, but when it gets cold the igniter isn't getting hot enough to fire the boiler. Again, sorry if thats been discussed
    Montpelier Vt
  • HVACNUTHVACNUT Member Posts: 3,412
    I entered your zips in "Find a contractor in your area" and came up with some good hits.
    @New England SteamWorks
    Maybe @Charlie from wmass is near. Not sure.

    I was going to run through your last post point by point, but the bottom line is the issues are definitely not DIY. You need a Pro.

    Rewire the ignition for an extended trial time? Are you nuts? On the first TFI, the igniter is powered for 35 seconds. If that doesn't work, there are two more trials, each powering the igniter for 40 seconds. And you want to play with that? Maybe let your neighbors know first so they can get the hell out of Dodge.

    Properly serviced and maintained, the burner should never look rusty.

    Actual BTU output can be calculated by clocking the gas meter. The Pro will know how.

    1 minute burner cycles are not acceptable.

    Contact the contractors above. If they aren't available, maybe they can suggest a trusted contractor who is.
  • SuperTechSuperTech Member Posts: 1,344
    After reading this thread I think @HVACNUT has the right answer. You are in over your head and quickly getting yourself into extremely dangerous situations. These combustion and ignition problems can be safely diagnosed and corrected while leaving the boiler as it was manufactured and intended to operate. Please for sake of everyone call a competent professional.
  • CSzCSz Member Posts: 5
    The problem is that the "pros" set it up this way. The 1 minute cycles, the not working internal circulation. This is not my doing. I pointed out to them that this is strange and they told me it is OK.
    Thanks for the tip with the 35/40 second powering of the igniter. That is definitely not the case here. I measured it reliably with a voltmeter. The igniter is never powered more than 25 seconds whether fire starts or not, so that is clearly a problem.
    @Tom_133 yes, the igniter and burner were changed in November last year.
    The 1 minute cycles really worry me. I do not know how to fix those. They depend to me on 3 factors and 3 factors only:
    1. The power of the fire (the BTUs and that is pretty much fixed by the model of the boiler).
    2. The difference in temperature between the lowest and highest temperature in the boiler (for me the range is 160F-180F) I think that his can be adjusted a little but how much? I need help here.
    3. The amount of heat that my radiant system in the house can disipate. Without major redesign and increasing its surface this cannot be helped.
    I am planning to put some cleaner in the radiant system, just in case it is clogged and it does not radiate enough.
    I can also play with the range of temperature if that is safe.
    What is the length of a normal burner cycle?
  • HVACNUTHVACNUT Member Posts: 3,412
    You stated you don't know what revenant pictures to post, so...
    Stand about 8 ft away from the boiler, take pics from at least 4 different angles. 360°. Post them and we'll go from there. Get the boiler and near boiler piping. So we can see the layout.
  • Tim_DTim_D Member Posts: 34
    If your burner cone and ignitor are "blackened" you most likely have a combustion problem. Blackening = carbon on the ignitor and can cause ignition issues. Gas pressures have to be set with a manometer to get correct combustion. I would recommend that you have a professional contractor in to go over it. WM has a contractor locator on their web site or you can call 800-654-2109.
  • pecmsgpecmsg Member Posts: 1,450
    Tim_D said:

    If your burner cone and ignitor are "blackened" you most likely have a combustion problem. Blackening = carbon on the ignitor and can cause ignition issues. Gas pressures have to be set with a manometer Combustion Analyzer to get correct combustion. I would recommend that you have a professional contractor in to go over it. WM has a contractor locator on their web site or you can call 800-654-2109.

  • HVACNUTHVACNUT Member Posts: 3,412
    I've got a feeling the OP wont be back. DIY coverup.
  • CSzCSz Member Posts: 5
    Thanks to all of you who gave me advice. I went to the WeilMcLain's contractor locator. I weeded out companies who focus on Oil burners, commercial only companies and II was left with 2 companies that seemed competent on a 25 mile radius around my home. The one I heard of before as being great is not taking new customers and the other one had the wrong phone number on the site. As I was saying I did not take matters in my own hands for lack of trying. Or because I am cheap and I don't want to pay a pro. a good pro is harder to find in practice than in theory.
  • HVACNUTHVACNUT Member Posts: 3,412
    You're not exactly living in the sticks so keep at it. Somebody has to know how to repair or replace your system.
  • lchmblchmb Member Posts: 2,991
    how about some pictures of the piping??
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