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Oil boiler to gas boiler conversion

Due to a flooded basement, thank you Irene, I am in the process of converting a 15 yr. old waterlogged oil fired boiler to a new gas fired boiler.  I live in Central New Jersey.  My oil burner heated both HWBB and domestic supply.  I want to separate the two.  I've gotten a quote from one contractor for two options for boiler and two options for water supply.  I'd greatly appreciate any feedback I can get as I am not well versed on the pros and cons of these systems.  In process of getting other quotes but these guys helped me out w/DHW issue that no other contractor I spoke to could offer a better solution than "call a plumber" so it's their job to lose.

First to the boiler:

Option 1: WM CGI-4E 85% AFUE  Seems like a significant upgrade from my Oil burner, which was probably running at about 65%.

Opton 2: WM Ultra 96% AFUE (I believe it would be the UG-105 or UG-155).  I've read some mediocre to bad reviews for this system but I'd like some knowledgable people to offer feedback.

Now to DHW:

Option 1: Indirect fired hot water tank (probably 40 Gallon) no particular brand given.

Option 2: Navien Tankless hot water heater (not sure of model).

I've spent about $3000/yr on oil since we bought the house in '06.  W/O getting into pricing specifics there is a large price gap between CGI4E/Indirect combo and Ultra/Navien combo.  I can figure out a rough ROI from each option but would like feedback,both good and bad, on each individual component.  If negative, please give an alternative if possible.

Sorry for the lengthy post and Thank you for any feedback.


  • Jean-David BeyerJean-David Beyer Member Posts: 2,532
    Opton 2: WM Ultra 96% AFUE

    The title is not necessarily a recommendation, but it is definitely not a criticism. I am not a professional, so I cannot help you picking a boiler because I do not know any of your other options.

    I converted from a 60 year old GE oil-fired boiler (70,000 BTU/hour input) to a W-M Ultra 3 in May 2009, and have no regrets. Of course it is too early to expect failures. I have two heating zones; one is slab on grade radiant, and one is fin-tube baseboard that is oversized on purpose to get more condensing. It comes with outdoor reset and I spent a lot of time getting the reset curves to provide as little heat as possible and yet provide enough heat at all times. The biggest issue with this boiler is to  be absolutely sure you get a qualified designer and installer. (This is probably true no matter what boiler you select.) In my opinion, this is actually more important than the particular brand of boiler you get. One test is to see if he does a proper heat loss calculation before selecting which boiler you get. Being interested in these things, I did my own heat loss calculation three different ways. You might as well skip the first one, but it is a check. All the others should come out with a lower value.

    1.) I looked at the nozzel of the oil burner and it was 1/2 gallon per hour. 70,000 BTU per hour input, and I always got enough heat.

    2.) On W-M's web site they have a worksheet and lots of tables to calculate heat loss. I filled that out and came up with 35,000 BTU/hour,  but the tables did not really fit my house, so I had low confidence.

    3.) I used the Slant/Fin program to calculate the heat loss. This came up with 30,000 BTU/hour.

    Now since the smallest Ultra-3 is 80,000 BTU/hour, any of these results would be OK if you wanted an Ultra 3, because the smallest they make is 80,000 BTU/hour. My house is about 1,100 square feet in New Jersey.

    Now my installing contractor did none of these things. He paced the length and width of my house and suggested the 105,000 BTU/hour model which I refused. I did not know this indicated incompetence.  Once installed, they refused to do a combustion test other than looking in the insection port to see if it lit. At the first annual service, they did not follow the maintenance procedures in the I&M manual, and they only allowed about 15 minutes for the service call. I estimate it takes 2 hours to do the procedure properly. They again refused to do a combustion test, saying it comes set from the factory. At that point I demoted them to former contractor.

    "Option 1: Indirect fired hot water tank (probably 40 Gallon) no particular brand given. "

    That is what I have. I use the W-M indirect, the tank-within-a-tank one, that is nominally 40 gallons. I live alone and use very little hot water, so this works perfectly. The recovery rate is so fast that I reduced the supply temperature from the defalut of 190F to 170F to get more condensing. I suspect this is more efficient of money than my former electric hot water heater that was starting to leak very slowly.

    The W-M indirect is made by Triangle Tube. I do not know if it makes any difference which you get. It is heavily insulated and has no venting to lose you energy up the chimney. I tend to mistrust the tankless type, having been stuck with one in France in 1950. As far as I know, their only advantage is they have less heat loss when you are not using it. For me, that is not a concern.
  • lchmblchmb Member Posts: 2,513

    Unfortunately for me I have had to many issue's with the WM Ultra to recommend one. I work for a company that services approximately 10 of them and only 1 has been trouble free (we follow all recommended procedures during service and do a combustion test in all cases). I will however say their tech support has been very good to deal with and have a strong understanding of their product.I have never used the Navien so I cannot speak about that but would recommend if you go with a mod/con boiler (which I would recommend) you go with an indirect with mixing valve. This way in the winter your only running one system not two for HW.

    As far as recommended boiler's, look over review's. Talk with your installer and see if he has a preference and if so talk with people he has installed the system for...That way you know what happened after the install...;)
  • Jean-David BeyerJean-David Beyer Member Posts: 2,532
    I have had to many issue's with the WM Ultra

    Would you be willing to tell what the issues were and what solutions you had to use to remedy the issues? So I can know what to look out for?
  • lchmblchmb Member Posts: 2,513
    flame failure

    The biggest issue's we've had so far are flame failure.. In two of them I cleaned the HX due to a large build up and set the unit with an analyzer, both were less than one year old. Unsure if the unit was set up properly in the beginning. I had two that needed new burner gaskets and ignitors.. I also had a call for a noise on start up and with the help of tech support revamped the speed on the inducer motor. I have had one system  where the board failed. I can accept that things break but....just dont like them personally. Maybe other's have good luck with them. All of the one's we service are run on propane. JDB I would suggest you get a service kit and cleaing brush for your unit to have on hand. It's not expensive and if you have any issue's its very nice to have. Also, make sure your unit is cleaned and serviced and the PH level of the boiler water is tested every year no matter what.. I do the burner gasket and ignitor now every service. 
  • Jean-David BeyerJean-David Beyer Member Posts: 2,532
    My experience.

    If the installers where you are are like the ones I have tried to deal with around here, chances are pretty good that they were not installed correctly.

    My boiler is about to start its third heating season. It runs all year to provide domestic hot water with an indirect fired water heater. My original contractor, now dismissed, seemed unable to service it properly, and perhaps unable to read the I&M manual. If they had a combustion analyzer, they left it at the home base. For some reason they were unable to answer the telephone, unable to reply to e-mails, and unable to answer written postal service carried letters. Somehow, they are still in business.

    My new contractor came to do the first service, equipped with a gasket set and a new ignitor. He said they always replaced both at every service because it was cheaper overall than a call back for leaks. The technician followed the manual pretty closely, but refused to test the pressure relief valve on the boiler or the P/T valve on the water heater. There seems to be a reluctance on the part of technicians to test them. The new contractor, the old contractor, and the technician for my previous oil burner would not do it. They claim if you pull the release, they never seal correctly. Well, in my opinion, this would indicate that they need at least inspection, and possibly replacement.  He also brought a cartridge (like for a calking gun) or Sentinel X-100 boiler additive and inserted it into the system. W-M insists that this be done on all new installations, but my original contractor did not do it. I even asked them to do it, but they said the water around here did not require it. I bought my own pH meter and have checked the pH of the water from time to time. I have not checked the pH since the X-100 has been in there,.

    Anyhow, the only trouble I had was a noisy circulator that the circulator manufacturer replaced free as a courtesy, and another time when the boiler would not run at all and the display was insane. It turned out that the PVC vent pipe had been put together with the purple primer, but they forgot to use the glue. Condensate leaked and filled up the top where the circuit board was, shorting everything out. The technician opened the unit and found all the water. We could not figure where it was coming from. He dried everything out and we tried it and it worked. But he said he could not consider it fixed, and neither could I. He left the unit open for a week and I watched it. It continued to fill with water, but I could not find the source. A week later, I though I found the leak (I was wrong) but he came over with the factory rep and the three of us found the problem. The W-M factory rep gave me a free new circuit board as a courtesy, which I really appreciate. The old one was working OK, but he did not want to have me run with it. So that problem was due to bad installation. If you use PVC venting, you must use both the purple stuff AND the glue.
  • lchmblchmb Member Posts: 2,513

    Following the manufacturer's requirements are of course a major aspect that must be followed! Properly sized header's and circulators are as important to the system as the boiler. I also agree with your second service man with respect to the service kit and ignitor. I do however test the water feeder and P.R.V. And yes I have replaced a number of them. Unfortunately I have also had those that stop leaking until the next day so it is frustrating. As far as the issue's with the vent pipe, that's not a brand specific item. That's a mistake made that would damage any system. Like I said earlier, I would not install one. But in your area, that may be their main boiler and the front line boiler for them. If that's the case and they have a good track record with them and the equipment to repair it I would not steer you away from it. Ask around and see what local companies are comfortable with..Also ask for references from people who have had them installed and call to see what they think...Take the time now so later you can enjoy your system...
  • meplumbermeplumber Member Posts: 678
    Aluminum HX.

    The problems with the Ultra were the same that Buderus had when the 142 came out. The aluminum block HX was eating itself. for lack of a better term. I am a Buderus cast iron fan. I also like the Weil Mclain cast iron boilers. However, like Ichmb, the Ultra has had too many failures for me to recommend one.

    I prefer the stainless heat exchanger boilers. I am a Viessmann man myself, but the Lochinvar Knight and Triangle Tube boilers are very capable as well.

    As far as DHW goes, it has a lot to do with usage that determines which application is best for you. Both an indirect and an on demand will save over a tankless coil.

    Good Luck.
  • Jean-David BeyerJean-David Beyer Member Posts: 2,532
    The aluminum block HX was eating itself. for lack of a better term.

    Was it eating itself on the fire side or the water side? I,.e, was it a water chemistry problem, an electrolysis problem, or something else?
  • lchmblchmb Member Posts: 2,513
    edited September 2011

    generally it's from the condensate in the unit (that I've seen). the line where it exit's the boiler plug's off and then sit's and corrodes the bottom side of the unit..This is also one of the reason's you have to be careful with the PH level. It will destroy the boiler from the inside..
  • TonySTonyS Member Posts: 849
    My opinion

    Weil mclain cgi.. good cast boiler

    Ultra...never cared for Aluminum

    Navien...installed one in my home 3 years ago, since then have sold a few of both standard and a model.

    one problem 3 years ago, bad alloy on flow switch. Nationwide problem sent new switch and have not had a problem since. Two adults and 2 teenagers.

    I have the standard model, if I were to do it again I would buy the A model(contains a small 2 quart tank that remains heated so there is no wait for hot water) otherwise you will wait another 30 seconds for hot water.

    I could live with the heat loss of 4 lbs of water for the convenience.

    Otherwise it makes hot water only when the water is on, exactly at the temperature you want at 98% efficiency

    Depending on your hot water needs, another choice would be a Triangle tube Excellence.
  • Robert O'BrienRobert O'Brien Member Posts: 2,938
    If I had gas

    available at my home,which I don't,I would install a Viessmann or Triangle Tube
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • PorterFNUPorterFNU Member Posts: 2
    New additions to options

    I've recently had a few more contractors in and have a few more options to get opinions on.

    1) Navien Combi CH210.  For both HWBB and DWS.  House is 2200 Sq. Ft. 4 BR, 2 1/2 bath with both dish and clothes washing machines.  Currently only two adults living in house.  Located in Central New Jersey.  Will this system be able to supply enough hot water for a full family, assuming we sell eventually sell to a larger family?  Any opinions good or bad?

    2) Triangle Tube PE-110.  Same questions as above.

    I appreciate all the feedback this topic has been getting.

  • HomeOwner1HomeOwner1 Member Posts: 134
    We are happy with our Navien

    We have a 3750 sq foot home with 3 bathrooms in New Jersey. Runs great, is efficient, heats the house just as well as our old cast iron boiler and always have hot water. We are happy with it.

    We looked at Triangle Tube as well, but the hot water side just was not enough to meet a normal house demand like yours or especially mine. The Navien does the trick.
  • SWEISWEI Member Posts: 7,356
    old requirement before options

    did anyone do a heat loss calculation?
This discussion has been closed.


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