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Repair v Replace for RayPak Ratherm boiler

katietx82 Member Posts: 3
edited January 2021 in THE MAIN WALL
I have a RayPak Raytherm H3 0135B that was installed in 2002, and I am debating how much life it has left in it. I know there are a lot of factors to answer that question, and I've included as much info here as possible, so any advice or education (never had boiler/ radiators before this house) is much appreciated. I'm fairly handy myself so also willing to consider anything I could/ should do myself.

It appears to be a water tube boiler with copper tubes, cast iron headers, and steel plates. About two years ago I replaced the pressure valve and expansion tank. This year I had a home energy audit that found unusually high CO readings, prompting me to have a service technician come out to take a look. The boiler has been working fine otherwise, and guy doing the energy audit said the CO was at least all being drafted up the flue as it should, but was still likely a sign something needed to be repaired. The service tech said there was a lot of soot on the unit and the gas valve needed to be replaced and the unit should be cleaned. He quoted me a price to clean the unit and replace the gas valve, mostly because they had to use a chemical solvent to clean the copper and it would take like 5 hours with two people and a shop vac, and there is no promise it will work after cleaning due to the age and how long it has been since it has been cleaned. He also recommended I consider just getting a new unit, and a sales rep quoted me a price to replace it with a Weil-Mclain CGa-3, which looks to have cast iron parts, but I am not sure what counts as being a cast iron boiler that will last decades.

Given that my current boiler is less than 20 years old and otherwise working fine (and has a recently replaced pressure valve and expansion tank), I am inclined to get it repaired and see if I can get another 10 years out of it. Is that crazy, and should I consider just replacing it? I haven't been able to find much about lifespan for RayPak boilers, but my home inspector when I bought the house in 2012 thought it could last 40-50 years, but I get that he is not necessarily a boiler expert. Should I consider having the gas valve replaced by the tech and then cleaning it myself? If it is of any help, below are the other readings from the service tech's visit.

O2 5.7 low
Co 539ppm high
Eff 99.8
Co2 8.8
T stk temp 252
T air 57.7
Draft .05
Draft in room.02


  • kcopp
    kcopp Member Posts: 4,431
    edited January 2021
    Please remove all pricing from your post... that's a no-no here.
    It sounds like it just needs a good cleaning.
    Why did the tech say the gas valve needed replacing?

    katietx82Erin Holohan Haskell
  • katietx82
    katietx82 Member Posts: 3
    edited January 2021
    Thanks for the flag about pricing. Updated with that info removed. He didn't say specifically why the gas valve needed replacing, but said that it would resolve the high CO issue. They adjusted the gas valve on a service visit a few years ago. Here are the notes from the that 2017 visit (when I replaced the pressure valve and expansion tank):

    found very high Co. reading over 2000ppm check inlet gas pressure 5.45
    manifold psi 3.68 this gas valve has no adjustments port to low gas pressure
    around 3.50 recommend new gas valve with circuit board and time sensor to regulate the pressure with the temp at this time had to adjust gas cock to 3/4 open to lower the gas on the manifold
    side now co at 87 ppm with is ok and manifold psi at 3.47
    EBEBRATT-Ed Member Posts: 15,512
    I would clean it and keep running it if they can resolve the Co issue. I see no reason they cant.

    If the hx is dirty lack of air will cause the Co to go up. I am also concerned about the low stack temp.

    You can clean it yourself vacuum it out and we have hosed them out with water after the vacuum but the water does make a mess

    Most of the soot and debris will be on top of the hx
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    I believe Raypaks are probably the best copper tube boiler out there. The designers knew the limitations of the design and provided instruction for proper installation. I have found other copper tube manufacturers make claims which are simply not true. I've seen a number running with no maintenance for probably decades and still were reliable.

    The low stack temp is a concern... if the water temp is below about 140F on the return for long periods of time, then a bypass line is needed to allow the boiler to run hotter (see the instructions)
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Zman
    Zman Member Posts: 7,569
    What type of heat do you have? In slab radiant or hot water baseboard?
    What is the operating setpoint, does it consistently reach that setpoint before cycling off?
    I am wondering if the boiler running at low temps is causing the low stack temp and the coils to foul.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • katietx82
    katietx82 Member Posts: 3
    edited February 2021
    Zman said:

    What type of heat do you have? In slab radiant or hot water baseboard?
    What is the operating setpoint, does it consistently reach that setpoint before cycling off?
    I am wondering if the boiler running at low temps is causing the low stack temp and the coils to foul.

    I have hot water radiators in several rooms that vary in height and width, but generally 2-3 ft tall and 2-4 ft wide, so I don't think that is slab or baseboard. Boiler is in the basement and heats the two levels above. I keep the thermostat set at 70 degrees (not sure if that is the set point you mean). It has been great at consistently keeping the house at that temp (no issues there).