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Replace tank boiler with High Efficiency Combi?

shortmort37
shortmort37 Member Posts: 1
My 25 year old Columbia boiler shows signs of failing - there are small leaks at heat exchanger, and the pressure is not keeping up. Time to replace it.

My house is about 2700 sq. ft. The hot water radiator system is 100 years old, and as you would expect, the water is rusty. Would I be better off avoiding a heater of this type, i.e., is a high efficiency heat exchanger likely to get fouled with sediment? I would, of course, install a filter on the return side.

(Oh: My steamfitter brother recommends running the hot water into my existing hot water heater during the winter - he says it's more efficient - and simply turn the combi heater off in the summer, letting the hot water heater provide hot water.)

Would I be better off going with a standard tank boiler? Can I get a vendor recommendation either way?

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 9,678
    THE MOST IMPORTANT THING IS TO SIZE THE BOILER CORRECTLY & PICK THE RIGHT CONTRACTOR. iF YOU BROTHER IS DOING THE JOB THEN THAT IS THAT.

    AS FAR A CONVENTIONAL BOILER VERSUS MOD CONS I PREFER CONVENTIONAL BUT YOU CAN READ ALL MANNER OF PREVIOUS POSTS ON THAT SUBJECT.

    WEATHER YOU PICK CONDENSING OR NON CONDENSING THERE IS NO RIGHT OR WRONG ANSWER THEY BOTH HAVE PROS AND CONS

    ASK 20 CONTRACTORS AND YOU WILL GET 20 DIFFERENT OPINIONS

  • Ironman
    Ironman Member Posts: 6,461
    I assume that by “tank” boiler you mean an atmospheric cast iron boiler? Is your current boiler gas or oil fired and will that be the same for a new boiler?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • hot_rod
    hot_rod Member Posts: 14,868
    A heat load calc should be the very first step, then we talk about type of boiler and size.

    If the home has plenty of heat emitters, radiators, whatever, it's quite possible to run lower SWT for much of the heating season. Less then 8-10% of the heating season are you at design temperature.

    Step 2 is an assessment of the heat emitters, how many, what size, output chart.

    The beauty of todays modulating boilers is they love low temperature operation and they can modulate firing rate to closely match the load of the home.

    Best money spent is upgrading the structure, insulation, weatherstrip, etc. Incentive $$ from many utilities for energy upgrades and equipment upgrades.

    Check dsireusa.org to see what incentives are available in your area.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Ironman