I live in the North East and have an oil fired tankless hot water heater as part of the forced hot water heating system. It’s 18 years old and the domestic hot water is not as hot as we would like. My HVAC company has checked things out (mixing valves, etc) and has determined the tankless coil is gunked up and should be replaced. He recommended installing a stand alone water heater rather than replacing the tankless coil. His rationale was that a new tankless coil would be a ‘throw away’ when the entire furnace is replaced (in the not too distant future) whereas the standalone could be hooked up to a new furnace. The tankless coil replacement is in the $500- $600 range. The standalone unit is in the $1400 range.
Which option to choose?
Replies
Replace the unit with an indirect fired water heater, using the boiler as a heat source. Stand-alone tank water heaters are inefficient, especially in the price range quoted, on the order of about 65%. A replacement boiler will be at leats 80% (AFUE) and can be purchused into the upper 90's (for enough $$). When you do replace your boiler with a new unit, this one will not be a "throw away" as your "HVAC company" told you.
Another suggestion, based on what you were told, get a few more opinions from other companies.
Thank You for the reply. My terminology may not have been correct. The HVAC tech said the unit would be a tank that is connected to the main furnace, so I guess stand-alone was not the correct term. Is this what you were referring to?
Hey Jimmie ,
Why not just go with a 40-50 gal. electric until you do the change over . The install for the electric should be less than the replacement of the coil . That way when the "not to distant future" finally does arrive(it might be some time) , all peices/parts will be of the same mfg. , vintage and warranty . Plus you will have a back-up hot water source for the future .
After the new equipment is installed just shut off the breaker(or physically remove the breaker and save if you,re afraid of accidental turn on),shut off water(both hot/cold ball valves) , drain tank(leave valve cracked open alittle bit).
Otherwise go for the new $tand alone .
Just my .02 ............
DAVE
Dave
He said he lives in the North East.... electric rates here are killers. Electric water heaters are cheap to buy but expensive to run here.
The indirect water tank heated by the oil fired boiler is most likely his best bet. Also, an intantaneous water heater (has no standby storage) fired by gas could be a contender as well. Depends on if he has gas available and at what cost.
Gas is not available.
Those tankless coils are horrible for your boiler efficiency.
Get the indirect tank, and be happy. The installer was 100% correct. Not to do this would be "Pennywise and Pound Foolish".
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Thank You.
I checked your web site but didn't see any installers located in Massachusetts. Can you recommend an installer. My oil burner/service company has been out twice to assess the situation but doesn't call me back with a proposal. I have to keep calling him. I'm wondering if he is too busy or doesn't want the work.
our power company gives away free water heater, if you build a new house they give you a new heater. The gas company will too.. 2+3=7
what area of mass?-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Weymouth. About 12 miles south of Boston.
Thank You
Actually, your best bet for good installers is often heatinghelp.comthey have a "find a contractor" feature which is well populated with high quality installers.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Thank You, again.
> ... would be a 'throw away' when the entire furnace is replaced (in the not too distant future) ....
Hmmm -- how distant is not too distant? Maybe hang on for a while with marginal hot water, save up some cash, and go for the whole shebang at once? One major advantage of getting the whole job done at once by the same contractor is that there'll never be any finger pointing at the other guy if anything goes wrong.
-- J.S.
The unit is 18 years old. I asked my HVAC person how long it should last before it would need to be replaced due to 'old age' or inefficiency. He didn't have an answer. He just said that the domestic hot water coming out should be hotter than it is and he was checking it by touch before the mixing valve. The mixing valve is new, anyway. I suppose I could live with marginal hot water but sometimes it is luke warm at best.
From what I keep hearing tankless is not the best way to go so maybe the external tank is the way to go. They may point fingers but the consumer typically ends up paying anyway (familar with the Big Dig in Boston?)
If it's simply a matter of water not being hot enough (flow is sufficient) then attach an electric unit (relatively cheap) in series after the current unit.
But first double-check that mixing valve.
happy?
Mixing valve is new. Who makes the electric units?
Everyone! Plain old electric WH, available at HD, Lowes, Sears, and just about anywhere else that sells plumbing stuff.
If ignorance is bliss why aren't more people
happy?
Oh, and just because the mixing valve is new doesn't mean it ain't broke or misadjusted.
If ignorance is bliss why aren't more people
happy?
What is the mixing valve used for in that system ?
Hilmar
A mixing valve is used when the water heater produces water hotter than needed (as is often the case with a boiler-attached water heater). The valve mixes hot water with cold, using a thermostatic control, so that a constant (lower) temperature results.
If ignorance is bliss why aren't more people
happy?
Hot water comes out of the tankless and gets mixed with the cold before going on to the bathroom and kitchen fixtures. Tankless temp is around 180. The mixing valve 'reduces' the temp to around 120. It's been a while since the HVAC tech gave me the numbers.
HVAC guy was judging the water temp coming out of the furnace before it reached the mixing valve. He said that the hot water pipe coming out of the furnace should be too hot to touch.
i'm a little late on this post, but I agree with one of the others that the mixing valve could be the problem, the adjustment of the valve needs to be checked. Luck.