[GBlist] Re: using Tankless Heater

[Sacie H Lambertson <dlambert@grasshoppernet.com>]

Hi Khalil,
	 Regarding the possibility of using a tankless heater for a RFH system, I
too received mixed messages from both Aquastar and Radiantec--ie the former
said sure, the latter said no; the latters explanation didn't entirely make
sense to me though.  
	What I have for RFH is a direct system--that is to say my floor and DHW
water all flows through the floor tubes (with the exception of the main
incoming cold water line which is 1" copper, I'm using PEX internally for
all my plumbing as well).  My floor is Radiantec's largest size, the 1" PXC
tube and R. tells me that I must keep the incoming water pressure
low--ideally at 50psi.  The longest run in my plumbing system stretches 64
feet so I don't feel that the combination of the low pressure requirement
from Radiantec will match well with the somewhat higher pressure
requirement of the tankless system.  This is my reasoning, not Radiantec's. 
	And, as much a I love the tankless heater for its wonderful economy, I
hate to put in two heating sytems, so although I haven't made a final
decision yet, I will probably put in a standard propane fired 50 gal. DHW
tank for everything.  The up side is that I'm also installing some good
used solar panels to pre-heat the water and given all the sunshine we have
here in Kansas, I won't be surprised if the panels can't supply most of my
hot water needs. 
	I think, if your building's foot print is compact and you won't be running
showers and dishwasher and washing machine at the same time, one good
tankless heater might be all you need for both the floor and potable hot
water.  Speireag up in New Hampshire uses a Myson for both domestic hot
water and a floor system and says it works well.  
	I'm posting this to the forum as well, as there may be other suggestions
out there.  Sacie Lambertson



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