We have a Polaris water heater that supplies hot water for a forced air hydronic heating system as well as hot domestic water in a 1950 era cape cod with relatively poor insulation and concrete block constrution/brick veneer. The unit is on the fritz and we are considering replacement options. Should we put in another similiar model, a gas furnace and seperate hot water tank (space very limited for this option) or a tankless system,. Any advice out there from someone who knows more than us?
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Replies
Assuming the system was adequate berore, it would obviously be simplest to replace the Polaris with another tankless heater. Look into the Bosch Aquastar units - they're far better.
Solar & Super-Insulated Healthy Homes
Thanks riversong. Any suggestions on how to size the replacement - not sure original was sized properly?
Any suggestions on how to size the replacement
Best bet is to ask your supplier.
Demand heaters are rated at maximum temperature rise at specified flow rates. So you need to estimate what your maximum expected flow rate is and the difference between water supply temperature (typically 45°-50°) and desired output temperature (typically 120°-140°).
The larger gas-fired units can supply 5-7 gpm at 55° rise, and 4-5 gpm at 75° rise.
Takagi and Rinnai also make good demand heaters.
http://www.eere.energy.gov/consumer/your_home/water_heating/index.cfm/mytopic=12830Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Since the Polaris is storage tank WH how can it be replaced with ANOTHER tankless..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
What is wrong with the Polaris?
The Polaris ain't cheap and with the SS tank I would look at getting it repaired.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
depending on your heat load (sounds high) I'd consider a wall hung mod/con boiler and separate storage tank as a more ideal option if replacement is in your future.
an on demand water heater would be an extremely inappropriate choice for this system, given your higher water temperature demands, you would take quite an efficiency hit over your current system (assuming it was properly set up in the first place).
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
As usual I agree with NRTRob.Mod con with an indiredt for hot water.Garett