Boiler Economizer

Chris Burt

I would like to use one of these on my Bosch Aquastar tankless heater. Is there a reason this can't be done. My system uses the fan for forced ventilation so the gas is going to keep moving even if it does cool off. I would definitely enjoy the lower utility bills do to increased efficiency. Between that and a GFXheat echanger I should be set. www.gfxtechnology.com

Frank Cheng

some pros and cons

I used to be interested very much in this subject, until I found this stuff is actually discouraged by many people from residential uses (I only found some applications in large commercial and industrial applications). The main problem in residential applications is condensate that may form in the flue for noncondensing units. This problem does not exist for condensing units. But, for the condensing unit, the flue temperature is very low (about 100 F or so). An economizer may not pay back its own cost from the money it saves. However, the economics depends on the price, and on the subject with which the heat exchanges, i.e. to exchange heat with cold water or cold combustion air, or room air, or something else. If you find a feasible one, please let me know.

On the other hand, GFX is feasible generally speaking, but it has to be perfectly plumbed. It works well for showers, but does not work well for tubs unless you install a storage tank and a circulator to store warmed water. I've installed several pieces. The pay-back time varies from 1-5 years. I think if you use showers a lot or mostly, it is worth installing.

Frank