Combination boiler plus storage tank for DHW

dbk

My contractor is recommending a Navien combination boiler plus a storage tank for domestic hot water, for periods of high demand. The tank would sit alongside the boiler. I was expecting to see him specify a non-combination boiler plus indirect fired heated tank, but no, he's adamant that it's just a storage tank. I just want a gut check here, does this configuration make sense?

Thanks!

Rich_49

The storage tank should indeed be an indirect heater to keep the water stored at 130* . What good is a storage tank full of warm water after a long period at standby ? Tell the contractor that you are paying the bill , this is your home and remind him that you are paying him . A preheat tank would make more sense for DHW .

RobG

What are your domestic hot water requirements?

EvanC

You can use an electric water heater as a storage tank but instead of powering the heater, wire a dhw pump into the lower thermostat. Gives you extra storage capacity and eliminates cold water sandwiching

Jack

...or you can go with the correct size boiler to heat the house and put the right size tankless next to it for your DHW loads. Why store water?

Rich_49

2 gas appliances as opposed to 1 that does 2 jobs . Hey , I need a new job , maybe you have a redundant position you need to fill for me .

njtommy

What time of heating system? He could be doing it to bring down the return temp to the condensing range. Also if ur on well water in the north it's not a bad idea because the water comes out around 40-45 degrees.