DHW best way

Joe Brix

Their larger stainless steel comercial water heaters might last longer then a glass lined tank.

Joe_55

DHW best way

Anyone can tell me the most efficient way to make DHW for
an 22 unit apt. house (many tenants have washing machines)

The present system uses a coil below the water line in the
steam boiler ( Peerless FHA 713) with #2 oil burner This setup realy kills the steam making .

Is there a separate system also using #2 oil that would be more efficient for this task? thanks JB.

kevin coppinger_4

I am surprised...

that a tankless coil keeps up with the hot water demand. You probably are better served witha stand alone oil fired water heater(Bock, John Wood, etc) kpc

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Joe_55

DHW best way

Kevin: Thank you for the info, will check with Bock about a light commercial unit thanks again

JB

Firedragon_4

JMO,

but I would investigate the separate heater for the summer, but not sure I'd do away with the tankless for the winter months.

If it's doing the job, it's very hard to beat a steam driven heater in the winter. Might want to have it piped so that the water heater becomes a booster in the winter.

Maybe the tankless isn't piped right if it's external? Maybe not piped right if it's internal??

These guys can help: hot water

Maybe just a new control system is in order?
This is currently shipping on more and more heaters due to it's incredible recovery capabilities: dhw control

You can always contact me too, we do have a book out on this subject: FiredragonEnt.com

Joe_55

Firedragon: Thank you for your opinion,The coil is piped OK with a Holby mixing valve for tempering, I was just wondering if having storage would be a better approach, and I'm sure this boiler even though wet base is probably not the most efficient (the boiler runs for DHW between steam cycles) and summer operation with a more efficient system would be a great savings.

Thanks for all the help JB.

Firedragon_4

How old is this setup and

what is the burner model?

Joe_55

Firedragon: approx 20yrs old with carlin 702 burner (two stage) BTW the coil is internal handles the job but drags down the steam effort

Firedragon_4

Okay, but

I'm confused by what you mean by 'the coil drags down the steam effort'. Is is because you can't run a higher water level?

One trick in the summer is to put the water level almost to the top of the glass.

A 20 year old coil has probably done it's job. I would replace it, but with an external. After three leaky indirects I went back to one in my own home, FACT!

JB_7

DHW bestway

firedragon: What I meant was when the boiler is in the heating cycle trying to establish pressure to trigger the timing cycle,a large demand for hot water delays the steam making.

Are you saying that an exterior coil would be a better approach to makeing hot water?

The coil is not 20yrs old it has been replaced a few times damaged by the push nipples probably because of turbulance.

Is there a way to add a storage tank to help with the DHW demand when the boiler is steaming?

I'll be looking for a more efficient means for summer operation
Thanks for all the help JB.

JB_7

Firedragon_4

I prefer

external coils to internal since they have more surface area exposed to the water and also have less pressure drop. That's the technical side of it, but also find they hold up better, JMO.

Anything works better producing DHW with storage, that's a FACT! If you don't have storage you must make up for it in recovery and Btu's. Pay me now, pay me later, I like storage.

Joe_55

Firedragon: What exactly is this external coil? Is it an Ergomax type. and do you feel your arrangement will work for a multible dwelling or how will it incorporate storage? many thanks JB.

Joe_55

Firedragon: What exactly is this external coil? Is it an Ergomax type. and do you feel your arrangement will work for a multible dwelling or how will it incorporate storage? many thanks JB.

Firedragon_4

If you go back up to my

'JMO' posting and click on the hot water link it will take you to TFI-Everhot, externals have made them famous, FACT!

Ergomax is virtually a copy of this proven design that goes back almost to day one in the central heating business when Cooper& Gerstein and Everhot ruled the roost.

BTW, our host has an external in his home too!

Joe_55

Firedragon: Thanks for your patience and help you are a great asset to this site. JB