ergomax E23 with T80 Munch

Jim_36

is this a bad match? will I get enough domestic production? Supplier wants me to use much larger boiler, but i do not want to greatly oversize heat source just to meet domestic demand - should I select a larger storage type indirect tank ?

thanks

PJO_5

Jim,

I'm not a contractor, but have an Ergo E23 in my home...added it last year with primary/secondary piping for the buffer/HX combo to my radiantoff my cast iron boiler.

I am assuming your using this setup for the buffer as well as the domestic.

I think it would work great, but the next question is; what else is in the system? If you have a bunch of radiant and just a little higher temp. stuff (baseboard, rads) then the Ergo could be at the "front end" of your primary piping (if you're doing that) if you're not doing priority, or vice-versa. If it's by itself, then I don't see the benefit as much if you have a high domestic demand...although it will still be better than a regular boiler.

Of course, with a modulating boiler you can oversize a bit and it won't hurt as much in the efficiency department...

My own system is 60/40 radiant/baseboard, with the Ergo right in the primary just after my lowest temp. zone of baseboard. The other side of the Ergo (normally domestic) is three zones of radiant, and the 1 1/4" piping is perfect for this. Works like a champ, but it's different than what you'll do...

Hope this helps. Take Care, PJO

DaveGateway

Wouldn't using a reverse indirect

in a primary loop require the boiler to always pump out over 140° water, defeating some of the modulation advantages (condensing advantages also)? With modulating, I'd think you'd want a regular indirect on a seperate priority based loop. The Vision controls would ramp up to high fire when this zone called and run a lower temp for the other heating zones. An ErgoMax would be better suited as Patrick mentioned where the indirect can buffer down a regular boiler for a lower temp zone.

Alex Giacomuzzi

Bad or Possible Match???

If you assume you will heat your domestic water to about 130 deg. F. you will need about 45K btuh input to the Munch. for EVERY gallon of heated water you need. If you need only 1 gpm you are in good shape.
If you need more -- possibly not then. The Ergomax will provide a relatively short supply buffer, not at all similar to a regular indirect. If you want full capacity from the E23 your supplier is correct ---- you can only get it with supplying additional input BTUH's. Probably in the 130K --- 150K range.

Options.....assuming you are using 2--3 gpm range:
1. Larger boiler & E23,
2. Same boiler and a properly sized indirect (for family needs), or
3. Same boiler & E23 & a regular 30 -- 40 gallon water heater in series acting as a controlled buffer tank after the E23.

I do not think you would be happy with putting in a whole new system and running out of hot water.
Good Luck...

PJO_5

In his case...

Depending on what else is there is what determines the temp. I think.

If all he has is the domestic, then he could have that Munchie cruising along at 140F output, and the return would be substantially lower - and thus condensing. Of course, with huge demand it would require a higher fire...but the return could always be 100-120F and thus condesing.

I personally would run it this way...maybe PAH could shime in here, but if you are feeding 135F water and it's a tankless set-up you are avoiding most of the legionella issues, right?

DaveGateway

I'm not so sure

The recovery and GPM ratings are always at 180° boiler water. Since an inverse indirect is just a tankless coil placed in a thermos bottle instead of a boiler, I wonder if enough heat transfer would occur as cold water went through the coil at a rapid rate. At least a regular indirect could sit idle with a full tank of cold water and absorb BTU's from the 140° HX coil over a longer period of time.

PJO_5

Same, but different :-)

My own system normally has about 140 to 145 primary water when it hits the Ergo...the primary pump is going about 8 gpm, and the radiant side pump is between 12 and 18 gpm depending on use.

I get a 12F drop through the Ergo after steady state at 12 gpm, so while I sometimes may be in condensing mode for short periods, remember that I've already been through the higher temp. zones and they are satisfied already. This last thing makes my system compare to this situation if you just look at the Ergo in both situations; he will be at a much higher temp. drop (six times mine), while I'm at much higher flow (about six times).

The higher temp drop may affect the "end" of the coils, but there are three coils, each 1/2" in the tank as opposed to a "normal" tankless coil (not "just a tankless coil in a thermos"). I don't have the information here, but I think the area of heat exchange is about twice as much.

While I think there are other factors, the scenario originally mentioned would work best if it was only for domestic, then better for other small zones (buffering from the Ergo would help a lot here), and would be bad if there were a lot of other zones with a possible heavy demand - especially higher temp. ones. If that's the case, a "normal" boiler or larger Munchie would work better.

Like others, the Ergo will go as far as the connected boiler lets it.