Ecomatic Problem

ScottMP

ans as a Buderus installer I will be interested to see what happens.

I understand the fuzzy logic that allows the the tank to "cost" to set point.

So the boiler coming up to a lower temperature and shutting off ? hhmm

I'd be interested to here.

Scott

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[Deleted User]

Anyone else experience this...

We installed an atomspheric 300K 2 stage boiler, and used a TTP phase 3 storage tank for DHW in an apartment complex. In order to keep the DHW from keeping the space heating calls too long, we had to pull the sensor out of the DHW well 3/4 of the way, and turn the DHW down to 112 degrees F. Never had a complaint of no DHW, but residents are compalining of no space heat.

With the DHW set for 112, the boiler limits out at 140 then comes back on at 130. This takes FOREVER for the DHW tank to be satisfied. In the mean time, the space heat circ is off...

Raised the DHW set point to 140, and the boiler limited out at 160, came back on at 150, but STILL takes for friggin ever to meet the set point of the DHW system.

Out of desperation, I jumpered the terminals 1&2 on the terminal strip, bypassing the Ecomatic, and running off the boilers operating limit of 180 degrees F.

I suspect it may be the tank in a tank design messing with the German logic, but not sure. Anyone else have this experience.

It's HELL when its been as cold as it has been here recently.

Thanks to Dennis Bellanti for talking me through it tonight.

ME

ScottMP

Mark

SHould'nt the ecomatic be ramping up on a DHW call ?

I mean more than what your getting ? I would think this would be going up around 160 on a real demand. Maybe the thermistor not being all the way in is not sensing the total drop in temp ?

The Turkey

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[Deleted User]

Scobble...

That is what THINK it is trying to do, but it is falling WAY short. There does seem to be a corelation between the set point of the tank and the maximum temperature coming from the boiler. The tank is a tank in a tank design, which is supposed to be an extremely efficient heat transfer method, but the boiler is not getting hot enough to satisfy the call FAST enough. It is keeping the DHW on for so long that the apartment building cools WAY down, and people start complaining. Then, once it comes out of DHW, it takes a while to get the mass of the heating flywheel running again due to bouncing off of pump logic.

With the tank set at 112, the boiler maxes out at different lower temperature then it will with a set point of 140, so I'm pretty sure its a logic thang. I'm going to try and track down Dr. Lou today and see if he has any suggestions. Heck who knows, it could be a bad mutha board.

I can tell you this. I've had situations with Ecomatics connected to Buderus tanks where the boiler DIDN'T stay extremely hot during a DHW call, and when the burners shut down, I looked at the boiler temp and thought "What the...??" only to watch the DHW tank COAST to its correct set point. That tells me that the logic is intelligent enough to track time and rate of recovery and know when it can shut down to avoid unnecessary overshoot. I'm just wondering if the tank in a tank design is fiddle faddling that part of the logic.

Any way, I KNOW I have a "box" of solutions. I'd just rather not defeat something I and the customer already paid for.

FWIW, Buderus Technical Support are an awesome bunch of guys.

ME

Dan_15

On my R2107 I have the high limit set to 190 and the DHW limit to 135. The controller seems to have learned over time how hot to run the boiler to satisfy DHW at different demands during the day. Sometimes it limits at 120 sometimes 140, it depends on how the controller feels about it. Bottom line, however, DHW always ends up at 135. Theoretically, a demand for DHW is supposed to override the reset curve and max out at the high limit for the boiler, if needed. Im also curious to know why yours shuts down much sooner.