Any advantage for using ALPHA2 over ALPHA1 if zone valves are kept open?

sunlight33

I have a Vitodens 200 with ODR and indoor temp feedback (via Vitotrol 300), two-zones baseboard heating with zone valves open all the time. Not sure if the Autoadapt can provide any benefit, so is ALPHA1 good enough?

SuperJ

The main benefit of an ECM circulator for you will be the reduced energy consumption. Just pick the best fixed speed or pressure setting to work for you, no need for autoadapt if nothing is changing.

sunlight33

Got my pump today, is it okay not to install the check valve? The shaft has a vertical orientation with the flow direction pointing up.

SuperJ

The shaft (or motor) should always be horizontal to prevent air buildup in the pump. The outlet can be horizontal or vertical.

Typically you need a check valve if you multiple pumps in parallel (like multiple zone pumps). For a primary pump, or a system with a single distribution pump you may not need the check valve.

sunlight33

Thanks, I will leave it out since it's one pump with multiple zone valves.

NY_Rob

If you have an indirect tank with it's own pump you may need that check valve...

sunlight33

It should be fine, this pump has been on 24 hours a day from October to April each year.
Now I am having fun testing out the autoadapt.

SuperJ

If you are running it in auto adapt it takes a couple days of heating cycles to adapt.

sunlight33

Thanks for the reminder, I will see how it performs during the cold snap tomorrow night, otherwise I will change to constant pressure 1.

sunlight33

Is it true that as soon as power is lost autoadapt is back to square one once the power is restored?
Also regarding the GPM number, has anyone compared it with an actual flow meter?

NY_Rob

sunlight33 said:

Also regarding the GPM number, has anyone compared it with an actual flow meter?

I have using differential pressure... at all speeds the Alpha under-reported GPM. FWIW- the pump curve chart was fairly accurate though.

Gordy

Yes the auto adapt has to readapt after power failure.

The gpm readout is not accurate.

SuperJ

Gordy said:

Yes the auto adapt has to readapt after power failure.

The gpm readout is not accurate.

I disagree with it has to readapt after a power failure. Grundfos says if you kill power or change modes, and then return to AutoAdapt it will basically pick up where it left off. Whatever learned parameters it has are stored in non-volatile memory.

I suspect the pressure or lack of check valve might affect the GPM readout. I have a hard time believing mine is under reporting GPM, based on my temp delta and boiler runtime I would guess it's over estimating significantly (I have a check valve installed in the pump). If the GPM was accurate my boiler would have to run a lot more to make up the BTU's. My system typically runs between 2-4gpm as indicated on the Alpha, but I often have a 30-50degF delta across my supply and return (panel rads with TRVs). My return stays pretty close to 100degF no matter how hot my supply gets it seems. My 100kbtu (input) boiler rarely runs more than 15-20% max duty cycle to maintain temps.

Gordy

Depends on how long the power is out. Unless they changed something. He has the alpha 1 no? which doesn’t have autoadapt.

I believe the memory is good as long as there is constant power.