Cleaning Alpha 2 circulator by running at higher speed
The Alpha 2 circulator in my hydronic system typically ran 8GPM @ 9 watts when set at Constant Speed Level 1. The pump has been in the system for 4 years and the steady state flow had slowly decreased to 4-5 GPM @ 8 watts.
I set the pump to run in Auto Adapt mode and flow rate moved very quickly into 20+ GPM. I left the pump at this setting for several minutes and then reset back to Constant speed L1 and now the pump is performing at its out of the box 8GPM.
is this typical? I’m planning to add a step in my annual maintenance list to exercise the pump.
The system is a converted gravity system with two Caleffi DirtMags with the bronze body type positioned on horizontal line before the boiler and a plastic body NA545366 on vertical line after.
Comments
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I would not bet the farm on those readings. I have seen them vary quite a bit when checked against accurate flow meters or balance valves. The flowrate is a calculated number from the microprocessor, it does not have an actual flow reading device on those small circs.
Is it doing the job of keeping the heat on?
However, when they start getting magnetite in the rotor can, that can drag down the rpm. Iron pipe systems are suspect for ferrous debris flaking off into the fluid flow. If you can isolate the circ, remove and disassemble it for a look inside.
The DirtMag is a multi pass device, it can take 30- 50 passages to pull all the fine particles and magnetite out. So some can slip by when you first start up.
The Caleffi XF is a good option for old piping systems, or fine passageways HP and mod cons. It is a separator and Y strainer combined with a rotating collar attached to brushes inside, to wipe the fine debris out.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
Here are the steps for getting to the rotor to check and clean. This may not be a factory authorized fix! :)
The life of a wet rotor type circulator is directly related to the fluid they swim in, for their entire life. The cleaner the better
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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”Is it doing the job of keeping the heat on?”
Yep, all working well. Just curious re the displayed data on pump.
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Follow-up on this discussion; believe the flow rate is indicative of the status of the TRV across all the radiators. As TRV open and close, the head decreases/increases with corresponding change in flow rate at a given pump speed.
And yes, I have several radiators with TRV sensor locked open to ensure minimum flow rates are maintained through the boiler.
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Is the boiler piped primary secondary or with a hydraulic sep? If so you should not need to lock TRVs open to keep flow moving. With all TRVs closed the Alpha will go into an "idle" mode where it barely spins just to get a reference point, around 7W.
Is the Alpha switched on by a relay box? Caleffi ZCR and some others have an exercise switch to run the pump.
The gpm readout is based on power consumption, rpm, and the calculations by in the computer, as I understand it.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1
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