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Replacement Power Head for Taco 556-G2/G3, 557-G2/G3 and 5101-G2/G3 Geothermal Valves
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MANUALS (2)
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Product Highlights
Description
Key Features:
- OEM Taco replacement power unit for 5101-G2 series mixing valves
- Self-contained power head that drives the valve mechanism in response to control signals and temperature feedback
- Factory-assembled housing with internal motor and linkage designed to mount on the existing valve body
- Allows service replacement of the actuator while retaining installed piping and valve connections
Compatibility & Applications:
- Intended for use with Taco 5101-G2 mixing valves that specify 555-173RP as the correct power unit
- Used in hydronic and domestic hot water applications where the mixing valve provides controlled outlet temperature
- Suitable for residential and light commercial systems that rely on 5101-G2 valves in radiant, space heating, or domestic hot water tempering applications
Installation & Operation Notes:
- Isolate the mixing valve from system pressure and shut off electrical power to associated controls before servicing
- Follow Taco instructions for removing the existing power unit from the 5101-G2 valve body
- Install the new 555-173RP power unit, making sure the actuator is correctly engaged with the valve stem and that mounting screws are securely tightened
- Reconnect wiring according to Taco diagrams, then restore power and system operation
- Verify that the valve responds properly to control changes and that outlet temperature tracks the setpoint over several operating cycles
Maintenance & Troubleshooting:
- Replace the power unit if the valve fails to modulate, does not respond to control signals, or if the actuator housing shows signs of damage or overheating
- Inspect associated control wiring, thermostats, and sensors if issues persist after installation of a new power unit
- Periodically check the mixing valve system for scale or debris that could affect valve travel, which in turn can increase actuator load
Specs
| Voltage: | 24V |
|---|---|
| Position: | Normally Closed |
| Application: | Replacement Part |
| Used With: | 556-G2 Zone Valve 557-G2 Zone Valve 5101-G2 Zone Valve |
Questions?
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Product Q&A
3 QuestionsQ: Is this head a replacement for my 557-G3 valves?
Asked by Robert 10 years ago
Add your answer
Verified Reply- SupplyHouse StaffYes, the correct replacement head for the 557-G3 is SKU:555-173RP.
Q: What is the warranty time frame for this valve? I too have had multiple failures of this valve. My current application has this valve mounted horizontally on vertical pipe and I have replaced 3 valves in the last 2 years.
Asked by Anonymous 14 years ago
Add your answer
I've had this valve for over 2 years with no problems. However, it is mounted vertically. I'm wondering if your horizontal mount is contributing to the problem?
Don't know if it has any sort of warranty ... I would suggest the valve be mounted on a horizontal pipe run with the power head on top so that any possible leakage from the valve has less potential to allow moisture to get to the power head.
I can , It looks familiar. Mine are mounted horizontally. I don't think it makes a difference. Mine are on three water source heat pumps. I have never asked about a warranty. I usually can get two years out of the solenoid part of the valve. The brass valve itself last a lot longer.
I am not sure on the warranty on this product. I have two of these installed in my house (also horizontally on vertical pipes) and have replaced only one of them once in the 9+ years I have had them in service. I do keep an extra on hand though just in case.
This is only the second failure I have had. I do not know what caused it. In fact, I am not really sure that the valve I replaced is bad as I have the feeling my system is not sending the proper signals to it. Overall, I have had good luck with it. Make sure you are getting the proper voltage and also make sure that the valve itself moves freely and is not mucked up with calcium or iron. Tony
I suspect the valve should be mounted vertical.I used one maybe 15 years mounted vertical,just installed one horizontal and had problem in two months.Hitting the valve caused it to allow compressor start.Have turned valve to vertical position and put a few drops of oil on plunger.Time will tell.
Q: Hi! What is the difference between this power unit and the Zone Valve Power Head (Series 570)? I am having a high failure rate with this power head and am looking for alternatives.
Asked by Anonymous 14 years ago
Add your answer
Verified Reply- PexSupply StaffThis is the power head for Taco's geothermal/open system zone valves. Unfortunately, heads for different series cannot be used interchangeably.
It depends on what is causing the failures, mechanical or electrical. In any case though, this valve is for geothermal applications and has a special "slow-closing" actuator required in geo applications. Are you using it for heating water? That might cause a problem.
They are one in the same ... I too had lots of problems with this power unit and I've replaced it about three times in the last 8 years or so. Eventually I replaced the valve along with it and I hope that fixes the root of the problem. Thinking the valve packing may have experienced leakage at times leading to moisture in the power head and failures.
There are several versions of the Taco valve. The one I currently use to control water input for my geothermal furnace is 555-173RP. I suggest not using any version that does not specify that it is for geothermal use. Other versions that I have tried have failed in a year or less. This one has so far worked fine for a year and a half (knock on wood).