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Kit-S Thermostat, AcuTemp, 633-600-012
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$148.50 each
In Stock
Get 14 Tue, Jul 7
Order by today, receive Tuesday
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Product Highlights
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35 Model, 45 Model, 55 Model, 85 Model
Description
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Weil-McLain 633-600-012 Kit-S Thermostat, AcuTemp
A Weil-McLain AcuTemp thermostat repair kit (control + sensor) used to control and monitor tank temperature on compatible Weil-McLain Aqua Plus/Aqua Pro indirect water heaters when the specified replacement kit is required.
Key Features
Compatibility & Applications
Installation & Operation Notes
Maintenance & Troubleshooting
User Reviews & Q&A Summary
A Weil-McLain AcuTemp thermostat repair kit (control + sensor) used to control and monitor tank temperature on compatible Weil-McLain Aqua Plus/Aqua Pro indirect water heaters when the specified replacement kit is required.
Key Features
- Thermostat repair kit that includes a control and a sensor
- Listed as used with 35 Model, 45 Model, 55 Model, and 85 Model
- Weil-McLain describes the AcuTemp as a microcontroller-based temperature control that monitors tank temperature change rate and controls the heat source to minimize temperature fluctuations while optimizing fuel efficiency
- Control features adjustable temperature settings for residential and commercial operating ranges
- Control input rating listed: 24 VAC, 60 Hz (with dry-contact output)
Compatibility & Applications
- Listed for 35/45/55/85 models on the SupplyHouse product listing.
- Weil-McLain parts catalog lists this as a thermostat repair kit for Aqua Plus Series 2 indirect water heater models (example: "Water Heater - 45" parts breakdown).
- Must only be used where the manufacturer specifies this exact part number: 633-600-012.
Installation & Operation Notes
- All work must be performed by a qualified and licensed professional and in accordance with applicable codes.
- Disconnect power before installing or servicing the control (electrical shock hazard).
- Follow the AcuTemp Installation Instructions and Operating Manual and the tank manual for mounting and wiring details (including 24 VAC field-supplied power and wiring to the boiler/zone control's domestic-water input).
- Manufacturer safety note: Scald hazard - exposure to 125°F or hotter water can cause scalding; the manufacturer states a mixing valve should be installed where point-of-use temperatures are 125°F or higher.
- The control's displayed value is described as an approximate temperature; the manufacturer suggests 120°F as a typical starting point and testing at the closest point of use for final adjustment.
Maintenance & Troubleshooting
- The AcuTemp instructions include built-in diagnostics:
- Sensor Error: sensor resistance out of range - check the sensor connection; if the connection is good, the sensor may need to be replaced.
- Self Test Error: internal hardware/software test failure - try cycling 24 VAC power; if it does not clear, the control should be replaced.
- If delivered water temperature is not matching the setpoint closely, follow the manufacturer's guidance to verify at point of use and adjust, and use a mixing valve where needed for final outlet temperature control.
User Reviews & Q&A Summary
- Digital upgrade / improved stability: Multiple reviewers describe replacing an older analog thermostat and reporting the newer control holds temperature more steadily and works well after installation.
- Power requirement note: Reviews mention the digital-style control may require 24V power; some users report it was easy to wire because a 24V transformer was already present.
- Shipping/service: Frequent comments highlight fast delivery and strong customer service.
- Q&A theme: One question asks if the kit includes the AcuTemp control; the verified response confirms it includes the control and the sensor.
Specs
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| Used With: | 35 Model 45 Model 55 Model 85 Model |
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Contact
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Product Reviews
4.73 out of 15 reviews
100% would recommend this product
5 star
87%
4 star
7%
3 star
0%
2 star
7%
1 star
0%
Most Liked Positive Review
Great service!
I bought and installed the analog thermostat to replace the same original that had failed. But it lasted less than a month. Perhaps an electrical storm shorted it out? In any case unit was constantly calling for hot water. I called SupplyHouse who asked I call Weil McClain to get a service person to approve a warrantee replacement. The WM person recommended I replace it with a digital version of the thermostat for my indirect water heater. Supply House sent out the digital version of the thermostat at no cost to me which was nice because it's an upgrade. I didn't expect that. I installed it and it's working as expected. Note that you will need to power the digital thermostat but my burner already had a 24v transformer set up so all I needed was to add the wiring to the thermostat. Piece of cake.
VS
Most Liked Negative Review
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replacement thermostat (replaced under warranty)
This was replaced under warranty by supplyhouse's excellent customer service team. The original unit with my weil mclain indirect water heater was set to 120 degrees and i was getting 147 degrees out of the faucets. turned down all the way to 95 degrees and still got over 140 deg water at faucet. Installed new thermostat and sensor and set to 120 degrees and still getting 145 degree water out of faucet. Guess I will be installing a mixing valve to be able to get a better adjustment on my hot water temp. In my opinion, the temp should be somewhat accurate with thermostat (I understand it does not need to be exact, but it should be closer to the set temp than what I have gotten with the old or the new thermostat). I would only recommend this due to it is what the mfr calls for and I dont know if you have any other options. Just need a mixing valve for final temp output adjustment.
Showing 1-10 of 15 reviews
I'm sure that I will buy this product again
SupplyHouse ROCKS! I ordered this part on Thursday night and received it on Saturday. In May 2026 I paid $18.00 less for this part than I did in July 2025, the price is unbeatable on the internet I installed the water heater in Aug 2021 and the RTD temp probe failed July 2025. This time the 24V transformer, temp control module and RTD temp probe failed. What am I doing wrong?
Elamcup
Kingsville Md
30 days ago
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Our 5 year old water heater is on the third AcuTemp?
SupplyHouse rules! The new Acutemp delivered in less than 48 hours on a Saturday and the unbeatable price is lower than it was 1 year ago. I installed the water heater in August 2021, the tank temp probe smoked in July 2025. This time the transformer, controller and temp probe all smoked. I have gotten pretty good at changing out temp probes. What am I doing wrong!? Hopefully these kits will continue to get cheaper because I have a feeling that I will be buying more.
Elamcup
Kingsville in the land of pleasant livin
1 months ago
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I would buy this product again
It was easy to install and works great
Mike
New york
1 years ago
Verified Buyer
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i would, but shouldn't have to
this is the second one that i bought in around a year, they should not fail this fast.
jim O
Thompson CT
2 years ago
Verified Buyer
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Would buy products fro this company
Recieved the thermostat for Weil MacLaine indirect water heater in time and worked perfectly. Excellent and very simple installment instruction was included. Thanks
Hashim
MD
2 years ago
Verified Buyer
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Great Upgrade
The thermostat went out of my older Weil-Mclain Aqua Plus 45 water heater with the large thermostat dial. Included instructions are very simple for upgrading to this digital one. Only need a 24 VAC circuit wire added for my unit.
Joe
Pennsylvania
3 years ago
Verified Buyer
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I would buy it again
Used it to replace mechanical thermostat in aquaplus water heater. Nice upgrade .
Eli
NJ
4 years ago
Verified Buyer
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i will buy again when needed
exact replacement, replacement was easy
Ken
MD
4 years ago
Verified Buyer
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I wanted a spare unit in case of problems
Fast service and the correct part as ordered.
curley
Port Clinton OH
4 years ago
Verified Buyer
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Super fast shipping/delivery
Ordered on a Saturday and had product in hand by Tuesday evening. The product was as advertised and was what I needed for replacement part.
Jd
PA
5 years ago
Verified Buyer
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Product Q&A
1 Question1 Question
Q: Does the subject item include the AcuTemp control 2000WM
Asked by Mark 9 years ago
Add your answer
Verified Reply- Supplyhouse StaffYes, it includes the control and the sensor.
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