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Bosch outdoor temperature sensor parts?

condenseit Member Posts: 20
edited December 2019 in Thermostats and Controls
I have a Bosch Greenstar 151 wall mounted combi boiler and my contractor put up and wired in an outdoor temperature sensor.
The brand new sensor mounted to my home is a Bosch part number 6 720 649 714, which is on its own and not connected to any wires reading at:
40F = 22 kΩ resistance
50F = 17 kΩ
70 F = 7 kΩ
The sensor I have is shaped like a hexagon.

I bought a used Bosch Greenstar FW200 Weather Compensation Boiler Control (87182262150) to work with the outdoor temperature sensor. The seller did not send the paired outdoor temperature sensor (shown in pictures below on his house). The FW200 is expecting to read temperature as resistance from sensor part number 6 720 610 967-10.2j and although there is not an expected resistance table in the FW200 documentation, my Bosch Greenstar 151 (ZWB42-3A) manual in Table 16.4.1 on page 59 says the outdoor temperature sensor resistances should be at:
-4 F = 2.392 Ω
10 F = 1.811 Ω
32 F = 1.149 Ω
50 F = 781 Ω
The expected sensor housing is shaped like a little house (Figure 15.1).

Where can I get the proper temperature sensor as the one I have appears to be reading resistances 20X to high?
The sensor in my housing is shaped like a wishbone with a single small element at the top.
Are these two sensors different other than the shape of the housing?
Can someone please help me find a part number for just the thermo resistor somewhere and not just the whole unit?
I believe I will be able to put the sensor element in the enclosure I have mounted.

I am calling Bosch on Monday to try to get the answer to this question, but any input is great appreciated.


  • condenseit
    condenseit Member Posts: 20
    From Bosch today !

    These sensor are both different

    Top one is 10K at 77 degrees F is for Buderus boilers and controls

    The bottom on for FW200 is a 4K sensor which comes with the FW200 part number 87472071010 for the outdoor sensor

    Senior Technician, Boilers/Controls (TT/ASA12-NA)
    Bosch Thermotechnology | 50 Wentworth Ave. | Londonderry, NH, 03053
    Tel. +1-800-283-3787 | ldy_tsbuderus@us.bosch.com