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Tim JA
Tim JA, HVAC Technician
Category: HVAC
Satisfied Customers: 2626
Experience:  Owner at Self-employed
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I have an underfloor heating system with 6 zones controlled

Customer Question

Good afternoon, I have an underfloor heating system with 6 zones controlled with TP 7000 units. They were installed in 2006 an 2 now need replacing. They are powered by 2 x AA batteries and are wired with a 3 core and earth cable to a control box. Could you please suggest a suitable replacement?
JA: Have you replaced parts of your central heating system before? If so, how long ago?
Customer: no, the system is run from a thermos tore boiler
JA: How long has this been going on with your Core central heating? What have you tried so far?
Customer: I have come to replace batteries and check each zone and contacts in 2 of the units have suffered corrosion from the batteries and broken
JA: Anything else we should know to help you best?
Customer: just want to find a replacement zone thermostat that I can fit to the existing cables
Submitted: 11 days ago.
Category: HVAC
Expert:  Tim JA replied 11 days ago.

Good evening, and welcome to the Technical section in JustAnswer, an independent paid question and answer platform that matches customers' questions to experts in various skills. My name is ***** ***** I'll be happy to help you today.

Please can you tell me, for each TP7000, which three terminals the 4 cores are connected to?

Customer: replied 11 days ago.
There are connections to com, heat on, heat off and earth
Expert:  Tim JA replied 11 days ago.

Please could you also tell me the terminal numbers.

Also, is the wiring the same for each TP7000?

Customer: replied 11 days ago.
Unfortunately I am at work now so cannot confirm. However, there is a sticker above the terminal block detailing com, heat on etc and from memory, there are only 3 connections
Expert:  Tim JA replied 10 days ago.

OK. Subject to you discovering anything different with the second TP7000, the good news is that there are lots of options. In each case you need a battery-powered "two-wire" thermostat. If your UFH controller makes use of that signal, then you will have to choose a thermostat that provides it. For example, the direct replacement for the TP7000 is the TP7001.

If you don't need to connect "HTG OFF", then I personally don't favour Danfoss thermostats - they seem to have a short lifespan. The first product that I would suggest is the Honeywell TP4. With this you would just park the spare conductor in a terminal block, to make it safe.

When you come to connect the new baseplate, please ensure that the power to the heating system is off ,

BTW you could use this opportunity for a grand upgrade to a "smart" system that offers Internet-based control over your system.