Question 1

I need a thermostat to show the tempereture of the hot water tank. It will consist of sensor wire 3 meters and an indicator to see the tempereture in

Accepted Answer

These units do not have a gauge attached. They are strapped on with an 'elasticated wire  and make contact with the cylinder by cutting a suitable hole in the insulation. I'd think that there may well be a suitable gauge out there somewhere. I could do with one myself actually so I'll have a look on 'google' By the way I'd go for one that does not need to be powered and works on contact.

Question 2

why are there no screws to undo to hold the cable?

Accepted Answer

The unit comes with a flexible tie (same as that used for net curtains) that goes around the cylinder. This tie has hooks and the thermostat has eyes. Thus the hook and eye system keep the unit tight to the cylinder. Make are that the thermostat has metal to metal contact so that it can register the temperature of the hot water.

Question 3

Why does this say 2x AA batteries required, this should be mains?

Accepted Answer

100% no batteries required it is hard wired into your heating / hot water junction box.

Question 4

I have  potterton ptt2 water cylinder thermostat with sensor which is obsolete now . would this honeywell l641a1039 be ok as a replacement

Accepted Answer

The Potterton PTT2 is not a conventional Cylinder Thermostat as it’s wired externally to the Tank with it’s own temp sensor. Sadly as you mentioned it’s now obsolete. The only option (if you can’t find another PTT2) is to replace it with a terminal box with heat resistant flex outlet to the new stat. Up to 3 wires from the original PTT2 will need to go to the new stat, new stat instructions will confirm it.

Finally the live wires will then be redundant and will require to be either terminated or spurred to a new useful output (plug socket box, a lamp etc)

Please ensure a qualified electrician does ANY electrical work or changes in your home heating setup.

ASIN	B003DTIWGO
Backlight	No
Best Sellers Rank	47,331 in DIY & Tools ( See Top 100 in DIY & Tools ) 64 in Thermostats 5,090 in Electrical
Brand Name	Honeywell
Colour	White
Connectivity Protocol	Wi-Fi
Connectivity Technology	Wired and Wi-Fi
Control Method	Touch
Control Type	Button Control
Controller Type	knob,manual
Customer Reviews	4.6 4.6 out of 5 stars (772)
Display Type	manual
Finish Type	Mixed
Global Trade Identification Number	05023220200093
Included Components	Cylinder Stat
Item Type Name	Cylinder Stat
Manufacturer	Honeywell
Manufacturer Part Number	L641A1039
Material Type	Plastic
Model Name	Cylinder Stat
Model Number	L641A1039
Mounting Type	Surface Mount
Number of Batteries	2 AA batteries required.
Number of Items	1
Power Source	AC
Product Style	Modern
Special Features	Manual Setting Knob, Tamperproof Temperature Setting
Specific Uses For Product	Indoor use only
Temperature Control Type	Manual
Unit Count	1.0 count
Voltage	230 Volts

Honeywell Cyl Stat L641A1039

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