ESi Electronic Hot Water Cylinder Thermostat – ESCTDE/B – Part 1

UPDATED -27 April 2022

Background

In order to save energy and better regulate the temperature of my domestic hot water in my Santon Premier Plus unvented cylinder, I decided to install a ESCTDE/B Electronic Dual Cylinder Thermostat manufactured by ESI Controls, I bought online from PlumbNation.

box

Installation

The ESCTDE/B has two thermisters, one for the temperature reading and control, the other is for over-temperature trip and is set for 80℃, I must have a big problem if this operates as my boiler output temperature is set to 68℃.

thermistor

Fortunately the Santon Premier Plus has a spare dry thermostat pocket which the thermistors are a perfect fit.

pocket

I marked the location of the thermister pocket on the outside of the cylinder cover and offered up the ESCTDE/B back-plate and marked the centre hole.  I’m not sure what the ESCTDE/B is specifically designed to fit, but the rear fixing was perplexing and I didn’t want to modify the casing of the unit in case I invalidated the warranty.

back
Rear fixing arrangment

I used a cut down 20mm Female Adapter as a center bush, this was cut to size and fixed to the front cylinder cover.

bush
20mm Female Adapter
bush
Cut down female adapter used as a through cover fixing method.
bush
Fixing bush installed.
bush
Inside cover showing bush and thermostat pocket.

ESCTDE/B fixed to the bush with the three back-plate screws and as the female adapter has a serrated edge, it holds very well, the existing cylinder thermostat was turned up to position 5 which is 72℃, I have left this in circuit as another backup to over-temperature, as mentioned earlier, my boiler output temperature is set to 68℃, so only under a fault condition should this protection operate.

fixed
Indirect temperature setting and top view of fixing to ESCTDE/B.
Cover
Thermistors sliding into cylinder pocket.

Connections

NOTE – The mains supply to the ESCTBE/B MUST be from the same source as the heating systems programmer, this will ensure that there is only one point of electrical isolation for safe working.

I used 1mm 4 core and earth from the ESCTDE/B to the heating connection box, the ESCTDE/B does not have an earth connection, so this wire was parked, the unit requires a permanent 230v feed, the temperature calling relay changeover contacts are NOT volt free, although they are simply wired in series with the existing cylinder thermostat.

If the Legionella setting is active on the ESCTDE/B, the unit will automatically switch 230v to the Domestic Hot Water motorised valve (NOTE- this overrides any programmer settings), which in turn will bring on the heating, the output from the ESCTDE/B will remain on for 1 hour when the tank temperature is above 61℃.

As the bending radius of the connecting wires within the unit is quite tight, I used ferrules on the end of the wires, this ensures that no ‘whiskers’ can cause problems later.

wire
Ready for wire stripping.
wires
Insulation removed and conductors twisted.
wire
Bootlace ferrule pushed on.
wires
Bootlace crimped and job done.

Conclusion

Finished installation all working, as my hot water system is directly fed, (no header tank), I did not need to enable the ‘disinfection mode’, this mode increases the water temperature to 61℃ for 1 hour to kill Legionella, however, as the feature exists, I set it to activate once per week.

finished
We had been away for a few days hence the water temperature was showing 21℃, the unit was initially set for 48℃ and the Red LED shows the cylinder is calling for heat.
finished
Picture showing wiring from ESCTDE/B to heating terminal box and the tank temperature now reached the set-point of 48℃.

Problem

Apologies for not updating this blog and a recent comment made me revisit this, so thank you.

I have decide to make a Part 2 to the ESi showing how I addressed the problem of the the heating coming on outside of the scheduled time due to the ‘legionella’ setting being on.

Part 2 is HERE.