Megaflow and insertion sensor

[londonbairn]

What is the best way to put the insertion sensor in without hacking off the casing etc?

Has anyone else did similar?

[top brake]

please refer to a Honeywell Connected Specialist

unvented cylinders should only be worked on by certified professionals

[londonbairn]

I will be using someone who is a specialist but I want to know in advance what others have done and what is best practice

[HenGus]

I am not familiar with MegaFlow unvented cylinders; however, my Oso unvented cylinder has the sensor fitted as follows:

1. Access via the electrical panel.

2. Probe inserted against tank by pushing it up to the desired height.

3. Probe lies against the cylinder and held firm by foam and tape.

4. Evohome temperature set below tank stat, and top limit safety stat working in series. If Evohome fails then tank stat will manage the temperature with the top limit as the safety fallback.

Ovo suggested this as their preferred solution for my tank model. Have you contacted Megaflow Support?

[Fursty Ferret]

I disconnected and isolated the immersion heater probe and inserted the temperature sensor down the hole instead. The hot water relay is then wired in series with the existing dual stat set to its maximum temperature as overheat protection only. The chap that came to service the boiler agreed that none of the above required certification as the wiring consisted of replacing an existing unit and the cylinder stat remained untouched and in service.

Honeywell also recommend that the micro-switch output from the motorised valve is wired through the dual stat in case the contacts weld closed or the valve sticks (both of which are fairly common and entirely defeat the point of a dual thermostat anyway).