Upgrade from PM2+ to PM5. Worth the £150 ($215)?

[Carl Watts]

The PM2+ is a great monitor, still got mine from 2001.

As long as the batteries never leak in it, then its always 100% repairable and the repair is simple due to the packaging used by the semiconductors on the board like PLCC and SOIC.

Later models moved to BGA and other very difficult components to replace, the type of components you see on your computer DRAM. When I have sticks of RAM fail I just throw them in the bin and put in a new one.

[Edward4492]

I'm an HVAC Tech Support advisor by trade. Nest thermostats are problematic unless there is a common wire connected. Nest will tell you they don't need a common wire. For consistent operation in all applications they do. If you have just two wires from your boiler connected to "R" and "W" on the Nest there is a potential for issues.

[sticky]

I'm an HVAC Tech Support advisor by trade. Nest thermostats are problematic unless there is a common wire connected. Nest will tell you they don't need a common wire. For consistent operation in all applications they do. If you have just two wires from your boiler connected to "R" and "W" on the Nest there is a potential for issues.

How would the lack of the common wire manifest itself with the Nest, i.e. what sort of issues would it cause.

The specific issue I have is as follows:
After the Nest set temperature is reached, the boiler continues to run the central heating. If I pull the plug between the diverter valve motor and the heat-link, I see the diverter valve move from M to W and the boiler switches off. It then comes on again as normal when the temperature drops. What part, if any, does the diverter valve motor play in informing the boiler to turn off? I assume the Nest tells the boiler to switch off once the room temp is reached, and the boiler then tells the Dirverter motor to return to default. Does the diverter motor have to say to the boiler "all done, you can power down now"?

Sorry if my assumptions or questions are stupid, clearly I'm not a heating engineer. I've had a plumber around already, and then a Nest Pro engineer, and so far no one can diagnose the fault. And I have another plumber around on Thursday.

[Citroen]

Please keep on-topic or this thread will be locked.

Discussions of mains wiring to Nest thermostats is a subject for an electronic forum, not an indoor rowing forum.
https://nest.com/support/article/When-N ... mon-C-wire
https://nest.com/support/article/How-to ... mode=guide

[sticky]

Please keep on-topic or this thread will be locked.

Discussions of mains wiring to Nest thermostats is a subject for an electronic forum, not an indoor rowing forum.
https://nest.com/support/article/When-N ... mon-C-wire
https://nest.com/support/article/How-to ... mode=guide

I apologise, I did try sending a Private message, but it sat in my outbox, I have no idea why it did not send.

[Citroen]

I apologise, I did try sending a Private message, but it sat in my outbox, I have no idea why it did not send.

A PM shows as sent only when the person you're sending it to opens it.

[Edward4492]

Sticky, please email me at:
edwardpeterson@hotmail.com
I'll give a detailed explanation. Sorry for the off topic stuff.