confused by your second paragraph and not quite sure what I’m looking for! Apologies- novice plumber here 🙈
what I meant was where does outlet 2 on the control/pressure valve go. is it a) blocked off or b) going into a pipe. from one of the photos it looks like its into a pipe, but its really hard to tell from here! If into a pipe, that pipe should be the cold feed to all your taps / bath / etc - in which case your plumbing at least at that point is correct - in which case that is eliminated as a possible root cause of your poor-hot-water-upstairs. If there is a lever valve in that pipe, you can prove if its the cold feed to your taps or not really easily - temporarily close it and see if your cold outlets stop working.
I know its a pain but it would really help if you drew the pipework as a logical diagram. shapes and bends don't matter - only valves , junctions and major objects.
@derek-m there are 2 thermostats in the tank- the top 1 is linked to the Midea system, the bottom one (in the photo) I was told by the plumber doesn’t do anything?? Maybe this is the stat for the emersion… I can’t see anything on the immersion itself.
The Midea controller does seem to have an option for immersion but I was told by the installer they were not compatible!! So frustrating!
the immersion stat is underneath the white plastic cover for the immersion. Its usually a simple plastic rotary dial. something like this red one:
you MUST isolate the supply before taking that cover off as there will be bare live wires. however, so long as it is set to a suitable temperature for legionella, which it sounds like it is, you shouldn't need to adjust it . where does the electrical wire from the immersion heater go? does it go to a simple on/off switch ? in which case a quick fix is to replace that with a programmable timed switch - and your house builders electrician should do that for you. But it really ought to be able to be linked to the heat pump controller so that it can set the times, temperatures, and/or do an immersion boost (if you tell it to).
Exactly what heat pump is it? do you have photos of the controllers and their wiring? a link to the manual?
The other "white box" stat is intended for use when a gas boiler is heating the cylinder - it turns off the zone valve controlling the flow of heating water into the cylinder coil when the temperature on the dial is met. It also has a safety limit stat that shuts off flow (and will not come back on until reset by a human) at a higher temperature (90 ish). This is so that very hot gas boiler flow cannot accidentally heat a cylinder to the point that the cylinder water is approaching boiling, because at that point bad things start to happen. However in a situation where the cylinder is heated only by heat pump, and controlled by the heat pump's stat, this stat is redundant, heat pumps physically cannot heat a cylinder that hot. But it has a wire going out of it somewhere so its doing something. chances are it'll be wired with the switched power to the cylinder zone valve looping through it as that would match common practice if the person who wired it up was in "gas boiler" mode. you should be able to ask your plumber/electrician to remove it and remove its from the wiring loop - but make triple sure the cylinder heating still activates afterwards.
@iancalderbank thanks for the explanation! There is a lever at outlet 1 but not at 2… it does go into a pipe though, and the pipe splits into 2 and goes up. I will take some time and see if I can draw I diagram over the coming days!
@iancalderbank thank you. Yes- the immersion. Just goes to an on off switch at the moment.
I’ve attached some pics of the heat pump- didn’t get given a manual but was sent one by this forum 👍🏻
Hi Curly,
Do you know where the cable supplying the on - off switch for the immersion heater is supplied from? Can you provide a closeup photo of your immersion heater?
@curlykatie you may well find that the wire out of the bottom of the switch goes into the immersion heater in the cylinder - just follow the wire. in which case its a dead simple on/off switch. the quick workaround is to replace that on/off switch with an electronic programmable time switch designed for an immersion, which your electrician should be 100% able to do.
from a quick RTFM of the midea manuals that I've been able to find, they don't have a system for controlling a legionella cycle or connections for an immersion. but I could be wrong. this needs someone who actually has , or installs midea heat pumps to comment.
@derek-mphoto attached. The switch is on the wall and the wire just below (as attached) - I am not sure where this goes to…
Switch off the immersion heater at the wall switch, then using a small spanner remove the nut holding the cover in place. Underneath you should find the thermostat adjustment, which needs to be set to 65C or thereabouts as detailed in the link below.
@iancalderbank thanks very much. This is really useful, at least I know what to ask for now with regards to the immersion control. I really do appreciate everyone’s help 😊
@derek-m I’ve done as advised! I couldn’t see any numbers on the adjustment but it was on the max so I’ve turned it down a bit and will see next time I use it 👍🏻
Electrician has been and reconnected the wire he ‘accidentally’ disconnected at the weekend so we now have heating upstairs again! I will have a play over the coming days with balancing the system and weather compensation as advised previously and will update. thanks all!
@derek-m morning! I am just having a look at all the flow rates for the system as you advised. None of them are set to above 2 at the moment. Once I have identified the coldest rooms, am I aiming to have the flow rate to these rooms at the max of 6 and then adjusting the flow to the others accordingly? If I understand it right, I should then be able to reduce the flow temp on the weather compensation? Thank you!
