Issue with Air to Water system.

Tar.Aldarion

Moved into a new A2 rated house with underfloor downstairs and rads upstairs. I turned on the stats upstairs and downstairs (1 stat upstairs, 2 stats downstairs for some reason) and no heating was happening at all. No matter what I set the stats to the temperature would climb to that number and the boiler would stop being pulled, but nothing was being heated at all, apart from the boiler - and always have hot water too. So firstly, what are the sensors measuring if they think the rooms are hot everywhere in the house when it is absolutely freezing everywhere? Three thermostats saying the temp is rising when nothing is changing?! Then I turn the stats to a lower temp, they stop pulling the boiler, and the stats say the temp is lowering, all the while no temp has changed anywhere.

After 5 days of no heating noticed that the underfloor suddenly was heating. Boiler company came out and were quite confused as it seemed the underfloor controls downstairs were pulling the upstairs heaters and upstairs was pulling downstairs they thought this as the upstairs stat turned on the underfloor heating system in the utility room downstairs - so their theory was that downstairs heated first and turned off upstairs, so they swapped some electrics at the boiler as a hack to make them pull the opposite way.

This has led to only upstairs heating from the downstairs stats with the underfloor system turning on to heat upstairs somehow in the utility and downstairs not heating at all, so they shouldn't have swapped them. So while it is warm upstairs in the bedrooms downstairs is icy now instead. Still the mysterious heating sensors are climbing and lowering without much change of temp in these rooms and the boiler seems to be heating these rooms most of the time, this week electricity is over €100 from heating alone, which is crazy.

I finally also figured out that if I try to turn on upstairs and downstairs at once, they are both pulling with a hot boiler but there is no heating happening at all at the rads or the underfloor, so that is likely why for the first 5 days there was no heating at all, then the upstairs one turned off (it goes to "off" on the stat sometimes all by itself) and then downstairs must have started heating. As to why upstairs turns on the underfloor system downstairs I have no idea.

The boiler company said they'll come out again but don't really know what's happening as of yet and may send an electrician too. Anybody have any idea? Driving us mad.

Boiler is this https://coolenergyshop.com/products/cool-energy-ecostore-ce-es300-all-in-one-heat-pump-hot-water-system

Stats are E91's, no idea what brand: Look similar to this: https://i.imgur.com/wDAGVlF.jpg

Tar.Aldarion

Here are some pictures of the system:

https://imgur.com/a/gsA3CAz

And here is what somebody on Reddit thought about the system today:

"Ok, so all the piping associated with the red expansion tank, serves the upstairs rads and the underfloor heating. All the piping associated with the white expansion tank, is for domestic hot water. The HQ400 pump on the ground, is a booster pump, for showers and taps. There are two zone valves at low level, to the left of the red vessel. I assume one serves the upstairs rads and the other serves the UFH manifold station, on the ground floor. These valves open on a call from the relevant stat, during a demand for heating.

This is the closest image I could find to your system set up, for the rads and underfloor heating, except your buffer and heat pump are combined into one unit. If the central heating system is piped like this, and it looks like it is, it's never going to work properly, with both zone valves open. You never pump "into" an underfloor heating mixing valve. In my opinion, the hot inlet to the UFH mixing valve, should be connected to the suction side of the primary pump.

https://cdn.shopify.com/s/files/1/2612/5402/files/Heating_Only_-_Underfloor_Radiators.png?v=1600765772

I believe this is why you can't have both zones on simultaneously. I'd contact the owner if i were you, and inform him that the central heating side of the system has not been plumbed correctly, unless the system is designed to provide heat to only one zone, at any one time, which is very unusual and obviously not ideal, when it's -2 Deg C outside.

BTW, that temperature reading on the stat is the temperature set-point, not the actual reading, from the room. In any case, the system would never reach 28Deg C. It's not sized to do that. It's typically only sized for 20-22 Deg C."

to which I said:

"Thanks so much for the info. The markings on the wall indicate that one is for UFH and one for rads yes, when the boiler technician saw that the stat upstairs called the valve to open yet the UFH manifold turned on downstairs he swapped around the electrics for calling those valves assuming it would solve the problem, which led to the swapping of issues, and upstairs working instead.

I don't really get where the issue is in my pipes vs that diagram due to not knowing the terminology but perhaps showing the engineer this info may help during the week.

As for the stat temps, here is a picture of mine now, I manually set the degrees desired and the other value changes accordingly, seems there is a one degree buffer either side for turning on and off, but it does look like it's supposed to be the current temperature E.G. I set it to 19C here and it's gone up to 18.8C with no actual temperature change. https://imgur.com/a/bQBBksx So unsure how it's actually deciding when it's hot or not, and seems to just guess.

Pulling boiler -> degrees go up slowly. Not Pulling boiler -> degrees go down slowly. -> Ambient temperature never actually changing.

That stuff doesn't matter as much anyway as long as I can actually get the heating on and off reasonably.

I'm the owner now, and while the developer said that he would fix anything before the sale, after the sale he told me to feck off. And of course there is also a shower leaking to the ceiling below which I'll have to deal with too."

Any other thoughts welcome!

Furze99

Good luck with it, I think these systems are beyond most competent DIY plumbers. Bit like the way car engines have gone.

Do know someone with a ground source heat pump and in weather like this, they have to light a stove.