Floor heating not working, any ideas?

d4n1

Hi all,

I recently moved in this apartment, built in 2013, which has floor heating.

When I first visited the apartment (a month before moving in) the heating seemed to work fine (it was actually so warm I was sweating inside).

After I moved in, I noticed the heating is not working well at all. Specifically:

1. The main living area (~45sqm) is controlled by a master thermostat, and despite the temp I set, I get max 21c,
2. Same living area seems to have uneven warm areas on the floor,
3. Two bedrooms are controlled by a different thermostat system, which only open the valves on the return pipes (so they seem tied to the overall temp set by the master thermostat in the living area)
4. Master bedroom floor is cold, despite the thermostat being cranked to the max,
5. Smaller bedroom floor is lukewarm, despite the thermostat being cranked to the max.

Called the landlord's contractor for looking into it, but all they said was that the system is supposed to be working, and that it just takes time for it to warm up.

After 3 days of thermostats set to max, nothing has really changed.

Here is the setup:

From left to right, the return pipes are:

1. Cold-ish (Living room 1)
2. Lukewarm (Living room 2)
3. Cold (???)
4. Cold (Bedroom 2 — I suspect Master Bedroom)
5. Cold-ish (Bedroom 1 — I suspect Second Bedroom)
6. Lukewarm (Bathroom)

The pipes here seem to be numbered as such:

1. Supply heat
2. Supply cooling
3. Return heat
4. Return cooling

I have no idea what's the possible issue - any guess?

I mentioned the possibility of some air in the pipes to the contractor, but he said it's not possible since it's a closed loop.

Also worth mentioning: previous tenant told me they never really turned on the heating in the bedrooms in 6 years, so I can't tell if it has ever worked or not.

Any lead is really appreciated, yours truly here is not faring well with the cold and humid Netherland winter.

Cheers!

Jamie Hall

Contractor has a point: there shouldn't be air in the system. That, sadly, doesn't mean there isn't.

Ideally you or your plumber would be able to find a way to isolate each loop and purge it — at least 20 litres per minute flow — until no bubbles were seen in the outflow. Not sure if I see a way to do that…

neilc

feel the floor tubes with your hand,

are they hot? warm? cool? cold?

same up top at the feed and return,

hot? warm? cool? cold?

d4n1

https://forum.heatinghelp.com/discussion/comment/1834131#Comment_1834131

Supply tubes are all warm (~30-40c as expected).

Return tubes I specified in the post, I'll write them here again:

1. Cool (Living room 1)
2. Lukewarm (Living room 2)
3. Cold (???)
4. Cold (Bedroom 2 — I suspect Master Bedroom)
5. Cool (Bedroom 1 — I suspect Second Bedroom)
6. Lukewarm (Bathroom)

d4n1

https://forum.heatinghelp.com/discussion/comment/1834130#Comment_1834130

You mean it's not possible to do the purging on this setup?

hot_rod

A better picture of the piping is needed. I'll bet there are purge ports on an engineered product like that.

In this pic, only one zone valve is open. They are open when you see the blue ring around the top.

The ones with the fluted tops are themostatic valves, not powered valves.

So assure they all open to get flow before you try purging.

d4n1

https://forum.heatinghelp.com/discussion/comment/1834176#Comment_1834176

Fair, here is a wider picture of the piping:

These seems to be the purge ports on the pipes to me, or am I wrong?

Also there are these valves in the system, which I think are to empty it?

As for the two insulated pipes being closed, those are for the cooling as far as I understand - here cooled water is provided during summer, and hot water during winter. That's why they're closed - but fair point to keep that in mind for bleeding/purging.

Honestly I would rather leave this to the contractor since I'm renting and don't want to be personally liable for any damages. Just was wondering if the issue may indeed be air in the system, or something else to consider.

Kaos

Looks like there is a TRV in series with the heat feed. Is there a remote bulb it is reading and what is it set to? Does that Alpha pump show you flow rate by chance?

Most likely you are not getting enough flow. Some zones valves need to go through a calibration procedure to set them, not familiar with the ones on your setup.

d4n1

https://forum.heatinghelp.com/discussion/comment/1834236#Comment_1834236

The TRV is set to 40c, and that’s the max value that can be legally set (judging from my heating contract and what the contractor told me).

Regarding the remote bulb, maybe it’s this box? (circled in orange) Not 100% sure

It is connected to a relay box (you can see it on the left), which itself controls the valves on supply and the thermostats for the bedrooms. But it is a mess of cables, I’ll try to draw up an electric diagram if that helps.

The pump doesn’t show the current flow I’m afraid. However it’s interesting to note that the supply gauge shows 4 bar pressure - isn’t that too much? I see the recommended pressure is ~2 bar.

psb75

I'll say it if no one else will, I've never seen any of that kind of piping, fittings, and devices before. I have seen a Gundfoss circulator but I don't recognize the form and read-out on its face. 4 bar of pressure is too high. It should be 1 Bar, not even 2. We don't know "what" is doing the heating. A "boiler", I presume? Fuel type? That is a very "tight" arrangement and all of the pipe insulation makes it hard to identify the components and understand the flow directions. If you provide a printed schematic of both the plumbing AND the electric it might be easier to understand than these photos. I will say that this installation looks very Dutch. But…that ain't much.

d4n1

https://forum.heatinghelp.com/discussion/comment/1834284#Comment_1834284

Fair questions, I should've included them earlier.

The Grundfoss circulator should be this one: https://product-selection.grundfos.com/products/alpha/alpha2-l/alpha2-l-25-40-180-98257789?pumpsystemid=2564059675&tab=variant-curves

The heating is done through district/central heating: essentially I get a pipe with warm water up to my apartment, and there is an installation (which I can't poke inside I'm afraid) that seems to be distributing that warm water among the floor heating and hot water (shower, taps) — note: one issue I'm having is also low-ish water pressure and long time to get warm water out (~40 secs) in some taps; might be connected?

This seems to be the distribution system used: https://www.proveiling.nl/WTH-vloerverwarming-verdeler/1389756/Detail.aspx

I'll try to draw up a proper schematic of the system to the best of my abilities and post it here.

Kaos

If this is a condo, the higher pressure is normal. @psb75 Euro setup, they like different parts, looks complicated because there is also radiant cooling.

Ok, if the TRV is keeping the supply at 40C, then the external supply is fine.

If the pump is set to max, then that is about all the flow you can get through your heating. You might be able to balance out the heat a bit. I would start with the zone where you want some more heat first. For that zone, see if you can open the flow setter a bit. If already maxed, you'll have to close the flow setter on a zone that has warm return a bit to get extra flow.

Overall, if the place is comfortable, your heat is working. You'll probably never get warm toes feel in a condo if they did a full surface radiant setup.

d4n1

https://forum.heatinghelp.com/discussion/comment/1834316#Comment_1834316

It is a condo indeed, at the 12th floor out of 22.

The only loop that has some warmth is the living area, all the others are basically cold.
Tried to close that one yesterday for ~1 hour to see if the temps on the other return pipes would increase, but I didn't notice anything.

Then again, it's a bit of guesswork since I don't have a heat camera and/or thermometer to check the temps on the pipes.

And also extra weird because I remember (and previous tenant has confirmed) the heating (at least in the living) was working quite well before I moved - when I visited the apartment I was legit sweating (we're talking 26c probably inside).

Kaos

Depending on the concrete thickness, it will take much more than 1h to feel a difference.