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Hi all,
Looking for some advice on my UFH, which was installed during a renovation 2 years ago. It's never worked particularly well, taking hours to warm up and sometimes not reaching temperature at all on colder days.
It's a 4-loop system with a Wilo pump and mixing valve, sharing a boiler with the radiators.
I've been trying to figure out what's going on and noticed a few things:
- Flow meters show 1–2 L/min when the boiler fires, but gradually drop to zero when it stops, even though the UFH pump is still running and the thermostat is calling for heat.
- Increasing the pump power actually seems to reduce the flow, sometimes to zero. Switching to constant-pressure mode (setting 2) has helped a bit.
- Turning the mixing valve up to 60–65c gives me consistent flow, but dropping it back to 45c causes it to stop again. Obviously don't want to run it that hot with engineered wood flooring.
- The bottom manifold heats up before the top one (which has the flow meters). Shouldn't this be the other way around?
- It also seems to struggle more when the radiators are on.
The thing I'm most suspicious about is that the arrow on the Wilo pump points downwards, towards the bottom manifold.Is that correct for this setup? Could the water be circulating backwards through the manifold?
I'm wondering whether the boiler pump is doing most of the work, which might explain why the flow stops when the boiler stops firing, and why turning up the UFH pump seems to make things worse.
I spoke to an engineer who basically said that if the room eventually gets warm, he'd leave it alone. But it's been rubbish since installation and I'm worried something isn't right. Also don't want there be damage from incorrect flow.
Interested in people's thoughts. (I've watched about as much YouTube plumbing content as I can manage...)
Looking for some advice on my UFH, which was installed during a renovation 2 years ago. It's never worked particularly well, taking hours to warm up and sometimes not reaching temperature at all on colder days.
It's a 4-loop system with a Wilo pump and mixing valve, sharing a boiler with the radiators.
I've been trying to figure out what's going on and noticed a few things:
- Flow meters show 1–2 L/min when the boiler fires, but gradually drop to zero when it stops, even though the UFH pump is still running and the thermostat is calling for heat.
- Increasing the pump power actually seems to reduce the flow, sometimes to zero. Switching to constant-pressure mode (setting 2) has helped a bit.
- Turning the mixing valve up to 60–65c gives me consistent flow, but dropping it back to 45c causes it to stop again. Obviously don't want to run it that hot with engineered wood flooring.
- The bottom manifold heats up before the top one (which has the flow meters). Shouldn't this be the other way around?
- It also seems to struggle more when the radiators are on.
The thing I'm most suspicious about is that the arrow on the Wilo pump points downwards, towards the bottom manifold.Is that correct for this setup? Could the water be circulating backwards through the manifold?
I'm wondering whether the boiler pump is doing most of the work, which might explain why the flow stops when the boiler stops firing, and why turning up the UFH pump seems to make things worse.
I spoke to an engineer who basically said that if the room eventually gets warm, he'd leave it alone. But it's been rubbish since installation and I'm worried something isn't right. Also don't want there be damage from incorrect flow.
Interested in people's thoughts. (I've watched about as much YouTube plumbing content as I can manage...)
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