Help!

homeowner17

I just moved into a house and find theres a weird perfumey/detergent-like smell when the radiant floor heating kicks on. It’s run by Navien ncb-190/080h combo-boiler. The house was a reno (completed in 2023), and they did a brand new subfloor and laid pine engineered hardwood floors and ceramic tile. I notice it the strongest in the mud room where the laundry is and there’s tile in that room. Anyone ever experience a weird perfume smell when running the radiant heating system? The temp in the photo says 137F but when I checked earlier it said 152F.

PC7060

I suspect someone spilled Tide or another liquid detergent on the floor and the heat is activating the scent. Check under the washer machine and dryer.

homeowner17

That was my thought at first too. But they haven’t lived in the house since June. Do you think it’s possible that the smell would still be that strong and potent? It’s a built-in staked washer dryer so it would be difficult trying to get it out. It’s so strong that even my coat hung up in the closet smells like that smell when I’m outside. My hair smells like it as well. It’s not just the room that smells, it clings to my clothing and hair.

mattmia2

Make sure the washer isn't leaking too. If it is soaked in to the floor it could hang around for years. Is there a mixing valve for the floors? 130 is way too hot for radiant.

homeowner17

I pulled out the washer and dryer and there were no leaks. I cleaned the floor just in case. The smell is still in the house when the heat kicks on. Where would I check to see if there’s a mixing valve? The boiler says 165 F when the heat kicks on. Zone 1 furthest to the right is the in-floor heating. @mattmia2

mattmia2

there is a thermostatic mixing valve right here:

Jamie Hall

A good chunk of the problem is that that water is much too hot for a radiant floor. Even if it isn't some strange spill problem, that is hot enough so that the tile adhesive and engineered flooring will be outgassing and will for years if you leave it at that temperature. The supply to the floor should never get over 110 F.

homeowner17

I took the temperature of the piping that runs to the flooring system and it was 155 F at the areas I circled in yellow (upstream of the mixing valve). But then I took the temperature of the tile floor and it was only 105F and the hardwood was 100F. @Jamie Hall

Jamie Hall

Yeah, the floor will be cooler. It radiates into the space, right? But that doesn't mean that the adhesive and flooring is cooler in contact with the hot pipe.

homeowner17

thanks @Jamie Hall how would I adjust the mixing valve to lower the temperature on zone 1? I think the water heater has to stay high around 160 F for the second floor radiators that are on zone 2.

Jamie Hall

I'm not at all convinced that that mixing valve is installed properly — the ones I've seen have the hot coming in one side, the cold (in this case the return) coming in the other, and the output from the centre pipe…

But… the black cap on the valve should turn to set the output temperature.

Kaos

Also a modcon running at 160F means you get no condensation, runnig the same efficiency as a standard boiler.

Most likely either outdoor reset is not installed or the curve is not set properly.

By running the system that hot during the shoulder season you are wasting around 10% fuel. I would figure out what the issue and adjust. A well set up reset curve should mean your zones are running most of the time.

This might also help with your too hot floor heat as it looks like that is a fixed adjustable bypass (not thermostatic). By dropping the temperature for the rads, it means that it will also drop the water temperature for the floor heat.

mattmia2

even without odr, if the only dh loads are radiant you can change it to fire at the temp for the floor.

the mixing valve could be frozen.

homeowner17

@Jamie Hall I should have someone out to look at it. Because even the return pipe is quite hot, too hot to touch and hold when the system is on. So the mixer if it actually works and was installed properly, likely wouldn’t cool the water down that much. I added of close up photo.

@Kaos yes the tankless water boiler I noticed will be sitting at around 110 F when the radiant floor isn’t on, then it’ll kick on and jump up to 165F. It’s does this constantly throughout the day and night.

Kaos

So that is not a thermostatic bypass. Looks like it is set to zero bypass so that is why you are having issues.

Simple think you can do is crank the floor heat and go to your boiler. Adjust the bypass until the water above it is feels like a nice hot bath. You want that water around 110F to 120F.

Eventually figure out why you don't have proper outdoor reset control. Getting this working properly is worth it for the fuel savings.

homeowner17

@Jamie Hall @mattmia2 @Kaos The heating company came out and adjusted the bypass to bring the temp down from 155F to 100F to the floor heating. That has seemed to have made the smell 90% better! But I noticed that it takes a lot longer to heat up the house. My Nest thermostat was tracking around 3.5 hrs to 4 hrs of heating, and now tracking 7.5 hrs of heating (when the temp outside hasn’t changed and I still have the thermostat set at 71F). I assume that’s normal? I’ve attached a photo of my Nest tracking.

I asked about the outdoor reset but (which isn’t installed - it’s sitting on top of the boiler in a box) but they said because the 2nd floor radiators are aluminum and not cast iron that they don’t hold heat for long, so with an outdoor reset it will cause the boiler to turn on and off so many times that it would just shut down so for us to not have the outdoor reset installed. Does that make sense?

EdTheHeaterMan

@homeowner17 said: "I asked about the outdoor reset but (which isn’t installed - it’s sitting on top of the boiler in a box) but they said because the 2nd floor radiators are aluminum and not cast iron that they don’t hold heat for long, so with an outdoor reset it will cause the boiler to turn on and off so many times that it would just shut down so for us to not have the outdoor reset installed. Does that make sense?"

Not really. the Nevian boiler does not turn off and on to maintain a lower temperature (unless the load is less than the turn down minimum output.) The reset temperature in the boiler is maintained by burning a smaller amount of gas. When the water temperature for Central Heat (CH) is reached the burner burns less gas. If the boiler water temperature for CH goes too low, the the gas burner increases the amount of gas it burns. That modulation of the amount of gas it burns will go up and down without cycling off. (unless the amount of gas is less than the minimum gas input)

If you are operating in the fringe seasons where the outdoor temperature is above 40°F then there will be some on off cycling but that will happen with or without outdoor reset turned on

Jamie Hall

As @EdTheHeaterMan said, the difference in run time is related to the difference in the temperature of the water going into the floor, and thus the floor temperature.

What isn't obvious — and which you can't get from the Nest at all — is that the boiler is burning less fuel to reach that lower temperature, so the total amount of fuel burned is actually probably less at the lower temperature and longer run times.

The other thing you mention is a longer recovery if the thermostat is turned up. That is completely normal for a radiant floor.

Kaos

You definitely want the outdoor reset sensor hooked up and the boiler configured properly.

A system running with outdoor reset will have much more even hot water temperature supply, this means the mass of emitters matters less. Your plumber has it backwards, when you mix high mass and low mass emitters, you WANT outdoor reset.

One thing to keep in mind that with a properly configured outdoor reset your thermostat runtimes will get even longer than what you see now. This is a good thing. This means the boiler is only supplying water just hot enough to heat the house and no more, which is great for fuel efficiency.

Jamie Hall

There is some merit in what @Kaos has to say just above. Like so many things in life, though, it is not hard and fast.

I'll give you just three examples. There are three properties which I manage almost completely. One is a church located in a highly sheltered location. One is a residence — fairly large — also in a highly sheltered location, but with a large sun load on sunny days. The third is a property located in a location with no shelter from the wind and a large sun load. The properties are within 5 miles of each other.

Outdoor reset works, and works well, on the church — but it is set (no surprise) to bring the temperature up on weekends by varying changing the setpoints on the reset curve. It's great. The residence in a sheltered location, on the other hand, does only moderately well with an outdoor reset (which it has), as it overheats rather dramatically on sunny days if it is set to be warm enough at night, or chills unacceptably at night if it is set to be correct during the day. The third application is more interesting in a sense: the actual heating load is very strongly influenced by wind speed — to the extent that the heating load is about the same at a 15 degree outside temperature with no wind as it is at 30 degrees outside with moderate winds, and drops almost to nothing on a sunny, still afternoon with no wind, even down close to zero.

So my conclusion to all that is… outdoor reset is great, provided the heating load is closely related to outdoor temperature and nothing else. If one were inclined to do so, one could augment the outdoor reset ambient temperature signal with a wind speed and direction signal and an effective insolation signal and get very good results. With current sensor hardware and a modest investment in computer programming, this could be done.

Unhappily for the tech. wizards, though, the old faithful mercury T87 in the third application controls the interior temperature within a degree, regardless of outside conditions, day in, day out (it's been there for about five decades now and is on its third boiler)… real hard to beat that.

Kaos

https://forum.heatinghelp.com/discussion/comment/1822313#Comment_1822313

Not advocating outdoor reset only, but some outdoor reset. Even a less aggressive curve will be much better than zero right now. Running at modcon at 160F means pretty much zero condensation, so about 85% efficient. With any reasonable curve you'll get that temp way down most of the year and bring the efficiency up to 95%+. The thermostats are still needed and will still control the space temperature, they will simply call for much longer heat cycles.

Areas of my house have a fair bit of solar gain, in those areas, I don't need any heat on a sunny day so those zones are pretty much off after 10am. The outdoor reset is not an issue, at night time, all the zones run pretty much the whole night (don't run night time setbacks) and space temperature changes by less than 0.5C.

With modcon/heat pump, outdoor reset is your friend. There is no reason not to run it.

homeowner17

thank you for all the responses. I’m very new at this so learning lots.

@Kaos I live in Canada and we are now getting into 0 C and below weather until about March. Is it still worth while having an outdoor reset installed now or can it wait until next year when the temps start to get above 0?

Jamie Hall

It should not be a difficult or time consuming install (more than anything it depends on how your boiler or mixing valve is controlled now), so I'd just go ahead and get it set up to do…

Kaos

https://forum.heatinghelp.com/discussion/comment/1822805#Comment_1822805

I can't see this being that big of an install job, it is just one wire to an outside sensor plus some settings on the unit. Make sure they enable reset control on the unit itself and set a reasonable curve. Since you have a mix of low mass baseboards and radiant floor, I would try option for "low mass radiant" first and see how it runs.

Still early in the heating season.

homeowner17

@Kaos @Jamie Hall Is it normal for the water temperature to the floors to drop ~15F when the other zone turns on? The water heater is set at 163F which gives zone 2 (second floor radiators) that temp, but noticed when zone 2 turns on, zone 1 (to radiant floor heating on first floor) drops significantly from 110F to 95F, while zone 2 is running. (To note the water boiler never changes in temp when this happens, stays at 163F).

The bypass mixing valve I have is just an manual one, would a thermostatic mixing valve ensure that the floors are getting a consistent temp regardless of another zone turning on?

First photo is the temp of zone 1 (to radiant floors) at the source without zone 2 being on, and second photo is after zone 2 turns on

Jamie Hall

Quite possibly normal. A manual mixing valve has no way of altering the flow from the two sources, and if the pressure in the manifold side drops when the second zone comes on, but the pressure in the return from the floor doesn't, you'll get more recirculation (and lower temperature).

I would suggest a thermostatic mixing valve where you can set the outlet temperature it will try to maintain. Several good makes.

homeowner17

Thanks @Jamie Hall any you can recommend ?

Kaos

I wouldn't sweat it. Turn up the mix valve a bit to split the difference if the floor heat feels too cold. I doubt water a couple of degrees warmer will cause the smell issues you had before.

hot_rod

most 3 way mix valves allow you to add an actuator to allow it to modulate the temperature looks like a Euro valve with the DN number on it

Also, if the boiler were on outdoor reset , a manual mix valve like that would track along with reset temperature

Does the system have glycol in it. A tiny amount of glycol leaking can have a a sweet smell to it. More so when it is hot, like when you car radiator boils over🫢