Where do I get an ACCURATE humidity meter?

[Tough Guy no. 1265]

dehumidifier it is

eaving it not the

its reading and

r, otherwise it's a pointless reading. The dehumidifier needs to know h= ow damp the room is, so it knows whether to turn off yet. How dry the a= ir is coming out of it is completely irrelevant.

the output side. The dehumidifier function thus gets it to move much fur= ther, so it moves far enough to switch the thing off.

air again, and eventually switches back on.

r heater above the heating element.

one that has to ask basic questions about them.

il the ROOM has a humidity of (value on dial)%, set by the user. The us= er doesn't give a shit about what is coming out of the unit, they care w= hat the ROOM is at. The only thing the dryness of the air coming out of= the unit tells you is how QUICKLY it is DRYING the room, it does not te= ll you how dry the room is. The air coming out of the dehumidifier will= ALWAYS be dry, so a sensor located at the out vent of the unit will gat= her no information apart from "the unit is switched on".

ater, the thermostat is always located at the bottom, with the INTAKE of= air.

s stupid as you, and just as I thought, the sensor is right at the front= behind the air intake filter, BEFORE the cooling pipes. Funny that.

ave a bit more clue than you.

? "the sensor is right at the front behind the air intake filter, BEFOR= E the cooling pipes"

ity, and are entirely unfamiliar with the methods used to work round the= m, but you also appear now to assume all dehumidifiers are like yours!

hysteresis of my humidistat is 1-2%, when the machine is OFF. I've onl= y ever seen the likes of what you describe on a really crap room thermos= tat for =A35, which actually had a resistor under the bi-metallic strip = because otherwise it clicked at about +/- 6C.

They shouldn't/. Working around the problem won't be accurate.

to work that way for a reason.

I've seen plenty bimetal thermostats which don't require a heating resis= tor, and only have a hysteresis of 1C.

-- =

I just sent my lawyer something for his birthday. Unfortunately, he was= n't home when it went off.

[tabbypurr]

ehumidifier it is

aving it not the

ts reading and

, otherwise it's a pointless reading. The dehumidifier needs to know how d amp the room is, so it knows whether to turn off yet. How dry the air is c oming out of it is completely irrelevant.

he output side. The dehumidifier function thus gets it to move much further , so it moves far enough to switch the thing off.

ir again, and eventually switches back on.

heater above the heating element.

ne that has to ask basic questions about them.

l the ROOM has a humidity of (value on dial)%, set by the user. The user d oesn't give a shit about what is coming out of the unit, they care what the ROOM is at. The only thing the dryness of the air coming out of the unit tells you is how QUICKLY it is DRYING the room, it does not tell you how dr y the room is. The air coming out of the dehumidifier will ALWAYS be dry, so a sensor located at the out vent of the unit will gather no information apart from "the unit is switched on".

ter, the thermostat is always located at the bottom, with the INTAKE of air .

imary school.

stupid as you, and just as I thought, the sensor is right at the front beh ind the air intake filter, BEFORE the cooling pipes. Funny that.

ve a bit more clue than you.

"the sensor is right at the front behind the air intake filter, BEFORE th e cooling pipes"

ty, and are entirely unfamiliar with the methods used to work round them, b ut you also appear now to assume all dehumidifiers are like yours!

hysteresis of my humidistat is 1-2%, when the machine is OFF. I've only ev er seen the likes of what you describe on a really crap room thermostat for £5, which actually had a resistor under the bi-metallic strip because ot herwise it clicked at about +/- 6C.

they should supply what the market wants, and do. It's not a problem it's a n issue.

o work that way for a reason.

or, and only have a hysteresis of 1C.

but aren't suitable to switch mains. Let us know if you understand the issu es here.

NT

[Tough Guy no. 1265]

he dehumidifier it is

r leaving it not the

en its reading and

fier, otherwise it's a pointless reading. The dehumidifier needs to kno= w how damp the room is, so it knows whether to turn off yet. How dry th= e air is coming out of it is completely irrelevant.

on the output side. The dehumidifier function thus gets it to move much = further, so it moves far enough to switch the thing off.

om air again, and eventually switches back on.

ctor heater above the heating element.

omeone that has to ask basic questions about them.

until the ROOM has a humidity of (value on dial)%, set by the user. The= user doesn't give a shit about what is coming out of the unit, they car= e what the ROOM is at. The only thing the dryness of the air coming out= of the unit tells you is how QUICKLY it is DRYING the room, it does not= tell you how dry the room is. The air coming out of the dehumidifier w= ill ALWAYS be dry, so a sensor located at the out vent of the unit will = gather no information apart from "the unit is switched on".

heater, the thermostat is always located at the bottom, with the INTAKE= of air.

n primary school.

t as stupid as you, and just as I thought, the sensor is right at the fr= ont behind the air intake filter, BEFORE the cooling pipes. Funny that.=

s have a bit more clue than you.

pid? "the sensor is right at the front behind the air intake filter, BE= FORE the cooling pipes"

tivity, and are entirely unfamiliar with the methods used to work round = them, but you also appear now to assume all dehumidifiers are like yours= !

The hysteresis of my humidistat is 1-2%, when the machine is OFF. I've = only ever seen the likes of what you describe on a really crap room ther= mostat for =A35, which actually had a resistor under the bi-metallic str= ip because otherwise it clicked at about +/- 6C.

What people want is accuracy.

Issue =3D problem, but in newspeak.

ed to work that way for a reason.

sistor, and only have a hysteresis of 1C.

Yes they are, because I bought them for that purpose and used them for i= t. Go take a look at some specs for basic room stats by the likes of Da= nfoss etc.

-- =

Ireland's worst air disaster occurred early this morning when a small tw= o-seater Cessna plane crashed into a cemetery. Irish search and rescue w= orkers have recovered 2826 bodies so far and expect that number to climb= as digging continues into the night.

[tabbypurr]

ha

nope

Bimetal room stats normally use compensation, and don't swing 1C. I can't see any sense using a 1C hysteresis for CH.

NT

[Tough Guy no. 1265]

Decent people do. Why would I want a vague dehumidifier which dries the room to some arbitrary level? Do you also have a thermometer that says it's somewhere between 15C and 25C?

Yes. The only people saying "issue" are the people that say "health and safety" before it. They're vague people who won't say what they mean.

Of the 5 models I've seen, only one had it. And it was actually LESS sensitive than the properly made ones without the workaround.

My digital ones have a 1C hysteresis, it's a very sensible amount. What would you want instead?

[tabbypurr]

buy something decent then

0.25C is about ideal and practical with digital, 0.5C is good & practical for bimetal. Room temp going up & down by 1C is obviously a waste of energy/money.

NT

[Tough Guy no. 1265]

The 4 without compensation worked perfectly.

I'm going to assume you're trying to be funny, because 1C is bugger all difference, not enough for the human body to detect. Having a smaller hysteresis will only cause the heating to cycle more than necessary, causing wear and tear, and annoyance from noise. For example my heating comes on for about 20 minutes at a time with a 1C hysteresis. I wouldn't want the bloody thing running for 5 minutes off and on.

[Tough Guy no. 1265]

Got it. I've now decided that the cheap digital one I had was actually correct. It reads 74% on the 75% damp salt test, and it agrees with your suggested wet bulb hygrometer at 60% in my living room. The cheap bimetallic analogue greenhouse thing (which probably came free with something) I calibrated to 75% with the salt, then it read 55% when the other two read 60%. I've thrown it in the bin.

However, the main problem is the dehumidifier. Its humidistat is also in agreement that it's 60% in my living room, when the dehumidifier is off! When it's running, it thinks it's 35%, so I can't set the dehumidifier properly at all. The sensor is at the front, next to the air intake, so should be reading the incoming air, hence the humidity of the living room, but it's rather close to the cold end of the compressor circuit, so is being affected by it when the dehumidifier runs. I had the dial set to 35%, and the dehumidifier was cycling on and off with a duty cycle of about a third. But the room is 60%, 25% higher than what I asked for, so it should be running flat out trying to dry the air! I've tried removing some of the plastic chassis around it so it gets more of the room air, and I've just switched it on, so we'll see what happens. I've set it to 50% and expect the dehumidifier to run continuously until the room drops from 60% to 50%.

[tabbypurr]

agreement that it's 60% in my living room, when the dehumidifier is off! When it's running, it thinks it's 35%, so I can't set the dehumidifier prop erly at all. The sensor is at the front, next to the air intake, so should be reading the incoming air, hence the humidity of the living room, but it 's rather close to the cold end of the compressor circuit, so is being affe cted by it when the dehumidifier runs. I had the dial set to 35%, and the dehumidifier was cycling on and off with a duty cycle of about a third. Bu t the room is 60%, 25% higher than what I asked for, so it should be runnin g flat out trying to dry the air! I've tried removing some of the plastic chassis around it so it gets more of the room air, and I've just switched i t on, so we'll see what happens. I've set it to 50% and expect the dehumid ifier to run continuously until the room drops from 60% to 50%.

What matters most is the RH at which it turns on. Whether it then runs for

10mins or an hour is minor.

NT

[tabbypurr]

the wallet can certainly detect it, making such stats a false economy

no more than otherwise

cobblers

NT

[Tough Guy no. 1265]

No it cannot. There will be bugger all difference with such a small change.

Half the hysteresis, twice the on and off cycles.

Silent your pump is it?

[Tough Guy no. 1265]

Incorrect. As it was when I bought it, if I set it to 40%, and the room was 60%, it would switch on for 5 minutes, then stop for 15 minutes, then switch on for 5 minutes, then stop for 15 minutes, and so on. It would hardly remove much water (a quarter of what it's capable of), so never achieve anything like the humidity I asked for. I've now removed the sensor completely from the unit and sat it a few feet away. It now works perfectly. When the humidity is higher than what I want, it runs until it's correct.

P.S., one minute you want my heating to have a fraction of a C hysteresis, and the next minute you're saying 20% hysteresis on the dehumidifier is ok!

[tabbypurr]

When indoor temp is 10C above outdoor, an overshoot of 1C consumes 10% more than necessary for comfort. An overshoot of 0.5C 5%, so your cheapie thermostat is wasting around 5% on your heating bills. Not worth it.

with the same amount of on time. Actually slightly less, as it puts out 5% less heat in total

the length of its onoff cycles has nothing to do with how noisy or annoying it is or isn't. Did you fit a cheapskate pump too?

NT

[tabbypurr]

Yes, CH hysteresis wastes money, DH hysteresis has little effect on the small run cost.

If you do learn any engineering let us know.

[Tough Guy no. 1265]

You may know something about engineering, but you have a lot to learn about pedantry.

Calculate the heat loss from a house at 20C with the outside at 5C. Now do the same with 21C and 5C. How much is the difference?

Now consider this. The people in the house will not be able to choose a temperature that precisely anyway, so having the stat more sensitive than the people choosing the temperature is utterly pointless.

[Tough Guy no. 1265]

No, 2.5% you fool. It's only too warm for half the time.

Besides, if the room is warmer than for comfort, turn it down 1C. Your body will feel the average anyway, so no matter what the hysteresis, you will feel at the mid point, because your body simply cannot detect changes that small.

But shorter cycles. What annoys people is a CHANGE in noise.

The number of cycles is what matters, you notice when a sound starts.

Actually my pump is in the loft where it should be. People with modern boilers with the pump inside them, and fans for ultra efficiency, they make noise. All I hear is the gas jet.

[tabbypurr]

yet you offer no basis for that.

didn't we already cover that? Maybe average outdoor temp in heating season is 5C where you are, it's higher here.

rubbish. I can set my thermostat to within 1/3C and do.

more cobblers. Stop digging.

NT

[tabbypurr]

Having once briefly used a stat with about 6C hysteresis I know what cobblers that statement is. It's easy to feel the cycles on poorly controlled CH.

I've never heard anyone complain about their CH pump noise. Fix your crappy system.

We all live with background noises without any great problem. you do talk rubbish.

they do. At least we agree on something.

NT

[Tough Guy no. 1265]

I was talking about ONE C, not SIX!

MY system is not noisy, but more modern ones are. The stupid ones with the pump inside the boiler, and a fan for the exhaust.

Exactly, a CONSTANT background noise, not one that starts up.

We agree on nothing. What do you mean by "they do"?

[Tough Guy no. 1265]

It's written below.

In a seperate post which I hadn't read yet.

If it was 10C, I wouldn't be heating the house.

Pointless. You couldn't tell the difference between 20C and 20.33C.