Humidity and effects on heat pump....

[badtlc]

Before I call my pro, I wanted to ask on here so I don't waste anyone's time....

My heat pump normally carries my house down to around 15-18 degrees. Around 25 degrees outside and 40-60% humidity, it usually takes around 20min to satisfy the t-stat on each call for heat.

Yesterday evening and last night, the humidity was 99% and around 25-27 degrees and heat pump barely held the temperature and never shut off.

I'm afraid there might be a refrigerant leak from a modification they made about a month ago (been too cold for the heat pump over that month) but thought I would ask about humidification first.

Thanks for any help.

[Airmechanical]

Before I call my pro, I wanted to ask on here so I don't waste anyone's time....

My heat pump normally carries my house down to around 15-18 degrees. Around 25 degrees outside and 40-60% humidity, it usually takes around 20min to satisfy the t-stat on each call for heat.

Yesterday evening and last night, the humidity was 99% and around 25-27 degrees and heat pump barely held the temperature and never shut off.

I'm afraid there might be a refrigerant leak from a modification they made about a month ago (been too cold for the heat pump over that month) but thought I would ask about humidification first.

Thanks for any help.

99% humidity is almost raining

try a different hygrometer (digital humidity meter)

at 25-27 degrees outside, in most cases the heat pump will run most of the day to heat properly

some people shut there heat pump off at 35 DEGREES, and use only backup heat, your light bill will probably be much lower than their's


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[badtlc]

99% is accurate. it was foggy which is essentially a very light misty rain.

And like I said, this heat pump system is over a year old and I am meticulous about its performance. Up to this point in time, it never ran non-stop until outside temps got below 20degrees but that was with lower humidity levels.

Will the increase in humidity affect the performance?

[kls-ccc]

Higher humidity outdoors will definetlly have an effect on your heat pump, as will any weather changes. With humidity you have a 2 fold effect.

#1 the humidity adds heat to the air which lets the heat pump extract more heat.

#2 the added humidity causes the outside coil to frost faster, requring more defrosts. So if the unit had demand defrost it will go into defrost more often, if it is time/temp more frost will build before defrost insulating the coil so less heat is transfered and when it does go into defrost it will stay in that mode longer.

Now if you add wind into the mix it is hard to say what the exact effect is going to be.

When in doubt, call a tech. It usually saves money in the long run.

[badtlc]

It is an Amana ASZ16. I think it is supposed to be demand defrost but it was also going 40+minutes between calls for defrost and sometimes over an hour.

Would a defective defrost board still call for defrost or just never defrost?

[Stamas]

Location?
Haven't got a broken pipe somewhere have you?
Usually no defrost.
Like Air said it would, if sized and working right run a good deal of the time.
Get some competent help there for that humidity thing.

[badtlc]

Location?
Haven't got a broken pipe somewhere have you?
Usually no defrost.
Like Air said it would, if sized and working right run a good deal of the time.
Get some competent help there for that humidity thing.

I think I said something wrong. I'm not talking about indoor humidity. The indoor humidity is 40% on the button.

There are no broken pipes.

The unit is about 0.5 ton over sized.

It sounds like I probably don't have a problem if 99% outside humidity at 25 degrees can wreak havoc on a heat pump.

[BaldLoonie]

My vote is frosting. At mid 20s and misting, that coil will frost FAST!

You sure on that demand defrost? Nothing in their spec sheet about it and the schematic shows a conventional defrost stat.

[hvacrmedic]

I think I said something wrong. I'm not talking about indoor humidity. The indoor humidity is 40% on the button.

There are no broken pipes.

The unit is about 0.5 ton over sized.

It sounds like I probably don't have a problem if 99% outside humidity at 25 degrees can wreak havoc on a heat pump.

Those conditions are guaranteed to wreak havoc on a heat pump. Every time we have freezing rain we get overloaded with calls from customers asking exactly the same question. Freezing rain, or mist, will block all airflow through the outdoor coil in a matter of minutes. Defrost cannot keep up with it, and in some cases the defrost cycle is completely unable to remove the ice from the hail guard, even though the coil itself may be dry as a bone.

[Stamas]

I think I said something wrong. I'm not talking about indoor humidity. The indoor humidity is 40% on the button.

There are no broken pipes.

The unit is about 0.5 ton over sized.

It sounds like I probably don't have a problem if 99% outside humidity at 25 degrees can wreak havoc on a heat pump.

No, sounds like it was me.

[Airmechanical]

i thought he meant inside

not so surprising outside


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[Rusty49]

asz16 has time /temp DF board