Heat Pumps and Electric Heating - York Heat Pump Not Quite Performing

Three years ago, we bought a house here in Louisville. It was my first home with a heat pump. It's a York, and is approximately 14-15 years old now.

The first two winters were no issue at all. Last spring, the contact switch on the outside unit welded together, and we had it replaced. Late last summer, we had to recharge the coolant as it was quite low. Other than that, the unit has been fine. I regularly change filters, I clean the coils (both exterior and interior) once or twice a year. I keep the external unit free of leaves, debris, snow, et cetera.

This past month, my electric bill doubled (part of that was rate increases, but part was my heat pump). It never QUITE reaches target temperature. I have kept the house set at 68 year round for the last three years with no trouble, and have been quite happy with the HP's performance. However, the best I can get out of the unit right now is 66.

At first I suspected dirty filter...the holidays had been crazy and I hadn't attended to it properly. So I checked the filter, the coils, et cetera. All was well there. The house was sitting at 62-63 degrees no matter what I did. The thermostat has been on its last leg for years, so I replaced it with a Rite Temp 8082c. The new tstat was set for heat-pump operation, 2 degree differential, electric heat, and then set target for 68 degrees. It works, and there is heat, but the unit never reaches target temp...it has maintained 66 degrees with 24x7 operation of the pump.

Emergency heat works fine. I ran it for about 45 minutes or so to bring the house back up to temp, then let the HP take over.

I've checked the outside unit...nothing seems untoward there. I hear no gurgling or flow sounds from the coolant line, as I did with low-pressure earlier last year. The interior unit is sparkling clean on the interior given its age. The unshielded coolant line is cool, and the shielded coolant line is hot (but not too hot to touch). All in all, it seems to be exchanging heat, just not enough to hit target.

One thing I did notice...the new thermostat looks to be kicking on aux heat (with a "2" on screen for stage-two), but it doesn't stay on. It kicks on, then kicks right off. Could it be that auxilliary portion of the electric heat isn't working (bad relay? bad wiring?), but the emergency portion is? Is that even possible? Is this a simple/inexpensive repair?

I really can't afford more months of doubled electric bills...I need to do something about this...but I even more certainly can't afford a whole new unit right now...any help or ideas would be greatly appreciated.


Cheers,
Jason

When they recharged it did they repair the leak? If not then I bet it's low again.

With Matt here
and the shielded coolant line is hot (but not too hot to touch). All in all, it seems to be exchanging heat, just not enough to hit target.
check for leak???? freon ok???? should be hot.

...the new thermostat looks to be kicking on aux heat (with a "2" on screen for stage-two), but it doesn't stay on. It kicks on, then kicks right off.

Why this new tstat???? Is it a programmable one. they dont work to good on a heat pump. After they set back and then when they turn the heat back up it turns on the EME or AUX heat on to help . So it cost you just about what you saved with the set back temp to come on back up to heat
That new tstat dont have a anticipator in it that you have to set for heat pump does it.

ED ;)

I'll check for leak where I can...it runs along our crawl-space and I'm not surehow well I'll be able to check for leaks there.

Regarding the tstat, I bought it because the old one is quite literally falling apart (it has been held together with tape since before I bought the house. And while the new one is a programmable, it presently is set to hold for 68 and not vary. Yes, it does have settings for heat pump, and yes, I have them set for that. I've triple confirmed my tstat setup with myself and the vendor.

Here's why I'm not leaning towards leak (again, new guy here...just voicing what's in my head)... On the old tstat (the original one installed with the unit, I believe) it never got more than 5 degrees close to target temp. Come to find out from the people that installed/maintained the unit over the years, that the thermostats they use have a 5 degree "differential." I replace the thermostat (which has a setting for "differential" as 2, 3, or 4 degrees...it was set to 4, but now to 2) and it never gets within more than the differential setting. When it was set at 4, it never got closer than four degrees below temp, and where it is now at 2, it never gets more than 2 degrees below temp. Now, if it was low pressure, why would it be able to perform well, except to very specific margins from the target? I thought about setting it for 70 so it would reach my desired target of 68, but then it will run 24x7 (as it has for a while now) and will kill by wallet.

That's why I wonder if the aux heat has a different (lower power?) relay than the emergency setting. Emergency switch works fine...it heats the house up (and raises my bill, I'm sure). But aux heat never seems to supplement the heat pump. Could it be a separate relay/wire/switch down in the internal unit?

I'm going to check the insulation outside (recently replaced), and check for a leak where I can, but this just seems too specific to be poor performance. Thoughts?

How much do you trust the guy/company that serviced your unit last fall? Before he decided you were low on freon, did he check anything else, like temperature differentials? Did he mention what your superheat was?

The first response of these HVAC companies on a maintenance call seems to be to add freon - "you're about two pounds low". But pressure in the system can be affected by a number of things, of which freon charge is only one. Dirty coils can be one cause, but they don't get paid to tell you to clean your inside coils (both sides, not just the side you can see - that's very important). I've even heard of a plugged drain raising the water level to the bottom of the coils creating a "low charge" scenario, though I don't know if this is really feasible.

The problem is, 9 out of 10 professionals will read your post and tell you that your heat pump "is getting old", "on its last legs" and needs to be replaced. "15 years" is a red flag, despite the fact that your HP should last 30 years.

You need to find an honest HVAC tech with alot of experience. Either that or you need to educate yourself on HVAC. It's a complicated subject and IMO closer to magic than say, computer programming or piloting an aircraft. HVAC techs need to be experts in electrical, electronic, fluid, and thermal disciplines - that's asking a lot. Truthfully the good ones should be paid alot more.

As for leaks, odds are the leak wouldn't be in the line-set, it would be on the inside coils. If the leak is on a connecting joint, it can be fixed. If the leak is from pit holes on the coil themselves, the coil needs to be replaced (It can't be fixed cost effectively). Coils can be replaced for about 1/3 the cost of a new system, but HVAC companies will try to talk you out of a "repair" route and into a "replace" route. As for leak checking, prices vary but an HVAC shop should do this for less than the price of a fancy dinner. Giving you an honest answer about the results - well that would be priceless.

Want a good read? Look at http: // www. toad.net/~jsmeenen/ (without the spaces, of course). It's an eye opening site.

btw, I'm just a HO - who has been through all too typical bad experiences with the profession. I'm still looking for a company that refuses to do installs and will only do repairs. That would remove their incentive to announce your system DOA or to do "maintenance" that is harmful to your systems health.

How much do you trust the guy/company that serviced your unit last fall? Before he decided you were low on freon, did he check anything else, like temperature differentials? Did he mention what your superheat was?

Not any more than I can throw them. They are the most reputable company in the area, which is like saying they are honest politicians. And the techs I've had out at the house have been decent guys, with strong knowledge, who even have gone so far to say: "I'm supposed to tell you to replace this, but your unit is clean and in decent order, and if this is the first time you've had to recharge in 15 years, then you're probably fine" -- but that doesn't mean I would trust him to take a bullet for me.

The first response of these HVAC companies on a maintenance call seems to be to add freon - "you're about two pounds low". But pressure in the system can be affected by a number of things, of which freon charge is only one. Dirty coils can be one cause, but they don't get paid to tell you to clean your inside coils (both sides, not just the side you can see - that's very important).

I've been meticulous in my care of this system (except for maybe the filter...sometimes I'm a week overdue on changing that). I clean both sides of the inner and outer coils. I check the insulation along the length of the line. I check/clean the drain line twice a year (when I clean the coils). I've done my best to understand the system as much as possible...and generally I've been able to diagnose/repair situations myself (replace insulation, diagnose a bad switch, needing refrigerant, et cetera). When he came out to put in refrigerant, he checked the line temp, the pressure at several points, the cleanliness/state of the coils, et cetera. He was the best tech I've had at the house...

The problem is, 9 out of 10 professionals will read your post and tell you that your heat pump "is getting old", "on its last legs" and needs to be replaced. "15 years" is a red flag, despite the fact that your HP should last 30 years.

Which is what the company-line to me is. The techs' story is different but they are restricted by their employment contract with the firm. I'd love to find a HVAC guy who would help me maintain this up-til-now excellent HP...

Want a good read? Look at http: // www. toad.net/~jsmeenen/ (without the spaces, of course). It's an eye opening site.

I'll check it out. Thanks!


Cheers,
Jason