Only does it when I'm not there...

[HomesteadHVAC]

So, I was sub-contracted by a guy who installs heat pumps but can't hook them up, set them up, or service them. There's lots of these guys out there. At least they're subbing out rather than attempting themselves.

I went to a year old install and found that the heat pump ran short cycles, didn't provide heat, and as the homeowner put it,"released condensation from the condensor periodically".

I found that the wrong piston was installed and that the blower speed was set too high. I also found that their furnace blower was set to run for 3, 30 minute periods in the morning which made them think it was another heat cycle. All is well now except for this "release of condensation" problem. I haven't been there for a few weeks but I was happy with the sc, sh, and delta T. I'm sorry but I don't remember the specifics. I do remember that the return was brought in through the right side of furnace which I don't like, especially since it is trying to move 1600 cfm.

All I can think of, is that it is a defrost cycle but it was 50 degrees outside. Customer said he was working outside and the unit ran for about 10 minutes, shut off, about 10 seconds later it "released a cloud of condensation" and sounded like it was "bogging" or trying to get going again, and then did start up again for 5 minutes and finished heat cycle.

Thoughts??????

[mark beiser]

Defrost cycle.
At 50ºF outdoor temperature, the coil will be operating just below freezing, and well below the dew point if it is humid out.
If it has time and temperature defrost, the unit will go into the defrost mode every time the timer is up and the defrost thermostat is closed, which typically happens around 27ºF.

[Williamsma]

10 minutes is generally the default time for most defrost boards. At 50deg, 10 minutes sounds too long for a defrost. The high pressure switch could be opening shutting off the compressor. Check the defrost termination stat. The other possible reason could be the unit has a soft defrost termination, this feature would stop the compressor before shifting the reversing valve. This was to reduce the end of cycle whoosh when the reversing valve shifted.

[HomesteadHVAC]

Can you explain why 10 minutes sounds too long for a defrost at 50 degrees? I don't understand.
It's a goodman 13 SEER. Just deleted my pics of model and serial a couple days ago because I thought all was well after this long without hearing from the customer.
Mark: time and temp defrost? Do you mean that regardless of the OD ambient, if the unit runs for a certain length of time, it will go into defrost?

[Kevin O'Neill]

Sounds like a shorted defrost thermostat. 13 Seer units usually do not run a coil that mmuch colder (20 degrees) than outside.

[dlove]

wait until it early morning when its not looking and sneak up on it. When it does it again. you Jump out and catch it...HA haaa gotcha..

[mark beiser]

Mark: time and temp defrost? Do you mean that regardless of the OD ambient, if the unit runs for a certain length of time, it will go into defrost?

If the defrost thermostat is closed, yes, it will go into defrost every time the timer is up, usually either 30, 60, or 90 minutes.
The defrost cycle lasts until the defrost thermostat opens, typically in the 65-70º range, or for 10 minutes, whichever comes first.

[HomesteadHVAC]

Thanks Mark, I'll have a look at the board. I haven't looked at this one yet. The heat pump may be working just fine. It's worth one more look to satisfy the customer and to educate myself more.

[courttech]

sounds like its working normally...does it have a quiet shift dip switch or dip pin which stops the compressor when shifting the rev valve during defrost

[Milk man]

At least they didn't call and say it was on fire when the steam raised from the unit.

[HomesteadHVAC]

I'll look for the dip switch this week.
Milk Man-haha, yeah, it could have gone that way I guess.

[courttech]

on carriers it says quiet shift on armstrong air it is a pin you take off that says delay...

[HomesteadHVAC]

And on Goodman?

[mark beiser]

And on Goodman?

Goodman doesn't have a "quiet shift" type option.

[courttech]

man...they all have their own thing...some dont have it at all....york affinity is yet another dip switch labeled something else and in a different spot...you need to get the contact numbers for all the different distributors...also its all in the manuals if they are on site. have fun..i did and still am...wait till you hit a commercial job with backview, back net, novar, emerson, microthermal, and chubb alarms monitoring, etc all different controls interlocked to sort through...there is no winning just remember, you didnt break it your just tryin to fix it. If I find out the goodman thing i will post it though.

[courttech]

Apparently they do...http://hvac-talk.com/vbb/showthread.php?t=994801

[mark beiser]

Apparently they do...http://hvac-talk.com/vbb/showthread.php?t=994801

I'll have to look into that, thanks.
I don't suppose the new control is a demand defrost instead of time/temp is it?

[HomesteadHVAC]

Well I went back to the heat pump to find that everything is working excellent except they don't like the defrost sound. Who does? I found a YouTube video of a Carrier going through a defrost cycle and showed it to the homeowner. She agreed that the heat pump makes a horrible sound and evaporates some steam but sounds different. I told her she has a Goodman, not a Carrier. It will sound different. She finally agreed.
I think a lot of homeowners have unreal expectations of sound levels and duct temperature. The good news is that I didn't sell her this 13 SEER unit without sound blanket so I don't have to explain myself, lol
Thank you for your advise.

[Kevin O'Neill]

You can sell her a sound blanket for her compressor. It will make it better. She will give you a big hug!

[Saturatedpsi]

So, I was sub-contracted by a guy who installs heat pumps but can't hook them up, set them up, or service them.

..and just when I thought I'd seen most everything.