calibrated orifice DFS2A

[Icehouse]

Since he is dealing with very low ambient temps, this system may not operate correctly under 68 degrees outside. He really needs a heat pump capable of defrosting itself.

That or a professional. 

[JWWebster]

Did the quarter inch tubing come with the mini split or was that something you got on your own Pat?

[maypo52]

I was following this post because I have a similar problem with freezing, and I think your comment about the indoor and outdoor temps being the same is my problem. I just had a couple of questions. If the outside temp is say 70, and the thermostat is set for 78 but the temp inside where the thermostat is 80, so the unit is still running trying to drive it down to 78, but the indoor temp at the "A" frame which is in the basement is about 70, Is that the scenario that will cause the freezing of the "A"frame? Is there anyway to prevent the system from freezing up? When you said "block off the condenser" did you mean to cover the vent on the outside unit to prevent the cooler outside air from flowing over the coils?  Hope that made sense to you. Thanks for any help you can provide.

Mark

This system will not operate correctly because the "outdoor temperature" is nearly the same as the "indoor temperature".
The unit is so efficient that too much refrigerant is condensing in the condenser. Remember that this is a critical charged unit, therefore the condenser,evaporator,suction line and liquid line will contain the proper amount of refrigerant. If at anytime there is an unbalanced condition, the system will fail to operate in the prescribed manner. The condenser has too much refrigerant due to the low ambient therefore starving the evaporator thus resulting in lower pressure which results in lower temperature (frost accumulation).
To remedy this situation, block off the condenser allowing the head pressure to build up to a corresponding pressure of a 95*F day. You will then notice the suction pressure will also rise and now is the time to check the superheat.

[JWWebster]

If you was in someplace colder like Nova scotia then you might want to jacket the outside unit to mimick the outside temp of summer. I wish he would say who concocted that smaller tubing idea. I can already tell ya the answer. The tubing was suppiled by you and since you went cheap with a minisplit you decided to go cheap with the copper. Just a guess.

[patvac]

hi, jw the mini slip i bought was a kit.
condenser, compressor, pipping and sleeve to go over it.it cost over 1200$because a friend got a discount for me of 300$. Local shop around sell it 2000$ install. After the test with the jacket and risses of temp over 85 degree peaks at around 95. Units work perfect (it's cycling on and off, no freezing of the coils). Unlikely i dont have the tools suggested by icehouse  but definitly it's a charging problem( bad gas quantity)I would like to go the way superheat  and ...)
to bad i dont have the special tools...

thank for your help and your patience

[JWWebster]

Je suis heureux vous l'ai obtenu fixe!

[patvac]

thank you