Installing heat pump during cold weather. Can it be done accurately?
I had a HVAC specialist (with a refrigeration license) tell me that he can not accurately determine the amount of R410 to put into my heat pump system because it was too cold. The ambient temperature was affecting the accuracy of his pressure measurements and he can not get any R410 out of his pink canister. He asked to come back when it was at least 50F outside.
Is this possible? I am assuming that there is a way a rounded this "problem" otherwise no heat pumps would be installed (or sold) during winter.
there is a way
it takes many years of experience and/or proper teaching for a tech to do it properly
even at 15 degrees and lower, the tech should be able to get the correct charge within 5-10%
Is lacking in training.
I don't care if its R22, or R410A.
You can charge it in winter at cold temps.
We get them as close as we can in the winter, then return in cooling mode to make sure it is perfect.
I'm very accurate no matter the temp, because I can weigh in the charge on a new heatpump.
It can be done. It can be a pain in the butt. I always like going back when it gets warmer and check them out anyways. As long as he's coming back out and not charging you to do it and you've been satisfied with the changeout anyways. Don't make a big deal out of it. He seems like a pretty conscientious guy if he's going to do that. You'll probably find it's not that far off from where it should be regarding the charge. Most of them aren't unless you have a really long or really short lineset.
I like DIY'ers. They pay better to fix.
He is not too consciencious if he left them with no heat pump and heat strips to take care of the rest of the season. they will be wasting alot of money without the heat pump operational.
Get someone else,... besides to do a proper subcooling procedure the outdoor temp needs to be at least 70 degrees, not 50...
We install year round and it get colder than a witch's *** here. Weighing in would mean you would start from scratch. Not something you would do with a new unit. Barring a leaker from the factory, calculating and weighing in for line length would be the only extra charging normally needed on a new start-up. Manufacturer's give you a temp / pressure chart for heat mode to make sure your close if you start up in cold weather. We go back once the frost is off the pumpkin and double check but I can only think of 2 times any adjustment of charge was necessary, and it was minimal.
A good HVAC tech knows how, an educated HVAC tech knows why!
Originally Posted by ascj
heaterman: why would you start from scratch? You just need to figure out how many feet of liquid line you have in the system and subtract 15 ft from it for your factory charge and add about 0.6 ounces refrigerant per ft of remaining liquid line.
ie... 50 ft line subtract 15 = 35ft
35ft x 0.6 ounces/ft = 21 ounces
convert to pounds if needed / 16
21/16 = 1.3 pounds
add an additional 1.3 pounds or 21 ounces
Be sure to use a liquid metering device when topping off R-410.
How do you know?
I used to refer my customers to this site as a backup to what I told them in the field, but I don't do it anymore because of posts like this. You NEVER have the full story unless you are standing right there! Did the installer just get done installing and the jug has been sitting in a cold truck all day? What kind of heatpump is it, does it have expanded data to allow getting the charge closer until Spring? I had a customer this week I had to get the charge close in heating mode and told them I would have to come back when its above 70 in the spring. If they came on here....depending on how they worded their question would you be recommending "get someone else"?
Originally Posted by Sonicview
Give a man a fish, he will eat for a day. Teach a man to fish, he will eat for a lifetime.
Give a man a capacitor, doesn't know what to do. Teach a man to install it, now he knows everything.
I agree with beenthere.. It is possible to change out any refrigerent... extreme cold takes a
little longer but is done all the time...
I will put the ladder away cuz I am inexperienced but smarter than u!
I think you missed that it was a new install, which you would just charge by weight.
Originally Posted by beshvac