Warm Weather Needed For Optimal Charge?

[jjnet]

Our new two stage heat pump came pre-charged for about a 15 foot line set. Ours is almost 40 feet, so it’s likely we need a careful charge involving some additional refrigerant. Our dealer has emphasized in the past that relatively warm weather above 60 is important to getting the charge correct.

After waiting 14 months to have our heat pump moved onto its pad from our driveway and 3 months for the lines to be brazed, these two things were finally done last week. But the individuals who connected the lines and tested the vacuum did not check the charge or add any refrigerant. They told us that the dealer would do the pressure test, etc., when he gets around to it. A quick call confirmed that he has no plans to do so in the short term. He told us he didn’t know when he could make it out here, but it would be at least several weeks and possibly several months.

We’re now in the final days of 55-60 degree weather for this fall. Within a short time we’ll have to wait for spring to find a day warm enough for ideally charging the system. How much does this matter to the efficiency of the heat pump in the upcoming heating season? Should we contact another dealer to have the system charged while we still have some warm weather left, or is it reasonable to go through a first heating season with potentially too little charge?

[12stones]

If this is a heat pump there should be charging instructions for charging it in the heat mode. Your contractor doesn't know what he is talking about if he is telling you he needs 60+ degrees to charge yours. I would find another contractor to get you running. The charge is very important in getting the correct amount of heat out of the unit.

[jjnet]

Thanks 12Stones, that's the info I needed. If there is a good procedure for charging in the cold, then I can give the contractor a month to make it out here. If he just can't get to it in that time frame, then I can call someone else at that point.

[tim fox]

you need the right charge in it if you are using it at all or you can damage the compressor.

[jjnet]

Thanks, Tim. We are not planning on powering up the heat pump until we have confidence that it's been correctly charged. Our contractor has told us that it's safe to fire it up with the factory charge, but we prefer not to.

[Black Adder]

Why didn't the tech measure the length of the lineset and at least add the recommended amount of refrigerant to make up the difference between 15' and the true length. As far as getting the correct charge right on the money, yes you do need warm weather and charge in cooling mode. You can come pretty close in heating mode but I always find it is more accurate in cooling mode. At the very least they can check the charge and at least get you running for the winter.

[BaldLoonie]

I've never trusted the factory charge but new heat pumps come with winter charging charts so you don't have to wait til spring to run them.

[tinknocker service tech]

any pro that knows heatpumps can charge then anytime of the year. yes it can be easer in the warmer months but there are times when life isnt perfect and to tell a coustomer you have to wait till summer for heat is just stipid. call a real company to finish the job
i have to ask. why has this gone on for this lenth of time?
why are you so willing to fall for this line after you have spent a lot of money on a new unit that has taken almost two years to install?

[mark beiser]

As others have said, they could have weighed in the "correct" charge based on the length of the refrigerant lines.
The unit can also be charged in the heat mode.

It is most accurate to charge in the cooling mode on warm/hot day with a normal load on the system, especially with fixed metering, but it isn't particularly difficult to get the charge very close when the conditions are not ideal.

[jjnet]

Thanks to all. At least now we have some idea why we were told that warm weather is best for charging. We were surprised and disappointed that the people hooking up the line set did not even add the recommended refrigerant for the difference between the 15 foot factory charge and the actual 40 foot length. We were even more surprised to be told that the visit to finalize the charging could not even be scheduled yet. We appreciate that people are busy with bigger projects, and we would prefer to keep the work with one contractor if possible. We will wait a month and then call in another contractor if there's no progress.

[beenthere]

I hope you didn't pay this guy yet.

14 monthes?

[smokin68]

14 months,then 3 months to braze lineset. This has to be a charity job( you're not paying anything or very little aren't you?) Nobody in their right mind would let their new heatpump sit in their driveway long enough for the warranty to expire,unless it was a freeby. Yes it can be charged RIGHT NOW, but you'll have to hire someone that knows how to, and that costs $$$$.

[jjnet]

Ours is not a freebie or charity job. Our contractor was paid for all the equipment at a normal markup almost exactly two years ago. To give you an idea of the markup he earned, our Carel humidifier sells at Johnstone for roughly $700 and we paid him $1200. I expect the Trane two stage XL19i heat pump and variable speed air handler had a comparable markup. All ductwork supplies were marked up 30% above Johnstone’s prices.

When we initially looked into forced air AC/heat with humidification we were told by four different contractors that the only way our house was ever going to get ducts was if we put them in ourselves. Duct installation required careful long-term planning to move out of one section of the house at a time while walls and ceilings were dismantled, ductwork was installed and then the whole business reassembled. We were told that even if they had a crew they could spare that long for one job, the duct install alone would cost $50k + and could never be financially justified.

The Trane equipment was delivered in early November, 2003. Trane recalled the heat pump and the replacement was delivered to our driveway in August, 2004. When snow started to fall in November, 2004, we told the contractor that it was greatly to his advantage to have the old heat pump removed and the new one on its pad before we had a major snowfall. He showed up unannounced on the day after Thanksgiving, 2004 and removed the original heat pump. He said that the trucker dropped the new one off too far from the pad and that he could not place it on its pad that day without additional equipment.

The first big snowfall hit in early January, 2005. It was a record-setter and required a backhoe to create a path to our house. There was no way that the heat pump was going to get to its pad before April or May.. When the snow finally melted, we found that despite everyone’s attempts to plow around it, the fins on the uphill side of the pump were badly dented. Fortunately, there appeared to be no damage to the coil itself.

We spent the first six months of 2004 consulting with several contractors on a manual J load calc and Manual D duct layout plan. After putting a lot of furniture, etc. into storage, we began to move out of the first sections of the house in November, 2004. Duct installation proceeded gradually as we had time and was finally finished in July, 2005. By that time the heat pump had been in our driveway nearly a year.

Our project was obviously at the bottom of the priority heap for our contractor because he was waiting on us for the undetermined amount of time it would take to get the ductwork in. We expected this and for that reason found it reasonable to wait for the heat pump setup and lineset brazing and charging from July into late October. That doesn’t explain why the charging wasn’t done after the lines were brazed and the vacuum checked. But you can see why we find it reasonable to give the contractor a month to get to the charging. New construction in our area is booming and every decent HVAC contractor is buried under current work and preparing bids for upcoming systems. Ours is just a little project in the middle of all the large custom home and commercial development work that’s happening around us.

And it’s not critical to get the system up and running in any particular time frame. We built our house in 1979 and have gotten by for heat just fine for 26 years with passive solar and a wood stove. A couple times a year when we’re in too much of a hurry to light the stove we turn on the electric baseboard heat. Except for the imminent loss of warm weather until spring, there’s no reason we need the charging done immediately.

We’re not trying to take work from the pros to save money and we’re not a charity case. We just wanted a forced air system and this is the only way it could happen.