Wrong heat pump installed, now what?

March 16, 2020 8:06 AM

I signed a contract to have a Mitsubishi MXZ-3C30NAHZ2 installed, they installed a MXZ-3C30NA2. The contractor's proposal is to "upgrade" the installed heat pump exterior unit with a crankcase heater and some boards. They also propose to pay the difference in rebates. They say that it will not violate the warranty since it will be all Mitsubishi parts and they talked to the factory representative. Is this possible? Should I just ask to have the wrong one removed and the correct one installed?

I'm concerned that this idea is just not going to work. I'm specifically concerned that the contractor thinks there is a MXZ-3C30NAHZ (no 2 at the end) installed at my house and that it can be upgraded to a MXZ-3C30NAHZ2 (with a 2 at the end). I emailed the contractor with this concern and they did not respond to this detail.

I'm concerned that this is not going to be warrantied even if they say it will be. If there is a recall or something and a technician from another company comes out they will say "I can't fix your unit because it is a mishmash of parts."

I live in upstate NY and want to use this for my primary heat during cold winters. While both these units are rated for colder temperatures, I understand that there capacity is reduced as they near the lowest temperatures they operate at.

I would like to just have the existing unit removed and an MXZ-3C30NAHZ2 installed.

Does the contractor's proposal seem possible? How do I verify that it is possible and warrantied? What is involved in removing the existing unit and installing a MXZ-3C30NAHZ2?

posted by bdc34 to Home & Garden (5 answers total)

Best answer: I have a heat pump - not that one though - and am located about 50 miles north of NYC. It looks like the most significant difference in the two units is the reduction in capacity as temperatures get lower, which is exactly what you're worried about. Without knowing more about how it's actually built I'd say that yes, it's possible that the same effect can be achieved with parts. I doubt it can be achieved at the same efficiency. However, if you've just had it installed and you have some leverage over them (i.e. you haven't paid them in full) I would push to replace the unit. It should not be difficult for them to replace at this point. It's probably a 1 day job.

Paying the difference in rebates would be a non-starter for me. They paid less for this unit, you should too. I would probably be ok with a "add some parts, pay me the cash difference" and take my chances on the warranty stuff, but I'd prefer the replacement if possible.
posted by true at 9:27 AM on March 16, 2020

Don't count on the warranty being honored unless you get it in writing form the manufacturer. Even then, I'd be wary.
posted by Tabitha Someday at 9:32 AM on March 16, 2020 [2 favorites]

Best answer: They installed a device with a different duty cycle from the one you agreed to. I'd insist it be replaced, at their cost.

If there are specs or engineering drawings that say you need the MXZ-3C30NAHZ2, the work's not done until there's a working MXZ-3C30NAHZ2 on your property. If you're going for the NYSERDA rebate, the contractor needs to be approved and part of the approval includes a checklist and (possible) 3rd party audit. If your device doesn't match the application and spec documents, you may not receive the rebate at all.

In a past life I was a renewable energy project auditor for provincial subsidies in Ontario. My projects were larger, but most subsidy programs come with a fairly fierce audit requirement because the administrative expectation is that there will be fraud. "Is the contracted device actually installed?" is check number one.

You're not being difficult in any way about this. The contractor goofed and is at fault.
posted by scruss at 9:53 AM on March 16, 2020 [4 favorites]

There was actually a similar problem when I got an AC installed; there were some part revisions and the newer model didn’t have exactly the same specifications. This impacted a rebate and the vendor gave me a discount to compensate. In theory the unit I got is a hair less efficient but the simple fact of the matter is it’s not something I’d ever notice.

For the upgrade part I’d ask for a letter from the upstream vendor (Mitsubishi) confirming suitability and then just go with it. Throwing away a complete AC unit is pretty bad for the environment, and they can’t be ethically reinstalled once initially opened.
posted by doomsey at 3:03 PM on March 16, 2020

Response by poster: In the end I asked the installer to install the correct unit. They pushed back some more but I just kept to short requests and answers. They report that the company they bought the unit from sent the wrong one. The installer removed the refrigerant and installed the correct exterior unit. The first unit is going to be reused at a discount to a customer who is aware of its history.
posted by bdc34 at 10:33 AM on June 9, 2020