Can I run my washing machine drain line into a condensate pump so it drains better?

Question

I have this ventless combination washer/dryer from LG:

https://www.lg.com/us/washer-dryer-combos/lg-WM3997HWA-washer-dryer-combo

The unit is installed on an upper level of my house. It's on the other side of the wall from a bathroom sink. They use the same supply/drain lines.

The drain pump in the washer recently burned out (one month after the warranty expired, of course).

Apparently this is a common problem when draining the unit into a wall drain, as opposed to a floor drain. Even though the instructions clearly say that a wall drain is fine, the drain pump is underpowered and can't capably move the water 2' up to the drain. This causes dry cycles to be extremely long, and the pump to eventually fail.

I know that the main options are:

1. Install a floor drain. I suspect this will be much more trouble than it's worth, since it'll mean taking up laminate floors, running new lines, etc.
2. Install a lower wall drain. I don't think this will work since it would be downstream of the sink, and I'd need to re-do all the venting.
3. Put the washer on a pedestal so the drain pump doesn't have to pump up.

I'm wondering if there's another option: get a condensate pump (like the one our central air conditioner uses), put it on the ground next to the washer, drain the washer into the pump, and have the pump force the water into the wall drain.

What I like about this idea:

• Condensate pumps are much less expensive than pedestals
• It's very quick to install
• I don't need to lift a 200-pound washer onto a pedestal

But I'm not sure whether a condensate pump can handle grey water from a washer.

Thoughts?

Answer 1

I think you have a couple of factors to consider in using a condensate pump.

One is the volume of water per unit time relative to what the pump can handle. A condensate pump is going to expect a trickle flow from the air conditioning system.

When used as a washing machine pump, the float will rise as the reservoir fills and activate the pump. Will the condensate pump remove water at a rate to match or exceed the washing machine?

Washing machines work in cycles. If the reservoir is too small to handle a maximum load cycle and the pump rate is too low, flooding may result.

On the other hand, if you can supplement the reservoir in some manner, the pump rate becomes less critical.

I don't think the water "quality" is going to be a problem. The output of a washing machine is grit/sand/dirt/fibers. The heavy stuff is going to collect in the reservoir and the suspended stuff is going to be pumped. I have a filter on our washing machine that catches all the washed-out material that used to enter my septic tank. I'm amazed at the grit/sand quantities, but also at the shed fibers that are captured. The low cost pumps typically use an impeller which is resistant to problems related to suspended material found in a washing machine output.

Answer 2

I'm not aware of any condensate pumps capable of handling that much water but you could use a small sump pump in a suitably sized basin. There is a condensate pump on Amazon that claims 4 gpm but I'm sure just about any washer drains more than that. The condensate that comes out of a furnace or boiler will be more corrosive and harsh than the water coming out of washer. That's not the problem, the capacity is.