Heat pump condensate pumps

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traderstu

332 posts

Ultimate Geek

#274570 29-Aug-2020 10:11

We have a Panasonic high wall heat pump installed on an inside wall of our house. A Mini Blue condensate pump has been fitted in the ceiling space. The only control connected to this pump are a pair of temperature probes that switch the pump on when the a/c is cooling, and turn the pump off when the a/c is heating.

We would like to fit a second high wall heat pump (probably another Panasonic) and are in the process of getting a couple of quotes. Both companies have confirmed that we will need a condensate pump for the new installation, one salesperson mentioned that if the condensate pump fails, the drip tray will overflow and we will end up with water running down the wall. I asked if there was any sort of safety switch that could be fitted to overcome this problem, he didn't know of anything, I asked him to raise this with their installers, the quote has come back with no allowance for this. (we are still waiting for the other quote).

A quick google tells me that there are options available like float switches, or mini tanks with integral safety switches that are small enough to fit between the wall and the indoor unit, and even miniature tanks and pumps that both fit behind the high wall unit. Has anyone had experience with this? Does anyone know of a safety switch that could be retro fitted to our existing heat pump? Is there a more elegant solution that I could specify for our new install?

Thanks in advance.

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3968 posts

Uber Geek

Lifetime subscriber

#2551817 29-Aug-2020 10:39

Assuming the room is regally occupied, and the overflow path is in a viable location it is unlikely to be worth the cost.

OldGeek

894 posts

Ultimate Geek

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Lifetime subscriber

#2551828 29-Aug-2020 10:56

I recently rented a property with a similar setup - heat pump on an internal wall with a condensation drain pump. This unit had a float switch on the condensation drain. Switching the unit off at 10pm on a summers evening then having the pump roar into life at 1am (because condensation continued to drain after the unit was switched off) was not a good thing. Getting the landlord and a serviceperson involved exposed me to all this.

The best solution is a condensation drain - no pump involved. If this is not possible you will always be vulnerable to a pump failure no matter where it is located or how it is switched.

--

OldGeek.

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SomeoneSomewhere

1804 posts

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Lifetime subscriber

#2551856 29-Aug-2020 11:19

Most pumps have a second set of safety contacts that operate at a higher water level than the normal ones that turn the pump on. These should be wired to stop the unit, but this isn't always done. Breaking the signal wire between the indoor and outdoor is easiest as most high-walls don't have a dedicated force stop input.

If the pump is noisy, it is likely either not fully primed (put a litre of water through it), or faulty. Most modern ones are quieter than the unit by some margin.

traderstu

332 posts

Ultimate Geek

#2551897 29-Aug-2020 13:02

Thanks for your comments.

This is the sort of thing that I have in mind. Cost is a couple of dollars.

What I am not clear on is whether or not the drip tray is deep enough to allow it's installation and operation. If it is, I'm guessing that the 'signal wire'could be broken at the indoor unit. Is this low voltage, or would my float switch need to be wired with a relay to achieve this?

@Oldgeek, noise of the pump is not an issue here. The mini Blue pump is dead quiet and will run dry, and in any event, what I am trying to achieve is to shut down the heat pump in the case of a condensate pump failure.

traderstu

332 posts

Ultimate Geek

#2551899 29-Aug-2020 13:06

Sorry, should have uploaded the dimensions:

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#2551920 29-Aug-2020 13:46

You can't put it in the unit drip tray. It needs to be in the pump's holding tank.

The signal wire is low voltage but not isolated from mains, so it should be rated to switch mains.

I would replace the pump when you get the new unit installed, and get them to hook up the fault contact.

traderstu

332 posts

Ultimate Geek

#2551929 29-Aug-2020 14:14

Thanks @SomeoneSomewhere, I shall do that.

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bfginger

1268 posts

Uber Geek

#2552043 29-Aug-2020 19:49

The Panasonic cassette heat pumps should have condensate pumps built in which would negate the need for third party add on pumps which can have a reputation for unreliably.

See page 24-29

https://www.panasonicaircon.co.nz/brochures/bro-ac-pac1920

SomeoneSomewhere

1804 posts

Uber Geek

Lifetime subscriber

#2552178 29-Aug-2020 23:13

Practically all cassettes do, as the normal install location essentially means that you can't have a gravity drain from the bottom of the unit.

I haven't seen cassettes mentioned anywhere else in this thread, so I'm not sure it's relevant.

Cassettes are rarely very practical in domestic situations, especially retrofit - you have to mess with framing, they require a big hole in the insulation, aesthetics, and cost.

traderstu

332 posts

Ultimate Geek

#2552319 30-Aug-2020 11:40

Yes, the company that I am still waiting for a quote from is going to price a cassette as an alternative option. I have pretty well ruled this out for the reasons that you mention. There is really only one location on the ceiling where an "aesthetically acceptable" install could be achieved, taking into account the location of light fittings etc, but this will mean that it is sitting directly over the dining room table and will blow air straight at the island bench in the kitchen. I know that the salesperson gave no consideration to the location of trusses or ceiling battens so I am certain that the positioning will be less than ideal. And to my eye, a high wall unit looks better than a cassette.

I still find it a bit strange that there is not an "off the shelf" solution to the leakage problem, after all this can occur in a gravity drain system as well. Perhaps I am over thinking things.

Kickinbac

427 posts

Ultimate Geek

#2552687 30-Aug-2020 22:32

traderstu:
Yes, the company that I am still waiting for a quote from is going to price a cassette as an alternative option. I have pretty well ruled this out for the reasons that you mention. There is really only one location on the ceiling where an "aesthetically acceptable" install could be achieved, taking into account the location of light fittings etc, but this will mean that it is sitting directly over the dining room table and will blow air straight at the island bench in the kitchen. I know that the salesperson gave no consideration to the location of trusses or ceiling battens so I am certain that the positioning will be less than ideal. And to my eye, a high wall unit looks better than a cassette.

I still find it a bit strange that there is not an "off the shelf" solution to the leakage problem, after all this can occur in a gravity drain system as well. Perhaps I am over thinking things.

Maybe you are overthinking things. Whats the worst that will happen if you have a leak? Its unlikely you wouldn’t notice, turn the unit off and then get it fixed. Even A/C units with gravity drains leak occasionally for a number of reasons.

Shanemc

76 posts

Master Geek

#2552882 31-Aug-2020 09:59

We have a Panasonic high wall with a condensate pump. In my daughters bedroom.

Has been a bit of a pain.

I think it was sitting on the pink batts in the ceiling, but must have moved against a roof joust. We started getting this strange noise and vibration. Didn't know what it was, Initially thought there was something wrong with the heat pump. It would happen quite randomly, even after the heat pump was off. Drove my daughter mad.

Then it failed anyway, around 3 years after install. Had a look at it and part of it had melted - perhaps lying on the pink batts wasnt a good idea. It was a min orange one.

I'm going to run a gravity drain across the wall instead, as we are planning to paint the room anyway.

Would avoid if you can.

traderstu

332 posts

Ultimate Geek

#2552915 31-Aug-2020 10:54

We have a mini blue pump in the ceiling space on the existing heat pump. The electrician has hung the pump from a daisy chain of zip ties. It doesn't look very elegant but it certainly eliminates the possibility of your noise problem. I was in the ceiling space the other day checking out it's operation. Admittedly, I was standing alongside the smart vent unit (running) but I couldn't hear the mini blue pump running. I could feel a slight vibration when I touched it.

Trying to organise a gravity drain in our situation would be a real mission, a frankly, something I am not willing to contemplate. I'm inclined to specify another mini blue pump. The 3 year warranty (5 yrs on a Mitsubishi) is quite enticing. Both of my sales people have mentioned a 1 year warranty - I don't know why they would do this when the mini blue pump is available in nz with a much better warranty. The price is not bad either at $299 rrp. The quote that I have had back includes an allowance for an un-named pump @ $400, with a 1 yr warranty.

@Shanemc, when yours failed how would you describe the leaking water? Was it a drip or a flood? I hope your not having to redecorate because of the mess that the heat pump made.

traderstu

332 posts

Ultimate Geek

#2552916 31-Aug-2020 10:54

@Shanemc, when yours failed how would you describe the leaking water? Was it a drip or a flood? I hope your not having to redecorate because of the mess that the heat pump made.

esawers

551 posts

Ultimate Geek

#2552920 31-Aug-2020 10:59

We had the same problem, decided to use the air conditioning for the first time a year or two ago, and during the night the whole house would shake for 7 seconds at a time, every 15 minutes.

Drove us batty, I ended up switching everything in the house off trying to isolate the noise, until I turned off the heat pump using the outside switch and the noise stopped.

Now we just don't use the air conditioning ;)

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