Heat Pumps

[FJW]

Hi Jablog

Not sure but just some advise on heat pumps.

If you can install the heat pump on an external wall you'll save far more money as you won't have to duct the pipe work through internal walls.

Make sure that the heat pump is the correct size for the room and that the additional rooms can still get the heat so get them to verify that they are using the correct size.

Get them serviced annually.

Don't always go for the cheapest unit as they can end up becoming the dearest.

Hope that helps

[ivanp]

Get them serviced annually.

By the way, what exactly is done during this annual service?

[Learning]

By the way, what exactly is done during this annual service?

All they need s the air filters to be cleaned and a clear ventilation gap around the exterior unit. Personally I wouldn't waste my money getting them serviced unless there's a problem or it's a condition of the warranty. They work exactly the same way as your fridges and freezers and how often do you get those serviced?

[ivanp]

Exactly. That's why I asked.
Cleaning air filters of the indoor unit once a year is way to late - they should be cleaned every 2-3 months.
Cleaning weeds/leaves around the outdoor unit should be done early, as they appear, and a technician is not need for such task. Also when installing myself I always make a concrete pad and use mounting blocks under the outdoor unit to provide good clearance of the unit from the ground and prevent weeds from growing under the unit and around it.

In my opinion annual service should include check of proper refrigerant level by checking actual subcooling/superheat values, or maybe using some other method. If that's not included, the service is useless - cleaning filters is not that complex to pay for that.

[Wayne]

Get them serviced annually.

Do you recommend to your LLs that they get their heat pumps serviced annually?
Do you waste their money?
I don't think that helps Fraser.

I had a PM tell me, after an inspection, that the filter needed cleaning.
My reply - get the tenant to do it!

[Davo36]

In my opinion annual service should include check of proper refrigerant level by checking actual subcooling/superheat values, or maybe using some other method. If that's not included, the service is useless - cleaning filters is not that complex to pay for that.

Can you elaborate a bit more on this? Like how exactly do you check the refrigerant is still there? What do you mean by "checking actual subcooling/superheat values, or maybe using some other method" ?

[Learning]

In my opinion annual service should include check of proper refrigerant level by checking actual subcooling/superheat values, or maybe using some other method.

It's a sealed system just like a domestic freezer. If there's a leak you'll know soon enough. How are you going to measure the values without compromising the insulation?

If you're not willing to pay an expert to service the heatpump in your kitchen, also know as a fridge, every year then why would you consider paying them to service the heatpump on your wall?

[ivanp]

Air conditioner (heat pump) is supposed to be a sealed system, but it has a service port with a valve on outdoor unit. The valve is similar to the ones used in tires of bikes or cars. This service port can be used any time to connect hoses with manifold and measure pressure etc. This doesn't compromise any insulation in any way. Technician just needs to open a cover on the right hand side of outdoor unit to access this. That's how technicians can check if there's enough refrigerant in system. I wouldn't do this annually, but it's probably a good idea to check this every few years to notice any minor leaks...

There's a big difference between a fridge/freezer and an air con (heat pump): the former is completely assembled on factory in sterile environment, probably using robotics, the latter is assembled by installer who is just a man. Both are supposed to be sealed systems, but clearly one is "more sealed" than another.

Indoor and outdoor units and copper pipes of a heat pump are affected by movements in a timber house, by vibration of an outdoor unit loosely fixed to ground, etc. These movements and vibrations can make the flared connections loose over time, resulting in leaks. These factors are not applicable to fridges.

Also the refrigerant R410a currently used in most air conditioners (heat pumps) has much higher working pressure than refrigerant in fridges (such as R134a or older), therefore heat pumps are more strict to quality (less tolerant to any issues) of installation, cleanliness of the system, etc

[Davo36]

Interesting, thanks guys.

[Bobsyouruncle]

Definitely don't waste money on annual servicing unless you have gone cheap. We have Healthaire in all our homes and they get checked every 3 years. Never missed a beat ever.

[sidinz]

When I bought, there was already a heatpump installed. When I renovated, I got it disconnected. For reasons of space, I can't put the old indoor unit back in and I'll need to get a new wall unit.

But I know nothing about heatpumps. So can I re-use the old outdoor unit, which is still in place? Are the components standardised, or are there compatibility issues to keep in mind?

When you see them mounted high on the wall, does this mean that the pipes are in the framing? How does retro-fitting work? Is it either ugly conduit up the wall or make holes in your gib?

[Learning]

I thought I’d use this thread rather that carry the “on going housekeeping issues” thread further off topic. Mrsaneperson’s last comment reminded me of a story a friend told me. They had a heat pump installed in their ageing mothers flat to help her out over winter. After a few months, she’d stopped using it and complained how expensive it was to run.

Before the heatpump she’d close the doors and just heat the room she was in at the time with a 2Kw column heater. She’d wrap up in four layers with a blanket on top, sit only a couple meters from the heater and maintain a bearable 14c room temperature.

When she got the new-fangled heatpump gizmo she’d whack it up to 30c, strip down to a single layer and heat the whole flat at once. Surprisingly her heating bill more than doubled.

[Wayne]

^ My point exactly - heard the same sort of thing many times (when you quiz people over what they did before and after the heat pump was installed.

Like for like the heat pump is 25% to 30% of the cost of running a 'normal' heater.

[ivanp]

There's no need to have +30C to use a single layer of clothes, we set our heat pumps +21C almost always, and that's enough for single layer

Also setting a heat pump to +30C doesn't make it heat the whole flat any faster than setting it to +21C.

It's just some tenants need some education on how to use heat pumps efficiently.

We had our largest power bills in NZ when we used 2kw column heaters, prior to installing heat pumps. Every heat pump added reduced our bill...

[Anthonyacat]

The temperature you need inside, funnily enough, depends what the temperature is outside. It's all relative.

When travelling Spain in summer and outside was 38-45C, walking into a hotel room cooled to 28C was instantly refreshing. We slept amazingly at 28C. I couldn't bear sleeping at 28C in NZ without a fan or wet towel or something, would be sweating all night.