Air Source Heat Pumps

richardc1983

Samtheman what does it state exactly in your manual.

In my manual doesnt state anything about the outdoor unit being cleaned.

So i guess its upto the installers to pass this info and reccomendation on as was passed onto me when installed.

Cardew

richardc1983 wrote: »

Samtheman what does it state exactly in your manual.

In my manual doesnt state anything about the outdoor unit being cleaned.

So i guess its upto the installers to pass this info and reccomendation on as was passed onto me when installed.

If installers had their way it would be need to be cleaned weekly by specially trained fitters.

thechippy

I agree Cardew,

There are always engineers that will try and rip you. Some advise a quarterly service, which is just a nonsense.

Why some manufacturers advise a 12 monthly service and some don’t mention it at all, I don’t know.
Rest assured though, if you have a component failure during warranty and they feel it’s due to lack of servicing, they won’t honour the warranty. They will do the same if they think it was the result of a poor installation.

The condenser is the single most important part of the system. It’s the primary heat exchanger.
It removes latent heat from the air in the winter for your heating and discharges it in the summer for your cooling. You only need a minor coating of dust / dirt on, or in the fins to reduce the performance.

I’ve come across 6 month old systems with filthy condensers - if left for another 6 months, a compressor failure would have been likely. Compressors are VERY expensive to replace. The compressor is expensive in the first instance and on most heat pumps, they are fiddly and time consuming to change.

Mind you, I’ve also seen 6 month old systems with very clean condensers - it depends on the environment they are in. However, it’s just not worth taking the chance. Remember that the engineer should also be checking for any fault codes they may have arisen and checking the refrigerant charge - both of which could prevent an expensive future fault.

In my experience the most common causes of a compressor failure are;

1. Dirty condensers
2. Poor initial installation
3. Refrigerant shortage

richardc1983

thechippy wrote: »

I agree Cardew,
Remember that the engineer should also be checking for any fault codes they may have arisen and checking the refrigerant charge - both of which could prevent an expensive future fault.

I get comms error fault coming up a lot. Have to reset at the mains.

Cardew

thechippy,

I seem to be playing the Devil's Advocate all the time on ASHPs - and yet from what I have read, and my experience, I am quite enthusiastic about the systems.

I am approaching this from(I hope) from an engineering background.(I am a Chartered Engineer - albeit electrical, and not earning my corn in that field..

Firstly how do you know what caused a compressor failure? Have the units been sent back to the manufacturers for analysis? Where are the results published?

If dirty condensers are critical - why no 'health warnings' from the manufacturers?

I serve on the Board of a complex in the USA where we have 125 ASHP systems. Situated on the beach, they are exposed to one of the most saline environments on earth.

They are between 5 and 6 years old and absolutely encrusted with salt, and we are just beginning to experience some failures. None have been serviced!

In UK there is a culture of 'jobs for the boys' and too many vested interests carving a lucrative income for themselves.

Boilers can only be serviced by Corgi fitters(or whatever they call themselves these days - RGI?) and the safety card is played all the time.

Unless you are a certified electrician, you can just about change a 13 Amp plug without falling foul of the law.

My expensive car costs a fortune to service, which is essentially an oil change.

One of the advantages of heat pumps was low maintenance - now 6 monthly servicing??? Mmmmmm

thechippy

Cardew,

Yes, compressors are often inspected when returned under warranty and they can tell the cause of failure!

Salty air is not the same as dust leaves and general filth.

I don’t “play the card”, or try and get myself unnecessary work.

All my work is through reputation because I’m honest and fair.

I have NOTHING to gain by giving advice on this forum. I use my own free time to advise you guys impartially as I’m in the trade and I feel it may help - is that ok??

I’m fed up of repeating myself and reiterate post 144

Let’s get this straight - are you calling me a liar!

thechippy

richardc1983 wrote: »

I get comms error fault coming up a lot. Have to reset at the mains.

I'll look into it Richard.
Might take a few days though, as I'm a but busy at the mo..;)

Cardew

thechippy wrote: »

Let’s get this straight - are you calling me a liar!

Lets also get this straight.
On an internet discussion forum, pointing out that your opinions appear to be at odds with the manufacturer's recommendations is a perfectly valid line to take.

As I said I appreciate the knowledge you bring to the forum, and it is fairly easy to spot bulls**t when it is being posted - and you do not fall into that category.

Until you posted the 6 monthly servicing requirement, I had never seen anything about that in the literature I have read.

I would point out that it is not 'salty air' I am talking about, but thick encrusted salt.

If you are correct about the 6 monthly servicing requirement, it will deter many people from getting an ASHP system.

thechippy

Hi Cardew,

If the ASHP’s which are encrusted in salt are slightly over spec, then they may be able to cope for a while, as the additional load can be “absorbed“. However, their service life will have been reduced overall - the compressors will probably fail earlier than they may have done.

I don’t have any idea why the manufacturers don’t emphasise the servicing of the outdoor unit and this seems illogical to me.

As I said, I have seen filthy condensers at 6 months and clean ones - depends on the environment.

I advise 6 monthly intervals, as it’s just not worth paying £600+ for a compressor change for the sake of £60-80 per year.

As I also said, it depends on the engineer - you need someone who is honest and you can trust. Local clients, I only charge £15 if I carry out the service when passing. Further than that, you must understand, that you have to take into account travel time, fuel etc. If someone is more than an hour away from me, I will advise the client to try and find a local engineer, as they will be more competitive.

Sorry if I appeared harsh, I just try to give honest advice and tell it how it is based on over 30 years of experience.

paceinternet

A few different approaches to ASHP maintenance.
I think you have the industrial/commercial camp who advocate service contracts, and for some customers, it is an insurance that they are doing something correctly. But there are many users who do absolutley nothing on a routine basis, and get by ok. If it stops working, it is usually a refridgerant issue, and they get it fixed.

Opposite end is the similar machine called the domestic refridgerator which gets zero routine maintence in it's, generally, very long life. But it does operate in a clean environment.

Here we have an ASHP product directed at the consumer, and depending on the environment, it will run for many years if it is kept clean. That cleaning process is simple enough for most competant people to do, and for the cost concious user, routine service engineer visits will not be necessary. As has been said, these products are often advertised as needing no maintenance.

Seems to me to be in the same situation as gas boilers, where a check/clean every year will mostly reveal absolutely nothing needs doing. So you have some people who are persuaded to have it done, and others who are comfortable doing it less frequently. You can be sure these people would do it regularly if their experiences were that by not doing it, they were suffering.

"Cardew",
Below is an extract from some Mitsubishi documentation which you may find helpfull:

1-4. PRECAUTIONS FOR SALT PROOF TYPE "-BS" MODEL
Although "-BS" model has been designed to be resistant to salt damage, observe the following precautions to maintain the
performance of the unit.
1. Avoid installing the uint in a location where it will be exposed directly to seawater or sea breeze.
2. If the cover panel may become covered with salt, be sure to install the unit in a location where the salt will be washed away by
rainwater. (If a sunshade is installed, rainwater may not clean the panel.)
3. To ensure that water does not collect in the base of the outdoor unit, make sure that the base is level, not at angle. Water
collecting in the base of the outdoor unit could cause rust.
4. If the unit is installed in a coastal area, clean the unit with water regularly to remove any salt build-up.
5. If the unit is damaged during installation or maintenance, be sure to repair it.
6. Be sure to check the condition of the unit regularly.
7. Be sure to install the unit in a location with good drainage.