Air source heat pump warranty and maintenance

by Mars

This article is a reply to a question asked by Endo on our air source heat pump review video on YouTube: “I assume these systems need a regular service check. Is it expensive?”

In response, we’ll address points surrounding our air source heat pump warranty and maintenance.

The honest starting point for this post is that I didn’t actually know. At no point during the sales and installation process was it ever mentioned to us that the air source heat pump had to be serviced. It was made out as if there was nothing really to service. This was never raised by other installers that visited our property to quote either.

With the distraction of building our veg patch, Coronavirus and spells of hot weather, the air source heat pump has not been a focal point for us, until we received Endo’s question.

Somewhat coincidentally, we received a call from Global Energy Systems (GES) a few days later as the COVID-19 lockdown in England was easing and our ASHP had been operational for a year, and they wanted to book us in for a service.

I politely declined because we were still in lockdown as a household and didn’t want any unnecessary foot traffic in the house. GES sent us their service pack for future reference.

The service package included the following:

  • Clean system filter
  • Check system anti-freeze level
  • Clean evaporator coil
  • Clear debris from fan
  • Clear debris from drip tray and ensure water is draining away correctly
  • Ensure heat pump system is safe

The price for this is £216/year.

This was followed by the fine print: “GES warranty customers require an Eco Care package to ensure warranty is valid.”

At no point during the sales process were we ever informed of this. To be fair, I think GES were largely transparent in their initial dealings with us and a lot of their financial forecasts and calculations have turned out to be quite accurate, but it is disconcerting to find out that our air source heat pump warranty, which is an expensive piece of kit, could be voided if we don’t use their company to perform the services.

Also, without sounding derogatory, the first five items of the service package are quite straightforward to do yourself, and the last point, ‘ensuring the heat pump is safe’, is just word fluff.

My advice for anyone in the market for an air source heat pump is to ask about the warranty of the unit and if there any service and maintenance contracts or strings attached.


Nigel 5 July 2020 - 08:49


Many thanks for looking into this and for the detailed reply. I thought some degree of servicing would be needed but it seems that servicing is a profitable arm to their business. No parts needed and I would imagine that the work could be done within 30 minutes. I wonder if the warranty is worth looking into when you have time to see if there are any other caveats and if it’s really worthwhile? You may find an independent company that can obtain all the parts (if needed) and service it for a more reasonable cost.

Home Farm 5 July 2020 - 09:28

Thanks for the feedback Nigel.

Yes, I agree that servicing and maintenance must factor into their business model, but it would have been better if they’d informed us about this when we were signing up with them. Nevertheless, I still think that GES are an above-board company, and their service and customer support has always been excellent. We can call them 24/7 (and we have) when we’ve had alarms on the ASHP, and they’ve always addressed these issues in a timely manner.

If anything should fail or stop working that can’t be fixed remotely, I have no doubt that they will be able to come out and rectify the issue at a reasonable expense.

As with all things pertaining to our ASHP, we will continue to keep posting updates,

Sandra Lee-snape 17 August 2021 - 08:08

We have had one gutted at the moment as it’s not working and we have no heating. It was not working properly when it was fitted. The installers have not returned calls. We should have had a Mitsubishi but ended up with a LG and to be honest it’s rubbish. It was very noisy and running cost high. At the moment we are in a standoff with both LG and the company that fitted it. We are at a loss as to what to do next.😟

Mars 17 August 2021 - 08:23

Hi Sandra. Was the heat installer MCS-accredited?

Andras Meszaros 6 July 2020 - 11:42

It is ridiculous 😒 that they never told you that in advance. You are right about maintaning yourself is easy. I did it on my own Samsung as well.

Home Farm 6 July 2020 - 12:00

Thanks Andras. I’m curious to know how you cleaned the evaporator coil. Any advice?

Mike 19 November 2020 - 16:19

Interesting comments. We too have an GES Caernarfon unit – same as yours. However, ours is now 2 years old.

GES have been excellent and no complaints from us – but just like you, servicing has never been mentioned. The booster burnt out very recently and they came and fitted a replacement. However, your servicing comment has made me think and tonight I’ll dig out the Warranty and take a look.

I’ve also had permission to replace the auto air vent in the system – I can see it leaking and rather than them send out and engineer then I’ll nip round to Screwfix and get a replacement for £7 and do it myself (with their permission).

I suspect we will ask for a service if nothing else but to protect the warranty.

Mars 19 November 2020 - 21:37

Very interesting Mike. Thanks for sharing.

When you say the booster burnt out, I assume you’re not connected to an old oil or gas boiler?

Can you please describe the issue you’re having with air vent and what you mean by it’s leaking?

Mike Hyland 20 November 2020 - 12:49

Sure. So, we only have the ashp no other method of heating. As you know, the ashp can only get to about 49c but every 7 days you need to lift it to reduce the threat of legionaries. The booster is used to do that. It’s just an electrical element that heats the water to the required temperature. It’s located inside the ashp just above the incoming water filter – long rectangular box. For whatever reason I noticed that the booster demand was huge one day and didn’t come on after that. GES connected with the system and concluded that it was faulty (The engineer said ‘burnt out’). They replaced it.

The auto air vent is also inside the unit and is just a standard plumbing component to allow air to find its way out of the system. It’s located behind the booster. Personally, I think the two events are linked. After the filter was cleaned then the air vent will vent all the air introduced by the filter compartment being opened. The auto air vent is a float and valve/needle device and it’s not uncommon for it to get debris lodged in the float or needle. If that happens then it’s just a low level leak. I can see it. Typically these units will be replaced at £7 rather than fixed. I’ll do that to save the bother of getting someone to visit etc etc.

I strongly suspect that the water pressure dropped to 0 because of the air vent and it caused the booster to burn out because of lack of flow – but I may be talking rubbish – it has been known 😀.

Mars 22 November 2020 - 08:49

Weather permitting, I’ll pop the side panel off this week and educate myself a bit further about the booster and air vent. Thank you for bringing this to my attention.

Pertaining to the booster, you said it didn’t come back on. Does that mean you had no hot water? I think in our case, the iBoost we have installed may be taking some strain off the booster as this takes us to 60C whenever possible.

Mike Hyland 22 November 2020 - 15:46

The booster not coming on meant that the legionnella cycle is not running. The hot water is fine. We had 7 days to fix the booster. I called GES and they temporarily reconfigured the ashp to do the legionnella cycle. The booster got fixed and GES reconfigured the ashp back to normal. They said that the ashp could do the legionnella cycle but it was inefficient.

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