Fix problem with Vaillant boiler heating system and room thermostat
Central heating was intermittent and not responding to the thermostat. After having a couple of locally recommended engineers look at the system and fail to properly diagnose the fault I came across this Which site which contained many satisfying reviews. Talking to Mark on the phone it was very clear that he was the engineer I was looking for. As a retired engineer of 60 years in electronics development I found we could discuss my problem successfully. Heat-Tech engineer George, came over to checkout the system and found it not to be wired according to published standards and recommended that rewiring was needed to enable efficient fault finding. Subsequently he got the heating working but there were occasional fault modes occurring and a new electronics board was needed. After fitting a replacement board the system is now working correctly. Costs of labour and parts were good value and I would call them again if required. I'm pleased with the fast and competent service from the company and would recommend Heat-Tech as a first choice. Thank you Mark and George.
Customer in Hertfordshire
Posted on 14/10/2023
, work completed 15/09/2023
Recommended
Very fast response … excellent work
Rang the office in the morning and they had just had a cancellation so van arrived 20 minutes later and installed new tap within half an hour. Very happy customer !
Customer in Hertfordshire
Posted on 18/05/2024
, work completed 14/05/2024
Recommended
Friendly staff who were quick and efficient with the Annual Review
We have used HeatTech for a number of years now as they got us "out of hole" when British Gas said just before Christmas that they couldn't come for 10 days despite the fact that we had a contract with them. Mark and his team fitted us in at short notice and fixed the problem so that we were warm over Christmas. We have continued to use HeatTech and are extremely satisfied with their service.
Customer in Hertfordshire
Posted on 11/07/2024
, work completed 08/07/2024
Recommended
Gas Leak
Had suspicious smell of gas. I decided to phone Mark Ockenden of Heat Tech Services as his firm are registered Gas Safe Engineers. I have used their services for Gas boiler installation, maintenance and general plumbing for many years. I have found his staff, well qualified and highly effecient. Mark arrived on time. He tested for a leak and determined it was minor but needed to be attended to. He found the leaking valve, which was embedded in my fireplace surround. To avoid damaging the fireplace, he lifted carpet and adjacent floorboard, cut the pipe and capped it with a soldered repair - all with my agreement. He put everything back in place and it looks just as it was before the repair was carried out. As usual - excellent service.
Customer in Hertfordshire
Posted on 14/11/2024
, work completed 28/10/2024
Recommended
Boiler Repair
I have used HeatTech since 2006. Always had professional excellent customer service from Mark and his staff. On Friday my boiler broke down. Within a few hours Mark was around at my property sorting the problem out and replacing the pump. As ever excellent service at a reasonable price, with fast time response which I am so grateful for. I will be using HeatTech again.
Customer in Hertfordshire
Posted on 16/09/2024
, work completed 13/09/2024
Recommended
Fast professional and highly knowledgeable
I called Mark around 6 pm Friday as my normal plumber was booked and I had not had hot water for a week despite my boiler apparently firing up. Mark asked for pictures of my set up and then called me back to use telephone triage with very easy guidance on things I needed to check which quickly led to an over the phone diagnosis of the problem (a failed valve); Mark clearly explained his pricing which was extremely reasonable and committed to come this morning (Saturday 9 am); he quickly confirmed it was a valve problem replaced it and explained how I could run my system more efficiently . Hot water worked perfectly after a few minutes. I recommend Mark very highly and will now use him/ Heat tech for all my boiler servicing work as I was so impressed.
Customer in Hertfordshire
Posted on 03/08/2024
, work completed 03/08/2024
Recommended
Punctual, polite and left neat and tidy
Removed radiators and capped pipes. Restored the upstairs heating and left the site clean and tidy with pipes labelled. Turned up on time, pleasant to deal with. Will use again.
Customer in Buckinghamshire
Posted on 24/04/2025
, work completed 17/04/2025
Recommended
Knowledgeable, efficient and painstaking perfectionists.
Heat Tech replaced our gas Worcester boiler with a new Vaillant gas boiler. At the last service they advised us that the Worcester boiler was beginning to fail and that making the change in the summer meant we could plan a mutually convenient time and make savings with a more reliable and more efficient boiler. The men, Francesco and James arrived exactly as promised and explained what they were going to do and why. They explained the sequence of work and where we could be least disturbed. They began by flushing out the system to clean all the radiators and pipes. They removed the old boiler and installed the new one. The boiler is built into an exterior wall so they also replaced the flu and the cowling. Unasked; they thought through and made adjustments in the connections and layout. We now have an expansion tank we can monitor and pressure controls in the house. Throughout their time here they were very careful and considerate and as quiet as possible. They immediately cleared up any debris or mess and took away every bit of old equipment and the packaging etc of the new. One example of their consideration was to make sure the Aga was alight and working after they had turned off the gas to check for leaks in the system. The Aga is notoriously difficult to relight. When all the work was complete they added two bottles of a corrosion inhibitor. They were a pleasure to have and we would like to thank them both.
Customer in Buckinghamshire
Posted on 23/06/2026
, work completed 19/06/2026
Recommended
Always Deliver
We use Heatech for all our heating and plumbing requirements. They have over the years replaced our boiler, radiator system, water tank as well undertaking our annual system servicing needs. They have always assisted us rapidly whenever we had a problem or emergency. They have just completed fitting a new heating system at my daughter’s house. The team are knowledgable, diligent, reliable and always polite and reliable. They are also v punctual and stay until the job is complete. Highly recommended by us on all fronts.
Customer in Hertfordshire
Posted on 06/08/2026
, work completed 05/08/2026
Recommended
Excellent work in the kitchen
I called them to help me install a new American fridge freezer that needed to be plumbed in . Francesco worked very transparently with me and worked through the best most organised way to feed through the piping and was not fazed when I asked him to also switch around the order of the dishwasher and washing machine at the same time I mentioned problems with the boiler too, and he had a good look at it all and checked all the obvious things we needed to organise a recall for a Main boiler service due time and it needing to be quoted, but overall I was very impressed withthe standard and professionalism of the work that he did in the kitchen
Customer in Hertfordshire
Posted on 15/06/2026
, work completed 11/06/2026
Recommended
Boiler Service
Excellent work and would have no hesitation in recommending Heat Tech.
2010-07-01 12:20:34.373
Posted on 07/10/2014
, work completed 07/10/2014
Recommended
Excellent Plumber
We have been using Mark Ockendon for over two years now and he is an amazing guy. His honesty and integrity are beyond what we have encountered with other tradespeople. He is very professional, clearly knows his trade and ultra-reliable. We never get the feeling of being “ripped-off” and always feel he goes that extra mile. It is safe to say that we have found our “plumber for life”.
Ju5t5h4z
Posted on 04/01/2014
, work completed 04/01/2014
Recommended
TOP BANANA
I first met Mark through a networking group. I have known him for over 5 years and would not hesitate to recommend him and in fact regularly do. He is honest and reliable and twice I have called him out on an emergency on a weekend, once when I had a gas leak and another time when a pipe burst. He has also put in a new shower, serviced the boiler, changed a tap and detected faults. He's an all round excellent worker and I cannot recommend him highly enough & he definitely wont rip you off!
Which? Trusted Traders Consumer
Posted on 02/02/2014
, work completed 02/02/2014
Recommended
HIGHLY RECOMMENDED
Mark and his team have been out to us several times over the past few years. They always do a good job and sort out our various plumbing issues, despite challenging conditions, always with a smile and at very reasonable rates. A great company, thoroughly recommend them.
CMR402438226
Posted on 10/07/2014
, work completed 10/07/2014
Recommended
Excellent Plumber
We used Heat Tech to come and fit our new bathroom taps. They came round quickly, the guy was very professional and got the job done to an excellent standard. Great value for money I highly recommend Heat Tech and will use them again I ever need anything done pluming related. Thanks for the help Heat Tech :-) A*
mattyb
Posted on 30/08/2014
, work completed 30/08/2014
Recommended
Heat Tech
Have used Mark and his team for three years and we are very happy to have found him, a professional and reliable service second to none.
Neil33
Posted on 18/05/2015
, work completed 18/05/2015
Recommended
Central heating, hot water and general plumbing.
I have been entirely satisfied with everything that Mark Ockendon and his team have done for me.
2011-07-13 12:16:03.147
Posted on 20/06/2015
, work completed 20/06/2015
Recommended
Great Service
Very professional - cannot fault. Will definitely use again.
Site User
Posted on 12/07/2015
, work completed 12/07/2015
Recommended
Would not hesitate to call him again
Our central heating had stopped working. We called Mark and after answering a few questions he said he would come round that afternoon and bring with him the parts he felt would be needed. He arrived promptly and after investigation replaced our timer control which resolved the problem. Mark was polite, knowledgeable and we would not hesitate to call him again if we had a boiler or plumbing problem
Clive, Chesham
Posted on 14/09/2015
, work completed 14/09/2015
Recommended
An exceptionally good plumber
I have used Heat Tech on a number of of occasions over the past year. This has included replacing a booster pump, changing a broken toilet flush valve and inlet valve and boiler service. Mark has also cured various longstanding problems with pipes and valves. He is always prepared to investigate the problem thoroughly rather than just curing the symptoms, and to explain what he is doing.
2011-07-29 17:32:12.717
Posted on 27/01/2016
, work completed 27/01/2016
Recommended
Boiler Service
Professional, polite and tidy when servicing my boiler. I can have no complaints and would recommend them.
Annie, Hertfordshire
Posted on 12/11/2015
, work completed 12/11/2015
Recommended
Always reliable and trustworthy
Mark installed our boiler a few years back and we have had it serviced by Heat Tech to service it ever since. They are always prompt, reliable and efficient.
Mandy G
Posted on 05/09/2016
, work completed 05/09/2016
Recommended
Thorough and professional
Mark and his team perform to the highest standards and deliver a quality service without fuss - highly recommended
Steve Dale
Posted on 15/03/2017
, work completed 15/03/2017
Recommended
Excellent. Extremely thorough and tidy work
Heat Tech came to us on two separate occasions in February this year (2017). Our neighbour recommended them. The first was to service our boiler and explain the whole complex heating and water system we had inherited after purchasing the property. No expansion tank was found so they added. The second visit was to sort the flush and cistern leak in the toilet but actually the whole old toilet & cistern had to be removed (nails and pipe rusted) and cleaned out and reconnected to the soil pipe. Although a new toilet might have solved some of the problem the connection to the existing soil pipe could have been a problem. The toilet was put back together and works absolutely fine. No extra charge. Their fees are reasonable and as I say very thorough work. It is good to recommend local people
Burrell
Posted on 11/09/2017
, work completed 11/09/2017
Recommended
Honest and professional
We are SO relieved to find a heating engineer that is honest and professional. Just before Christmas, we very nearly fell victim to an unscrupulous plumber who insisted that a new boiler was our only option when ours failed. The hard sell made us very uncomfortable so friends recommended we call Mark. Thank goodness we did! Mark was able to identify the problem immediately - and very kindly took the time to explain how he was going to fix it. Thanks to his knowledge and skill, our boiler is now up and running and there was no question we needed a new one! I'm so grateful for Mark's honesty and have absolutely no hesitation in recommending him.
Julie
Posted on 17/01/2018
, work completed 17/01/2018
Recommended