Dereli Teknik
Frequently asked questions
If your question is not here, message us on WhatsApp.
Do not touch any electrical switches or the boiler, and do not light any flame. Open the windows, turn off the gas valve at the meter, leave your home and call 187, the gas emergency line, from outside.
İlhan speaks only Turkish. Write to us in English on WhatsApp: he reads your message and replies with a translation app.
How often should a combi boiler be serviced?
Once a year, ideally before winter. Regular servicing lowers gas use and makes a breakdown in the middle of winter less likely.
How long does a service take?
A standard boiler service takes about 45–60 minutes. For repairs, the time depends on whether a part needs replacing.
Which boilers do you work on?
We work on all gas combi boilers. We are an independent service; when choosing parts, we show you options that are suitable and of good quality, and we decide together.
Can I find out the price in advance?
For a service, we give you a clear price in advance on WhatsApp. For a fault, the price is given after the on-site diagnosis, and we never start work without your approval.
Do you work at weekends?
We are open on Saturdays from 09:00 to 18:00. On Sundays you can contact us for emergencies.
Do you speak English?
No, İlhan speaks only Turkish, but you can write to us in English on WhatsApp: he reads your message and replies using a translation app. Photos of the boiler and the display help a lot.
Do you give a guarantee?
We give a one-year guarantee on our workmanship. If the same fault comes back within that time, we don't charge.
What should the boiler's water pressure be?
When the boiler is cold, the pressure gauge should usually read between 1 and 2 bar. If the pressure keeps dropping, there may be a leak in the boiler or in the system; message us and we'll take a look.
What information will you ask for?
Your boiler's brand and model (written on the label just below the front cover), the problem, and the code if there is one on the display. Sending a photo of the code on WhatsApp speeds things up.
Which areas do you cover?
We come to your home anywhere in Kocaeli: İzmit, Gebze, Darıca, Çayırova, Dilovası, Körfez, Derince, Gölcük, Başiskele, Kartepe, Karamürsel and Kandıra. Service areas
Message us on WhatsApp
Just tell us your boiler's brand and the problem. İlhan speaks only Turkish: write in English and he replies using a translation app. From a photo of the display or the error code we can often tell roughly what the fault is.
Phone (Turkish only): +90 535 255 88 00
Your contactİlhan Dereli (speaks Turkish)
Working hoursWeekdays 08:00–20:00
Saturday 09:00–18:00AreaAll of Kocaeli, at your home