Firebird Combi C26 Hot Water Issue

8 Jan 2016
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United Kingdom
I have read a post from around 2 years ago and we have exactly the same problem. The resolution to the problem was not included in the post. Can anybody help lease?

When we turn on the hot water tap, about 10 seconds later, we get hot water - which is great!. However, if the tap is kept running for a further 10-15 seconds, then the water actually turns cold and takes about 5 or 6 minutes to come back to temperature.

Also, this only happens after the boiler is left for more than 1/2 hour or so.

We have replaced the flow switch thermistor and the burner photocell but they havn't resolved the problem. Rather than continuing to pay for parts to be replaced without the problem being solved, I was wondering if anyone could suggest what the problem/solution might be.

Thanks in advance.

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You have just copied someone else's posting from three years ago.

To even try to help you we need a proper explanation of YOUR own problem.

If its working on CH then how would you ever think the photo cell could be the problem?

Have you considered calling an engineer? When was it last serviced?

Hi Tony, thanks for your response.
I copied the old post because when I Googled my problem and searched the forums it came up and it was identical to my problem.

We moved into this property in March 2014 and according to the boiler passport it was installed in January 2011. We have had it serviced twice and it has been repaired for numerous other faults during the past 2 years, the last time being a replacement PCB. The engineer who services it said he would have a think about this latest problem and get back to us. I had previously called Firebird and they recommended replacing the flow switch thermistor which did not solve it. Recently, since we have had this problem, the lock out light came on. I rang the engineer and he told me how to reset it. Then on another forum I saw that replacing the photocell had cured a lock out problem and also a dirty photocell had caused an intermittent hot water problem.

Tony, I am a novice with oil boilers, give me a truck or bus with a problem and I can probably diagnose it for you. It is just that this boiler has cost us a small fortune since we moved in and I am just trying to save a few quid. Also, we live on Anglesey and oil boiler engineers are few and far between.

The problem is identical to that on the copied post so it is not a unique problem. Any advice you could offer would be much appreciated.
There can be many causes of ignition lock outs. Photocells are just one.

Does it run perfectly on CH ?

If so then to me that discounts the photocell as being relevant.

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Yes, CH seems okay Tony. I agree now that the photocell is not the cause of the hot water problem as I have replaced it already and we still have the problem. Everything seems to work okay, its just the hot water does not always stay hot as I described in the initial post!

If you have any other suggestions I would much appreciate it. Many thanks.
Your problem is not associated with being an oil fired boiler but something else.

The three components which could be involved would be the DHW demand switch, the hot water temperature sensor and the PCB. But probably less likely to be the PCB.

Would need careful diagnostic observation as it faults.

First port of call should be the rate of flow you are expecting. Make sure that it is within the prescribed parameters. If you are running for 15 mins, and through a 3/4" tap, then you may be expecting too much. If that area is correct, then check the DHW thermistor, and then the PCB. A little patience, and a competent technician should have no problem in rectifying the problem.

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